KR20050097579A - Method of phase transition of amorphous material - Google Patents

Abstract

The present invention relates to a phase change method of an amorphous material, comprising depositing an amorphous material on an insulating substrate, forming a cover layer using an oxynitride film on the amorphous material, and depositing a metal on the cover layer. It provides a phase change method of the amorphous material comprising the step of, and the phase change of the amorphous material.

According to the present invention, the metal is diffused through the cover layer between the amorphous material and the metal, thereby significantly reducing the metal contamination problem caused by the problem of the direct contact between the conventional metal and the amorphous material.

Description

Method of phase transition of amorphous material

The present invention relates to a method of phase change of an amorphous material, and more particularly, to a method capable of realizing a uniform thin film without directly contacting a metal with an amorphous material.

A thin film transistor (TFT) is a switching device that uses a polysilicon thin film as an active layer, and is generally used in active devices of active matrix liquid crystal displays, switching devices of electroluminescent devices, and peripheral circuits. .

Such thin film transistors are usually manufactured by direct deposition, high temperature heat treatment, or laser heat treatment. Among them, the laser heat treatment method is crystallized (or phase change, or below, phase change below) at a low temperature of 400 ° C or lower than the former two. It is possible to have high field effect mobility, but it is preferred to manufacture polycrystalline silicon on a large-area substrate due to uneven phase change, expensive equipment, and low productivity. There is also a problem that is not suitable for.

Another method of crystallizing amorphous materials, in particular amorphous silicon, is the solid phase crystallization method, which allows the use of low-cost equipment to obtain uniformly phase-changed crystals. This necessitates problems such as low productivity and the inability to use glass substrates.

On the other hand, the method of changing the phase of amorphous silicon using a metal has been studied a lot of advantages that can be changed in a short time at a lower temperature than the solid phase crystallization method, metal induced crystallization (metal induced crystallization) One.

Metal-induced crystallization is a technique of phase-changeing amorphous silicon from an implanted metal by directly contacting at least one portion of a specific kind of metal on the amorphous silicon thin film and lateral phase change from the contacted portion, or by doping the metal into the amorphous silicon thin film. .

However, in the case of changing the phase of amorphous silicon by using the conventional method of metal induction crystallization, device characteristics are degraded due to metal contamination in the region where amorphous silicon and metal are in direct contact, thereby adding a process of removing contaminated parts separately. Etc., productivity falls remarkably.

In addition, when the thin film transistor is patterned on the source and drain regions to form a thin film, or when the thin film transistor is patterned on one side of the source and drain regions, the amorphous silicon may not be completely phase-changed so that the amorphous portion and the crystallized portion may exist together. There was also a problem.

That is, the conventional method of inducing crystallization of amorphous silicon has the advantage of lowering the crystallization temperature, while the inherent characteristics of the thin film are degraded due to metal contamination penetrating into the phase-changed thin film. It is being proposed to do.

Therefore, if the conventional metal induction crystallization method is to be used, reducing the amount of metal used to minimize the contamination of the thin film from the metal is the most important problem, the ion concentration of the metal through the ion implanter for this purpose 10 High temperature treatment, rapid thermal treatment or laser irradiation by deposition at ¹² to 10 ¹⁴ cm ^-2 , and thin film by spin coating method by mixing viscous organic thin film and liquid metal in the conventional metal induction crystallization method A method of phase-changing amorphous silicon by depositing and then performing a heat treatment process has been proposed.

However, even in the case of the proposed method up to now, the contamination of the thin film by the metal used cannot be greatly improved, and the present reality is still problematic in terms of the size and uniformity of grain size.

The present invention has been made to overcome the above problems, and an object of the present invention is to provide a method capable of significantly improving the metal contamination problem of a thin film by allowing phase change without directly contacting a metal with an amorphous material.

Another object of the present invention is to realize a thin film having a uniform grain size even when a small amount of metal is used, and to improve productivity without the need for a metal etching process.

The present invention comprises the steps of depositing an amorphous material on an insulating substrate to achieve the above object; Forming a cover layer including a silicon oxynitride layer on the amorphous material; Depositing a metal thin film on the cover layer; It provides a phase change method of an amorphous material comprising the step of changing the amorphous material.

The method may further include depositing a buffer layer on an insulating substrate before depositing the amorphous material.

The present invention also comprises the steps of depositing a metal thin film on an insulating substrate; Depositing a buffer layer on the metal thin film; Depositing an amorphous material over the buffer layer; Forming a cover layer including a silicon oxynitride layer on the amorphous material; It provides a phase change method of an amorphous material comprising the step of changing the amorphous material.

The insulating substrate preferably includes an insulating film formed on a flexible metal substrate.

The insulating film is preferably formed by stacking one or more thin films of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicate film, and an organic film.

The buffer layer is preferably formed by stacking one or more thin films of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicate film, and an organic film.

The cover layer may be formed by stacking multiple layers of at least one of a silicon oxide film, a silicon nitride film, a silicate film, or an organic film and a silicon oxynitride film.

The cover layer is preferably formed through any one of chemical vapor deposition, deposition using pyrolysis, printer or spin coating.

The oxynitride film is deposited by chemical vapor deposition using any one selected from xylene (SiH ₄ ), ammonia or nitrogen, and any one selected from nitrogen oxide (N ₂ O) or oxygen, or an oxynitride film is deposited. It is preferable to deposit by the sputtering method used as a target.

The cover layer is preferably deposited to a thickness of less than 0.1nm 1000nm.

The metal is nickel (Ni), cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver (Ag), gold (Au), indium (In), tin ( Sn), arsenic (As) or antimony (Sb) or an alloy containing at least one of the above elements is preferable.

In addition, the present invention provides a method of manufacturing a semiconductor device, comprising: depositing an amorphous material on an insulating substrate; Forming a cover layer on which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the amorphous material; Depositing a metal thin film on the cover layer; In the phase change method of the amorphous material comprising the phase change of the amorphous material, the metal is cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver ( A method of phase change of an amorphous material, which is Ag, gold (Au), indium (In), tin (Sn), arsenic (As), or antimony (Sb) or an alloy containing one or more of the above elements, is provided.

The method may further include forming a buffer layer on which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the insulating substrate before depositing the amorphous material.

The present invention also comprises the steps of depositing a metal thin film on an insulating substrate; Forming a buffer layer in which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the metal thin film; Depositing an amorphous material over the buffer layer; Forming a cover layer on which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the amorphous material; In the phase change method of the amorphous material comprising the phase change of the amorphous material, the metal is cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver ( A method of phase change of an amorphous material, which is Ag, gold (Au), indium (In), tin (Sn), arsenic (As), or antimony (Sb) or an alloy containing one or more of the above elements, is provided.

The insulating substrate preferably includes an insulating film formed on a flexible metal substrate.

The metal thin film is preferably deposited to a thickness of 0.001nm or more and 1000nm or less.

The depositing of the metal thin film may include forming a metal thin film having a thickness of 0.2 nm to 1000 nm on the cover layer; It is preferred to include etching to a thickness of less than 0.2 nm.

It is preferable to pretreat the buffer layer, the amorphous material or the cover layer in order to improve the coupling property of the interface between the buffer layer and the amorphous material, the interface between the amorphous material and the cover layer, or the interface between the cover layer and the metal.

The pretreatment includes a solution treatment method containing hydrofluoric acid (HF), a chemical vapor deposition method using plasma (PECVD), a surface treatment method using ions, an ozone treatment method, a surfactant, an acid solution, a base, a salt or an alkaline solution. It is preferable to use any one method selected from among the chemical treatment methods used.

The depositing of the amorphous material may be performed by stacking two or more deposition films formed by any one of sputtering, chemical vapor deposition, and thermal decomposition.

In the case of depositing the amorphous material by pyrolysis, it is preferable to further include removing the amorphous material deposited on the back surface of the insulating substrate through a selective etching process after the crystallization of the amorphous material.

The phase change step of the amorphous material is preferably performed in a temperature range of 400 degrees to 1400 degrees using an energy source of radiant heat, visible light or ultraviolet light.

The phase change of the amorphous material is preferably achieved by growing grains laterally around the nucleus generated by the metal diffused from the metal thin film.

After the phase change step of the amorphous material further comprises the step of re-changing the phase-changed material, the phase change step is a temperature range of 400 degrees to 1400 degrees using an energy source in the radiant heat, visible or ultraviolet region It is preferred to be made from.

The phase change step may be performed after removing the cover layer, or after laminating at least one new cover layer.

The method of using radiant heat for the phase change or re-phase change comprises the steps of raising the temperature; Maintaining a temperature at which a phase change occurs; It is preferable that the step is made to lower the temperature.

The step of raising the temperature preferably includes a pre-heat treatment step.

In the phase change material, the surface density of the metal is preferably 10 ¹¹ to 10 ¹⁵ atoms / cm 2.

The crystal structure of the phase-change silicon thin film preferably has a circular or disc shape and is made of grain having a size of 3 to 200 μm.

The crystal structure of the phase change silicon thin film is preferably the same crystal direction of each grain.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

1A to 1D are process flow charts illustrating preferred embodiments of the present invention in the order of process. First, an insulating substrate 100, a buffer layer 200, an amorphous material 300, a cover layer 400, and a metal 500 are described. Are deposited sequentially. (FIG. 1A)

Although the insulating substrate 100 is not particularly limited, it is preferable to use one of a single crystal wafer covered with glass, quartz, and an oxide film in consideration of temperature and thin film uniformity applied for phase change of an amorphous material. An insulating film formed on a metal substrate may be used.

The buffer layer 200 is not essential in the process and may be omitted.

The cover layer 400 serves to uniformly diffuse the metal into the amorphous material layer and protect the thin film from unnecessary metal contamination.

The insulating layer on the buffer layer 200, the cover layer 400, and the metal substrate may be formed of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicate film, an organic film, or the like. Alternatively, two or more films of the same kind or different types may be stacked to form a multilayer film.

The silicon nitride film is generally formed by chemical vapor deposition using xylene (SiH ₄ ), ammonia and nitrogen gas, or by sputtering using a nitride film target.

When the nitride film is used as the cover layer, the metal can be diffused even at a thickness of 350 nm. However, since the heat resistance is weak, the cover layer is often broken when heat treatment or laser irradiation is performed at 600 degrees or more.

The silicon oxide film is generally formed by blowing oxygen at a high temperature, by a chemical vapor deposition method using a gas of xylene (SiH ₄ ) and oxygen, or by a sputtering method using an oxide film target. When used as a cover layer, since the metal is difficult to diffuse at a thickness of 10 nm or more, there is a limit to be formed to a thickness of several nm.

The silicon oxynitride film is formed by chemical vapor deposition using a gas of xylene (SiH ₄ ), ammonia or nitrogen as a nitrogen source, and nitrogen oxide or oxygen as an oxygen source. Or the sputtering method using the target of an oxynitride film is also possible.

When the oxynitride film is used for the cover layer or the like, the metal can be diffused even at a thickness of 350 nm like the nitride film, and there is an advantage that the problem of the nitride film in which the thin film is broken at a high temperature can be solved. This is because the thin film is strengthened by the bonding of oxygen in the general nitride film, thereby preventing the cover layer from being broken even during heat treatment or laser irradiation of 600 degrees or more.

The cover layer 400 is preferably formed to a thickness within the range of 0.1 to 1000nm at a temperature of 650 ℃ or less, the deposition method is most preferably by the plasma enhanced chemical vapor deposition (PECVD) method, but is not limited thereto. It may be deposited by a general chemical vapor deposition method, a deposition method using pyrolysis, a printer or a spin coating method.

Meanwhile, the metal 500 deposited on the cover layer 400 serves as a crystallization medium or an inducer of an amorphous material. The metal 500 is preferably deposited to a thickness of 0.001 nm or more and 1000 nm or less.

As a deposition method, a method using an ion implanter, a PECVD method, a sputtering method, a method using a shadow mask, or the like, a coating method using a liquid metal dissolved in an acid solution, an organic film and a liquid metal Any one selected from a mixed spin coating method and a method using a gaseous gas containing a metal may be used, and the present invention is not particularly limited thereto, and may be deposited by another method.

In addition, the metal 500 deposited on the top of the cover layer is preferably deposited as a thin film within a surface density of 10 ¹² to 10 ¹⁸ cm ^-2 , nickel (Ni), cobalt (Co), palladium (Pd), Monometals such as platinum (Pt), iron (Fe), copper (Cu), silver (Ag), gold (Au), indium (In), tin (Sn), arsenic (As), and antimony (Sb) Alternatively, the deposition may be performed using an alloy containing one or more of the above elements.

And since it is not easy to deposit the metal into a uniform thin film of 0.2 nm or less, first, a thickness of 0.2 nm or more and 1000 nm or less is deposited to a desired thickness, and then etching to a desired thickness of 0.2 nm or less through a separate etching process. Can also be used.

As described above, after the amorphous material 300, the cover layer 400, and the metal 500 are sequentially deposited, the phase change of the amorphous material 300 is performed, and the phase change of the amorphous material 300 is external. In this case, the metal is diffused into the amorphous material by applying thermal energy, and grains are grown in the amorphous material through the diffused metal.

The heat energy source used at this time is not particularly limited, but it is preferable to use radiant heat, visible light, ultraviolet rays, lasers, and the like.

In addition, the phase change of the amorphous material 300 may be made in a state where an electric field, a magnetic field, or an electromagnetic field is applied.

As a method of applying heat energy, a method such as heat treatment, rapid heat treatment, laser or ultraviolet irradiation is widely used, and the heat treatment method may be a halogen lamp, an ultraviolet lamp, a furnace, etc., but is not limited thereto.

When the heat treatment method is selected, it is preferable to change the phase in a temperature range of 400 to 1400 ° C., and either one of the methods of rapid heat treatment or long time heat treatment within the temperature range may be used, or both may be used. Do.

The rapid heat treatment method is preferably a method of heat treatment several times or more within a time of several tens of seconds within the temperature range of 500 to 900 ℃, the long-term heat treatment method is a method of heat treatment for more than 1 hour in the 400 to 500 ℃ temperature range, such a Since the temperature range is not absolute, rapid or long-term heat treatment may be performed at other temperature ranges as necessary.

When the amorphous material 300 is phase-changed as described above, the metal 500 diffuses into the cover layer 400 to form a precipitate in the amorphous material 300. In the case of amorphous silicon, the metal dissilicide nucleus is formed. (MSi ₂ , precipitation) is formed. Grain grows laterally around the formed nucleus and a grain boundary 340 is created between adjacent grains 320 (FIG. 1B).

When the grains 320 continue to grow until they are in contact with adjacent grains and are no longer able to grow, the phase change of the amorphous material is completed (FIG. 1C).

After the amorphous material is completely phase-changed, the metal 500 and the cover layer 400 are removed by etching to obtain a polycrystalline thin film according to the present invention (FIG. 1D).

On the other hand, the amorphous material 300 is generally used a lot of amorphous silicon, but is not limited to this embodiment may be applied to other materials of the present invention.

In general, amorphous silicon thin films are formed by chemical vapor deposition, sputtering, or pyrolysis. In the case of deposition using pyrolysis, most of the glass substrates are erected and deposited, so that an amorphous silicon film is deposited on the back of the substrate. have.

Therefore, in the case of using the pyrolysis method, an additional step of selectively etching the back side of the amorphous silicon film is required. If there is no cover layer as in the prior art, contamination or damage of the surface used as an element is inevitable due to the etching process, thereby preventing this. There is a problem that the process for further preceded.

However, as in the embodiment of the present invention, the metal-induced crystallization method of first forming a cover layer and a small amount of metal thin film on the surface used as an element, and then crystallizing by using radiant heat, energy source in the ultraviolet region or energy in the visible region. When using, since the top layer is protected even after the crystallization process, there is an advantage that the amorphous silicon film on the back can be removed through the selective etching process without additional protection process,

As a result, after etching the silicon using chemical or plasma, since the upper cover layer can be removed and the device can be manufactured, the surface of the phase-change polycrystalline silicon thin film can be protected before the device fabrication.

FIG. 2 illustrates a method of changing the amorphous material by forming the cover layer 400 in two parts as another embodiment of the present invention. In this embodiment, each cover layer 400 has a different thickness. The first part and the second part may be sufficient, and the first part or the second part may be either a single layer or a double layer, respectively.

In particular, in the above embodiment, the lower layer of the first portion and the second portion is preferably formed of a film made of the same material, and the upper layer of the second portion may be made of a different material from the lower layer.

On the other hand, prior to the phase change step of the amorphous material it is preferable to pre-heat treatment at a temperature range of 200 to 800 ℃, if the pre-heat treatment can not only obtain the dehydrogenation effect in the thin film, the upper portion of the metal 500 Since the oxide film is formed to reduce the diffusion amount of the metal, there is an advantage that the grain can be large. In addition, since the metal 500 is diffused through the cover layer 400 through preheating, there is an effect of pre-forming a metal precipitate or a nucleus in the amorphous material 300. Pre-heat treatment may be achieved by any one of the above-described heat treatment method.

In addition, after the phase change step of the amorphous material, the amorphous material may be re-changed in the same manner as the phase change to more completely crystallize the amorphous material.

The phase change phase is a process to remove structural defects remaining in the crystallized material even after the phase change, thereby making the crystallization of the amorphous material more complete and improving the field effect mobility. have. Since the phase change step uses a method of applying thermal energy similarly to the phase change step, a method such as heat treatment, rapid heat treatment, laser irradiation, ultraviolet ray, or visible light irradiation is used.

When the phase change of the amorphous material is completed through the above process, it is preferable that the crystal structure in the crystallized thin film is composed of circular or disc-shaped grains, and the size of each grain is also preferably about 3 to 200 μm. Since the grain size is changed by the density of the metal 500 as can be seen in FIG. 8 to be described later, it is possible to form grain of a desired size by adjusting the density of the metal.

As such, there is a method of controlling the grain size to form a small grain size by treating the surface of the amorphous material with hydrofluoric acid (HF) or the like, which will be described later.

In addition, when the metal density contained in the phase change material becomes excessive, it acts as a contaminant to reduce device characteristics. Therefore, limiting the plane density of the metal in the crystallized material within the range of about 10 ¹¹ to 10 ¹⁵ atoms / cm 2. desirable.

3 illustrates a method of phase change of an amorphous material by partially patterning a metal 500 on a cover layer 400 according to another embodiment of the present invention. In this embodiment, a portion of the metal 500 is partially changed. Patterning may be performed using any one of photolithography, photoresist, and shadow mask.

4A to 4C illustrate another embodiment of the present invention, in which a metal 500, a buffer layer 200, and an amorphous material 300 are sequentially deposited on an insulating substrate 100, and then the phase change of the amorphous material 300 is performed. In this embodiment, unlike the other embodiments, the metal 500 is diffused upward through the buffer layer 200, and each grain in the amorphous material 300 deposited on the buffer layer 200. The 320 are grown toward the grain boundary 340 to show that the amorphous material is changed to polycrystalline.

5A to 5D illustrate a buffer layer 200, an amorphous material 300, a cover layer 400, and a metal 500, respectively, on an insulating substrate 100 according to another embodiment of the present invention (FIG. 5A). Pre-heating the amorphous material 300 (FIG. 5B), patterning the heat-treated metal 500, the cover layer 400, and the amorphous material 300 (FIG. 5C), and the amorphous material ( Phase change 300 and the phase change of the amorphous material, including the step of removing the metal 500 and the cover layer 400 (Fig. 5d).

6a to 6c is another embodiment of the present invention, unlike the embodiment disclosed in FIGS. 5a to 5d includes the step of depositing the cover layer 400 'on the deposited metal layer 500 once more, so that the cover layer is The metal layer 500 is formed on and under the structure (FIG. 6A).

Patterning the amorphous material 300, the first cover layer 400, the metal layer 500, and the second cover layer 400 ′ by an etching technique using a photoresist before the phase change of the amorphous material. (B) (b) crystallizing the amorphous material 300 and removing the first cover layer 400, the metal 500 and the second cover layer 400 ′ (FIG. 6c). Phase change.

In the various embodiments of the present invention disclosed in FIGS. 1 to 6, each component, a deposition method of each of the components, and a phase change method of an amorphous material are applied to the corresponding contents described above with reference to FIG. 1. It is of course included to relate the phase change of amorphous material.

7 to 9 show pictures of polycrystalline silicon phase-changed in a preferred embodiment according to the present invention using silicon as an amorphous material.

7A or 7B show that 50 nm of amorphous silicon is deposited on the buffer layer, 150 nm of silicon nitride is deposited on the buffer layer, and 10 ¹³ cm ^-2 of nickel is deposited on the metal using glass as an insulating substrate, and then heat treated at 430 ° C. for 1 hour. It shows the case where the phase change by heat treatment several times at 20 seconds at 750 ℃.

Figure 7a is a result of repeating 5 times for 20 seconds at 750 ℃, Figure 7b 20 times, it can be seen that the grains are growing laterally, and the higher the number of repetitions it can be seen that a good quality of polycrystalline.

8A to 8C show that the grain size varies according to the amount of metal, using glass as an insulating substrate, silicon oxide film as 100 nm, buffer layer as 50 nm, silicon silicon film as 50 nm, cover layer 60 nm, and nickel as metal, respectively. In the deposition, the amount of the metal was changed to a pre-heat treatment at 500 ° C. for 5 minutes, followed by 20 times at 20 ° C. for 20 seconds to show phase change.

8A shows nickel 5 × 10 ¹² cm ⁻² , FIG. 8B shows nickel 8 × 10 ¹² cm ⁻² , and FIG. 8C shows nickel 10 ¹³ cm ⁻² . As the amount of metal deposited increases, It can be seen that the size is reduced.

Figure 9a or 9b shows the surface of the polysilicon thin film phase-induced by the metal induced by the prior art (Fig. 9a) and the present invention (Fig. 9b), the polycrystalline silicon thin film crystallized by forming a 60nm cover layer of the present invention The root mean square (RMS) roughness value of 0.92 nm is 1.33 nm compared to the conventional technique, and thus it can be seen that the surface roughness of the thin film is excellent when the cover layer is used according to the present invention.

10 is an electron micrograph of polycrystalline silicon crystallized using an oxynitride film as the cover layer 400.

Looking at the specific process, after depositing the 100 nm buffer layer 200 and the 50 nm amorphous silicon thin film 300 using the oxide film on the substrate 100 in sequence and the cleaning process, the silicon oxynitride film is deposited on the cover layer 400 It was.

At this time, the silicon oxynitride film is a radio frequency (RF power) of 0.5 W / ㎠, deposition pressure and a gas ratio of xylene (SiH ₄ ): ammonia (NH ₃ ): nitrogen oxide (N ₂ O) = 1: 64: 40 The deposition temperature was deposited under the conditions of 1 Torr and 350 degrees, respectively.

After forming 50 nm of an oxynitride film, 10 ¹⁴ atoms / cm <2> of nickel metals were vapor-deposited, forming a laminated structure, and heat-processing at 560 degreeC for 30 hours using the furnace. Figure 10 shows the grains of polysilicon after crystallization by electron micrograph, it can be seen that the average grain size is 7㎛.

It is interpreted that trace metal diffuses through amorphous oxynitride into amorphous silicon to form a NiSi ₂ form of precipitate, which forms a nucleus, and crystals grow laterally from the nucleus to form disc-shaped grains. Through this, it can be seen that the oxynitride film can be used as a cover layer 400 capable of diffusing a small amount of metal.

11A and 11B illustrate grain orientations and grains 320 of phase-change thin films, respectively, by a metal-mediated method using a metal back scattered diffraction (EBSD) device and a metal-induced crystallization method using a cover layer 400. ) Shows the size.

In the case of the metal-mediated crystallization without the cover layer 400, the grain structure after the phase change has a needle-like structure. 11A shows that the crystal grains of 2 μm or less are formed in an disordered form.

In contrast, in the case of metal-induced crystallization using the cover layer 400, the crystal grains are formed in a circular shape or a disc shape after phase change. This is because grain grows laterally around the nucleus. In FIG. 11B, the average grain size is 17 μm.

Also, by mapping the electron scattering diffraction pattern, the orientation of the crystal grains can be analyzed. In the crystal directions of FIGS. 11A and 11B, in the case of the conventional metal-induced crystallization without the cover layer in the region of 10 μm, the disordered orientation is obtained. Have

On the other hand, in the case of the metal-mediated crystallization method using the cover layer 400, since the grain size is 17 μm, it can be seen that the orientation in one grain is the same. As a result, it can be seen that there is a difference in the crystal structure from the conventional method.

FIG. 12 shows the cover layer 400 while varying the gas ratio of [ammonia] / [silylene] to determine how the metal diffuses into the amorphous silicon 300 region according to the condition of depositing the cover layer. Metal induced crystallization was carried out by rapid heat treatment at 650 degrees.

At this time, it was confirmed by using the ultraviolet wavelength to check the crystallinity. When the crystallization is completed after the phase change, a peak of reflectivity generally appears in a wavelength of 275 nm, and the degree of crystallization is compared with the crystallinity of the phase-changed silicon based on 100% of the single crystal silicon.

As shown in FIG. 12, an oxynitride film, which is a cover layer, was formed on the amorphous silicon while varying the ratio of [ammonia] / [silene] to 35, 64, and 100. At this time, according to the degree of crystallization confirmed using ultraviolet rays, when the ratio of [ammonia] / [silylene] is 35, no crystallization appears at all, which can be confirmed through the appearance of a pattern similar to amorphous silicon.

On the other hand, when the ratio of [ammonia] / [sylene] is 64 and 100, it can be seen that the crystallinity is almost the same as that of single crystal silicon, and both cases show crystallinity of 90% or more.

13A or 13B are optical micrographs showing the difference in grain shape depending on the presence or absence of hydrofluoric acid (HF) treatment on the amorphous silicon thin film 300 as a pretreatment before forming the cover layer 400.

In order to confirm the dependence of crystallization on the surface treatment of the amorphous silicon thin film, a 50 nm amorphous silicon thin film is formed on the glass substrate 100 on which the 100 nm oxide film is deposited by chemical vapor deposition. FIG. 13A illustrates a case in which a hydrofluoric acid (1%) treatment is performed on the surface of amorphous silicon for 20 seconds, followed by deposition of 50 nm of an oxynitride film as a cover layer. FIG. 13B illustrates the surface of amorphous silicon in acetone and methanol for 5 min each. After cleaning using a pure water and washed with oxidized nitride film as a cover layer is formed by 50nm each.

In both cases, nickel metal was deposited on the top of the cover layer at a surface density of 7 × 10 ¹³ atoms / cm ² , and heat-treated at 630 degrees using a rapid heat treatment apparatus equipped with a halogen lamp for crystallization.

13A and 13B are optical micrographs confirming crystallized silicon after etching the cover layer, respectively, and it can be seen that the average grain sizes are 22 μm and 5 μm, respectively. As a result, it can be seen that the grain size is formed to be four times smaller through the surface treatment of the amorphous silicon thin film.

This is because when hydrofluoric acid treatment is performed on an amorphous silicon thin film, defects are formed on the surface while removing about 1 nm of native oxide on the surface, so that the metal diffused through the cover layer is generated as a nucleus in the defect. It seems to be different from unprocessed.

Such surface treatment is not limited to only the surface of the amorphous silicon, but is also required to improve the bonding property of the interface between each layer to be stacked. For example, the interface or cover layer of the buffer layer 200 and the amorphous material 300 ( It may also be applied to the interface between the 400 and the metal 500.

As the surface treatment method, in addition to the method of surface treatment using hydrofluoric acid (HF) for the underlying layer film at the interface, chemical vapor deposition (PECVD) using plasma, surface treatment method using ions, method using ozone, interface The method using an active agent, the method using an acid solution, the method of chemically processing using a base, a salt, or an alkali solution, etc. are mentioned.

The present invention has been described above with reference to the preferred embodiments of the present invention, but the present invention is not limited thereto and may be variously modified and modified. Such changes or modifications are also based on the technical spirit described in the claims of the present invention described below. As long as it belongs to the scope of the present invention will be natural.

According to the present invention, the metal is diffused through the cover layer between the amorphous material and the metal, thereby preventing the metal contamination problem caused by the direct contact between the conventional metal and the amorphous material.

In addition, by forming the cover layer on the amorphous material has an advantage that can prevent the contamination or oxidation of the surface of the amorphous material thin film.

Furthermore, according to the present invention, it is possible to control the amount of metal disilide precipitate formed in the amorphous material thin film by adjusting the nitrogen concentration of the nitride film formed as the cover layer, and by adjusting the density of the metal or pre-treatment on the amorphous material. There is an advantage to control the size of the.

1A to 1D are cross-sectional views showing one embodiment of a phase change method of an amorphous material according to the present invention.

2 is a cross-sectional view showing another embodiment of the method of phase change of an amorphous material according to the present invention.

Figure 3 is a cross-sectional view showing another embodiment of the method of phase change of an amorphous material according to the present invention.

4A to 4C are cross-sectional views showing yet another embodiment of the method of phase change of an amorphous material according to the present invention.

5a to 5d are cross-sectional views showing yet another embodiment of the phase change method of the amorphous material according to the present invention.

6A to 6C are cross-sectional views showing yet another embodiment of the method of phase change of an amorphous material according to the present invention.

7A or 7B are optical micrographs of polysilicon crystallized by a phase change method of an amorphous material according to the present invention.

8a to 8c are optical micrographs of polycrystalline silicon crystallized by varying the amount of metal in the phase change method of the amorphous material according to the present invention.

9A or 9B are atomic force microscope surface photographs of polycrystalline silicon films crystallized according to the prior art and the present invention, respectively.

10 is an electron micrograph of a polysilicon phase changed by using an oxynitride film as a cover layer

11A or 11B are photographs obtained by using an electron back-scattered diffraction apparatus for a polysilicon thin film which has been phase-changed through a metal induction crystallization method using a conventional metal induction crystallization method and a cover layer, respectively.

12 is a view showing the difference in crystallinity according to the deposition conditions of the cover layer in the phase change method using the oxynitride film as the cover layer

13a or 13b is an optical micrograph showing the difference in grain size with or without hydrofluoric acid (HF) treatment on the surface of the amorphous silicon thin film

* Description of the symbols for the main parts of the drawings *

100: insulating substrate 200: buffer layer

300: amorphous material 320: grain

340: grain boundary 400: cover layer

500: metal

Claims (30)

Depositing an amorphous material on the insulating substrate; Forming a cover layer including a silicon oxynitride layer on the amorphous material; Depositing a metal thin film on the cover layer; Phase change of the amorphous material Phase change method of amorphous material containing The method of claim 1, And depositing a buffer layer on an insulating substrate before depositing the amorphous material. Depositing a metal thin film on an insulating substrate; Depositing a buffer layer on the metal thin film; Depositing an amorphous material over the buffer layer; Forming a cover layer including a silicon oxynitride layer on the amorphous material; Phase change of the amorphous material Phase change method of amorphous material containing The method according to claim 1 or 3, The insulating substrate is a phase change method of an amorphous material comprising an insulating film formed on a flexible metal substrate The method of claim 4, wherein The insulating film is a phase change method of an amorphous material formed by stacking one or more thin films of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicate film, and an organic film. The method according to claim 2 or 3, The buffer layer is a phase change method of an amorphous material formed by stacking at least one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicate film, and an organic film The method according to claim 1 or 3, The cover layer is a phase change method of an amorphous material in which at least one thin film of a silicon oxide film, a silicon nitride film, a silicate film, or an organic film and a silicon oxynitride film are stacked in multiple layers. The method according to claim 1 or 3, The cover layer is a phase change method of an amorphous material formed through any one of chemical vapor deposition, thermal decomposition deposition, printer or spin coating method The method according to claim 1 or 3, The oxynitride film is deposited by chemical vapor deposition using any one selected from xylene (SiH ₄ ), ammonia or nitrogen, and any one selected from nitrogen oxide (N ₂ O) or oxygen, or an oxynitride film is deposited. Phase change method of amorphous material deposited by sputtering method used as target. The method according to claim 1 or 3, The cover layer is a phase change method of the amorphous material is deposited to a thickness of less than 0.1nm 1000nm. The method according to claim 1 or 3, The metal is nickel (Ni), cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver (Ag), gold (Au), indium (In), tin ( Sn), arsenic (As) or antimony (Sb) or phase change method of amorphous material which is an alloy containing one or more of the above elements Depositing an amorphous material on the insulating substrate; Forming a cover layer on which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the amorphous material; Depositing a metal thin film on the cover layer; In the phase change method of the amorphous material comprising the step of changing the amorphous material, The metal is cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver (Ag), gold (Au), indium (In), tin (Sn), arsenic ( As) or antimony (Sb) or phase change method of amorphous material which is an alloy containing at least one of the above elements The method of claim 12, And forming a buffer layer in which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on an insulating substrate before the depositing of the amorphous material. Depositing a metal thin film on an insulating substrate; Forming a buffer layer in which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the metal thin film; Depositing an amorphous material over the buffer layer; Forming a cover layer on which at least one of a silicon oxide film, a silicon nitride film, and an organic film is stacked on the amorphous material; In the phase change method of the amorphous material comprising the step of changing the amorphous material, The metal is cobalt (Co), palladium (Pd), platinum (Pt), iron (Fe), copper (Cu), silver (Ag), gold (Au), indium (In), tin (Sn), arsenic ( As) or antimony (Sb) or phase change method of amorphous material which is an alloy containing at least one of the above elements The method according to any one of claims 1, 3, 12, 14, The insulating substrate is a phase change method of an amorphous material comprising an insulating film formed on a flexible metal substrate The method according to any one of claims 1, 3, 12, 14, The metal thin film is a phase change method of an amorphous material deposited to a thickness of 0.001nm or more and 1000nm or less The method according to any one of claims 1, 3, 12, 14, Depositing the metal thin film, Forming a metal thin film having a thickness of 0.2 nm to 1000 nm on the cover layer; Etching to a thickness of less than 0.2 nm Phase change method of amorphous material including The method according to any one of claims 1, 3, 13, 14, A phase change method of an amorphous material which is pretreated with the buffer layer, the amorphous material or the cover layer in order to improve the coupling property of the interface between the buffer layer and the amorphous material, the interface between the amorphous material and the cover layer, or the interface between the cover layer and the metal. The method of claim 18, The pretreatment includes a solution treatment method containing hydrofluoric acid (HF), a chemical vapor deposition method using plasma (PECVD), a surface treatment method using ions, an ozone treatment method, a surfactant, an acid solution, a base, a salt or an alkaline solution. Phase change method of amorphous material using any one of chemical treatment methods used The method according to any one of claims 1, 3, 12, 14, The depositing of the amorphous material may include a phase change method of an amorphous material formed by stacking two or more deposition films formed by any one of sputtering, chemical vapor deposition, and thermal decomposition. The method of claim 20, In the case of depositing the amorphous material by the pyrolysis method, after the crystallization step of the amorphous material, further comprising the step of removing the amorphous material deposited on the back of the insulating substrate through a selective etching process, the phase change method of the amorphous material The method according to any one of claims 1, 3, 12, 14, The phase change step of the amorphous material is a phase change method of the amorphous material made in the temperature range of 400 to 1400 degrees using an energy source in the radiant heat, visible or ultraviolet region The method according to any one of claims 1, 3, 12, 14, Phase change of the amorphous material is a phase change method of the amorphous material formed by grain growth laterally around the nucleus generated by the metal diffused from the metal thin film The method according to any one of claims 1, 3, 12, 14, After the phase change step of the amorphous material further comprises the step of re-changing the phase-changed material, the phase change step is a temperature range of 400 degrees to 1400 degrees using an energy source in the radiant heat, visible or ultraviolet region Phase change method of amorphous material in The method of claim 24, The re-phase change step is performed after removing the cover layer, or the phase change method of the amorphous material made after laminating one or more new cover layer The method of claim 24, Method of using radiant heat for the phase change or re-phase change, Raising the temperature; Maintaining a temperature at which a phase change occurs; Lowering the temperature Phase change method of amorphous material In claim 26 The step of raising the temperature is a phase change method of amorphous material comprising a pre-heat treatment step The method according to any one of claims 1, 3, 12, 14, In the phase change material, the surface density of the metal is 10 ¹¹ ~ 10 ¹⁵ atoms / ㎠ phase change method of the amorphous material The method according to any one of claims 1, 3, 12, 14, The crystal structure of the phase-change silicon thin film has a circular or disk shape, the phase change method of the amorphous material consisting of grains having a size of 3 ~ 200㎛ The method according to any one of claims 1, 3, 12, 14, The crystal structure of the phase change silicon thin film is a phase change method of an amorphous material having the same crystal direction of each grain