JP3190512B2 - Semiconductor fabrication method - Google Patents

Semiconductor fabrication method

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Publication number
JP3190512B2
JP3190512B2 JP03796994A JP3796994A JP3190512B2 JP 3190512 B2 JP3190512 B2 JP 3190512B2 JP 03796994 A JP03796994 A JP 03796994A JP 3796994 A JP3796994 A JP 3796994A JP 3190512 B2 JP3190512 B2 JP 3190512B2
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silicon film
amorphous silicon
film
surface
forming
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JPH07226374A (en
Inventor
久 大谷
昭治 宮永
宏勇 張
直人 楠本
順一 竹山
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株式会社半導体エネルギー研究所
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Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor having crystallinity used for a thin film device such as an insulated gate field effect transistor.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a crystalline silicon semiconductor thin film used for a thin film device such as a thin film type insulated gate field effect transistor (hereinafter referred to as a thin film transistor), a plasma CVD method or a thermal CVD method is used. There is known a method of crystallizing an amorphous silicon film formed by using laser light irradiation or heating. A crystalline silicon film or a crystalline silicon film is generally a polycrystalline silicon film,
A silicon film called a microcrystalline silicon film or a microcrystal. Further, it refers to a silicon film having a crystal component or a crystal structure.

[0003]

Crystallization by laser light irradiation has a problem that the crystallinity in the film becomes non-uniform due to the non-uniformity of the laser beam and the fluctuation of the output. An object of the present invention is to provide a technique for obtaining a silicon thin film having uniform crystallinity when crystallization of an amorphous silicon film by laser light irradiation.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an amorphous silicon film having a crystal nucleus formed on one surface and dehydrogenation to form an unpaired bond. The gist of the present invention is to obtain a crystalline silicon film by irradiating laser light or intense light from the side where a nucleus is formed to grow a crystal nucleus.

[0005] One surface of the amorphous silicon film refers to one of the back surface or the front surface of the amorphous silicon film formed on a glass substrate which is a substrate having an insulating surface, for example. . Note that as the substrate, a quartz substrate or a semiconductor substrate on which an insulating film is formed over a surface can be used.

[0006] As a method for dehydration or dehydrogenation, a method by heat treatment can be mentioned. This heat treatment is desirably performed in a vacuum or an inert atmosphere. This heat treatment needs to be performed at a temperature lower than the crystallization temperature of the amorphous silicon film from which hydrogen is to be released. This is because if the heat treatment is performed at a temperature higher than the crystallization temperature, the amorphous semiconductor will be crystallized, and sufficient crystallization cannot be performed in the subsequent crystallization by laser light irradiation.

The crystallization temperature of an amorphous silicon film is generally 600
However, as will be described in detail later, the introduction of a catalytic element that promotes crystallization causes the crystallization temperature to reach 550 ° C. or lower. Therefore, in this case, the heat treatment at a temperature lower than the crystallization temperature is preferably lower than or equal to 500 degrees, preferably lower than or equal to 450 degrees.

The reason why the heat treatment is performed in a vacuum or an inert atmosphere is to prevent an unnecessary thin film such as an oxide film from being formed on the surface of the amorphous silicon film.

By subjecting this amorphous silicon film to a heat treatment at a temperature lower than the crystallization temperature, uniform and thorough dehydrogenation can be performed in the film. This improves the in-plane distribution of crystallinity of the silicon semiconductor film and the uniformity of the crystal grain size. With the use of the crystalline silicon film, a thin film transistor with uniform characteristics can be formed over a large-area substrate.

In order to form a crystal nucleus, a catalyst element for promoting crystallization is introduced into one surface of the amorphous silicon film and heated at a temperature higher than the crystallization temperature of the amorphous silicon film. Will be In this case, since the crystallization temperature of the amorphous silicon film is lowered to 550 ° C. or lower by the introduction of the catalytic element, the temperature of the heat treatment for forming the crystal nuclei is 500 ° C., preferably 550 ° C. Can be done in degrees or more.

[0011] The order of the heat treatment step for dehydrogenation and the heat treatment step for forming crystal nuclei may be performed first. Further, the heat treatment step for dehydrogenation may be performed before the introduction of crystal nuclei. An excimer laser is generally used as a laser beam, but it goes without saying that the configuration of the present invention does not limit the type of laser at all, and any laser may be used.

It is desirable that the laser beam is emitted in a vacuum or an inert atmosphere. This is to prevent dangling bonds of the amorphous silicon film generated as a result of dehydration from being combined with oxygen, hydrogen, or nitrogen in the air, which is an active gas.

The present invention is characterized in that crystallization is promoted by forming a large number of dangling bonds in an amorphous silicon film. This is based on the following experimental facts that were revealed in experiments performed by the present inventors.

That is, as a result of irradiating a KrF excimer laser beam (wavelength: 248 nm) on an amorphous silicon film from which hydrogen was completely removed from a non-single-crystal silicon film, the crystallinity was significantly improved. It is based on.

An amorphous silicon film generally contains a large amount of hydrogen, and this hydrogen neutralizes dangling bonds. However, the present inventors have recognized that the existence of the dangling bond is extremely important in the crystallization from the amorphous state in the molten state based on the above experimental facts. Have been found to promote instantaneous crystallization in a molten state by intentionally forming.

At this time, if an oxide film or the like is formed on the surface of the silicon semiconductor film by exposing the surface of the silicon semiconductor film to air, the dangling bonds that have been formed are neutralized. It is very important to perform crystallization by laser irradiation in an inert atmosphere.

The temperature lower than the crystallization temperature of the amorphous silicon semiconductor is a temperature at which the amorphous silicon semiconductor starts to crystallize by the heat treatment.

Heat annealing before crystallization by laser light irradiation at a temperature equal to or lower than the crystallization temperature substantially improves the crystallinity even if the silicon film once crystallized is irradiated with laser light. This is based on an experimental result that the crystallinity is significantly lower than that of a film crystallized by irradiating laser light in an amorphous state without being observed.

Therefore, it is extremely important that hydrogen is extracted from the amorphous silicon semiconductor film at a temperature lower than the crystallization temperature of the amorphous semiconductor film. However, in the structure of the present invention, it is extremely important to thoroughly remove hydrogen from the amorphous silicon semiconductor film and to generate as many dangling bonds in the film as possible. It is necessary to perform heat treatment for dehydrogenation at a temperature as high as possible.

The major feature of the dehydration by heating is that the dehydration can be performed uniformly and thoroughly. As a result, a polycrystalline silicon semiconductor film having a large particle size and a uniform particle size can be obtained.

In the above, crystallization by laser light irradiation has been mainly described, but a method of intense light irradiation instead of laser light may be employed. In particular, it is useful to perform crystallization using rapid thermal annealing (RTA) by irradiation with infrared light. Since infrared light is hardly absorbed by the glass substrate and easily absorbed by the silicon film,
The silicon film can be selectively heated.

Further, according to the present invention, a catalyst element for promoting crystallization is introduced into one surface of the amorphous silicon film, and then a heat treatment is carried out to form crystal nuclei by the action of the catalyst element. Laser light is irradiated from the surface on which crystal nuclei are formed (one surface of the amorphous silicon film), and crystal growth is performed from the crystal nuclei. It is characterized by the following. At this time, before the introduction of the catalytic element, or before the formation of crystal nuclei after the introduction of the catalytic element,
Alternatively, a heat treatment for promoting dehydrogenation from the amorphous silicon film is performed after the formation of the crystal nuclei.

The laser light irradiation for crystallization is performed by
It is important to perform the process from the side of the amorphous silicon film on which the crystal nuclei are formed. This is because the crystal quality of the crystalline silicon film obtained when laser light is irradiated from the side of the amorphous silicon film where the crystal nuclei are formed, and the surface where the crystal nuclei of the amorphous silicon film are formed Is based on the results found by comparing the film quality of a crystalline silicon film obtained when laser light is irradiated from the opposite surface side.

The irradiation direction of the laser beam is limited for the following reasons. As a result of the study on the variation in characteristics during laser crystallization, it was found that two main causes were the difference in crystallinity caused by the temperature distribution in the laser irradiation part and the accidental nucleation. It has arrived. To explain the reason in more detail, the laser light intensity distribution generally has a Gaussian distribution, and the temperature of the amorphous silicon film also has a distribution along with this distribution. As a result, in the crystallization process through melting or partial melting, the temperature should be lower than the melting point of the amorphous silicon film from a low temperature or a high heat diffusion, and crystallization should occur. Crystal nuclei do not always exist, and crystallization is expected to occur explosively when the supercooled liquid comes into contact with the crystal nuclei. Further, it is expected that uniform crystallization is difficult because the crystal nuclei themselves are irregularities at the interface with silicon oxide.

In order to avoid this phenomenon, it is desirable that the portion where the molten portion first drops to a temperature lower than the melting point and the portion where the crystal nuclei are present coincide. For this purpose, the present inventors have tried to introduce a crystal nucleus controlled in advance before laser crystallization and then perform laser crystallization. As a result, when a material having a higher transmittance of laser light and a higher thermal conductivity than amorphous silicon is used as a crystal nucleus, that is, a material which is reduced to a melting point of silicon or lower faster than amorphous silicon is used. In such a case, it has been found that crystal growth starts therefrom, and that a good crystalline silicon thin film can be obtained. As such a material, many crystalline materials can be cited as candidates. Among them, as a material that can be epitaxially grown, particularly, a fine crystal grain of crystalline silicon, or a crystalline silicon after adding a nickel catalyst to amorphous silicon. Nickel silicide or the like obtained by heating is particularly desirable.

In the place where the crystal nucleus is introduced, the crystal nucleus is not uniformly introduced into the entire amorphous silicon film, but is introduced near the upper interface with the substrate or near the interface with the base.
Further, it has been found that a crystalline silicon film having the best characteristics can be obtained by irradiating the direction of laser light irradiation from the interface side where the crystal nuclei are introduced. The introduction of crystal nuclei at the interface is considered to be due to the fact that crystal growth is sufficiently possible in the film thickness direction, and is considered to have the effect of increasing one crystal grain. The direction of laser irradiation may be caused by the effect of heating the interface through the crystal nucleus, or the effect of temperature gradient in the film thickness direction, but the mechanism has not been completely elucidated. Absent.

The catalyst element for promoting crystallization of the amorphous silicon film is preferably Ni, Pt, Cu, Ag, Au,
One or a plurality of elements selected from In, Sn, Pb, P, As, and Sb can be used. Also VI
One or more elements selected from Group II elements, IIIb, IVb, and Vb elements can also be used.

As a method for introducing a catalytic element for promoting crystallization, a method in which a solution containing the catalytic element is applied to the surface of the amorphous silicon film is useful.

In particular, in the present invention, it is important that the catalytic element is introduced in contact with the surface of the amorphous silicon film. This is extremely important in controlling the amount of the catalytic element.

The catalyst element may be introduced on the upper surface or the lower surface of the amorphous silicon film. If the catalytic element is introduced on the upper surface of the amorphous silicon film, a solution containing the catalytic element may be applied onto the amorphous silicon film after the amorphous silicon film is formed. If the catalyst element is introduced into the lower surface of the silicon film, a solution containing the catalyst element is applied to the base surface before forming the amorphous silicon film, and the catalyst element is held in contact with the base surface. I just need.

By adopting the structure of the present invention, the following basic significance can be obtained. (A) The concentration of the catalyst element in the solution can be strictly controlled in advance to increase the crystallinity and reduce the amount of the element. (B) If the solution is in contact with the surface of the amorphous silicon film,
The amount of the catalyst element introduced into the amorphous silicon is determined by the concentration of the catalyst element in the solution. (C) Since the catalytic element adsorbed on the surface of the amorphous silicon film mainly contributes to the crystallization, the catalytic element can be introduced at a minimum necessary concentration. (D) A crystalline silicon film having good crystallinity can be obtained without requiring a high-temperature process.

As a method of applying a solution containing an element that promotes crystallization on the amorphous silicon film, an aqueous solution, an organic solvent solution, or the like can be used as the solution. Here, “containing” includes both the meaning of being included as a compound and the meaning of being included simply by being dispersed.

As the solvent containing the catalyst element, a solvent selected from polar solvents such as water, alcohol, acid and ammonia can be used.

When nickel is used as a catalyst and this nickel is contained in a polar solvent, nickel is introduced as a nickel compound. Typical examples of the nickel compound include nickel bromide, nickel acetate, nickel oxalate, nickel carbonate, nickel chloride, nickel iodide, nickel nitrate, nickel sulfate, nickel formate, nickel acetylacetonate, and 4-cyclohexylbutyric acid. A material selected from nickel, nickel oxide, and nickel hydroxide is used.

Examples of the solvent containing a catalytic element include non-polar solvents such as benzene, toluene, xylene, carbon tetrachloride,
Chloroform and ether can be used.

In this case, nickel is introduced as a nickel compound. As the nickel compound, typically, a compound selected from nickel acetylacetonate and nickel 2-ethylhexanoate can be used.

It is also useful to add a surfactant to the solution containing the catalyst element. This is to increase the adhesion to the surface to be coated and control the adsorption. This surfactant may be applied in advance on the surface to be coated.

When nickel alone is used as the catalyst element, it must be dissolved in an acid to form a solution.

The above is an example in which a solution in which nickel as a catalytic element is completely dissolved is used. However, even if nickel is not completely dissolved, a powder composed of nickel alone or a nickel compound is dispersed in a dispersion medium. A material such as an emulsion which is uniformly dispersed in the emulsion may be used. Alternatively, a solution for forming an oxide film may be used. As such a solution, OCD (Ohka Diffusion) of Tokyo Ohka Kogyo Co., Ltd.
Source) can be used. When this OCD solution is used, a silicon oxide film can be easily formed by applying it on the surface to be formed and baking it at about 200 degrees. Further, since it is free to add impurities, it can be used in the present invention.

The same applies to the case where a material other than nickel is used as the catalyst element.

When nickel is used as a catalyst element for promoting crystallization and a polar solvent such as water is used as a solution solvent for containing the nickel, when these solutions are directly applied to the amorphous silicon film, the solution becomes elastic. It may be lost. In this case, a thin oxide film having a thickness of 100 ° or less is first formed, and a solution containing a catalyst element is applied thereon, whereby the solution can be applied uniformly. It is also effective to improve the wetting by adding a material such as a surfactant to the solution.

Also, by using a non-polar solvent such as a toluene solution of nickel 2-ethylhexanoate as a solution, it can be applied directly to the surface of the amorphous silicon film. In this case, it is effective to apply a material such as an adhesive used in applying the resist in advance. However, care must be taken when the amount of coating is too large, since this would hinder the addition of the catalytic element to the amorphous silicon.

The amount of the catalyst element contained in the solution depends on the type of the solution, but as a general tendency, the amount of nickel is 200 ppm to 1 ppm, preferably 50 ppm to 1 ppm (in terms of weight) based on the solution. It is desirable. This is a value determined in view of the nickel concentration in the film after crystallization is completed.

The amorphous silicon film to which the catalytic element is added is subjected to a heat treatment to form a crystal nucleus, and then is irradiated with a laser beam, so that the entire surface of the amorphous silicon film is uniformly transformed into a crystalline silicon film. It can be crystallized. In the crystallization process using this laser, a very specific phenomenon has been observed. In the case where no crystal nucleus is introduced, the same crystallization can be performed with a considerably small laser power as compared with the laser power required for performing the entire crystallization. Generally, in order to crystallize a microcrystallized amorphous film,
It is said that higher laser power is required (because the absorbed laser power is small due to different transmittance) than crystallizing a film that does not contain a crystal component, but the opposite trend is true. This is one of the great advantages of the present invention.

By adjusting the introduction amount of the catalyst element,
The density of crystal nuclei can be controlled. The state in which the crystal nuclei are formed can be regarded as a state in which components having crystallinity and amorphous components are mixed as a whole. Here, by irradiating a laser beam, crystal growth can be performed from a crystal nucleus existing in the component having crystallinity, and a silicon film with high crystallinity can be obtained. That is, small crystal grains can be grown into large crystal grains. Therefore, the crystal growth distance, the size of the crystal grains accompanying the crystal growth, the number of crystal grains, and the like can be controlled by appropriately setting the amount of the catalyst element to be initially introduced and the laser power.

Instead of laser light irradiation, a method of irradiating strong light, particularly infrared light, may be employed. Since infrared light is hardly absorbed by glass and easily absorbed by a silicon thin film, it is useful because the silicon thin film formed on the glass substrate can be selectively heated. This method using infrared light is called rapid thermal annealing (RTA) or rapid thermal process (RTP).

The method of introducing the catalytic element is not limited to the use of an aqueous solution or a solution such as alcohol, but a wide range of substances containing the catalytic element can be used.
For example, a metal compound or oxide containing a catalyst element can be used.

[0048]

According to the present invention, a crystal nucleus is formed on one surface of an amorphous silicon film and its vicinity by the action of a catalytic element, and a large number of dangling bonds are artificially formed in the amorphous silicon film. By subsequently irradiating laser light or strong light from the side where the crystal nuclei are formed, crystal growth can be performed from the crystal nuclei, and a crystalline silicon film having good crystallinity can be obtained.

Further, a crystal nucleus is formed by the action of a catalytic element on the amorphous silicon film in which a large number of dangling bonds are artificially formed, and then the crystal nucleus is irradiated with laser light or strong light. Crystal growth from
A good crystalline silicon film can be obtained.

[0050]

【Example】

[Embodiment 1] In this embodiment, the effect of a heat treatment for dehydrogenation when an amorphous silicon film is crystallized by irradiating a laser beam is shown based on experimental results.

First, a silicon oxide film as a base protective film is
Glass substrate (Corning 705)
9) An amorphous silicon film (a-
(Si film) was formed to a thickness of 1000 ° under the following conditions. RF power 50 W Reaction pressure 0.05 torr Reaction gas flow rate H 2 = 45 sccm SiH 4 = 5 sccm Substrate temperature 300 degrees

Two kinds of the above samples were produced. One type was subjected to no heat treatment, and the other type was subjected to heat treatment at 500 ° C. for 1 hour in a nitrogen atmosphere which is an inert gas. This heat treatment is for removing hydrogen from the amorphous silicon film and artificially forming dangling bonds in the film. Then, Kr having a wavelength of 248 nm is applied to both in vacuum.
Crystallization was performed by irradiating an F excimer laser. This step was performed only for one shot while changing the energy density of the laser beam. The substrate was irradiated with laser light without being heated.

Raman spectra were measured to examine the crystallinity of the two types of samples prepared as described above. In FIG. 1, the curve indicated by A is the peak wave number (cm −1 ) of the Raman spectrum of the sample that was heat-treated at a temperature of 500 ° C. for 1 hour before the laser light irradiation, and the energy density of the irradiated laser light (mJ / 7 is a graph showing the relationship between the measured values and cm 2 ). The curve indicated by B is the relationship between the peak of the Raman spectrum and the wave number (cm -1 ) of the sample which was not subjected to the heat treatment before the irradiation with the laser light, and the energy density (mJ / cm 2 ) of the irradiated laser light. FIG.

Referring to the curve A in FIG. 1, the heat treatment before the irradiation with the laser beam allows the peak 521 of the single crystal silicon to be obtained even at a low laser energy density.
It can be seen that a value close to cm -1 can be obtained. In general, the peak of the Raman spectrum of a film obtained by crystallizing an amorphous silicon film is 521 cm, which is the peak of the Raman spectrum of single crystal silicon.
It is known that the closer to −1 , the larger the crystal grain size of this film and the better its crystallinity. From this fact, it is concluded that a silicon film having a large crystal grain size and higher crystallinity can be obtained by performing the heat treatment for dehydrogenation.

Further, it can be seen from the curve B that the crystallinity greatly depends on the energy density of the laser beam when the heat treatment for desorbing hydrogen is not performed. Further, it can be seen that good crystallinity cannot be obtained unless a laser beam having a large energy density is irradiated.

In general, the energy density of an excimer laser is liable to fluctuate and lacks stability. However, when the relationship as shown by the curve A is obtained, there is little dependence of the crystallinity on the intensity of the laser light.
A crystalline silicon film having uniform crystallinity can be obtained without much influence of the instability of the excimer laser.

However, in the case of the curve B, that is, when the heat treatment for dehydrogenation is not performed, the crystallinity becomes non-uniform due to the fluctuation of the energy density of the laser beam.

In the actual manufacturing process, it is a major problem how to manufacture a device having uniform characteristics. Therefore, it is useful to obtain a crystalline silicon film that is stable and exhibits good crystallinity without depending on the energy density of the laser beam as shown by the curve A.

Referring to FIG. 1, it is concluded that the sample subjected to the heat treatment for dehydrogenation is crystallized by a laser beam having a low energy density as shown by a curve A. From this, it is concluded that the minimum energy density (threshold energy density) for generating crystallization can be reduced by performing the heat treatment for dehydrogenation.

From this, it can be concluded that the threshold energy density for crystallization can be reduced by thoroughly removing hydrogen from the amorphous silicon film and forming a large number of dangling bonds. .

[Embodiment 2] In this embodiment, a step of incorporating a catalyst element that promotes crystallization by incorporating a catalyst element that promotes crystallization into an aqueous solution, applying the catalyst element to an amorphous silicon film,
A heat treatment step for forming a crystal nucleus, a heat treatment step for dehydrogenation, and a crystallization step by laser light irradiation will be described.

With reference to FIG. 2, the process up to the point of introducing a catalytic element (here, nickel is used) will be described. In this embodiment, Corning 7059 glass is used as the substrate 11. The size is 100mm x 100mm
And

First, the amorphous silicon film 12 is formed by plasma CVD.
It is formed to a thickness of 100 to 1500 ° by a method or an LPCVD method. Here, the amorphous silicon film 12 is formed to a thickness of 1000 ° by a plasma CVD method. (Figure 1
(A))

Then, a hydrofluoric acid treatment is performed to remove dirt and a natural oxide film.
Å is formed. If the contamination can be ignored, the oxide film 13
Instead, a natural oxide film may be used as it is.

The exact thickness of the oxide film 13 is unknown because it is extremely thin, but it is considered to be about 20 °.
Here, the oxide film 1 is irradiated with UV light in an oxygen atmosphere.
3 is formed. Film formation conditions are UV in oxygen atmosphere.
For 5 minutes. This oxide film 13
As a film forming method, a thermal oxidation method may be used. Further, a treatment by hydrogen peroxide may be used.

The oxide film 13 is used for spreading the acetate solution over the entire surface of the amorphous silicon film in the subsequent step of applying a nickel-containing acetate solution, that is, for improving the wettability. It is. For example, when an acetate solution is directly applied to the surface of an amorphous silicon film, nickel cannot be introduced into the entire surface of the amorphous silicon film because the amorphous silicon repels the acetate solution. That is, uniform crystallization cannot be performed.

Next, an acetate solution is prepared by adding nickel to the acetate solution. The concentration of nickel is 25 ppm. Then, 2 ml of this acetate solution is dropped on the surface of the oxide film 13 on the amorphous silicon film 12, and this state is maintained for 5 minutes. Then, spin dry using a spinner 15 (200
0 rpm, 60 seconds). (Fig. 1 (C), (D))

The concentration of nickel in the acetic acid solution is 1
If it is at least 10 ppm, preferably at least 10 ppm, it will be practical. When a nonpolar solvent such as a toluene solution of nickel 2-ethylhexanoate is used as the solution, the oxide film 1
3 is unnecessary, and a catalytic element can be directly introduced on the amorphous silicon film.

By performing this nickel solution coating step once or more times, a layer containing nickel having an average thickness of several to several hundreds of mm is formed on the surface of the amorphous silicon film 12 after spin drying. 14 can be formed. In this case, nickel in this layer 14 diffuses into the amorphous silicon film in the subsequent heating step, and acts as a catalyst for promoting crystallization. This layer is not always a complete film.

After the application of the solution, the state is maintained for one minute. The concentration of nickel finally contained in the silicon film 12 can be controlled also by the holding time. The control of the nickel concentration can be performed by the nickel concentration in the solution.

Then, a heat treatment is performed in a heating furnace at 550 ° C. for one hour in a nitrogen atmosphere. As a result,
Partially crystalline silicon thin film 1 formed on substrate 11
2 can be obtained. That is, crystal nuclei can be introduced in this step. At the same time, dangling bonds are formed in the silicon thin film 12 in this step. FIG. 3A schematically shows this state. FIG. 3A shows a state where crystal nuclei 21 formed by introducing nickel are formed on the surface of amorphous silicon film 12 formed on glass substrate 11. FIG. 4 shows a cross-sectional photograph of the silicon thin film corresponding to FIG. FIG. 4 shows a state in which a crystal nucleus is formed on the surface of an amorphous silicon film formed on a glass substrate by introducing nickel, and the crystal nucleus grows slightly. In FIG. 4, the slightly grown crystal component is indicated by a black square. Although a silicon oxide film is formed on the surface of the glass substrate, FIG.
In the photograph shown in (1), it cannot be distinguished from the glass substrate.

The above-mentioned heat treatment can be performed at a temperature of 500 ° C. or higher. However, if the temperature is low, the heating time must be prolonged, and the production efficiency decreases. Further, if the temperature is 550 degrees or more, the problem of heat resistance of a glass substrate used as a substrate will surface.

In this embodiment, the method of introducing a catalytic element on the amorphous silicon film has been described, but a method of introducing a catalytic element below the amorphous silicon film may be employed. in this case,
Before forming the amorphous silicon film, the catalyst element may be introduced onto the base film using a solution containing the catalyst element.

After the formation of the crystal nuclei, heat treatment is further performed at 400 ° C. for 3 hours in a nitrogen atmosphere to thoroughly remove hydrogen. In this step, a large number of dangling bonds are formed in the film. In this way, a silicon film 12 having a crystallinity in which crystal nuclei are introduced and in which dangling bonds are formed is obtained. Next, a KrF excimer laser (wavelength: 248 nm, pulse width: 30 nsec) was irradiated in a nitrogen atmosphere for 200 to 200 nm.
Irradiation with a few shots at a power density of 350 mJ / cm 2 completely crystallizes the silicon film 12. This process is strong light,
In particular, irradiation with infrared light may be used. In this process,
It is important to perform the laser light irradiation from the upper surface side of the silicon film 12 in which the catalyst element is introduced and the crystal nucleus is formed.

FIG. 3B schematically shows a state in which the crystal growth is performed as indicated by 22 from the crystal nucleus indicated by 21 when the laser beam 20 is irradiated. . The crystallization grows around the crystal nucleus 21 as shown by arrows in FIGS. 3 (A) and 3 (B). As the crystallization proceeds, a polycrystalline structure as indicated by 23 in FIG. 3C can be obtained.

[Embodiment 2] In this embodiment, a catalyst element is introduced into the surface of an amorphous silicon film formed on a glass substrate, dehydrogenation is further performed, and crystal nuclei are formed. An example in which crystallization is performed by laser light irradiation will be described.

FIG. 5 shows the steps of this embodiment. First, a silicon oxide film 52 is formed on a glass substrate 51 as a base film at 1000.
To a thickness of Then, an amorphous silicon film 53 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, as shown in Example 2, nickel is introduced as a catalyst element using a solution. Conditions such as the concentration of nickel are the same as in the second embodiment. In this step, nickel is brought into a state of being held in contact with the surface of amorphous silicon film 53. (FIG. 5 (A))

Next, a heat treatment is performed at 400 ° C. for 2 hours.
Dehydration is performed on the amorphous silicon film. By this step, a large number of dangling bonds are formed in the amorphous silicon film. (FIG. 5 (B))

The process for dehydrogenation is performed at a temperature of 350 to 50 degrees.
It is preferable to carry out at a temperature of 0 degrees. When the catalytic element is not introduced, it is effective to perform dehydration at a temperature of about 500 to 550 ° C. However, when the catalytic element is introduced, the crystallization temperature of the amorphous silicon film becomes 550. Degrees, the hydrogen needs to be removed at a temperature of 500 degrees or less.

Next, a heat treatment for forming crystal nuclei 54 is performed. The heat treatment for forming the crystal nuclei 54 includes 5
This is performed in an inert atmosphere at 50 degrees for 1 hour. (FIG. 5 (C))

This crystal nucleus forming step needs to be performed at a temperature higher than the crystallization temperature. However, it is important that the crystallization is performed to such an extent that crystal nuclei are formed without completely progressing the crystallization.

Next, by irradiating a KrF excimer laser beam 55, a crystal is grown from a crystal nucleus.
It is important that the laser light irradiation is performed from the side of the amorphous silicon film on which the crystal nuclei are formed. In this step, crystal growth is performed from the crystal nucleus, and the crystalline silicon film 5 is grown.
6 can be obtained. (FIG. 5 (D))

[Embodiment 3] In this embodiment, a heat treatment for forming a crystal nucleus is performed after a catalyst element is introduced, a heat treatment for dehydrogenation is further performed, and a crystal is irradiated by laser light irradiation. This is an example of performing the conversion. FIG. 6 shows a manufacturing process of this embodiment. The reference numerals shown in FIG. 6 are the same as those shown in FIG.

First, a silicon oxide film 52 having a thickness of 1000 ° is formed on a glass substrate 51 as a base film. Then, an amorphous silicon film is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, as shown in Example 2, nickel is introduced as a catalyst element using a solution. In this step, nickel is brought into a state of being held in contact with the surface of amorphous silicon film 53. (FIG. 6 (A))

Next, heat treatment for forming crystal nuclei is performed. The heat treatment for forming the crystal nuclei 54 is 550
This is performed in a nitrogen atmosphere under the condition of 1 hour. (FIG. 6
(B))

Next, heat treatment is performed at 400 degrees for 2 hours.
Dehydration is performed on the amorphous silicon film. By this step, a large number of dangling bonds are formed in the amorphous silicon film. (FIG. 6 (C))

Next, by irradiating a KrF excimer laser beam 55, a crystal is grown from a crystal nucleus.
It is important that the laser light irradiation is performed from the side of the amorphous silicon film on which the crystal nuclei are formed. In this step, crystal growth is performed from the crystal nucleus, and the crystalline silicon film 5 is grown.
6 can be obtained. (FIG. 6 (D))

[Embodiment 4] In this embodiment, a catalytic element is introduced into the lower surface (the surface in contact with the substrate side) of the amorphous silicon film, and then a heat treatment for dehydrogenation is performed. This is an example in which a crystal nucleus is formed, and the laser light is finally irradiated from the substrate side to perform crystallization.

FIG. 7 shows a manufacturing process of this embodiment. First, a silicon oxide film is formed as a base film 72 on a glass substrate by a sputtering method. The thickness of the silicon oxide film is 500 to 30
00 °, for example, 1500 °. Next, as shown in Example 2, nickel is introduced as a catalytic element to the surface of the base film 72 using a solution. By this step, a state in which the catalyst element is provided in contact with the surface of the base film is realized.

Next, an amorphous silicon film 73 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, a heat treatment for releasing hydrogen is performed to release hydrogen in the film and form a large amount of dangling bonds. This heat treatment for dehydrogenation is performed in a nitrogen atmosphere.
The heat treatment is performed at 350 to 500 degrees, for example, 450 degrees for 2 hours. (FIG. 7 (B))

Next, heat treatment for forming crystal nuclei is performed. This step is performed at a temperature of 500 ° C. or higher, which is the crystallization temperature of the amorphous silicon film into which the catalytic element has been introduced. Here, heat treatment is performed at 550 ° C. for one hour in a nitrogen atmosphere. In this step, crystal nuclei 74 are formed at the interface between base film 72 and the amorphous silicon film and in the vicinity thereof. (FIG. 7
(C))

Next, a laser beam is irradiated from the glass substrate 71 side to crystallize the amorphous silicon film 75. In this step, the crystal nucleus 74 grows by the energy of the laser beam, and a crystalline silicon film 75 can be obtained.
(FIG. 7 (D))

The laser light used here needs to pass through the glass substrate. Therefore, it is necessary to use laser light having a wavelength of 400 nm or more. For example, a XeO excimer laser with a wavelength of 538 nm or a wavelength of 5
A 58 nm HgCl excimer laser can be used.

[Embodiment 5] In this embodiment, a catalytic element is introduced into the surface of the base film on which the amorphous silicon film is formed, and then the amorphous silicon film is formed. A crystal nucleus is formed at the interface with the amorphous silicon film and in the vicinity thereof, and hydrogen is removed from the amorphous silicon film by heat treatment to form a large number of dangling bonds in the amorphous silicon film. The amorphous silicon film is formed by irradiating a laser beam from the side where the crystal nuclei are formed.

FIG. 8 shows a manufacturing process of this embodiment. The reference numerals shown in FIG. 8 are the same as those shown in FIG. First, a silicon oxide film is formed as a base film 72 on a glass substrate 71 to a thickness of 1000 ° by a sputtering method. Next, nickel as a catalyst element is applied to the surface of the base film 72 using a solution by the method described in the second embodiment. (FIG. 8A)

Next, an amorphous silicon film 73 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Then, heat treatment for forming crystal nuclei is performed at 550 ° C. for one hour in a nitrogen atmosphere. In this step, crystal nuclei 74 are formed at the interface between base film 72 and amorphous silicon film 73 and in the vicinity thereof. (FIG. 8 (B))

Next, heat treatment for dehydrogenation is performed. This step is performed at 450 ° C. for 2 hours in a nitrogen atmosphere. In this step, hydrogen is thoroughly discharged from the amorphous silicon film 73, and a large number of dangling bonds are formed in the film. (FIG. 8 (C))

Next, a laser beam 76 is irradiated from the substrate 71 side to grow a crystal nucleus 74 to obtain a crystalline silicon film 75.
(FIG. 8 (D))

In this case, it is important to irradiate the substrate 71 with laser light. In this step, when the laser light 76 is applied from the surface of the amorphous silicon film, that is, the surface on which no crystal nuclei are formed, only the same effect as that of the crystalline silicon film formed only by the irradiation of the laser light can be obtained. I can't.

[Embodiment 6] In this embodiment, an amorphous silicon film is formed on a glass substrate via a base film, and then a heat treatment step for dehydrogenation is performed. A catalytic element that promotes crystallization is introduced into the surface of the silicon film, and then a heat treatment for forming a crystal is performed. Finally, the surface side on which the crystal nuclei are formed (the exposed amorphous silicon film surface side) Is irradiated with laser light from the substrate to grow crystals from crystal nuclei.

FIG. 9 shows a manufacturing process of this embodiment. First,
A base film 92 is formed on a glass substrate 91, and an amorphous silicon film 93 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, a heat treatment step for dehydrogenation is performed. The dehydration process is performed in a nitrogen atmosphere at 400 degrees for 2 hours.
(FIG. 9A)

Next, nickel as a catalytic element is introduced into the surface of the amorphous silicon film 93 by the method described in the second embodiment.
The conditions and the like are the same as in the second embodiment. (FIG. 9 (B))

Next, heat treatment for forming a crystal nucleus is performed. This step is performed at 550 ° C. in a nitrogen atmosphere.
Perform under the condition of time. In this step, crystal nuclei 94 are formed on the surface of amorphous silicon film 93 and in the vicinity thereof. (FIG. 9
(C))

Next, as shown in FIG.
The crystalline silicon film 96 is obtained by irradiating KrF excimer laser light from the surface on which 4 is formed.

[Embodiment 7] In this embodiment, a thin film transistor (generally called a TFT) is formed by using a crystalline silicon film on a glass substrate manufactured by using the method described in Embodiments 1 to 6. Is made. The thin film transistor described in this embodiment can be used for pixels of a liquid crystal display device, peripheral circuits, and other integrated circuits. The method for producing a thin-film crystalline silicon semiconductor used in this embodiment
Any of the crystalline silicon films shown in the first to sixth embodiments may be used.

FIG. 10 shows a manufacturing process of a thin film transistor. FIG. 10A shows a silicon oxide film 102 serving as a base film and a crystalline silicon film 10 crystallized on a glass substrate 101.
3 is shown. Silicon oxide film 102
Is 1500 °, and the thickness of the crystalline silicon film is 10 °.
00 °.

In the state of FIG. 10A, the crystalline silicon film 103 is patterned to form an island-shaped semiconductor layer 104 constituting an active layer of the thin film transistor. (FIG. 10
(B))

The active layer is a layer in which a source region, a channel formation region, and a drain region are formed.

Next, the silicon oxide film 1 constituting the gate insulating film
05 is formed to a thickness of 1000 ° by a sputtering method. Then, an N-type crystalline silicon film for forming a gate electrode is formed to a thickness of 5000 ° by low pressure thermal CVD. As the gate electrode, aluminum, metal, or a semiconductor and a multilayer film thereof may be used.

By patterning the N-type crystalline silicon film,
A gate electrode 106 is formed. (FIG. 10 (C))

Next, as shown in FIG. 10D, phosphorus ions are doped by an ion implantation method (or a plasma doping method). This doping is performed on the gate electrode 1
06 is used as a mask. And 107 and 10
Nine regions are made N-type. Thus, the source / drain region 107, the drain / source region 109, and the channel forming region 108 are formed in a self-aligned manner.

Next, the source / drain region 107 and the drain / source region 109 are activated by irradiation with laser light or strong light. It is effective to perform RTA (rapid thermal annealing) using infrared light as strong light. In this case, since the silicon film can be selectively heated, effective activation can be performed without damaging the glass substrate 101.

Next, an interlayer insulating film 110 is formed using silicon oxide or polyimide. Then, patterning for forming holes for electrodes is performed, and a source / drain electrode 111 and a drain / source electrode 112 are formed of aluminum or other metal. At the same time, a gate wiring (not shown) is formed.
Thus, a thin film transistor using the crystalline silicon film is formed.

[Embodiment 8] In this embodiment, a nitride film is formed on at least one surface of an amorphous silicon film, and crystallization is promoted at the interface between the nitride film and the amorphous silicon film and in the vicinity thereof. A crystal nucleus is formed by using a catalytic element to be formed, and a laser beam is irradiated from a surface on which the crystal nucleus is formed, thereby obtaining a crystalline silicon film.

The reason for forming the nitride film is to reduce the roughness of the interface with the amorphous silicon film and improve the flatness of the interface by forming the nitride film. By forming crystal nuclei at the interface having flatness, crystal nuclei can be formed uniformly. Then, uniform crystal growth can be performed in the subsequent crystallization step by laser light irradiation. Further, since the silicon nitride (SiN x ) film functions as an anti-reflection film, when a nitride film is formed on the surface of the amorphous silicon film, the laser power is effectively used by irradiating a laser beam from the surface side. A configuration that can be used.

The manufacturing process of this embodiment will be described with reference to FIG. First, the base film 1 is formed on the surface of the glass substrate 121.
As 22, a silicon oxide film is formed with a thickness of 1000 °.
As the base film 122, a silicon nitride film or an aluminum nitride film may be used.

Next, the amorphous silicon film 123 is formed by plasma CVD.
It is formed to a thickness of 1000.degree. According to the method described in the second embodiment, nickel is used as a catalyst element for promoting crystallization in the amorphous silicon film 12.
3 to the surface. (FIG. 11A)

Next, as shown in FIG. 11B, a nitride film 124 is formed by a plasma nitriding method. The plasma nitriding method is a method in which plasma is generated by high-frequency discharge in a reduced-pressure atmosphere of ammonia to form a nitride film. The thickness of the nitride film is 50 to 500, for example, 200.
And it is sufficient. In addition to the plasma nitriding method, a method of applying heat energy under a reduced pressure atmosphere of ammonia may be used.

Next, as shown in FIG. 11C, a heat treatment for forming crystal nuclei is performed. This step is performed at 550 ° C. for one hour in a nitrogen atmosphere. In this step, crystal nuclei 120 are formed.

Next, as shown in FIG. 11D, a heat treatment for dehydrogenation is performed. This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. In this step, dehydrogenation from the amorphous silicon film 123 is promoted, and a large number of dangling bonds are formed in the amorphous silicon film 123.

Next, as shown in FIG. 11E, a laser beam (KrF excimer laser) 125 is irradiated to cause crystal growth from the crystal nucleus 120. Thus, a crystalline silicon film 126 is obtained.

Embodiment 9 In this embodiment, as shown in FIG. 12, a catalytic element is first introduced into the surface of an amorphous silicon film, and then a nitride film is formed on the surface of the amorphous silicon film. Then, a heat treatment for dehydrogenation is further performed, and a heat treatment for forming crystal nuclei is further performed. Finally, a laser beam is irradiated from the side where the crystal nuclei are formed to crystallize the amorphous silicon film. Is performed.

FIG. 12 shows a manufacturing process of this embodiment. First, an underlayer 122 is formed on a glass substrate by sputtering.
A film is formed to a thickness of 000 mm. Next, the amorphous silicon film 123 is formed by plasma CVD or low pressure thermal CVD to form
It is formed to a thickness of 0 °. Then, nickel as a catalyst element is introduced into the surface of the amorphous silicon film 123 by the method described in the second embodiment.

Next, the nitride film 124 is formed by the plasma nitriding method.
Is formed to a thickness of about 200 °. (FIG. 12 (B))

Next, as shown in FIG. 12C, a heat treatment for dehydration is performed. This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours.

Next, as shown in FIG. 12D, heat treatment for forming crystal nuclei is performed. This step is performed at 550 ° C. for one hour in a nitrogen atmosphere. In this step, crystal nuclei 120 are formed at the interface between nitride film 124 and amorphous silicon film 123 and in the vicinity thereof.

Next, a laser beam (KrF excimer) 125 is irradiated from the side of the amorphous silicon film on which the crystal nuclei are formed, that is, the side of the surface on which the nitride film 124 is formed, to grow the crystal nuclei 120. Thus, a crystalline silicon film 126 is obtained.

[Embodiment 10] In this embodiment, as shown in FIG. 13, an amorphous silicon film formed on a substrate having an insulating surface is first subjected to a heat treatment for dehydrogenation.
Next, a catalytic element is introduced into the surface of the amorphous silicon film, then a nitride film is formed on the surface of the amorphous silicon film into which the catalytic element has been introduced, and then heat treatment for forming crystal nuclei is performed. The laser light is irradiated from the side where the crystal nuclei are formed to crystallize the amorphous silicon film.

Hereinafter, the manufacturing process of this embodiment will be described with reference to FIGS. First, a base film 122 is formed on a glass substrate 121.
Is formed to a thickness of 1000 ° by a sputtering method. Next, the amorphous silicon film 123 is formed by plasma CVD or reduced pressure heat C.
It is formed to a thickness of 1000 ° by the VD method.

Next, a heat treatment for dehydrogenation is performed.
This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. By this step, the amorphous silicon film 123
During the dehydration, dangling bonds are formed in the film. (FIG. 13A)

Then, nickel as a catalyst element is introduced into the surface of the amorphous silicon film 123 by the method described in the second embodiment. (FIG. 13 (B))

Next, the nitride film 124 is formed by plasma nitriding.
Is formed to a thickness of about 200 °. (FIG. 13 (C))

Next, as shown in FIG. 12D, heat treatment for forming crystal nuclei is performed. This step is performed at 550 ° C. for one hour in a nitrogen atmosphere. In this step, crystal nuclei 120 are formed at the interface between nitride film 124 and amorphous silicon film 123 and in the vicinity thereof.

Next, a laser beam (KrF excimer) 125 is irradiated from the side of the amorphous silicon film on which the crystal nuclei are formed, ie, the side of the surface on which the nitride film 124 is formed, to grow the crystal nuclei 120. Thus, a crystalline silicon film 126 is obtained.

[Embodiment 11] In this embodiment, a nitride film (generally, a silicon nitride film is used) is formed on a light-transmitting substrate, and then crystallization is promoted on the surface of the nitride film. To introduce a catalytic element, and then form an amorphous silicon film, and further perform a heat treatment to form a crystal nucleus,
Further, a heat treatment for removing hydrogen from the amorphous silicon film is performed, and finally, a laser beam is irradiated from the substrate side to grow crystal nuclei to obtain a crystalline silicon film.

The manufacturing process of this embodiment will be described with reference to FIG. First, a nitride film (silicon nitride film) 132 is formed on a glass substrate to a thickness of about 500 to 3000 、, for example, 2000 Å by a plasma CVD method.

Next, as shown in Example 2, a solution containing nickel (an acetate solution containing nickel) is applied to the surface of the nitride film 132, and nickel as a catalyst element is applied to the surface of the nitride film 132. It is in the state provided in contact.
(FIG. 14A)

Next, the amorphous silicon film 133 is formed by plasma CVD.
The film is formed to a thickness of 1000.degree. Then, as shown in FIG.
Is performed for the formation of. This process is performed in a nitrogen atmosphere at 550 ° C. for one hour. The crystal nucleus as used herein refers to a region in an amorphous semiconductor provided with dehydrogenation or dangling bonds, in which at least a nucleus portion has a single crystal seed.

Next, heat treatment for dehydration is performed to form a large number of dangling bonds in the amorphous silicon film 133. This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. (FIG. 14C)

Next, the laser light 1 was applied from the glass substrate 131 side.
By irradiating the crystal 34, the crystal nucleus 130 is grown, and a crystalline silicon film 135 is obtained. At this time, laser light 1
As 34, it is necessary to use one having a wavelength that transmits the glass substrate 131. When a quartz substrate is used as the substrate, a laser beam in an ultraviolet region, for example, a KrF excimer laser (wavelength: 248 nm) can be used. Further, a XeCl excimer laser having a wavelength of 308 nm and transmitting through a silicon nitride film may be used. Alternatively, RTA by irradiation with infrared light may be used. Further, strong light equivalent to the above laser light may be used.

[Embodiment 12] In this embodiment, a nitride film (generally a silicon nitride film is used) is formed on a light-transmitting substrate, and then crystallization is promoted on the surface of the nitride film. Then, an amorphous silicon film is formed, and thereafter, a heat treatment is performed to remove hydrogen from the amorphous silicon film, and a heat treatment is further performed to form crystal nuclei. Finally, by irradiating laser light from the substrate side, crystal nuclei are grown to obtain a crystalline silicon film.

The manufacturing process of this embodiment will be described with reference to FIG. First, a nitride film (silicon nitride film) 132 is formed on a glass substrate 131 by a plasma CVD method at 500 to 3000 °.
A film is formed to a thickness of, for example, 2000 °.

Next, as shown in Example 2, a solution containing nickel (an acetate solution containing nickel) was applied to the surface of the nitride film 132, and nickel as a catalytic element was coated on the surface of the nitride film 132. It is in the state provided in contact.
(FIG. 15 (A))

Next, the amorphous silicon film 133 is formed by plasma CVD.
The film is formed to a thickness of 1000.degree.

Next, heat treatment for dehydration is performed to form a large number of dangling bonds in the amorphous silicon film 133. This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. (FIG. 15 (B))

Then, as shown in FIG. 15C, heat treatment for forming crystal nuclei is performed. This process is performed in a nitrogen atmosphere at 550 ° C. for one hour. In this step, crystal nuclei 130 are formed at the interface between nitride film 132 and amorphous silicon film 133 and in the vicinity thereof.

Next, the laser light 1 was applied from the glass substrate 131 side.
By irradiating the crystal 34, the crystal nucleus 130 is grown, and a crystalline silicon film 135 is obtained. (FIG. 15D)

At this time, it is necessary to use a laser beam having a wavelength that transmits through the glass substrate 131.

Embodiment 13 In Embodiment 2, the catalyst element is introduced into the surface of the amorphous silicon film by adding the catalyst element to the solution and applying this solution to the surface of the amorphous silicon film. In the method, an extremely thin oxide film is formed on the surface of the amorphous silicon film in order to improve the wettability of the solution.

In this embodiment, a nitride film is used as a film for improving the wettability of the solution. That is, the nitride film on the surface of the amorphous silicon film is used for the following purposes (1) and (2). (1) To improve wettability at the time of applying a solution containing a catalyst element. (2) In order to improve crystallinity when growing crystals from crystal nuclei formed on and near the surface of the amorphous silicon film.

Hereinafter, the manufacturing process of this embodiment will be described with reference to FIG. First, a silicon oxide film serving as a base film 152 is formed to a thickness of 1000 ° on a glass substrate 151 by a sputtering method. Next, plasma CVD or reduced pressure heat C
An amorphous silicon film 153 is formed to a thickness of 1000 ° by the VD method. Next, an extremely thin nitride film 154 is formed to a thickness of about 20 to 100 ° by a plasma nitriding method. The nitride film 154 plays a role in improving wettability of a solution containing a catalytic element applied in a later step, and improving crystallinity in a subsequent crystal nucleus forming step and a crystal growing step. (FIG. 16A)

Then, nickel, which is a catalytic element, is introduced into the surface of the nitride film 154 by the same steps as those described in the second embodiment. Here, an acetate solution obtained by adding nickel to an acetate solution (the nickel concentration is 25 pp in terms of weight)
m) is applied on the amorphous silicon film 153 on which the nitride film 154 is formed, thereby introducing nickel. The detailed conditions are the same as those described in the second embodiment. In this step, nickel is deposited on the amorphous silicon film 1 through the nitride film.
53 will be introduced to the surface. (FIG. 16 (B))

Next, a heat treatment for forming a crystal nucleus is performed, and the crystal nucleus 150 is formed by the nitride film 154 and the amorphous silicon film 153.
Formed at and near the interface with. This step is performed in a nitrogen atmosphere at 550 ° C. for one hour. (FIG. 15 (C))

Next, a heat treatment for dehydrogenation is performed.
This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. (FIG. 16 (D))

Next, crystallization is performed by irradiating KrF excimer laser beam 155 from the surface on which crystal nuclei 150 are formed, that is, from the surface on which nitride film 154 is formed. In this step, the crystal nucleus 150 grows and the crystalline silicon film 156 can be obtained. (FIG. 16E)

[Embodiment 14] In this embodiment, an extremely thin nitride film is provided on the surface of an amorphous silicon film, and a solution containing a catalytic element is applied on the nitride film to form an amorphous silicon film 153. And then heat treatment for dehydrogenation is performed, and then heat treatment forms crystal nuclei at and near the interface between the amorphous silicon film and the nitride film. Is irradiated with laser light from the side on which the crystal nuclei are formed to obtain a crystalline silicon film.

FIG. 17 shows a manufacturing process of this embodiment. First, a silicon oxide film is formed as a base film 152 on a glass substrate 151 to a thickness of 1000 ° by a sputtering method. Next, an amorphous silicon film 153 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, a nitride film 154 is formed to a thickness of about 20 to 100 ° by a plasma nitriding method. (FIG. 17A)

Then, nickel, which is a catalytic element, is introduced into the surface of nitride film 154 by the same steps as those described in the second embodiment. Here, an acetate solution obtained by adding nickel to an acetate solution (the nickel concentration is 25 pp in terms of weight)
m) is applied on the amorphous silicon film 153 on which the nitride film 154 is formed. The detailed conditions are the same as those described in the second embodiment. In this step, nickel is introduced to the surface of the amorphous silicon film 153 via the nitride film 154. (FIG. 17B)

Next, heat treatment for dehydrogenation is performed.
This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. (FIG. 17C)

Next, a heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C., 1
Perform under the condition of time. In this step, crystal nuclei 150 are formed at and near the interface between amorphous silicon film 153 and nitride film 154. (FIG. 17D)

Next, a KrF excimer laser beam 155 is irradiated from the nitride film 154 side to thereby obtain a crystal nucleus 150.
And a crystalline silicon film 156 can be obtained.
(FIG. 17E)

[Embodiment 15] In this embodiment, an amorphous silicon film is provided on a substrate having an insulating surface, and a heat treatment for dehydrogenation is further performed. An extremely thin nitride film is provided on the surface, and a catalyst element-containing solution is applied on the nitride film to introduce the catalyst element into the surface of the amorphous silicon film. A crystal nucleus is formed at the interface between the film and the nitride film and in the vicinity thereof, and a laser beam is irradiated from the side where the crystal nucleus is formed last to obtain a crystalline silicon film.

FIG. 18 shows a manufacturing process of this embodiment. First, a silicon oxide film is formed as a base film 152 on a glass substrate 151 to a thickness of 1000 ° by a sputtering method. Next, an amorphous silicon film 153 is formed to a thickness of 1000 ° by a plasma CVD method or a low pressure thermal CVD method. Next, heat treatment for dehydrogenation is performed. This step is performed in a nitrogen atmosphere at 400 degrees for 2 hours. (FIG. 18
(A))

Next, a nitride film 154 is formed to a thickness of about 20 to 100 ° by a plasma nitriding method. (FIG. 18
(B))

Then, nickel, which is a catalytic element, is introduced into the surface of nitride film 154 by the same steps as those described in the second embodiment. Here, an acetate solution obtained by adding nickel to an acetate solution (the nickel concentration is 25 pp in terms of weight)
m) is applied on the amorphous silicon film 153 on which the nitride film 154 is formed. The detailed conditions are the same as those described in the second embodiment. In this step, nickel is introduced to the surface of the amorphous silicon film 153 via the nitride film 154. (FIG. 18 (C))

Next, a heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C., 1
Perform under the condition of time. In this step, crystal nuclei 150 are formed at and near the interface between amorphous silicon film 153 and nitride film 154. (FIG. 18D)

Next, a KrF excimer laser beam 155 is irradiated from the nitride film 154 side, so that the crystal nucleus 150 is irradiated.
And a crystalline silicon film 156 can be obtained.
(FIG. 18E)

[0168]

According to the present invention, the catalytic element is added to the amorphous silicon film in which a crystal nucleus is formed on one surface by the introduction of the catalytic element and hydrogen is released, and a dangling bond is formed. By irradiating laser light or intense light from the surface on which the crystal nuclei are formed, the crystal nuclei can be crystal-grown, and a crystalline silicon film can be obtained.

[Brief description of the drawings]

FIG. 1 shows the relationship between the peak of the Raman spectrum of a polycrystalline semiconductor film obtained by employing the structure of the present invention and the irradiation energy density of a laser.

FIG. 2 shows a manufacturing process of an example.

FIG. 3 shows a state of crystal growth.

FIG. 4 shows a cross-sectional photograph of a silicon thin film.

FIG. 5 shows a manufacturing process of an example.

FIG. 6 shows a manufacturing process of the example.

FIG. 7 shows a manufacturing process of an example.

FIG. 8 shows a manufacturing process of the example.

FIG. 9 shows a manufacturing process of an example.

FIG. 10 shows a manufacturing process of the example.

FIG. 11 shows a manufacturing process of the example.

FIG. 12 shows a manufacturing process of the example.

FIG. 13 shows a manufacturing process of the example.

FIG. 14 shows a manufacturing process of the example.

FIG. 15 shows a manufacturing process of the example.

FIG. 16 shows a manufacturing process of the example.

FIG. 17 shows a manufacturing process of the example.

FIG. 18 shows a manufacturing process of the example.

[Explanation of symbols]

 11 Glass substrate 12 Amorphous silicon film 13 Oxide film 14 Nickel-containing layer 15 Spinner 21 Crystal nucleus 20 Laser beam 51 Glass substrate 52 Underlayer (silicon oxide film) 53 Amorphous silicon film 54 Crystal nucleus 55 laser light 56 crystalline silicon film 71 glass substrate 72 underlayer 73 amorphous silicon film 74 Crystal nucleus 76 Laser light 75 Crystalline silicon film 91 Glass substrate 92 Underlayer 101 Glass substrate 102 Bottom Base film 103 Amorphous silicon film 104 Island semiconductor layer 105 Gate insulating film (silicon oxide film) 106 ··· Gate electrode 107 ··· Source / drain region 109 ··· Drain / source region 108 ··· Channel formation region 110 ··· Interlayer insulating film 111 ··· Source / drain electrode 112 ..Drain / source electrodes

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoji Miyanaga 398 Hase, Atsugi-shi, Kanagawa Pref. Examiner at Semiconductor Energy Laboratory Co., Ltd. Sonoko Miyazaki (56) References JP-A-5-198507 (JP, A) (58) Field surveyed (Int.Cl. 7 , DB name) H01L 21/20 H01L 29/786

Claims (20)

(57) [Claims]
1. A step of introducing a catalyst element for promoting crystallization to one surface of an amorphous silicon film, and a step of forming a crystal nucleus on a surface of the amorphous silicon film on which the catalyst element is introduced. A step of dehydrogenating the amorphous silicon film; and irradiating the amorphous silicon film with a laser beam or an equivalent intense light from the surface of the amorphous silicon film where crystal nuclei are formed, A step of crystallizing a film.
2. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film; a step of dehydrogenating the amorphous silicon film; Forming a crystal nucleus on the surface side on which the catalytic element is introduced, and irradiating the amorphous silicon film with a laser beam or a similar intense light from the surface side on which the crystal nuclei are formed, A step of crystallizing a film.
3. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film, and a step of forming a crystal nucleus on a surface of the amorphous silicon film on which the catalyst element is introduced. Forming a dangling bond in the amorphous silicon film; and irradiating the amorphous silicon film with a laser beam or a strong light equivalent thereto from the side of the amorphous silicon film where crystal nuclei are formed, Crystallizing a crystalline silicon film.
4. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film; a step of forming dangling bonds in the amorphous silicon film; Forming a crystal nucleus on the surface of the silicon film on which the catalytic element is introduced, and irradiating a laser beam or a strong light equivalent thereto from the surface of the amorphous silicon film on which the crystal nuclei are formed; Crystallizing a crystalline silicon film.
5. A step of dehydrogenating an amorphous silicon film; a step of introducing a catalytic element for promoting crystallization to one surface of the amorphous silicon film; Forming a crystal nucleus on the side where the catalytic element is introduced, and irradiating a laser beam or an equivalent strong light from the side where the crystal nuclei of the amorphous silicon film are formed, A step of crystallizing a film.
6. A step of forming a dangling bond in an amorphous silicon film; a step of introducing a catalytic element for promoting crystallization to one surface of the amorphous silicon film; Forming a crystal nucleus on the surface of the silicon film on which the catalytic element is introduced, and irradiating a laser beam or a strong light equivalent thereto from the surface of the amorphous silicon film on which the crystal nuclei are formed; Crystallizing a crystalline silicon film.
7. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film, and forming a silicon nitride film in contact with the surface of the amorphous silicon film where the catalyst element is introduced. Performing a dehydrogenation of the amorphous silicon film; forming a crystal nucleus on a surface of the amorphous silicon film on which a catalytic element is introduced; Irradiating a laser beam or an intense light equivalent thereto from the surface side on which the crystal nuclei are formed to crystallize the amorphous silicon film.
8. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film, and forming a silicon nitride film in contact with the surface of the amorphous silicon film where the catalyst element is introduced. Forming a crystal nucleus on the surface of the amorphous silicon film on which the catalytic element has been introduced; performing dehydrogenation in the amorphous silicon film; A step of irradiating a laser beam or a strong light equivalent thereto from the surface on which the crystal nuclei are formed to crystallize the amorphous silicon film.
9. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film, and forming a silicon nitride film in contact with the surface of the amorphous silicon film where the catalyst element is introduced. Forming a dangling bond in the amorphous silicon film; forming a crystal nucleus on a surface of the amorphous silicon film on which a catalytic element is introduced; Irradiating a laser beam or a strong light equivalent thereto from the surface of the silicon film on which crystal nuclei are formed to crystallize the amorphous silicon film.
10. A step of introducing a catalyst element for promoting crystallization to one surface of the amorphous silicon film, and forming a silicon nitride film in contact with the surface of the amorphous silicon film where the catalyst element is introduced. Forming a crystal nucleus on the surface of the amorphous silicon film on which the catalytic element is introduced; forming dangling bonds in the amorphous silicon film; Irradiating a laser beam or a strong light equivalent thereto from the surface of the silicon film on which crystal nuclei are formed to crystallize the amorphous silicon film.
11. A process for forming an amorphous silicon film, wherein the step of performing dehydrogenation of the amorphous silicon film, a catalyst source which promotes crystallization on one surface of the amorphous silicon film
Introducing nitrogen and contacting the surface of the amorphous silicon film with the catalytic element introduced therein with nitrogen.
Forming a silicon nitride film, and forming a crystal nucleus on a surface of the amorphous silicon film on which the catalytic element is introduced.
Forming a laser beam from a side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
12. A step of forming a silicon nitride film, and introducing a catalytic element for promoting crystallization to the surface of the silicon nitride film.
And forming an amorphous silicon film on the surface of the silicon nitride film.
When the crystal nucleus on the side in contact with the silicon nitride film of the amorphous silicon film
Forming , dehydrogenating the amorphous silicon film, and forming a laser from the side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
13. A step of forming a silicon nitride film, and introducing a catalyst element for promoting crystallization to the surface of the silicon nitride film.
And forming an amorphous silicon film on the surface of the silicon nitride film.
When, and performing dehydrogenation of the amorphous silicon film, a crystal nucleus the on the side in contact with the silicon nitride film of the amorphous silicon film
Forming a laser beam from the side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
14. A step of forming an amorphous silicon film, and forming a silicon nitride film in contact with a surface of the amorphous silicon film.
A step, the crystal on the surface of the amorphous silicon film through the silicon nitride film
Introducing a catalytic element that promotes the formation of a crystal, and forming a crystal nucleus on the surface of the amorphous silicon film on which the catalytic element is introduced.
Forming an amorphous silicon film, dehydrogenating the amorphous silicon film , and forming a laser from the side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
15. A step of forming an amorphous silicon film, and forming a silicon nitride film in contact with a surface of the amorphous silicon film.
A step, the crystal on the surface of the amorphous silicon film through the silicon nitride film
Introducing a catalytic element that promotes the formation of the amorphous silicon film, dehydrogenating the amorphous silicon film, and forming a crystal nucleus on the surface of the amorphous silicon film on which the catalytic element is introduced.
Forming a laser beam from a side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
16. A step of forming an amorphous silicon film, a step of dehydrogenating the amorphous silicon film, and forming a silicon nitride film in contact with a surface of the amorphous silicon film
A step, the crystal on the surface of the amorphous silicon film through the silicon nitride film
Introducing a catalytic element that promotes the formation of a crystal, and forming a crystal nucleus on the surface of the amorphous silicon film on which the catalytic element is introduced.
Forming a laser beam from a side of the amorphous silicon film where crystal nuclei are formed.
Irradiating light or strong light equivalent thereto,
Crystallizing a film .
17. The method according to claim 1, wherein:
In the section , Ni, Pt, Cu, Ag, as a catalytic element,
A method for manufacturing a semiconductor, comprising using one or more elements selected from Au, In, Sn, Pb, P, As, and Sb.
18. any of claims 1 to 1 6 1
In the paragraph , as a catalyst element, a group VIII, a group IIIb, a group IVb,
A semiconductor manufacturing method using one or more kinds of elements selected from Vb group elements.
19. A method for forming a crystal nucleus on one side and dehydrogenating an amorphous silicon film from a side on which the crystal nucleus is formed with a laser beam or an equivalent intensity thereof. A semiconductor manufacturing method, comprising irradiating light to grow crystals from the crystal nuclei.
20. With respect to an amorphous silicon film in which a crystal nucleus is formed on one surface side and a dangling bond is formed, a laser beam or a laser beam equivalent thereto is applied from the surface side on which the crystal nucleus is formed. A method for manufacturing a semiconductor, comprising irradiating strong light to grow a crystal from the crystal nucleus.
JP03796994A 1994-02-10 1994-02-10 Semiconductor fabrication method Expired - Fee Related JP3190512B2 (en)

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JP3917205B2 (en) 1995-11-30 2007-05-23 株式会社半導体エネルギー研究所 Method for manufacturing semiconductor device
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TWI313059B (en) 2000-12-08 2009-08-01 Sony Corporatio
KR100611659B1 (en) 2004-07-07 2006-08-10 삼성에스디아이 주식회사 Thin Film Transitor and Method of fabricating thereof
KR100656495B1 (en) 2004-08-13 2006-12-11 삼성에스디아이 주식회사 Thin film transistor and method fabricating thereof
KR20080111693A (en) 2007-06-19 2008-12-24 삼성모바일디스플레이주식회사 Fabricating method of polycrystalline silicon, tft fabricated using the same, fabricating method of the tft, and organic lighting emitting diode(oled) display device comprising the same

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