JP2010171165A - Organic semiconductor device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a metal oxide film on the surface of a source-drain electrode without putting a damage into the surface of an organic gate insulation film and to restore a damaged layer after forming the metal oxide film on the source-drain electrode. <P>SOLUTION: The organic semiconductor device includes: source-drain electrodes 12 and 13 that are formed apart from each other on a substrate 11 having insulation properties on its surface; metal oxide films 14 and 15 formed on the surface of the source-drain electrodes 12 and 13; an organic semiconductor layer 16 that is formed on the substrate 11 and covers the metal oxide films 14 and 15; a gate insulation film 17 formed on the organic semiconductor layer 16; and a gate electrode 18 formed on the gate insulation film 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic semiconductor device and a method for manufacturing the same.

  Currently, organic TFTs (Thin Film Transistors) are being actively researched and developed for application to various electronic devices. In particular, there is a great interest in the application technology of flexible display backplanes, and it is desired to produce high-definition organic TFTs.

  In the organic TFT, a TFT having a relatively short channel length can be manufactured by using the bottom contact structure, and a high-definition back plane can be realized.

Originally, TFTs have improved drive capability in inverse proportion to the channel length, but organic TFTs with bottom contact structure have a relatively high contact resistance formed at the interface between the organic semiconductor and the electrode, so that the drive capability is in inverse proportion to the channel length. Improvement may not be obtained.
In particular, when an organic semiconductor exhibiting excellent characteristics is used, this phenomenon occurs remarkably. Therefore, reduction of the contact resistance between the organic semiconductor and the electrode is a big problem in the organic TFT.

  As a method for reducing the contact resistance between the organic semiconductor and the electrode, there is a method using an oxidized metal electrode. By oxidizing the metal electrode, the organic semiconductor layer grown on the surface thereof is easier to grow than when there is no oxide film. For example, the grain size when pentacene is deposited as the organic semiconductor layer is larger on the oxide film than on the metal electrode. As described above, since the large-sized grains are grown, the contact resistance is reduced, so that the carrier injection efficiency for the p-type organic semiconductor can be improved. As a typical example, a case in which a gold (Au) electrode is oxidized has been reported (see, for example, Non-Patent Document 1). Compared with a gold electrode that is not oxidized, an oxidized organic electrode has two or more digits in the organic semiconductor. It has been confirmed that the contact resistance between the electrode and the electrode is reduced and the effect is very large.

However, when an oxidation process by oxygen (O ₂ ) ashing is performed as a process for oxidizing the surface of the source / drain metal electrode in the manufacturing process of the organic TFT, the surface of the organic gate insulating film on which the organic semiconductor layer to be a channel is formed Will be damaged. As a result, problems such as a decrease in driving capability and occurrence of hysteresis occur.

B. Stadlober et al., Adv. Funct. Mater. 2007, 17, 2687-2692

  The problem to be solved is that when an oxidation process for oxidizing the surface of the source / drain metal electrode is incorporated in the manufacturing process of the organic TFT, the surface of the organic gate insulating film on which the organic semiconductor layer to be a channel is formed is damaged. As a result, problems such as a decrease in driving capability and occurrence of hysteresis occur.

  The present invention forms a metal oxide film on the surface of the source / drain electrode without damaging the surface of the organic gate insulating film, or repairs the damaged layer after forming the metal oxide film on the surface of the source / drain electrode. Enable.

  An organic semiconductor device (first organic half device) according to the present invention includes a source / drain electrode formed on a surface of a substrate having an insulating surface and a metal formed on the surface of the source / drain electrode. An oxide film; an organic semiconductor layer that is formed on the substrate and covers the source / drain electrodes formed with the metal oxide film; a gate insulating film formed on the organic semiconductor layer; A gate electrode formed on the gate insulating film above the source / drain electrodes is provided.

  In the first organic semiconductor device according to the present invention, the organic semiconductor layer is formed by covering the metal oxide film formed on the surface of the source / drain electrode, and the gate insulating film is further formed. It can be seen that is formed after the metal oxide film. Therefore, even if the gate insulating film is formed of an organic insulating film, damage that occurs when the metal oxide film is formed, for example, damage that causes a threshold voltage (hereinafter referred to as Vth) shift is included in the gate insulating film. Absent.

  An organic semiconductor device (second organic half device) of the present invention includes a gate electrode formed on a surface of a substrate having an insulating surface, and an organic insulating film formed on the substrate and covering the gate electrode A gate insulating film, a source / drain electrode formed on the gate insulating film on both sides above the gate electrode, a metal oxide film formed on the surface of the source / drain electrode, An organic semiconductor layer is formed on the gate insulating film and covers the source / drain electrodes on which the metal oxide film is formed, and a polycrystal is formed on the gate insulating film on which the source / drain electrodes are not formed. A paraxylylene film is formed.

  In the second organic semiconductor device of the present invention, the polyparaxylylene film is formed on the gate insulating film on which the source / drain electrodes are not formed. As a result, damage on the surface of the gate insulating film, for example, a damage layer causing Vth shift when the metal oxide film is formed on the surface of the source / drain electrode is covered with the polyparaxylylene film. Therefore, the Vth shift is suppressed.

  The organic semiconductor device manufacturing method (first manufacturing method) according to the present invention includes a step of separately forming a source / drain electrode made of metal on a surface of a substrate having an insulating surface; Forming a metal oxide film by oxidizing the metal surface; forming an organic semiconductor layer covering the source / drain electrodes on which the metal oxide film is formed; and the organic semiconductor. Forming a gate insulating film on the layer; and forming a gate electrode on the gate insulating film above the source / drain electrodes.

  In the first manufacturing method of the organic semiconductor device of the present invention, after the step of oxidizing the metal surface of the source / drain electrode to form the metal oxide film, the organic semiconductor layer is formed by covering the metal oxide film. Further, a gate insulating film is formed. Therefore, since the gate insulating film is formed after the metal oxide film, even if the gate insulating film is formed of an organic insulating film, damage caused when the metal oxide film is formed on the gate insulating film, for example, Vth shift Damage that causes no damage.

  The organic semiconductor device manufacturing method (second manufacturing method) of the present invention includes a step of forming a gate electrode on a substrate having an insulating surface, and a gate comprising an organic insulating film covering the gate electrode on the substrate. Forming an insulating film; forming a metal source / drain electrode on the gate insulating film on both sides above the gate electrode; and oxidizing the surface of the source / drain electrode to oxidize the metal A step of forming a material film; a step of treating a hydroxyl group on the gate insulating film on which the source / drain electrodes are not formed; and covering the metal oxide film on the gate insulating film treated with the hydroxyl group Forming an organic semiconductor layer.

  In the second manufacturing method of the organic semiconductor device of the present invention, the polyparaxylylene film is formed on the gate insulating film on which the source / drain electrodes are not formed. As a result, damage on the surface of the gate insulating film, for example, a damage layer causing Vth shift when the metal oxide film is formed on the surface of the source / drain electrode is covered with the polyparaxylylene film. Therefore, the Vth shift is suppressed.

  The organic semiconductor device manufacturing method (third manufacturing method) of the present invention includes a step of forming a gate electrode on the surface of a substrate having an insulating surface, and an organic insulating film covering the gate electrode on the substrate. Forming a gate insulating film, forming a resist pattern having openings in regions where source / drain electrodes are formed on the gate insulating film above both sides of the gate electrode, and forming the resist pattern A step of forming the source / drain electrodes made of metal on the gate insulating film by metal film formation using a mask; and a surface of the source / drain electrodes in a state where the resist pattern is formed to oxidize the metal oxide film A step of removing the resist pattern together with the metal film formed on the resist pattern during the metal film formation, A step of forming an organic semiconductor layer covering the metal oxide film on over gate insulating film.

  In the third manufacturing method of the organic semiconductor device of the present invention, when the metal oxide film is formed on the surface of the source / drain electrode, the gate insulating film is covered with the resist pattern, so that damage to the surface of the gate insulating film is caused. For example, damage causing Vth shift does not occur. Therefore, the Vth shift is suppressed.

  The organic semiconductor device manufacturing method (fourth manufacturing method) of the present invention includes a step of forming a gate electrode on a substrate having an insulating surface, and a gate comprising an organic insulating film covering the gate electrode on the substrate. A step of forming an insulating film, a step of forming a source / drain electrode made of metal having a metal oxide film formed by oxidizing a surface on the gate insulating film on both sides above the gate electrode, and the gate insulating film A step of forming an organic semiconductor layer covering the metal oxide film, and forming a source / drain electrode made of metal having a metal oxide film formed by oxidizing the surface on the gate insulating film; Forming a metal source / drain electrode on the first support substrate at a distance, oxidizing a surface of the source / drain electrode to form a metal oxide film, and the gold A second support substrate is pressed against the surface of the oxide film, and the source / drain electrodes on which the metal oxide film is formed are transferred to the second support substrate, and the first support substrate is transferred from the source / drain electrodes. And removing the second support substrate from the source / drain electrode by transferring the source / drain electrode from the second support substrate onto the gate insulating film.

  In the fourth method for manufacturing an organic semiconductor device of the present invention, the first support substrate damaged when the metal oxide film is formed on the surface of the source / drain electrode is removed. Since only the source / drain electrodes on which the metal oxide film is formed are formed by being transferred onto the gate insulating film, damage to the surface of the gate insulating film, for example, damage causing Vth shift does not occur. Therefore, the Vth shift is suppressed.

  In the first organic semiconductor device of the present invention, since the metal oxide film is formed on the surface of the source / drain electrode without causing damage to the surface of the gate insulating film, the Vth shift is suppressed, the driving capability is reduced, and the hysteresis is reduced. There is an advantage that a problem such as occurrence of the problem can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In the second organic semiconductor device of the present invention, the metal oxide film is formed on the surface of the source / drain electrode, and the damaged layer generated on the surface of the gate insulating film is repaired. There is an advantage that problems such as lowering of hysteresis and occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In the first manufacturing method of the organic semiconductor device of the present invention, since the metal oxide film is formed on the surface of the source / drain electrode without causing damage to the surface of the gate insulating film, the Vth shift is suppressed and the driving ability is reduced. There is an advantage that problems such as the occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In the second manufacturing method of the organic semiconductor device according to the present invention, the metal oxide film is formed on the surface of the source / drain electrode, and the damaged layer generated on the surface of the gate insulating film is repaired. There is an advantage that problems such as lowering of hysteresis and occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In the third manufacturing method of the organic semiconductor device of the present invention, a metal oxide film is formed on the surface of the source / drain electrode, and damage to the surface of the gate insulating film is prevented by the resist pattern, so that the Vth shift is suppressed. Therefore, there is an advantage that problems such as a decrease in driving capability and occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In the fourth manufacturing method of the organic semiconductor device of the present invention, the metal oxide film is formed on the surface of the source / drain electrode and the surface of the gate insulating film is not damaged, so that the Vth shift is suppressed and the driving ability is reduced. There is an advantage that problems such as the occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

1 is a schematic cross-sectional view showing a first example of a configuration of an organic semiconductor device according to a first embodiment of the present invention. It is a schematic structure sectional view showing the 2nd example of composition of an organic semiconductor device concerning a 2nd embodiment of the present invention. It is manufacturing process sectional drawing which showed the 1st example of the manufacturing method of the organic-semiconductor device which concerns on 3rd Embodiment of this invention. It is manufacturing process sectional drawing which showed the 2nd example of the manufacturing method of the organic-semiconductor device which concerns on 4th Embodiment of this invention. It is manufacturing process sectional drawing which showed the 3rd example of the manufacturing method of the organic-semiconductor device which concerns on 5th Embodiment of this invention. It is manufacturing process sectional drawing which showed the 4th example of the manufacturing method of the organic-semiconductor device based on 6th Embodiment of this invention.

<1. First Embodiment>
[First example of configuration of organic semiconductor device]
A first example of the configuration of the organic semiconductor device according to the first embodiment of the present invention will be described with reference to the schematic configuration cross-sectional view of FIG.

As shown in FIG. 1, source / drain electrodes 12 and 13 made of metal are formed on a substrate 11 whose surface is insulative.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
The source / drain electrodes 12 and 13 are made of, for example, gold (Au).
Metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13. When the source / drain electrodes 12 and 13 are made of gold, the metal oxide films 14 and 15 are gold oxide.
For the source / drain electrodes 12 and 13, for example, nickel (Ni), platinum (Pt), copper (Cu), or the like may be used. Even when these metals are used, a metal oxide film of the metal is formed on the surfaces of the source / drain electrodes 12 and 13 as described above.
The source / drain electrodes 12 and 13 may be formed of the metal oxide film.

An organic semiconductor layer 16 that covers the metal oxide films 14 and 15 is formed on the substrate 11.
For example, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used for the organic semiconductor layer 16. Alternatively, a low molecular material such as pentacene or porphyrin, a high molecular material such as triisopropylsilylethynyl pentacene [TIPS-pentacene], polyallylamine, or the like can be used.

A gate insulating film 17 is formed on the organic semiconductor layer 16.
The gate insulating film 17 is made of, for example, an organic insulating film. For example, poly-para-Xylylene can be used as the organic insulating film material. Polyparaxylylene can be formed by, for example, a thermal CVD method.
In addition, when the organic semiconductor layer 16 is formed of TIPS-pentacene, the gate insulating film 17 includes an amorphous fluororesin (for example, Cytop (manufactured by Asahi Kasei Corporation) Trade name)), fluorine-based polymers can be used. The amorphous fluororesin and the fluoropolymer can be formed by, for example, spin coating.
When the organic semiconductor layer 16 is formed of P3HT, the gate insulating film 17 is made of polyvinylphenol (PVP) or polymethyl methacrylate (PMMA) in addition to polyparaxylylene. it can. The PVP and PMMA can be formed by spin coating, for example.

A gate electrode 18 is formed on the gate insulating film 17.
For the gate electrode 18, for example, gold (Au) is used. When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .
In this way, the organic semiconductor device 1 is configured.

In the organic semiconductor device 1, the organic semiconductor layer 16 is formed so as to cover the metal oxide films 14 and 15 formed on the surfaces of the source / drain electrodes 12 and 13, and the gate insulating film 17 is further formed. This indicates that the gate insulating film 17 is formed after the metal oxide films 14 and 15. Therefore, even if the gate insulating film 17 is formed of an organic insulating film, damage to the gate insulating film 17 when the metal oxide films 14 and 15 are formed, for example, on the gate insulating film 17 causing a Vth shift. Formation of the hydroxyl group does not occur.
Therefore, the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 without damaging the surface of the gate insulating film 17, so that the Vth shift is suppressed, the driving capability is reduced, and the hysteresis is reduced. Problems such as occurrence can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

<2. Second Embodiment>
[Second Example of Configuration of Organic Semiconductor Device]
A second example of the configuration of the organic semiconductor device according to the second embodiment of the present invention will be described with reference to the schematic configuration cross-sectional view of FIG.

As shown in FIG. 2, a gate electrode 18 is formed on a substrate 11 having an insulating surface.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
The gate electrode 18 is made of, for example, gold (Au). When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .

A gate insulating film 17 made of an organic insulating film covering the gate electrode 18 is formed on the substrate 11.
The gate insulating film 17 is made of, for example, an organic insulating film. For example, polyvinylphenol (PVP) is used as the organic insulating film material. Alternatively, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), acrylic resin, epoxy resin, polyimide resin, or the like can be used.

On the gate insulating film 17, source / drain electrodes 12, 13 are formed apart from each other. The source / drain electrodes 12 and 13 are made of, for example, gold (Au).
Metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13. When the source / drain electrodes 12 and 13 are made of gold, the metal oxide films 14 and 15 are gold oxide.
For the source / drain electrodes 12 and 13, for example, nickel (Ni), platinum (Pt), copper (Cu), or the like may be used. Even when these metals are used, a metal oxide film of the metal is formed on the surfaces of the source / drain electrodes 12 and 13 as described above.
The source / drain electrodes 12 and 13 may be formed of the metal oxide film.

A poly-para-xylylene film 21 is formed on the gate insulating film 17 where the source / drain electrodes 12 and 13 are not formed.
The thickness of the polyparaxylylene film 21 is preferably 1 nm to 50 nm. More preferably, it is 5 nm to 10 nm.

An organic semiconductor layer 16 covering the metal oxide films 14 and 15 is formed on the gate insulating film 17.
For example, pentacene is used for the organic semiconductor layer 16. Alternatively, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used.
The organic semiconductor layer 16 may be made of a low molecular material such as pentacene or porphyrin, or a polymer material such as triisopropylsilylethynyl pentacene [TIPS-pentacene] or polyallylamine.
Thus, the organic semiconductor device 2 is configured.

In the organic semiconductor device 2, the polyparaxylylene film 21 is formed on the gate insulating film 17 where the source / drain electrodes 12 and 13 are not formed. As a result, the damage layer 25 on the surface of the gate insulating film 17 generated when the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13, for example, the damage layer 25 causing the Vth shift, is not polyparaxyl Covered by the len film 21. Therefore, the Vth shift is suppressed.
Therefore, the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13, and the damage layer 25 causing the Vth shift generated on the surface of the gate insulating film 17 is repaired by the polyparaxylylene film 21. ing. Therefore, the Vth shift is suppressed, and problems such as a decrease in driving capability and occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

<3. Third Embodiment>
[First Example of Manufacturing Method of Organic Semiconductor Device]
A first example of the structure of the method for manufacturing an organic semiconductor device according to the third embodiment of the present invention will be described with reference to the manufacturing process sectional view of FIG.

As shown in FIG. 3A, source / drain electrodes 12 and 13 made of metal are formed on a substrate 11 having an insulating surface.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
Then, a resist pattern (not shown) having openings in regions where the source / drain electrodes are to be formed is formed by resist coating and photolithography.
Thereafter, for example, gold (Au) is deposited on the substrate 11 by vapor deposition. At this time, gold is also deposited on the resist pattern.
Next, by removing the resist pattern together with the gold deposited on the resist pattern, the source / drain electrodes 12 and 13 made of gold are formed apart from each other on the substrate 11.
The source / drain electrodes 12 and 13 may be formed by, for example, forming a metal film (not shown) on the substrate 11 and then patterning the gold film by a photolithography technique and an etching technique. Good. Moreover, you may produce using methods, such as a normal plate printing technique and the printing technique by an inkjet system.
In addition, by forming an organic polymer layer that can be crosslinked on the substrate 11, adhesion to a gold substrate can be improved. Examples of the organic polymer that can be crosslinked include polyvinylphenol (PVP) and novolac resins. For example, the hydroxyl group of the organic polymer layer that can be cross-linked is subjected to a cross-linking reaction with a cross-linking agent, so that the solvent resistance can be increased and the subsequent photolithography process can be performed without problems.

Next, as shown in FIG. 3B, the metal surfaces of the source / drain electrodes 12 and 13 are oxidized to form metal oxide films 14 and 15. When the source / drain electrodes 12 and 13 are made of gold, metal oxide films 14 and 15 of gold oxide are formed.
For example, oxygen (O ₂ ) plasma treatment is performed to oxidize the surfaces of the source / drain electrodes 12 and 13 to form the metal oxide films 14 and 15.
In the oxygen plasma treatment, for example, the power was 200 W, the pressure of the treatment atmosphere was 133 Pa, and the treatment time was 3 minutes.
For the oxidation step, UV ozone treatment may be used.
In the UV ozone treatment, for example, ultraviolet light having a wavelength of 254 nm is used as UV light, the pressure of the treatment atmosphere is 10 kPa, and the treatment time is 10 minutes. As a light source that emits ultraviolet light having a wavelength of 254 nm, for example, there is a mercury lamp. In addition, if it is an ultraviolet light source, it will not be limited to the said wavelength.
The source / drain electrodes 12 and 13 may be made of, for example, nickel (Ni), platinum (Pt), copper (Cu), or the like. Even when these metals are used, a metal oxide film of the metal can be formed on the surface by the same oxidation process as described above.

Next, as shown in FIG. 3 (3), an organic semiconductor layer 16 covering the source / drain electrodes 12, 13 having the metal oxide films 14, 15 formed thereon is formed on the substrate 11.
For the formation of the organic semiconductor layer 16, for example, an ink jet printing technique is used. For example, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used as the film forming material. Further, spin coating, plate printing, or the like may be used as the film forming technique.
The organic semiconductor layer 16 may be made of a low molecular material such as pentacene or porphyrin, or a polymer material such as triisopropylsilylethynyl pentacene [TIPS-pentacene] or polyallylamine.

  The organic semiconductor layer 16 has no metal oxide films 14 and 15 on the surface of the metal oxide films 14 and 15 (for example, gold oxide film) formed by oxidizing the surfaces of the source / drain electrodes 12 and 13. It becomes easier to grow than the surface of the source / drain electrode on the metal film (for example, gold film). For example, the grain size of the organic semiconductor layer when pentacene is deposited as the organic semiconductor layer 16 is larger on the metal oxide films 14 and 15 (for example, gold oxide film) than on the metal film (for example, gold film). . As described above, since the large-sized grains are grown, the contact resistance is reduced. Therefore, when operating the p-type organic semiconductor device, carriers from the source / drain electrodes 12 and 13 to the organic semiconductor layer 16 are increased. Injection efficiency is increased. As a result, the contact resistance between the source / drain electrodes 12 and 13 and the organic semiconductor layer 16 can be reduced.

Next, as shown in FIG. 3 (4), a gate insulating film 17 is formed on the organic semiconductor layer 16.
The gate insulating film 17 is formed of, for example, an organic insulating film. For example, poly-para-xylylene is used as the organic insulating film material. For example, a thermal CVD method is used as the formation method.
When the organic semiconductor layer 16 is formed of TIPS-pentacene, the gate insulating film 17 is made of an amorphous fluororesin (for example, Cytop (product of Asahi Kasei Corporation) Name)), and can also be formed of a fluorine-based polymer. The amorphous fluororesin and the fluoropolymer can be formed by, for example, spin coating.
When the organic semiconductor layer 16 is formed of P3HT, the gate insulating film 17 may be formed of polyvinyl phenol (PVP) or polymethyl methacrylate (PMMA) in addition to polyparaxylylene. it can. The PVP and PMMA can be formed by spin coating, for example.
For example, in film formation of PVP, after applying PVP, baking is performed at 150 to 180 ° C. for 1 hour. At this time, since the PVP is crosslinked by the crosslinking agent added to the PVP, the subsequent photolithography process can be performed.
That is, by cross-linking the hydroxyl group in polyvinylphenol (PVP) by a cross-linking reaction using a cross-linking agent, it is possible to increase the resistance of the organic solvent used thereafter.

Next, as shown in FIG. 3 (5), a gate electrode 18 is formed on the gate insulating film 17. The gate electrode 18 is formed on the gate insulating film 17 between the source / drain electrodes 12 and 13, for example.
The gate electrode 18 is formed by, for example, forming a metal film (not shown) on the gate insulating film 17 and then patterning the metal film by a photolithography technique and an etching technique.
For example, gold (Au) is used for the metal film. When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .
Further, as a forming method, a lift-off method, a plate printing method, an ink jet printing method, or the like may be used.

  In the first manufacturing method of the organic semiconductor device, after the step of oxidizing the metal surfaces of the source / drain electrodes 12 and 13 to form the metal oxide films 14 and 15, the metal oxide films 14 and 15 are coated. Thus, the organic semiconductor layer 16 is formed, and the gate insulating film 17 is further formed. Therefore, since the gate insulating film 17 is formed after the metal oxide films 14 and 15, even if the gate insulating film 17 is formed of an organic insulating film, the metal oxide films 14 and 15 are formed on the gate insulating film 17. Damage that causes a Vth shift. That is, generation of a hydroxyl group that causes a Vth shift on the gate insulating film 17 does not occur.

  Therefore, since the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 without damaging the surface of the gate insulating film 17, the Vth shift is suppressed, the driving ability is lowered, and the hysteresis is generated. There is an advantage that such a problem can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  Further, a mask process is used when patterning the photoresist in the process of forming the source / drain electrodes 12 and 13, and this mask process is a process that is conventionally used when forming the source / drain electrodes. Therefore, in the first manufacturing method, there is generally no additional mask process that increases the process load and increases the cost.

<4. Fourth Embodiment>
[Second Example of Manufacturing Method of Organic Semiconductor Device]
A second example of the method of manufacturing an organic semiconductor device according to the fourth embodiment of the present invention will be described with reference to the manufacturing process sectional view of FIG.

As shown in FIG. 4A, a gate electrode 18 is formed on a substrate 11 having an insulating surface.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
The gate electrode 18 is formed by, for example, forming a metal film (not shown) on the substrate 11 and then patterning the metal film by a photolithography technique and an etching technique.
For example, gold (Au) is used for the metal film. When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .
The gate electrode 18 may be formed by a lift-off method, a plate printing method, an ink jet printing method, or the like.

Next, as shown in FIG. 4B, a gate insulating film 17 made of an organic insulating film covering the gate electrode 18 is formed on the substrate 11.
The gate insulating film 17 is formed of, for example, an organic insulating film. For example, polyvinylphenol (PVP) is used as the organic insulating film material. For example, spin coating is used as the formation method. After coating, baking is performed at 150 ° C. to 180 ° C. for 1 hour. At this time, since the PVP is crosslinked by the crosslinking agent added to the PVP, the subsequent photolithography process can be performed.
That is, by cross-linking the hydroxyl group in polyvinyl phenol (PVP) by a cross-linking reaction using a cross-linking agent, it is possible to increase the resistance of the organic solvent used thereafter.
As the organic insulating film material, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), acrylic resin, epoxy resin, polyimide resin, or the like can be used.

Next, as shown in FIG. 4C, source / drain electrodes 12 and 13 made of metal are formed on the gate insulating film 17 apart from each other. For example, the source / drain electrodes 12 and 13 are formed on both sides above the gate electrode 18.
A resist pattern (not shown) having openings in regions where source / drain electrodes are to be formed is formed on the gate insulating film 17 by resist coating and photolithography.
Thereafter, gold (Au), for example, is deposited to a thickness of, for example, 50 nm on the gate insulating film 17 by an evaporation method, for example, a resistance heating evaporation method. At this time, gold is also deposited on the resist pattern.
Next, by removing the resist pattern together with the gold deposited on the resist pattern, the source / drain electrodes 12 and 13 made of gold are formed apart from each other on the gate insulating film 17.
The source / drain electrodes 12 and 13 are formed by, for example, forming a metal film (not shown) on the gate insulating film 17 and then patterning the gold film by a photolithography technique and an etching technique. May be. Moreover, you may produce using methods, such as a normal plate printing technique and the printing technique by an inkjet system.

Next, as shown in FIG. 4 (4), the surfaces of the source / drain electrodes 12, 13 are oxidized to form metal oxide films 14, 15.
For example, oxygen (O ₂ ) plasma treatment is performed to oxidize the surfaces of the source / drain electrodes 12 and 13 to form the metal oxide films 14 and 15. When the source / drain electrodes 12 and 13 are made of gold, metal oxide films 14 and 15 of gold oxide are formed.
In the oxygen plasma treatment, for example, the power was 200 W, the pressure of the treatment atmosphere was 133 Pa, and the treatment time was 3 minutes.
For the oxidation step, UV ozone treatment may be used.
In the UV ozone treatment, for example, ultraviolet light having a wavelength of 254 nm is used as UV light, the pressure of the treatment atmosphere is 10 kPa, and the treatment time is 10 minutes. As a light source that emits ultraviolet light having a wavelength of 254 nm, for example, there is a mercury lamp. In addition, if it is an ultraviolet light source, it will not be limited to the said wavelength.
The source / drain electrodes 12 and 13 may be made of, for example, nickel (Ni), platinum (Pt), copper (Cu), or the like. Even when these metals are used, a metal oxide film of the metal can be formed on the surface by the same oxidation process as described above.

  When the metal oxide films 14 and 15 are formed, the surface of the gate insulating film 17 is damaged by oxygen plasma or the like, and a damaged layer 25 is generated. For example, as the damage layer 25, a hydroxyl group (OH group) is generated on the surface of the gate insulating film 17.

Next, as shown in FIG. 4 (5), the damaged layer 25 on the gate insulating film 17 where the source / drain electrodes 12 and 13 are not formed is processed.
For example, the damage layer 25 may be processed by selectively forming a poly-para-xylylene film 21 on the gate insulating film 17 where the source / drain electrodes 12 and 13 are not formed. Form.

The polyparaxylylene film 21 is formed by vapor deposition polymerization. At this time, the nucleation rate of polyparaxylylene is higher on the gate insulating film 17 which is an organic insulating film than on the source / drain electrodes 12 and 13. For this reason, by selecting the film thickness of the polyparaxylylene film 21 to an optimum film thickness for selective growth, the gate insulation can be achieved without growing polyparaxylylene on the source / drain electrodes 12 and 13. Polyparaxylylene can be selectively grown only on the film 17.
For the selective growth of polyparaxylylene, di-para-xylylene is used as a raw material. As an example of film forming conditions, the substrate temperature is 25 ° C., the film forming rate is 1 nm / s, and the pressure of the growth atmosphere is 1 Pa. Set.
This selective growth of polyparaxylylene is carried out under reduced pressure using a dedicated apparatus (not shown). This dedicated apparatus is composed of, for example, three parts: a vaporization furnace, a decomposition furnace, and a vapor deposition chamber. An object (the gate insulating film 17 on which the source / drain electrodes 12 and 13 are formed) is placed in the vapor deposition chamber. Diparaxylylene (for example, powder) which is a film forming material is installed in the vaporizing furnace. After depressurizing the inside of the apparatus, the vaporizing furnace is heated (120 ° C. to 180 ° C.) to vaporize diparaxylylene. When this gas is drawn by the vacuum pump and flows to the deposition chamber side and passes through a high-temperature (650 ° C. to 700 ° C.) decomposition furnace, it is thermally decomposed into monomers. When this monomer comes into contact with the object (gate insulating film 17) in the room-temperature deposition chamber, heat is removed and polymerized on the surface to form a high molecular weight polyparaxylylene film.
The thickness of the polyparaxylylene film 21 is preferably 1 nm to 50 nm. More preferably, it is 5 nm to 10 nm.

  In the oxygen plasma treatment for forming the metal oxide films 14 and 15, the polyparaxylylene film 21 is coated with a hydroxyl group generated in a region where a channel on the gate insulating film 17 that causes a Vth shift is formed. The Thereby, an organic TFT device in which the Vth shift is suppressed can be manufactured.

Alternatively, the step of treating the hydroxyl group is not shown, but the gate insulating film 17 on which the source / drain electrodes 12 and 13 are not formed is dehydrated with a silane coupling agent. As a result, hydroxyl groups generated in the region where the channel on the gate insulating film 17 is formed are reduced.
Examples of the silane coupling agent used in the silane coupling treatment include octadecyltrichlorosilane (OTS) and hexamethyldisilazane (HMDS).
In the silane coupling treatment, no hydroxyl group is present on the source / drain electrodes 12 and 13, and therefore no silane coupling reaction occurs. On the other hand, a silane coupling reaction occurs on the gate insulating film 17 of the organic insulating film having a hydroxyl group. That is, the hydrogen of the hydroxyl group present on the gate insulating film 17 and the hydroxyl group of the silane coupling agent combine to generate H ₂ O, and the oxygen of the hydroxyl group present on the gate insulating film 17 and the silane coupling agent. The silicon (Si) bonds to form a Si—O bond. Thereby, the hydroxyl group on the outermost surface of the gate insulating film 17 that causes a threshold voltage (Vth) shift can be eliminated.

Next, as shown in FIG. 4 (6), an organic semiconductor layer 16 covering the source / drain electrodes 12, 13 having the metal oxide films 14, 15 formed thereon is formed on the gate insulating film 17. .
The organic semiconductor layer 16 is formed by vapor-depositing pentacene by, for example, resistance heating vapor deposition. For example, the film forming speed is set to 0.05 nm / s (0.5 Å / s), the temperature of the film forming atmosphere is set to 60 ° C., and the pressure of the film forming atmosphere is set to 10 ⁻⁵ Pa. To do. As a result, a pentacene polycrystalline thin film oriented in the C-axis direction can be formed.
Alternatively, for example, an ink jet printing technique is used to form the organic semiconductor layer 16. For example, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used as the film forming material. Further, spin coating, plate printing, or the like may be used as the film forming technique. The organic semiconductor layer 16 may be made of a low molecular material such as pentacene or porphyrin, or a polymer material such as triisopropylsilylethynyl pentacene [TIPS-pentacene] or polyallylamine.

  The organic semiconductor layer 16 has no metal oxide films 14 and 15 on the surface of the metal oxide films 14 and 15 (for example, gold oxide film) formed by oxidizing the surfaces of the source / drain electrodes 12 and 13. It becomes easier to grow than the surface of the source / drain electrode on the metal film (for example, gold film). For example, the grain size of the organic semiconductor layer when pentacene is deposited as the organic semiconductor layer 16 is larger on the metal oxide films 14 and 15 (for example, gold oxide film) than on the metal film (for example, gold film). . As described above, since the large-sized grains are grown, the contact resistance is reduced. Therefore, when operating the p-type organic semiconductor device, carriers from the source / drain electrodes 12 and 13 to the organic semiconductor layer 16 are increased. Injection efficiency is increased. As a result, the contact resistance between the source / drain electrodes 12 and 13 and the organic semiconductor layer 16 can be reduced.

  In the second method for manufacturing an organic semiconductor device, the polyparaxylene film 21 is formed on the gate insulating film 17 where the source / drain electrodes 12 and 13 are not formed. As a result, the damage layer 25 on the surface of the gate insulating film 17 generated when the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13, for example, the damage layer 25 causing the Vth shift, is not polyparaxyl It is covered and repaired by the len film 21. Therefore, the Vth shift is suppressed.

  Alternatively, the damage layer 25 on the surface of the gate insulating film 17 generated when the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 due to the silane coupling treatment, that is, the cause of the Vth shift. The resulting hydroxyl group is excluded. Therefore, the Vth shift is suppressed.

  Accordingly, the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 and the damaged layer 25 generated on the surface of the gate insulating film 17 is repaired. Problems such as lowering and occurrence of hysteresis can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

<5. Fifth embodiment>
[Third Example of Manufacturing Method of Organic Semiconductor Device]
A third example of the method of manufacturing an organic semiconductor device according to the fifth embodiment of the present invention will be described with reference to the manufacturing process sectional view of FIG.

As shown in FIG. 5A, a gate electrode 18 is formed on a substrate 11 having an insulating surface.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
The gate electrode 18 is formed by, for example, forming a metal film (not shown) on the substrate 11 and then patterning the metal film by a photolithography technique and an etching technique.
For example, gold (Au) is used for the metal film. When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .
The gate electrode 18 may be formed by a lift-off method, a plate printing method, an ink jet printing method, or the like.

Next, as shown in FIG. 5B, a gate insulating film 17 made of an organic insulating film covering the gate electrode 18 is formed on the substrate 11.
The gate insulating film 17 is formed of, for example, an organic insulating film. For example, polyvinylphenol (PVP) is used as the organic insulating film material. For example, spin coating is used as the formation method. After coating, baking is performed at 150 ° C. to 180 ° C. for 1 hour. At this time, since the PVP is crosslinked by the crosslinking agent added to the PVP, the subsequent photolithography process can be performed.
That is, by cross-linking the hydroxyl group in polyvinyl phenol (PVP) by a cross-linking reaction using a cross-linking agent, it is possible to increase the resistance of the organic solvent used thereafter.
As the organic insulating film material, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), acrylic resin, epoxy resin, polyimide resin, or the like can be used.

Next, as shown in FIG. 5 (3), a resist pattern 31 having openings 32 and 33 formed in the region for forming the source / drain electrodes on the gate insulating film 17 is formed by resist coating and photolithography. To do. For example, the openings 32 and 33 are formed on both sides above the gate electrode 18. The resist pattern 31 is preferably formed in a reverse taper shape.
Thereafter, for example, gold (Au) is deposited on the gate insulating film 17 by vapor deposition. At this time, gold is also deposited on the resist pattern 31. Here, gold was deposited to a thickness of 50 nm using, for example, a resistance heating vapor deposition method.
As a result, the source / drain electrodes 12 and 13 made of gold are formed on the gate insulating film 17 apart from each other.
At this time, since the resist pattern 31 is formed in a reverse taper shape, a gap is generated between the source / drain electrodes 12 and 13 and the resist pattern 31, and the source / drain electrodes 12 and 13 are It is formed.

Next, as shown in FIG. 5 (4), the surface of the source / drain electrodes 12, 13 is oxidized with the resist pattern 31 formed to form metal oxide films 14, 15.
The treatment for oxidizing the surfaces of the source / drain electrodes 12 and 13 is performed by oxygen plasma treatment. In the oxygen plasma treatment, for example, the power was 200 W, the pressure of the treatment atmosphere was 133 Pa, and the treatment time was 3 minutes.
For the oxidation step, UV ozone treatment may be used. In the UV ozone treatment, for example, ultraviolet light having a wavelength of 254 nm is used as UV light, the pressure of the treatment atmosphere is 10 kPa, and the treatment time is 10 minutes. As a light source that emits ultraviolet light having a wavelength of 254 nm, for example, there is a mercury lamp. In addition, if it is an ultraviolet light source, it will not be limited to the said wavelength.
The source / drain electrodes 12 and 13 may be made of, for example, nickel (Ni), platinum (Pt), copper (Cu), or the like. Even when these metals are used, a metal oxide film of the metal can be formed on the surface by the same oxidation process as described above.
In the oxidation step, since a gap is formed between the source / drain electrodes 12 and 13 and the resist pattern 31, the side wall portions of the source / drain electrodes 12 and 13 are also oxidized to form the source / drain electrodes. The metal oxide films 14 and 15 are formed so as to cover the electrodes 12 and 13.
Subsequently, by removing (lift-off) the resist pattern 31 together with the gold deposited on the resist pattern 31, the source / drain electrodes 12 and 13 made of gold are formed on the gate insulating film 17 apart from each other. . For the lift-off, for example, a solvent that dissolves the resist is used. For example, acetone is used.
FIG. 5 (4) shows a state immediately before the resist pattern is removed.

Next, as shown in FIG. 5 (5), an organic semiconductor layer 16 covering the source / drain electrodes 12, 13 having the metal oxide films 14, 15 formed thereon is formed on the gate insulating film 17. .
The organic semiconductor layer 16 is formed by vapor-depositing pentacene by, for example, resistance heating vapor deposition. For example, the film forming speed is set to 0.05 nm / s (0.5 Å / s), the temperature of the film forming atmosphere is set to 60 ° C., and the pressure of the film forming atmosphere is set to 10 ⁻⁵ Pa. To do. As a result, a pentacene polycrystalline thin film oriented in the C-axis direction can be formed.
Alternatively, for example, an ink jet printing technique is used to form the organic semiconductor layer 16. For example, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used as the film forming material. Further, spin coating, plate printing, or the like may be used as the film forming technique. The organic semiconductor layer 16 may be made of a low molecular material such as pentacene or porphyrin, or a polymer material such as triisopropylsilylethynyl pentacene [TIPS-pentacene] or polyallylamine.

  The organic semiconductor layer 16 has no metal oxide films 14 and 15 on the surface of the metal oxide films 14 and 15 (for example, gold oxide film) formed by oxidizing the surfaces of the source / drain electrodes 12 and 13. It becomes easier to grow than the surface of the source / drain electrode on the metal film (for example, gold film). For example, the grain size of the organic semiconductor layer when pentacene is deposited as the organic semiconductor layer 16 is larger on the metal oxide films 14 and 15 (for example, gold oxide film) than on the metal film (for example, gold film). . As described above, since the large-sized grains are grown, the contact resistance is reduced. Therefore, when operating the p-type organic semiconductor device, carriers from the source / drain electrodes 12 and 13 to the organic semiconductor layer 16 are increased. Injection efficiency is increased. As a result, the contact resistance between the source / drain electrodes 12 and 13 and the organic semiconductor layer 16 can be reduced.

In the third method for manufacturing an organic semiconductor device, when the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13, the gate insulating film 17 is covered with the resist pattern 31. For this reason, damage, for example, damage that causes a Vth shift does not occur on the surface of the gate insulating film 17, so that the Vth shift is suppressed.
Therefore, the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 and the resist pattern 31 prevents the surface of the gate insulating film 17 from being damaged. It is possible to avoid problems such as the occurrence of That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.
In addition, since the region where the oxygen plasma treatment is performed is limited by the resist pattern 31, it is possible to cope with a high-definition process.
Further, since the resist pattern 31 used when forming the source / drain electrodes 12 and 13 is used as it is as a mask pattern when forming the metal oxide films 14 and 15, the metal oxide films 14 and 15 are formed. There is no need to form a new mask pattern. Therefore, the number of masks does not increase.

<6. Sixth Embodiment>
[Fourth Example of Manufacturing Method of Organic Semiconductor Device]
A fourth example of the method for manufacturing an organic semiconductor device according to the sixth embodiment of the present invention will be described with reference to the manufacturing process sectional view of FIG.

As shown in FIG. 6A, a gate electrode 18 is formed on a substrate 11 having an insulating surface.
As the substrate 11, for example, a glass substrate or a plastic substrate is used. Alternatively, it may be a substrate formed on the surface with an insulating film such as silicon oxide, silicon nitride, or an organic insulating film.
The gate electrode 18 is formed by, for example, forming a metal film (not shown) on the substrate 11 and then patterning the metal film by a photolithography technique and an etching technique.
For example, gold (Au) is used for the metal film. When gold is used, it is preferable to use chromium (Cr) for the adhesion layer.
For the metal film forming the gate electrode 18, a general electrode material such as aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), nickel (Ni) can be used. .
The gate electrode 18 may be formed by a lift-off method, a plate printing method, an ink jet printing method, or the like.

Next, as shown in FIG. 6B, a gate insulating film 17 made of an organic insulating film covering the gate electrode 18 is formed on the substrate 11.
The gate insulating film 17 is formed of, for example, an organic insulating film. For example, polyvinylphenol (PVP) is used as the organic insulating film material. For example, spin coating is used as the formation method. After coating, baking is performed at 150 ° C. to 180 ° C. for 1 hour. At this time, since the PVP is crosslinked by the crosslinking agent added to the PVP, the subsequent photolithography process can be performed.
That is, by cross-linking the hydroxyl group in polyvinyl phenol (PVP) by a cross-linking reaction using a cross-linking agent, it is possible to increase the resistance of the organic solvent used thereafter.
As the organic insulating film material, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), acrylic resin, epoxy resin, polyimide resin, or the like can be used.

  Next, as shown in FIG. 6 (3), the source / drain electrodes 12, 13 made of metal having the surface oxidized to form the metal oxide films 14, 15 are transferred onto the gate insulating film 17. Form. At this time, for example, the source / drain electrodes 12 and 13 are transferred so that the space between the source / drain electrodes 12 and 13 is positioned on the gate electrode 18.

Next, as shown in FIG. 6 (4), an organic semiconductor layer 16 covering the source / drain electrodes 12, 13 having the metal oxide films 14, 15 formed thereon is formed on the gate insulating film 17. .
The organic semiconductor layer 16 is formed by vapor-depositing pentacene by, for example, resistance heating vapor deposition. For example, the film forming speed is set to 0.05 nm / s (0.5 Å / s), the temperature of the film forming atmosphere is set to 60 ° C., and the pressure of the film forming atmosphere is set to 10 ⁻⁵ Pa. To do. As a result, a pentacene polycrystalline thin film oriented in the C-axis direction can be formed.
Alternatively, for example, an ink jet printing technique is used to form the organic semiconductor layer 16. For example, poly (3-hexylthiophene) [P3HT: poly (3-hexylthiophene)] is used as the film forming material. Further, spin coating, plate printing, or the like may be used as the film forming technique. The organic semiconductor layer 16 may be made of a low molecular material such as pentacene or porphyrin, or a polymer material such as triisopropylsilylethynyl pentacene [TIPS-pentacene] or polyallylamine.

  The organic semiconductor layer 16 has no metal oxide films 14 and 15 on the surface of the metal oxide films 14 and 15 (for example, gold oxide film) formed by oxidizing the surfaces of the source / drain electrodes 12 and 13. It becomes easier to grow than the surface of the source / drain electrode on the metal film (for example, gold film). For example, the grain size of the organic semiconductor layer when pentacene is deposited as the organic semiconductor layer 16 is larger on the metal oxide films 14 and 15 (for example, gold oxide film) than on the metal film (for example, gold film). . As described above, since the large-sized grains are grown, the contact resistance is reduced. Therefore, when operating the p-type organic semiconductor device, carriers from the source / drain electrodes 12 and 13 to the organic semiconductor layer 16 are increased. Injection efficiency is increased. As a result, the contact resistance between the source / drain electrodes 12 and 13 and the organic semiconductor layer 16 can be reduced.

  The steps of forming the source / drain electrodes 12 and 13 made of metal having the metal oxide films 14 and 15 formed by oxidizing the surface on the gate insulating film 17 are as follows.

As shown in FIG. 6 (5), the source / drain electrodes 12 and 13 made of metal are formed on the first support substrate 41 apart from each other. The distance between the source / drain electrodes 12 and 13 is determined in consideration of, for example, the width of the gate electrode 18.
For the first support substrate 41, for example, a glass substrate is used.
First, a gold (Au) film, for example, is formed on one surface as a metal film on the first support substrate 41 by resistance heating vapor deposition.
Next, a polydimethylsiloxane plate (hereinafter referred to as a PDMS plate) is prepared so that polydimethylsiloxane (PDMS) is in contact with a region other than the region serving as the source / drain electrodes. By contacting the PDMS plate with the gold film, the gold film other than the region where the source / drain electrodes are formed is removed with the PDMS plate. At this time, a pressure of, for example, 5 kPa is applied in an atmospheric pressure atmosphere, and the gold film is pressed against the first support substrate 41 side for 30 seconds. Since the adhesion between the PDMS and the gold film is greater than the adhesion between the gold film and the first support substrate 41 which is a glass substrate, an unnecessary portion of the gold film can be easily removed from the first support substrate 41. it can.
As a result, the source / drain electrodes 12 and 13 made of gold are formed on the first support substrate 41 apart from each other.

Next, as shown in FIG. 6 (6), the surfaces of the source / drain electrodes 12, 13 are oxidized to form metal oxide films 14, 15.
The surfaces of the source / drain electrodes 12 and 13 are oxidized by oxygen plasma treatment to form metal oxide films 14 and 15 made of gold oxide.
Since the first support substrate 41 is a glass substrate, the oxidation process can be performed without problems even under relatively strong oxygen plasma processing conditions. For example, it is possible to cope with an oxidation condition in which the power is 200 W, the pressure of the processing atmosphere is 133 Pa, and the processing time is stronger than 3 minutes.
For the oxidation step, UV ozone treatment may be used. In the UV ozone treatment, for example, ultraviolet light having a wavelength of 254 nm is used as UV light, the pressure of the treatment atmosphere is 10 kPa, and the treatment time is 10 minutes. As a light source that emits ultraviolet light having a wavelength of 254 nm, for example, there is a mercury lamp. In addition, if it is an ultraviolet light source, it will not be limited to the said wavelength.

Next, as shown in FIG. 6 (7), the source / drain electrode 12 having the metal oxide films 14 and 15 formed thereon by pressing the second support substrate 42 against the surfaces of the metal oxide films 14 and 15. , 13 are transferred to the second support substrate. At this time, for example, a pressure of 5 kPa is applied in an atmospheric pressure atmosphere to press the second support substrate 42 toward the metal oxide films 14 and 15 for 30 seconds. A PDMS substrate is used as the second support substrate 42.
At this time, since the adhesion between the PDMS substrate and the metal oxide films 14 and 15 made of gold oxide is larger than the adhesion between the gold film and the first support substrate 41 of the glass substrate, the metal oxide film 14, The source / drain electrodes 12 and 13 on which 15 is formed are peeled off from the first support substrate 41.
As a result, as shown in FIG. 6 (8), the first support substrate 41 (see FIG. 6 (7)) is peeled off from the source / drain electrodes 12, 13, and the second support substrate 42 of the PDMS substrate is easily removed. The source / drain electrodes 12 and 13 are transferred to the side.
In this manner, a transfer plate on which the source / drain electrodes 12 and 13 covered with the metal oxide films 14 and 15 are formed.

  Next, as shown in FIG. 6 (9), the source / drain electrodes 12 and 13 are formed on the gate insulating film 17 by plate printing. That is, the source / drain electrodes 12 and 13 are pressed against the gate insulating film 17 side for 30 seconds by applying a pressure of, for example, 5 kPa in an atmospheric pressure atmosphere. The source / drain electrodes 12 and 13 are transferred from the second support substrate 42 onto the gate insulating film 17, and the second support substrate 42 is removed from the source / drain electrodes 12 and 13. At this time, the gate insulation between the metal oxide films 14 and 15 of gold oxide and the organic insulating film (for example, PVP) is higher than the adhesion between the metal oxide films 14 and 15 of gold oxide and the second support substrate 42 of PDMS. Since the adhesiveness with the film 17 is higher, the source / drain electrodes 12 and 13 made of gold are transferred onto the gate insulating film 17 which is an organic insulating film.

In the fourth method for manufacturing an organic semiconductor device, the first support substrate 41 damaged when the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 is removed. Since only the source / drain electrodes 12 and 13 on which the metal oxide films 14 and 15 are formed are transferred onto the gate insulating film 17, the surface of the gate insulating film 17 is damaged, for example, causing Vth shift. No damage will occur. Therefore, the Vth shift is suppressed.
Further, since the metal oxide films 14 and 15 are formed on the surfaces of the source / drain electrodes 12 and 13 and the surface of the gate insulating film 17 is not damaged, the Vth shift is suppressed, the driving ability is reduced, and hysteresis is generated. The problem can be avoided. That is, the driving ability can be improved and the occurrence of hysteresis can be prevented, so that the transistor characteristics can be improved.

  In addition, since plate printing is used, it is possible to cope with high definition and large area processes. Further, since the source / drain electrodes 12 and 13 can be oxidized on the first support substrate 41, the process margin is large. For example, it can cope with strong oxidation conditions.

  The organic semiconductor device 1 of the first embodiment, the organic semiconductor device 2 of the second embodiment, and the organic semiconductor devices fabricated in the third to sixth embodiments are used in various electronic devices. It can be used for a transistor to be mounted. For example, it can be used for a transistor that forms part of a circuit such as a display backplane, an RF-ID tag, a sensor, or a memory device.

  DESCRIPTION OF SYMBOLS 1 ... Organic semiconductor device, 11 ... Board | substrate, 12, 13 ... Source / drain electrode, 14, 15 ... Metal oxide film, 16 ... Organic-semiconductor layer, 17 ... Gate insulating film, 18 ... Gate electrode

Claims (14)

Source / drain electrodes formed on the surface of a substrate having an insulating surface spaced apart from each other;
A metal oxide film formed on the surface of the source / drain electrode;
An organic semiconductor layer that is formed on the substrate and covers the source / drain electrodes on which the metal oxide film is formed;
A gate insulating film formed on the organic semiconductor layer;
An organic semiconductor device comprising a gate electrode formed on the gate insulating film above the source / drain electrodes. The source / drain electrodes are made of gold,
The organic semiconductor device according to claim 1, wherein the metal oxide film is formed of gold oxide. The source / drain electrodes are made of gold oxide,
The organic semiconductor device according to claim 1, wherein the metal oxide film is formed of gold oxide. A gate electrode formed on the surface of the substrate having an insulating surface;
A gate insulating film made of an organic insulating film formed on the substrate and covering the gate electrode;
A source / drain electrode formed on the gate insulating film on both sides above the gate electrode,
A metal oxide film formed on the surface of the source / drain electrode;
An organic semiconductor layer formed on the gate insulating film and covering the source / drain electrodes on which the metal oxide film is formed;
An organic semiconductor device, wherein a polyparaxylylene film is formed on the gate insulating film on which the source / drain electrodes are not formed. The source / drain electrodes are made of gold,
The organic semiconductor device according to claim 4, wherein the metal oxide film is made of gold oxide. The source / drain electrodes are made of gold oxide,
The organic semiconductor device according to claim 4, wherein the metal oxide film is made of gold oxide. Forming a source / drain electrode made of a metal on a surface of a substrate having an insulating surface;
Oxidizing the metal surface of the source / drain electrode to form a metal oxide film;
Forming an organic semiconductor layer covering the source / drain electrodes on which the metal oxide film is formed on the substrate;
Forming a gate insulating film on the organic semiconductor layer;
A method of manufacturing an organic semiconductor device, comprising: forming a gate electrode on the gate insulating film above the source / drain electrodes. Forming a gate electrode on the surface of the substrate having an insulating surface;
Forming a gate insulating film made of an organic insulating film covering the gate electrode on the substrate;
Forming a source / drain electrode made of metal on the gate insulating film on both sides above the gate electrode,
Oxidizing the surface of the source / drain electrode to form a metal oxide film;
Treating the damaged layer on the surface of the gate insulating film where the source / drain electrodes are not formed;
The manufacturing method of the organic-semiconductor device which has the process of forming the organic-semiconductor layer which coat | covers the said source / drain electrode in which the said metal oxide film was formed on the said gate insulating film which processed the said damage layer. The method of manufacturing an organic semiconductor device according to claim 8, wherein the step of treating the damaged layer forms a polyparaxylylene film on the gate insulating film on which the source / drain electrodes are not formed. The method for manufacturing an organic semiconductor device according to claim 8, wherein in the step of processing the damaged layer, a dehydration process is performed on the gate insulating film on which the source / drain electrodes are not formed with a silane coupling agent. Forming a gate electrode on the surface of the substrate having an insulating surface;
Forming a gate insulating film made of an organic insulating film covering the gate electrode on the substrate;
Forming a resist pattern having openings in regions where source / drain electrodes are formed on the gate insulating film on both sides above the gate electrode;
Forming the source / drain electrodes made of metal on the gate insulating film by metal film formation using the resist pattern as a mask;
Forming a metal oxide film by oxidizing the surface of the source / drain electrode with the resist pattern formed;
Removing the resist pattern together with the metal film formed on the resist pattern during the metal film formation;
The manufacturing method of the organic-semiconductor device which has the process of forming the organic-semiconductor layer which coat | covers the said source / drain electrode in which the said metal oxide film was formed on the said gate insulating film. The method of manufacturing an organic semiconductor device according to claim 11, wherein the resist pattern is formed in a reverse taper shape. The method for manufacturing an organic semiconductor device according to claim 11 or 12, wherein the treatment for oxidizing the surface of the source / drain electrode is performed by oxygen plasma treatment or UV ozone treatment. Forming a gate electrode on the surface of the substrate having an insulating surface;
Forming a gate insulating film made of an organic insulating film covering the gate electrode on the substrate;
Forming a source / drain electrode made of metal having a metal oxide film formed by oxidizing a surface on the gate insulating film on both sides above the gate electrode;
Forming an organic semiconductor layer that covers the source / drain electrodes on which the metal oxide film is formed on the gate insulating film;
A step of forming a source / drain electrode made of metal having a metal oxide film formed by oxidizing the surface on the gate insulating film,
Forming a source / drain electrode made of metal on the first support substrate separately;
Oxidizing the surface of the source / drain electrode to form a metal oxide film;
A second support substrate is pressed against the surface of the metal oxide film, and the source / drain electrodes on which the metal oxide film is formed are transferred to the second support substrate, and the first support substrate is transferred from the source / drain electrodes. Removing the process,
A method of manufacturing an organic semiconductor device, comprising: transferring the source / drain electrodes from the second support substrate onto the gate insulating film and removing the second support substrate from the source / drain electrodes.

Images