JP2005317272A - Manufacturing method of electron emitting element and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an uneasy electron emission by using an electron emitting element having a surface terminal, while manufacturing the element by a simple method. <P>SOLUTION: The manufacturing method of the electron emitting element comprises a first process of preparing a substrate on the surface of which, a first conductive film and a second conductive film are arranged with a certain distance, a second process applying an termination treatment to the first conductive film and the second conductive film by hydrogen through carbon, and a third process removing hydrogen terminating the second conductive film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electron-emitting device and a method for manufacturing an image display device.

  Examples of the electron-emitting device include a field emission type (FE type), an MIM type, an MIS type, and a surface conduction type. Such an electron-emitting device includes, as a basic structure, a cathode electrode having an electron-emitting material and a gate electrode for extracting electrons from the electron-emitting material.

  As an application apparatus for these electron-emitting devices, for example, a flat panel display in which a large number of the electron-emitting devices are arranged on the same substrate can be cited. In recent years, flat panel displays have been required to display images with higher definition. Therefore, an electron-emitting device with a small beam diameter of the emitted electron beam is desired.

  In order to reduce the beam diameter, it is advantageous to set the electric field strength formed during driving low. Accordingly, an electron-emitting material that can emit electrons in a lower electric field is expected to be applied to a high-definition image display device, and therefore, its development is desired. Furthermore, if the surface of the electron emission portion is flat, it is expected to further suppress the spread of the beam.

As such an electron-emitting material that can emit electrons in a low electric field, diamond is available. Patent Documents 1 and 2 disclose electron-emitting devices in which a diamond surface is terminated with hydrogen or oxygen.
JP-A-9-199001 JP-A-10-208620

  However, since an electron-emitting device capable of emitting electrons in a low electric field is likely to emit electrons, attention must be paid to its manufacturing method.

  For example, in the case where an electron emitting portion capable of emitting electrons in a low electric field is formed by terminating the surface of the electron emitting material as described above, a member that is not intended to be terminated (for example, a gate electrode or an electron emitting element). In some cases, electron emission from a conductive member other than the cathode electrode, such as wiring for supplying voltage, becomes a problem. For example, even when an electron emission layer having a low work function is selectively formed only on the cathode electrode, the material of the electron emission layer supplies a voltage to an unintended member (for example, a gate electrode or an electron emission element). In some cases, it may adhere to a conductive member other than the cathode electrode such as a wiring for carrying out or remain as a residue after patterning. In such a case, a portion that should not be an electron emission portion is supposed to be a region where electrons can be emitted. Unintentional electron emission causes unintentional light emission in the image display device, resulting in deterioration of display image quality and uniformity.

  Therefore, as a manufacturing method for preventing electron emission from the conductive member other than the cathode electrode (other than the portion desired to be the electron emission portion) as described above, an electron emission structure is provided on the conductive member other than the cathode electrode. It is normal practice to employ a process in which the electron emission material is not disposed on the conductive member other than the cathode electrode or the above-described termination treatment is not performed on the surface of the conductive member other than the cathode electrode. Is called.

  Specifically, for example, prior to the deposition of the electron emission material and the termination treatment of the electron emission material described above, a mask is disposed on the conductive member other than the cathode electrode, and the deposition and termination treatment of the electron emission material are performed. Remove the mask after finishing. However, adopting such a process leads to an increase in man-hours, resulting in an increase in cost. In addition, such a process may change the characteristics of the electron emission material. In particular, electron-emitting materials that can emit electrons in a low electric field often have chemically active surfaces or important shapes and properties of the surface. There are cases where emission characteristics are lowered and an electric field required for electron emission is increased. In particular, when the mask peeling process as described above is performed in a wet process, it is necessary to immerse the electron-emitting material in the solution, and there is a concern about deterioration of the electron-emitting material. This problem is significant when the material is a carbon-based material. Therefore, when using a material capable of emitting electrons in a low electric field, it is important to control the surface of the electron emitting material, and optimization of the manufacturing process is important.

  An object of the present invention is to provide a manufacturing method for easily manufacturing an electron-emitting device having a low driving voltage and a small beam diameter. Furthermore, an image display apparatus having good image display characteristics is formed by arranging a large number of electron-emitting devices formed by such a manufacturing method.

  In other words, a first aspect of the present invention is a method for manufacturing an electron-emitting device, the first step of preparing a substrate in which a first conductive film and a second conductive film are arranged on the surface thereof at intervals, A second step of terminating the surface of the first conductive film and the second conductive film with hydrogen via carbon; a third step of removing hydrogen that terminates the second conductive film after the second step; It is characterized by including.

  Further, the present invention is further characterized in that "the second step includes a step of heating the substrate in an atmosphere containing carbon and / or hydrogen", "the third step selectively includes the first step. 2 ”,“ the energy is an ultraviolet ray ”,“ the third step is performed in an oxygen-containing atmosphere ”,“ the energy is an electron beam ” Another characteristic is that it is an ion beam.

  According to a second aspect of the present invention, there is provided a method of manufacturing an electron-emitting device, the first step of preparing a substrate in which a first conductive film and a second conductive film are spaced apart from each other on the surface; It includes a second step of heating the substrate in an atmosphere containing carbon and / or hydrogen, and a third step of selectively applying energy to the second conductive film.

  Further, the second of the present invention described above is further that "the third step is a step of removing hydrogen on the second conductive film by selectively applying energy to the second conductive film". "The energy is ultraviolet rays, electron beams or ion beams".

  According to a third aspect of the present invention, there is provided a method for manufacturing an electron-emitting device, the first step of preparing a substrate on which a conductive film is disposed, and the conductive film disposed in an atmosphere containing carbon and / or hydrogen. A second step of heating the substrate, and a third step of selectively applying energy to the surface of the substrate on which the conductive film is not disposed after the second step. .

  The third aspect of the present invention is further characterized in that “the third step is a step of removing hydrogen on a portion of the substrate surface where the conductive film is not disposed”. To do.

  The present invention also provides a method of manufacturing an image display device comprising a plurality of electron-emitting devices and a light emitter that emits light by electrons emitted from the plurality of electron-emitting devices. Each is manufactured according to the first to third aspects of the present invention.

  According to the manufacturing method of the present invention, an electron-emitting device capable of emitting electrons in a low electric field can be easily produced. As a result, an electron-emitting device with a low driving voltage, good beam diameter controllability, and high efficiency can be manufactured. Further, such a manufacturing method can provide an electron source having good driving characteristics and form an image display device.

  The present invention will be described below with reference to the drawings. However, the size, material, shape, relative arrangement, driving method, driving voltage, and the like of each member in the following examples are not intended to limit the scope of the present invention only to them.

  FIG. 1 shows an example of an electron emission apparatus in which an anode electrode is disposed above an electron emission element of the present invention. FIG. 1A is a cross-sectional view schematically showing how the electron emission device is driven, and FIG. 1B is a plan view schematically showing the state when the electron emission device is driven. FIG. In the figure, 1 is a substrate, 2 is a cathode electrode, 3 is a gate electrode, 4 is an anode electrode, 5 is a carbon film, 6 is a drive power supply, 7 is an anode power supply, and 11 is a dipole layer.

  In this device, a drive voltage Vg [V] is applied between the cathode electrode 2 and the gate electrode 3, and simultaneously, a voltage Va [V] higher than Vg is applied to the anode electrode 4, thereby functioning as an electron emission film. Then, electrons are emitted from the laminate of the carbon film 5 and the dipole layer 11, and the emission current Ie [A] flows between the cathode electrode 2 and the anode electrode 4.

  The electron-emitting device described here is a type of electron-emitting device that emits electrons by applying an electric field between two opposing electrodes (cathode electrode 2 and gate electrode 3). In the embodiment shown in FIG. 1, a carbon layer 5 is disposed on the surfaces of the cathode electrode 2 and the gate electrode 3, and a dipole layer 11 is formed on the surface of the carbon layer 5 on the cathode electrode 2 side. .

  The electron emission structure of the electron emission device shown in FIG. 1 will be described with reference to FIGS.

FIG. 4 is a diagram schematically showing a cross section of the electron emission portion. In FIG. 4, 2 is a cathode electrode and 5 is a carbon layer. For example, a diamond-like carbon (DLC) film can be used. Reference numeral 11 denotes an interface between the carbon layer 5 and a vacuum. In the figure, the surface of the carbon layer 5 is terminated with hydrogen. In general, hydrogen atoms are slightly positively polarized (δ ⁺ ). As a result, carbon atoms on the surface of the carbon layer 5 are slightly negatively polarized (δ ⁻ ), and as a result, a dipole layer (electric double layer) 11 is formed.

  Here, as the dipole layer 11, an example in which the surface of the carbon layer 5 (interface with the vacuum) is terminated with hydrogen is shown. However, the material forming the dipole layer 11 in the present invention is not limited to hydrogen. The material that terminates the surface of the carbon layer 5 is one that lowers the surface level of the carbon layer 5 when no voltage is applied between the cathode electrode 2 and the extraction electrode (gate electrode and / or anode electrode). However, hydrogen is preferably used.

  The principle of electron emission from the electron emission film having the above-described dipole layer 11 will be described with reference to the band diagrams of FIGS. FIG. 5A shows a case where no voltage is applied between the extraction electrode 23 and the cathode electrode 2. FIG. 5B shows a case where a drive voltage is applied between the extraction electrode 23 and the cathode electrode 2. The extraction electrode 23 is a gate electrode, an anode electrode, or a combination of both. In the figure, 2 is a cathode electrode, 5 is a carbon layer, 23 is an extraction electrode, 24 is a vacuum barrier, 25 is an electron, and 26 is an interface between the carbon layer 5 having a dipole layer formed on its surface and a vacuum.

  The above-described dipole layer 11 causes the surface of the carbon layer 5 to be electrically charged even though no driving voltage is applied between the cathode electrode 2 and the extraction electrode 23 as shown in FIG. A state equivalent to the case where the multilayer potential δ [V] is applied is formed.

  As shown in FIG. 5B, when the drive voltage V [V] is applied between the cathode electrode 2 and the extraction electrode 23, the potential drop of the carbon layer 5 proceeds. The vacuum barrier 24 is also lowered in conjunction with the potential drop of the carbon layer 5. Therefore, the spatial distance of the electrons 25 supplied from the cathode electrode 2 through the carbon layer 5 can be reduced by the driving voltage V [V]. By setting the film thickness of the carbon layer 5 in advance to a tunneling film thickness (preferably 10 nm or less), when the drive voltage V [V] is applied between the cathode electrode 2 and the extraction electrode 23, the electrons Thus, a state in which 25 can tunnel the carbon layer 5 is formed. As a result, the emission of the electrons 25 to the vacuum is realized. The drive voltage V [V] in the electron-emitting device of the present invention is preferably 50 [V] or less, and more preferably 5 [V] or more and 50 [V] or less.

  The material that terminates the surface of the carbon layer 5 is 0.5 eV or more, preferably 1 eV, in a state where the surface level of the carbon layer 5 is not applied with a voltage between the cathode electrode 2 and the extraction electrode 23. It is preferable to pull down the above. However, in the electron-emitting device of the present invention, when the driving voltage is applied between the cathode electrode 2 and the extraction electrode 23 and when the driving voltage is not applied, the surface of the carbon layer 5 is quasi. The position must exhibit a positive electron affinity.

The voltage applied to the anode electrode is generally in the range of 10 kV to 30 kV. For this reason, the electric field strength formed between the anode electrode and the electron-emitting device is generally considered to be approximately 1 × 10 ⁵ V / cm or less. Therefore, it is preferable to prevent electrons from being emitted from the electron-emitting device by this electric field strength. Therefore, the electron affinity of the surface of the insulating layer 2 on which the dipole layer is formed is preferably 2.5 eV or more in consideration of the film thickness of the insulating layer described later.

  The film thickness of the carbon layer 5 can be determined by the driving voltage, but is preferably set to 20 nm or less, more preferably 10 nm or less. Further, as a lower limit of the film thickness of the carbon layer 5, it is sufficient that electrons supplied from the cathode electrode 2 form a barrier to be tunneled (the carbon layer 5 and the vacuum barrier 24) during driving. From the viewpoint of reproducibility and the like, it is preferably set to 1 nm or more.

Further, it is important that the carbon layer 5 in this embodiment substantially functions as an insulating layer. When the main body of the carbon layer 5 is amorphous carbon such as diamond-like-carbon (DLC), for example, a resistivity of about 1 × 10 ⁸ to 1 × 10 ¹⁴ Ωcm can be obtained and it functions as a dielectric. Is preferable. However, in the present invention, the material of the insulating layer 5 is not limited to carbon. However, from the viewpoint of electron emission characteristics and manufacturability, the material of the insulating layer 5 is preferably carbon.

  Thus, in the electron-emitting device according to the present invention, the carbon layer 5 always exhibits a positive electron affinity, so that a clear electron emission amount can be turned on at the time of selection (ON) and at the time of non-selection (OFF).・ Off ratio can be secured. An electron-emitting device that can ensure a clear on / off ratio of the amount of electron emission when selected and not selected is an electron source that needs to emit electrons from an arbitrary electron-emitting device among many electron-emitting devices. It can be preferably applied to an image display device.

The carbon layer 5 to which the present invention is preferably applied is a layer from which electrons can be emitted with a low electric field strength of less than 1 × 10 ⁶ V / cm. In the carbon layer 5 described with reference to FIGS. 4 and 5, by applying an electric field of less than 1 × 10 ⁶ V / cm, electrons can be emitted. That is, electrons can be emitted by applying an electric field of less than 1 × 10 ⁶ V / cm between the extraction electrode 23 and the carbon layer 5.

  Therefore, the electron-emitting device of the present invention differs from the surface conduction electron-emitting device in that the electron emission efficiency (Ie / If (where If indicates the current (device current) flowing between the cathode electrode and the extraction electrode). , Ie indicates a very high current (emission current) flowing between the cathode electrode and the anode electrode) In the electron-emitting device of the present invention, the distance between the gate electrode and the cathode electrode can be separated by 1 μm or more. As a result, an electron emission efficiency of 30% or more can be realized, and can be as high as 60% or more, and a surface conduction electron-emitting device that has undergone a manufacturing process called “activation” has an electron emission efficiency of several%. The distance between the carbon film on the gate electrode side and the carbon film on the cathode electrode side is several nanometers.

  An example of a manufacturing process of the electron-emitting device shown in FIG. 1 will be described with reference to FIGS.

  FIG. 2 is a schematic view showing three steps in the manufacturing process of the electron-emitting device according to the present invention. The three steps are [Step 1]: a step of preparing a substrate having a first conductive film and a second conductive film (FIG. 2A), and [Step 2]: a first conductive film and / or a second conductive film. A step of forming a dipole layer on the surface of the conductive film (FIG. 2B) and [Step 3]: a step of removing an unnecessary portion of the dipole layer from the dipole layer formed on the substrate (FIG. 2C )). And an example of the manufacturing process for obtaining the structure shown to Fig.2 (a) is shown by Fig.3 (a)-(e). An example of a manufacturing process for obtaining the structure shown in FIG. 2B is shown in FIG. An example of a manufacturing process for obtaining the structure shown in FIG. 2C is shown in FIGS.

  Further, each step will be specifically described.

[Step 1] Step of preparing a substrate having a first conductive film and a second conductive film Step 1 is a step of forming a first conductive film and a second conductive film on the substrate (FIG. 2A). . This step 1 can be formed by the following steps 1 to 5, for example. In the example described below, a case where the first conductive film includes the electrode 2 and the carbon layer 5 and the second conductive film includes the electrode 3 and the carbon layer 5 will be described.

(Process 1)
First, a conductive film 31 (a member to be the electrode 2 and the electrode 3) is laminated on the substrate 1 whose surface has been sufficiently cleaned (FIG. 3A).

Examples of the substrate 1 include quartz glass, glass with reduced impurity content such as Na, blue plate glass, a substrate made of a laminate in which SiO ₂ is laminated on the substrate surface, and an insulating substrate made of ceramics. Or one can be used.

  The conductive film 31 is formed by a general vacuum film forming technique such as vapor deposition or sputtering. Examples of the material of the conductive film 31 include metals such as Be, Mg, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, Cu, Ni, Cr, Au, Pt, and Pd, or alloy materials. Is appropriately selected. The thickness of the conductive film 31 is set in the range of several tens of nm to several mm, and preferably selected in the range of several hundred nm to several μm.

(Process 2)
Next, a carbon layer 5 is deposited on the conductive film 31 as shown in FIG.

  The carbon layer 5 preferably has good flatness. Specifically, the surface roughness is preferably rms (root-mean-square) and not more than 1/10 of the average film thickness of the carbon layer 5. Further, the value of rms is preferably 10 nm or less, more preferably 1 nm or less. Note that rms is expressed as a square root of a value obtained by averaging the squares of deviations from the average line to the measurement curve. It is also a standard adopted in the JIS standard.

(Process 3)
A pattern of a photoresist mask 32 is formed on the conductive film 31 in order to separate the conductive film 31 into the electrode 2 and the electrode 3 by photolithography (FIG. 3C).

(Process 4)
Next, etching is performed to separate the conductive film 31 into the electrode 2 and the electrode 3 (FIG. 3D). In the etching process of the conductive film 31 and the carbon layer 5, it is desirable that the etching surface is smooth. Therefore, an etching method may be selected depending on a material to be used. Dry etching or wet etching may be used.

(Process 5)
A structure in which the first conductive films (2 and 5) and the second conductive films (3 and 5) shown in FIG. 3E are arranged on the surface of the substrate 1 with a space therebetween by removing the mask 32. Can be formed.

  Usually, the distance w (see FIG. 1) between the first conductive film and the second conductive film is determined based on the material and resistance value of the electron-emitting device, the electrical characteristics of the carbon layer 5, and the required electron-emitting beam. It is appropriately set depending on the shape and the like. Usually, w is preferably set to several tens of nm or more and 100 μm or less. Reducing the distance w is most effective for reducing the drive voltage of the electron-emitting device, and it is desirable to make it several μm or less. However, if the distance w is reduced, the alignment accuracy in the step 3 described later may not be secured. Therefore, preferable w is 500 nm or more and 10 μm or less.

[Step 2] Step of Forming Dipole Layer Step 2 is a step of forming the dipole layer 11 on the first conductive film (2, 5) and / or the second conductive film (3, 5) formed in Step 1. Yes (FIG. 2B). This step can also be regarded as a kind of so-called surface treatment process. In particular, here, an example in which the dipole layer 11 is formed on the surface of the carbon layer 5 formed in the above steps 1 to 5 will be described.

  Here, an example will be described in which the formation of the dipole layer 11 is performed by surface termination of the first conductive films (2, 5) and the second conductive films (3, 5). Furthermore, here, the surfaces of the first conductive film (2, 5) and the second conductive film (3, 5) are chemically modified to terminate the surfaces of the first conductive film and the second conductive film with hydrogen. A method for performing the processing will be described. Furthermore, in the example demonstrated here, the example of the method performed by heat processing is demonstrated as said surface termination method. As a method of forming the dipole layer 11 by such a termination treatment with hydrogen, for example, the following step 6 can be used.

(Step 6)
The substrate 1 on which the first conductive film and the second conductive film are formed in the step 1 is placed in the heat treatment furnace 33. Then, the substrate 1 is heated while introducing the gas 34 into the heat treatment furnace 33 (FIG. 3F).

  As the heat treatment, various heat treatment furnaces can be used. For example, a lamp heating furnace or an electric furnace may be used. The heat treatment temperature is appropriately selected depending on the structure to be terminated, the material to be terminated, the time required for termination. Specifically, the heat treatment temperature is required to be 400 ° C. or higher and generally 500 ° C. or higher, and the upper limit is set to be equal to or lower than the softening point of the substrate 1. As the gas 34 in the heat treatment, hydrogen gas or a mixed gas of hydrogen gas and carbon is used. In particular, a mixed gas of hydrogen gas and hydrocarbon gas is suitable. Moreover, if it is hydrocarbon gas, it will not specifically limit, However, Chain hydrocarbon, such as acetylene gas, ethylene gas, methane gas, is preferable.

  The pressure in the heat treatment may be about atmospheric pressure or under reduced pressure. It is preferable to depressurize the inside of the heat treatment furnace 33 and exhaust the moisture and other gases in the furnace once, and then introduce the gas to a desired pressure.

  It is also preferable to clean the surfaces of the first conductive film and the second conductive film prior to the heat treatment. Alternatively, a heat treatment for a desired period from when the substrate 1 is put into the furnace 33 to when the heat treatment in the gas is started can be applied to the cleaning.

  When this heat treatment step is completed and the substrate 1 is taken out from the heat treatment furnace 33, the above-described dipole layer 11 is formed on the exposed portions of the surfaces of the first conductive film and the second conductive film (carbon film 5). (FIG. 2B).

[Step 3] Step of Removing Dipole Layer in Unnecessary Region Step 3 is a step of removing an unnecessary portion of the dipole layer from the dipole layer 11 formed in Step 2 (FIG. 2C). For example, the dipole layer in the unnecessary region can be removed by selectively applying energy to the dipole layer in the unnecessary region, more specifically, for example, by the following step 7.

(Step 7)
With respect to the structure formed in Step 2 (FIG. 2B), the mask 35 is aligned in the atmosphere, and the unnecessary dipole layer 11 is irradiated with ultraviolet light 36 through the opening of the mask 35 to generate hydrogen. Unnecessary dipole layer 11 is eliminated by altering the termination structure. (FIG. 3G).

  The mask 35 is made of, for example, a base material that transmits ultraviolet light, such as quartz glass, and an opening through which ultraviolet light can be transmitted is prepared by not providing a metal film only in a portion corresponding to a region where the dipole layer 11 is to be removed. It is possible to adopt one having a different structure. The mask 35 is not necessarily limited to the metal mask. What is necessary is that the energy for irradiating the unnecessary dipole layer 11 has a structure that can sufficiently block the portion (mask portion) corresponding to the region where the dipole layer 11 is to be left. The mask 35 preferably has an opening in a region corresponding to a region where the dipole layer 11 is desired to be removed. Further, as shown in FIG. 2C, a region corresponding to the surface of one conductive film (members denoted by reference numerals 3 and 5 in FIG. 2C), the first conductive film, and the second conductive film. Have openings in a region corresponding to the surface of the substrate 1 that is not covered with and a region corresponding to a part of the other conductive film (members denoted by reference numerals 2 and 5 in FIG. 2C). As a result, the electron emission region can be positioned with higher accuracy.

  The disappearance of the dipole layer 11 is considered to correspond to the fact that the hydrogen of the termination structure is removed from the surface of the conductive film that has been bonded to form a dangling bond. Moreover, this process 7 can also be performed in air | atmosphere. In this case, since the amount of oxygen can be effectively increased on the surface, this corresponds to oxygen termination of the surface of the conductive film in which an unnecessary dipole layer is formed among the surfaces of the conductive film. Can think.

  The atmosphere for performing step 7 is preferably an oxygen atmosphere (or air), and may be an oxidizing atmosphere (for example, an ozone atmosphere). In order to shorten the processing time, it is desirable to perform step 7 while heating the substrate 1.

  In step 7, not only the unnecessary dipole layer is eliminated, but also a part or all of the carbon layer located under the unnecessary dipole layer may be removed by etching.

  Therefore, the process 7 can be replaced with a normal etching process. That is, physical etching using electrons or ions may be used, or chemical etching may be used. However, the technique needs to be able to selectively remove unnecessary dipole layers.

  Further, in step 7, it is necessary not to deteriorate the electron emission capability in the necessary dipole layer. In step 7, as a result of selectively removing an unnecessary dipole layer, electrons are emitted from an unintended region (a region where electrons are not desired to be emitted) due to the formation of fine irregularities on the surface of the conductive film. It is necessary not to have a structure that is easily handled.

  Therefore, the method of removing only the unnecessary dipole layer (unnecessary termination structure) reduces the possibility of reducing the electron emission capability of the surrounding necessary dipole layer and newly forming an unnecessary electron emission portion. It is effective because it can. Ultraviolet rays can be said to be the optimum process in the present invention as the energy applied to remove and alter the unnecessary dipole layer 11.

  In step 3, the termination structure (dipole structure) formed in the unintended region on the substrate 1 in step 2 is removed. Therefore, since the structure capable of emitting electrons (termination structure) formed in the unintended region is removed, the accuracy required for the region (position) where the processing in step 2 is performed can be reduced.

  In the present invention, a mask is provided in a region where it is not desired to form a structure capable of emitting electrons, and then the above step 2 is performed, and then the above step 3 is performed after the mask is removed by a known technique such as lift-off. You can also. In this case, an electron-emitting structure (termination structure) that may be formed by a residue generated by patterning (steps such as the lift-off process) before performing step 3 or the like before step 3 is performed. The structure capable of emitting electrons (termination structure) that may be formed by various processes of (1) is surely removed in Step 3.

  The electron-emitting device of the present invention can be formed by the manufacturing method described in steps 1 to 3 above.

  In the above-described example, the first conductive film (2, 5) corresponding to the cathode electrode and the second conductive film (3, 5) corresponding to the gate electrode are arranged on the same substrate 1. Indicated. However, in addition to the first conductive film and the second conductive film, conductive members such as wirings connected to the respective conductive films may be disposed on the same substrate 1. The wiring can be formed before step 1 or 2 is performed, or can be formed after step 2 is performed. In the case where a conductive member such as a wiring is formed before performing Step 1 or 2, the process in Step 3 (step of removing a dipole layer in an unnecessary region) is also performed on the conductive member such as the wiring. preferable.

  In the example shown in FIG. 1A, an example in which the electron-emitting device is composed of a first conductive film, a second conductive film, and an anode electrode (ie, an example of a three-terminal structure) is shown. However, the present invention does not exclude the case of a so-called two-terminal structure composed of the first conductive film and the anode electrode as the electron emission device. Further, the present invention does not exclude electron emission devices having four or more terminals.

  In the case of a four-terminal structure, both the remaining two electrodes other than the anode electrode and the cathode electrode may be disposed on the substrate 1 together with the cathode electrode. In addition, one of the remaining two electrodes other than the anode electrode and the cathode electrode may be disposed on the substrate 1 together with the cathode electrode.

  In any case, the cathode electrode (corresponding to the first conductive film (2, 5)) is disposed on the substrate 1 together with the cathode electrode before the processing in step 2 (the step of forming a dipole layer) is performed. It is preferable to perform the process in the above step 3 (a step of removing a dipole layer in an unnecessary region) on the conductive member. Thereby, a dipole layer (or a dipole layer that may be formed) formed on the surface of the conductive member on the substrate 1 other than the cathode electrode can be removed.

  In the present invention, the gate electrode (corresponding to the second conductive film (3, 5)) is not only used as a so-called extraction electrode for extracting electrons from the cathode electrode side. For example, an electric field for extracting electrons from the cathode electrode side is formed by a potential applied to the cathode electrode and a potential applied to the anode electrode, and the gate electrode controls the amount of electrons emitted from the cathode electrode side. It may be used to stop the emission of electrons from the cathode electrode side. Alternatively, the electric field for extracting electrons from the cathode electrode side is formed by the potential applied to the cathode electrode, the potential applied to the anode electrode, and the potential applied to the gate electrode, and the gate electrode is further emitted from the cathode electrode side. It may be used to control the amount of emitted electrons or to stop the emission of electrons from the cathode electrode side. Therefore, the gate electrode in the present invention can be called a control electrode.

  Next, application examples of the electron-emitting device to which the manufacturing method of the present invention is applied will be described below. The manufacturing method of the present invention can be applied to an electron source in which a plurality of electron-emitting devices are arranged on a substrate, an image display device using an electron source and a light emitter.

  Various arrangements of the electron-emitting devices in the electron source can be adopted. As an example, a case will be described below in which each electron-emitting device includes a cathode electrode and a gate electrode. For example, in the arrangement form of the electron sources, a plurality of electron-emitting devices are arranged in a matrix in the X direction and the Y direction, and the cathode electrodes (the first conductive material described above) constituting a plurality of electron-emitting devices arranged in the same row. One of the film (2, 5)) or the gate electrode (the aforementioned second conductive film (3, 5)) is connected in common to the wiring in the X direction to form a plurality of electron-emitting devices arranged in the same column There is a so-called matrix arrangement in which the other of the cathode electrode or the gate electrode to be connected is commonly connected to the wiring in the Y direction.

  Hereinafter, an electron source in a matrix arrangement will be described with reference to FIG. In FIG. 6, 41 is a substrate, 42 is an X direction wiring, and 43 is a Y direction wiring. Reference numeral 44 denotes an electron-emitting device according to the present invention. 2 denotes the electrode of the first conductive film, and 3 denotes the electrode of the second conductive film.

The m X-directional wirings 42 are made of Dx ₁ , Dx ₂ ,... Dx _m , and can be made of a conductive metal or the like formed using a vacuum deposition method, a printing method, a sputtering method, or the like. The wiring material, film thickness, and width are appropriately designed. Y-direction wiring _{43, Dy 1,} Dy _2, ... made of n wirings of Dy _n, is formed in the same manner as the X-direction wiring 42. An interlayer insulating layer (not shown) is provided between the m X-direction wirings 42 and the n Y-direction wirings 43 to electrically isolate both (m and n are both Positive integer).

An interlayer insulating layer (not shown) is made of SiO ₂ or the like formed using a vacuum deposition method, a printing method, a sputtering method, or the like. For example, it is formed in a desired shape on the entire surface or a part of the substrate 41 on which the X direction wiring 42 is formed, and in particular, the film thickness and material so as to withstand the potential difference at the intersection of the X direction wiring 42 and the Y direction wiring 43. The manufacturing method is appropriately set. The X direction wiring 42 and the Y direction wiring 43 are drawn out as external terminals, respectively.

  The electrode 2 of the first conductive film constituting each electron-emitting device 44 is one of the m X-directional wirings 42 and the electrode 3 of the second conductive film constituting each electron-emitting device 44 is n Y It is electrically connected to one of the directional wirings 73.

  Next, an example of a method for driving an electron source having a plurality of electron-emitting devices arranged in a matrix will be described.

  A scanning signal is applied to the X direction wiring 42. Specifically, scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 44 arranged in the X direction is connected to the X direction wiring 42. On the other hand, a modulation signal synchronized with the scanning signal is applied to the Y-direction wiring 43. Specifically, a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 44 arranged in the Y direction according to an input signal is connected. A desired electron-emitting device (selected) is supplied by supplying a signal (voltage) to the X-direction wiring selected from the X-direction wiring 42 and the Y-direction wiring selected from the Y-direction wiring 43, respectively. The electron-emitting device) can be driven. The drive voltage applied to the selected electron-emitting device 44 is a difference voltage between the scanning signal and the modulation signal applied to the selected electron-emitting device. Although an example in which a scanning signal is applied to the gate electrode 3 and a modulation signal is applied to the cathode electrode 2 is shown here, the modulation signal is applied to the gate electrode 3 and the scanning signal is applied to the cathode electrode 2. May be.

  In the above configuration, individual elements can be selected and driven independently using a simple matrix wiring. An example of an image display device configured using such a simple matrix electron source will be described with reference to FIG. FIG. 7 is a schematic view in which a part of the face plate 56 and a part of the support frame 52 are removed so that the inside of the image display device can be seen.

In FIG. 7, reference numeral 41 denotes a substrate on which a plurality of electron-emitting devices are arranged as shown in FIG. Reference numeral 51 denotes a rear plate to which the substrate 41 is fixed. Reference numeral 56 denotes a face plate in which a light emitter film 54 made of a light emitter such as a phosphor, a metal back 55 and the like are formed on the inner surface of a transparent substrate 53 such as glass. Reference numeral 52 denotes a support frame, and a rear plate 51 and a face plate 56 are connected to the support frame 52 using an adhesive such as frit glass. Reference numeral 57 denotes an envelope. For example, an adhesive such as frit glass is applied to the connecting portion of the support frame 52, the rear plate 51, and the face plate 56 for 10 minutes or more in a temperature range of 400 to 500 ° C. in vacuum or nitrogen. It can obtain by sealing by baking in the arrange | positioned state. The terminal _Dx 1 _{~Dx m} and _Dy 1 _{~Dy n} can connect to _Dx 1 _{~Dx m} and _Dy 1 _{~Dy n} described in FIG. 6, are extended terminals to the outside of the envelope 57 .

  The envelope 57 includes the face plate 56, the support frame 52, and the rear plate 51 as described above. The rear plate 51 is provided mainly for the purpose of reinforcing the strength of the substrate 41. Therefore, when the substrate 41 itself has sufficient strength, the rear plate 51 can be omitted. That is, the support frame 52 may be sealed directly to the substrate 41, and the envelope 57 may be configured by the face plate 56, the support frame 52, and the substrate 41. On the other hand, by installing a support body (not shown) called a spacer between the face plate 46 and the rear plate 51, the envelope 57 having sufficient strength against atmospheric pressure can be configured.

  In addition, the envelope (panel) which performed the sealing process may perform a sealing process.

  The sealing step is performed by heating the envelope (panel) 57, exhausting it through the exhaust pipe 5 (not shown) by the exhaust device, exhausting the inside of the envelope, and then sealing the exhaust pipe. . In order to maintain the pressure after sealing the envelope 57, a getter process may be performed. As the getter, an evaporation type such as Ba or a non-evaporation type can be used. Further, if the sealing step is performed in a vacuum chamber, it is not necessary to separately provide the sealing step after the sealing step. That is, the envelope 57 in which the inside is maintained in a vacuum state can be formed by the sealing step without requiring a sealing step.

In the image display apparatus using the electron source of the matrix arrangement, in each electron-emitting device by applying a voltage through terminals Dx ₁ ~Dx _m and Dy ₁ ~Dy _n, from desired electron-emitting devices Electrons can be emitted. In addition, electrons are emitted by emitting electrons from a desired electron-emitting device by the above-described method in a state where a voltage Va of 10 kV or higher is applied to the metal back 55 or the transparent electrode (not shown) via the high-voltage terminal 58. The electrons collide with the light emitter 54, and light is emitted to form an image.

  In addition to the above-described configuration, the image display device according to the present invention further includes a receiver (tuner) that selects and receives a broadcast signal such as a television broadcast, thereby forming an image display device for television broadcast, for example. it can. The image display apparatus according to the present invention can be used as an image display apparatus as an optical printer configured using a photosensitive drum or the like, in addition to a display apparatus such as a video conference system or a computer.

  In the method for manufacturing an image display device according to the present invention, a plurality of electron-emitting devices are formed on a substrate by the above-described steps 1 to 3, and then a substrate on which the plurality of electron-emitting devices are formed, a support frame, a face plate, It can be formed by performing the assembly process of the envelope 57 described above using

  Hereinafter, embodiments of the present invention will be described in detail.

[Example 1]
In this example, an electron-emitting device having the carbon layer 5 having the dipole layer 11 shown in FIG. 6 was produced. Hereinafter, the manufacturing process of the electron-emitting device created in this example will be described in order.

(Process 1)
First, quartz glass was used for the substrate 1, and after sufficient cleaning, TiN having a thickness of 100 nm was formed as the cathode conductive film 31 by sputtering (FIG. 3A).

(Process 2)
A carbon layer 5 having a thickness of 4 nm was deposited on the conductive film 31 by sputtering. Film formation was performed in an argon atmosphere using graphite as a target. The carbon layer 5 had a resistivity of 1 × 10 ¹¹ Ω · cm. (FIG. 3B).

(Process 3)
A resist mask 33 was formed with a film thickness of 1 μm using a photolithography method. (FIG. 3C) w was 5 μm.

(Process 4)
Next, the carbon layer 5 and the TiN film 31 were continuously dry etched. In addition, in order to completely etch the TiN film 31, a condition for slightly etching the quartz glass substrate 1 was selected (FIG. 3D).

(Process 5)
Next, the resist mask 33 was removed using a stripping solution. (FIG. 3 (e)).

(Step 6)
Furthermore, the substrate 1 on which the first conductive film 2, the second conductive film 3, and the carbon film 5 produced in the steps 1 to 5 are placed in a heat treatment furnace 33 under a condition shown below, and methane and hydrogen are mixed. Heat treatment was performed in a gas atmosphere. FIG. 3 (f)
Heat treatment temperature: 630 ° C
Heating method: Lamp heat treatment time: 60 minutes Mixed gas ratio: Methane / hydrogen = 15/6
Pressure during heat treatment: 6KPa
By this step, the dipole layer 11 was formed on the surface of the carbon layer 5. The surface of the carbon layer 5 in this state was very flat. When the carbon layer 5 and the dipole layer 11 were formed on the Si substrate by the same method as described above, rms was 0.2 nm. Therefore, the rms of the laminate of the carbon film and the dipole layer 11 is 0.2 nm.

(Step 7)
The metal mask 35 was installed in an apparatus using a high-pressure mercury lamp as an ultraviolet light source, and irradiated with ultraviolet light 36 continuously for 10 minutes in a state where the metal mask 35 was opposed and positioned with some space. FIG. 3 (g)
As a result, the electron-emitting device of this example was completed. Further, an electron-emitting device not subjected to step 7 was similarly manufactured as Comparative Example 1.

  The electron-emitting device formed according to this example and the electron-emitting device of Comparative Example 1 were driven in an arrangement as shown in FIG. 1 in a vacuum chamber.

  An anode voltage (Va) of 5 kV was applied to the anode electrode. The distance (H) between the cathode electrode and the anode electrode is 2 mm, and the drive voltage (Vg) between the cathode electrode and the gate electrode is a pulse voltage (pulse width 1 msec, frequency 500 Hz, duty 20%, pulse peak value 40V. ) Was applied.

  When driven under the above conditions, both the electron-emitting device of this example and the electron-emitting device of Comparative Example 1 exhibited good electron emission characteristics.

  Next, a pulse voltage having a waveform similar to that of the pulse voltage and a pulse peak value of −40 V was applied so that the voltage on the cathode electrode side was higher than that on the gate electrode side. As a result, the electron-emitting device produced in this example did not emit electrons even when a voltage was applied in the reverse direction (voltage at which the cathode electrode side was higher in potential than the gate electrode side). The electron-emitting device was confirmed to emit electrons from the gate electrode side.

  As a result, in the electron-emitting device of this example, the carbon layer 5 has a dipole layer formed on both sides of the cathode electrode side and the gate electrode side in (Step 6). It was found that the dipole layer was removed.

  As shown in this example, an electron-emitting device capable of emitting electrons with a low electric field and capable of stable driving was able to be manufactured despite the simple configuration and manufacturing method.

[Example 2]
In this example, an electron-emitting device was produced in the same manner as in Example 1 except that Steps 2, 3, 6, and 7 of Example 1 were changed. Below, the manufacturing process of a present Example is demonstrated in order. Note that a description of the same steps as those in Example 1 is omitted.

  (Step 1) Same as Example 1.

(Process 2)
Next, a DLC film of about 3 nm was deposited by ECR plasma CVD. The growth conditions are shown below.
Gas: CH ₄
Microwave power: 400W
Substrate bias: -90V
Gas pressure: 25mmPa
Substrate temperature: The room temperature carbon layer 5 had a resistivity of 1 × 10 ⁹ Ω · cm.

(Process 3)
The resist mask 33 was formed with a film thickness of 0.6 μm by using a photolithography method. w was 3 μm.

  (Step 4) and (Step 5) are the same as in Example 1.

(Step 6)
In the heat treatment furnace 33, heat treatment was performed with hydrogen gas under the following conditions.
Heat treatment temperature: 630 ° C
Heating method: Lamp heat treatment time: 120 minutes Gas: Hydrogen heat treatment pressure: 200 Pa
By this step, the dipole layer 11 was formed on the surface of the carbon layer 5. The surface of the carbon layer 5 in this state was slightly different in flatness from that of Example 1. When the carbon layer 5 and the dipole layer 11 were formed on the Si substrate by the same method as described above, rms = 0.4 nm. Therefore, the rms of the laminate of the carbon film and the dipole layer 11 is 0.4 nm.

(Step 7)
The metal mask 35 was placed in a proximity semiconductor exposure apparatus using an ultrahigh pressure mercury lamp as a light source, and exposed to ultraviolet light 36 for 2 minutes in an aligned state.

  As a result, the electron-emitting device of this example was completed.

  The electron-emitting device manufactured in this example was arranged and driven in the vacuum chamber as shown in FIG.

  Va was 5 kV, H = 2 mm, and the pulse voltage applied between the cathode electrode and the gate electrode was a pulse width of 1 msec, a frequency of 500 Hz, and a duty of 20%. As a result, the electron-emitting device of this example could be driven with a pulse peak value of 30V.

  This is because the use of the semiconductor exposure apparatus in step 7 enables finer processing, and the distance W between the cathode electrode and the gate electrode of the electron-emitting device can be reduced as compared with the first embodiment.

[Example 3]
In this example, an electron-emitting device was produced in the same manner as in Example 1 except that Step 7 of Example 1 was performed using the apparatus shown in FIG. Below, the manufacturing process of a present Example is demonstrated in order. Note that a description of the same steps as those in Example 1 is omitted.

  (Steps 1 to 6) Same as Example 1.

(Step 7)
The substrate 1 on which the first conductive film 2, the second conductive film 3, the carbon film 5, and the dipole layer 11 formed in Steps 1 to 6 were disposed was disposed in the electron beam irradiation apparatus 91. Then, scanning was performed using the electromagnetic lens 93 so that only the surface on the gate electrode side was irradiated with the electron beam 92.

  Also in the electron-emitting device produced by the above steps, a good electron-emitting device was produced as in Example 1. Then, between the cathode electrode (first conductive film (2, 5)) and the gate electrode (second conductive film (3, 5)) so that the potential on the cathode electrode side becomes higher than the potential on the gate electrode side. When voltage was applied, electron emission from the gate electrode side was not confirmed. In addition, the flatness of the electron beam irradiation part (the surface of the second conductive film (3, 5)) hardly changed before and after the electron beam irradiation.

  In this embodiment, electrons are irradiated, but it can be also performed by a method of irradiating ions.

[Example 4]
In this embodiment, 1000 electron-emitting devices 44 created by the same production method as in the first embodiment are arranged in the row direction and 1000 in the column direction so that the electron sources arranged in a matrix are arranged. Formed (see FIG. 6). Then, using this electron source, an image display device shown in FIG. 7 was produced.

  On the substrate 41, wirings (42, 43) and an interlayer insulating layer (SiO2) were produced. The X direction wiring 42 was connected to the cathode electrode (electrode 2 in the first conductive film), and the Y direction wiring 43 was connected to the gate electrode (electrode 3 in the second conductive film).

  The manufacturing method of each electron-emitting device is basically the same as that in Example 1, but Step 7 in Example 1 is replaced with Step 7 in Example 2. In this embodiment, the surface of the gate electrode (the surface of the second conductive film) and the wiring were irradiated with ultraviolet rays. Each electron-emitting device 44 was arranged at a pitch of 300 μm in width and 300 μm in length.

  Further, as Comparative Example 2, an electron source prepared in the same manner as in this example except that ultraviolet rays were not irradiated was prepared.

  After fixing the substrate 41 (Example 4 and Comparative Example 2) including the electron source manufactured as described above to the rear plate 51, the face plate 56 having the metal back 55 as the anode electrode 4 and the phosphor film 54. 7 and sealed through an outer frame 52 to form the image display device shown in FIG. The distance H between the substrate 41 and the metal back 55 was set to be 2 mm.

  A drive circuit was connected to these image display devices, and an image was displayed by driving a desired electron-emitting device. In the image display device of this example, a display image with good uniformity and good contrast was obtained. On the other hand, the image display device using the electron source of Comparative Example 2 was not uniform compared to the image display device of Example 4. This was found to be due to unintended electron emission from the gate electrode or the end of the wiring. Therefore, as in this embodiment, it is possible to manufacture an image display device with good display characteristics by irradiating ultraviolet light to a region that does not require a dipole layer other than the electron emission portion to eliminate unnecessary dipole layers. it can.

It is a schematic diagram of an example of the electron emission apparatus by this invention. It is process drawing which shows typically an example of the manufacturing method of the electron emission element by this invention. It is process drawing which shows typically another example of the manufacturing method of the electron emission element by this invention. It is a figure which shows typically the structure of the carbon layer which has a dipole layer which can be used for this invention. It is a schematic diagram which shows the electron emission principle in the carbon layer of FIG. It is a plane schematic diagram which shows an example of the electron source using the electron-emitting element of this invention. It is a perspective view which shows an example of the image display apparatus using the electron-emitting element of this invention. It is a schematic diagram which shows the manufacturing process of the electron emission element in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Cathode electrode 3 Gate electrode 4 Anode electrode 5 Carbon layer 6 Drive power supply 7 Anode power supply 8 Conductive particle 9 Aggregate 10 Base material 11 Dipole layer 12 Carbon 13 Hydrogen 23 Lead electrode 24 Vacuum barrier 25 Electron 31 Conductive film 32 Mask 33 Heat treatment furnace 34 Gas 35 Mask 36 Ultraviolet ray 41 Electron source substrate 42 X direction wiring 43 Y direction wiring 44 Electron emission element 51 Rear plate 52 Support frame 53 Glass substrate 54 Fluorescent film 55 Metal back 56 Face plate 57 Envelope 58 High pressure Terminal 61 Insulation layer

Claims (12)

A method for manufacturing an electron-emitting device, comprising:
A first step of preparing a substrate in which a first conductive film and a second conductive film are spaced apart on the surface;
A second step of terminating the surface of the first conductive film and the second conductive film with hydrogen via carbon;
A third step of removing hydrogen that terminates the second conductive film after the second step;
A method for manufacturing an electron-emitting device, comprising:   The method of manufacturing an electron-emitting device according to claim 1, wherein the second step includes a step of heating the substrate in an atmosphere containing carbon and / or hydrogen.   The method of manufacturing an electron-emitting device according to claim 1, wherein the third step includes a step of selectively irradiating the second conductive film with energy.   The method of manufacturing an electron-emitting device according to claim 3, wherein the energy is ultraviolet light.   The method of manufacturing an electron-emitting device according to claim 4, wherein the third step is performed in an atmosphere containing oxygen.   4. The method of manufacturing an electron-emitting device according to claim 3, wherein the energy is an electron beam or an ion beam. A method for manufacturing an electron-emitting device, comprising:
A first step of preparing a substrate in which a first conductive film and a second conductive film are spaced apart on the surface;
A second step of heating the substrate on which the first conductive film and the second conductive film are disposed in an atmosphere containing carbon and / or hydrogen;
A third step of selectively applying energy to the second conductive film after the second step;
A method for manufacturing an electron-emitting device, comprising:   8. The electron-emitting device according to claim 7, wherein the third step is a step of removing hydrogen on the second conductive film by selectively applying energy to the second conductive film. Manufacturing method.   9. The method of manufacturing an electron-emitting device according to claim 7, wherein the energy is ultraviolet light, electron beam, or ion beam. A method for manufacturing an electron-emitting device, comprising:
A first step of preparing a substrate on which a conductive film is disposed;
A second step of heating the substrate on which the conductive film is disposed in an atmosphere containing carbon and / or hydrogen;
A third step of selectively applying energy to the substrate surface on which the conductive film is not disposed after the second step;
A method for manufacturing an electron-emitting device, comprising:   11. The method of manufacturing an electron-emitting device according to claim 10, wherein the third step is a step of removing hydrogen on a portion of the substrate surface where the conductive film is not disposed. A method of manufacturing an image display device comprising a plurality of electron-emitting devices and a light emitter that emits light by electrons emitted from the plurality of electron-emitting devices,
12. A method for manufacturing an image display device, wherein each of the plurality of electron-emitting devices is manufactured by the manufacturing method according to claim 1.

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