JPH07226374A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To provide a method of obtaining a crystalline silicon through a thermal treatment which is carried out at a specific temperature for a specific time using catalytic element that promotes crystallization, wherein an irradiation operation is carried out together with a thermal treatment at the same time. CONSTITUTION:A very thin oxide film 13 is formed on an amorphous silicon film 12 provided onto a glass board 11, and a water solution such as acetate water solution where 10 to 200ppm (adjusted) of catalytic element such as nickel or the like is added is dripped down on the oxide film 13. The glass board 11 is made to stand in this state for a specific time and then spin-dried by a spinner 15. The glass board 11 is thermally treated at a temperature of 550 deg.C for four hours and furthermore irradiated with laser rays for the formation of a crystalline silicon film. In this constitution, a water solution is controlled in concentration of catalytic element, whereby a formed crystalline silicon film can be precisely controlled in concentration of catalytic element. Thus, a semiconductor device of high characteristics can be obtained by the use of this crystalline silicon film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a crystalline semiconductor used in a thin film device such as an insulating gate type field effect transistor.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a crystalline silicon semiconductor thin film used in a thin film device such as a thin film insulating gate type 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 the amorphous silicon film formed by (1) by irradiating laser light or heating. A crystalline silicon film or a crystalline silicon film generally means a polycrystalline silicon film,
A silicon film called a microcrystalline silicon film or a microcrystal. Further, it means a silicon film having a crystal component or a crystal structure.

[0003]

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

[0004]

According to the present invention, a crystal nucleus is formed on one surface of the amorphous silicon film, and hydrogen is extracted to form an unpaired bond. The gist is to obtain a crystalline silicon film by growing crystal nuclei by irradiating laser light or intense light from the side where the nuclei are formed.

The one surface of the amorphous silicon film means, for example, the back surface or one of the surfaces of the amorphous silicon film formed on the glass substrate which is a substrate having an insulating surface. . As the substrate, a quartz substrate or a semiconductor substrate having an insulating film formed on its surface can be used.

As a method for dehydrogenating or dehydrogenating, a method by heat treatment can be mentioned. This heat treatment is preferably performed in a vacuum or an inert atmosphere. Further, this heat treatment needs to be performed at a temperature equal to or lower than the crystallization temperature of the amorphous silicon film from which hydrogen is discharged. This is because when the heat treatment is performed at a temperature equal to or higher than the crystallization temperature, the amorphous semiconductor is crystallized, and sufficient crystallization cannot be achieved in the subsequent crystallization by irradiation with laser light.

The crystallization temperature of an amorphous silicon film is generally 600.
As described in detail below, the crystallization temperature is about 550 ° C. or lower, although the temperature is about 550 ° C. by introducing a catalytic element that promotes crystallization. Therefore, in this case, the heat treatment at the crystallization temperature or lower is appropriately 500 ° C. or lower, preferably 450 ° C. or lower.

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

By heat-treating this amorphous silicon film at a temperature not higher than the crystallization temperature, uniform and thorough dehydrogenation can be carried out in the film. This improves the in-plane distribution of crystallinity and the uniformity of crystal grain size of the silicon semiconductor film. By using this crystalline silicon film, it becomes possible to form a thin film transistor with uniform characteristics on a large-area substrate.

To form crystal nuclei, a catalytic element that promotes crystallization is introduced into one surface of the amorphous silicon film and heated at a temperature equal to or higher than the crystallization temperature of the amorphous silicon film. Be seen. 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 this crystal nucleus is 500 ° C., preferably 550 ° C. It can be done more than once.

Either the heat treatment step for discharging hydrogen or the heat treatment step for forming crystal nuclei may be performed first. The heat treatment step for discharging hydrogen may be performed before the introduction of crystal nuclei. Although an excimer laser is generally used as the laser light, it goes without saying that the structure of the present invention does not limit the kind of the laser and any laser may be used.

It is desirable that the laser light is applied in a vacuum or an inert atmosphere. This is to prevent the dangling bonds (dangling bonds) of the amorphous silicon film generated as a result of hydrogen desorption from bonding with oxygen, hydrogen or nitrogen in the air which is an active gas.

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

That is, as a result of irradiation of KrF excimer laser light (wavelength of 248 nm) on an amorphous silicon film which has been thoroughly dehydrogenated from a non-single crystal silicon film, the experimental result shows that the crystallinity is significantly improved. It is based on.

The amorphous silicon film generally contains a large amount of hydrogen, and this hydrogen neutralizes dangling bonds. However, the present inventors have recognized from the above experimental fact that the existence of dangling bonds is extremely important in the crystallization from amorphous in the molten state, and the dangling bonds in the amorphous state are very important. The inventors have found a method of promoting instantaneous crystallization in a molten state by intentionally forming.

Further, 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 to the air, the dangling bonds thus formed are neutralized. It is very important to carry out crystallization by laser irradiation in an inert atmosphere.

The temperature not higher than the crystallization temperature of the amorphous silicon semiconductor is the temperature at which the amorphous silicon semiconductor starts to be crystallized by the heat treatment.

The heating annealing before crystallization by irradiation with laser light at a temperature not higher than the crystallization temperature results in almost the improvement of crystallinity even if the silicon film once crystallized is irradiated with laser light. This is based on the experimental result that the crystallinity is remarkably lower than that of a film which is not seen and is crystallized by irradiating laser light in an amorphous state.

Therefore, it is extremely important to carry out hydrogen desorption from the amorphous silicon semiconductor film at a temperature below the crystallization temperature of the amorphous semiconductor film. However, in the structure of the present invention, it is also extremely important to thoroughly remove hydrogen from the amorphous silicon semiconductor film to generate as many unpaired bonds as possible in the film, and therefore, to the extent that crystallization does not occur. It is necessary to perform heat treatment for hydrogen discharge at a temperature as high as possible.

The major feature of hydrogen discharge by heating is that hydrogen discharge can be carried out uniformly and thoroughly. As a result, a polycrystalline silicon semiconductor film having a large grain size and a uniform grain size can be obtained.

In the above, crystallization by irradiation with laser light has been mainly described, but a method by irradiation with intense light may be adopted instead of laser light. Especially, it is useful to perform crystallization by using rapid thermal annealing (RTA) by irradiation of infrared light. Infrared light is difficult to be 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 that promotes crystallization is introduced into one surface of the amorphous silicon film, and then heat treatment is performed so that crystal nuclei are formed by the action of the catalyst element in the amorphous silicon film. On one surface and in the vicinity thereof, and then laser light is irradiated from the side where the crystal nuclei are formed (one surface side of the amorphous silicon film) to grow crystals from the crystal nuclei. It is characterized by At this time, before the introduction of the catalytic element, or after the introduction of the catalytic element and before the formation of crystal nuclei,
Alternatively, heat treatment for promoting dehydrogenation from the amorphous silicon film is performed after the formation of the crystal nuclei.

Irradiation of laser light for crystallization is
It is important to carry out from the surface side of the amorphous silicon film on which crystal nuclei are formed. This is because the film quality of the crystalline silicon film obtained by irradiating the laser light from the surface of the amorphous silicon film on which the crystal nuclei are formed and the surface of the amorphous silicon film on which the crystal nuclei are formed. Is the result found by comparing with the film quality of the crystalline silicon film obtained when the laser beam is irradiated from the opposite surface side.

The reason for limiting the irradiation direction of the laser light is as follows. As a result of studying the variation in characteristics during laser crystallization, it was recognized that the two main reasons were the difference in crystallinity due to the temperature distribution in the laser irradiation area and the accidental nucleation. Arrived To explain this reason in more detail, the intensity distribution of the laser light generally has a Gaussian distribution, and the temperature of the amorphous silicon film also has a distribution in accordance 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 where the temperature is low or where heat is diffused, and crystallization should occur. Crystal nuclei do not always exist, and it is expected that crystallization will occur explosively when the supercooled liquid comes into contact with the crystal nuclei. Further, since the crystal nuclei themselves have irregularities at the interface with silicon oxide, it is expected that uniform crystallization will be difficult.

In order to avoid this phenomenon, it is desirable that the portion where the melted portion first falls below the melting point and the portion where the crystal nuclei exist coincide. Therefore, the inventors tried to introduce a pre-controlled crystal nucleus before laser crystallization and then perform laser crystallization. As a result, when a material having higher laser conductivity and higher thermal conductivity than amorphous silicon is used as the crystal nucleus, that is, a material that lowers to the melting point of silicon faster than amorphous silicon is used. In this case, it was found that crystal growth started from there and a good crystalline silicon thin film could be obtained. As such a material, many crystalline materials can be listed as candidates. Particularly, as a material capable of epitaxial growth, fine crystal grains of crystalline silicon or amorphous silicon after nickel catalyst is added. Nickel silicide or the like obtained by heating is particularly desirable.

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

The catalytic element that promotes crystallization of the amorphous silicon film is preferably Ni, Pt, Cu, Ag, Au,
One or more elements selected from In, Sn, Pb, P, As, and Sb can be used. Also, VI
It is also possible to use one or more kinds of elements selected from the group II elements, IIIb, IVb, and Vb elements.

As a method of introducing the catalytic element that promotes crystallization, a method of applying a solution containing the catalytic element to the surface of the amorphous silicon film is useful.

Particularly 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 catalytic element.

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

By adopting the configuration 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 enhance 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 catalytic element introduced into the amorphous silicon depends on the concentration of the catalytic element in the solution. (C) Since the catalytic element adsorbed on the surface of the amorphous silicon film mainly contributes to crystallization, the catalytic element can be introduced at the required minimum 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, the inclusion includes both the meaning of being contained as a compound and the meaning of being contained by simply dispersing.

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 the catalyst and this nickel is included in the polar solvent, nickel is introduced as a nickel compound. The nickel compound is typically nickel bromide, nickel acetate, nickel oxalate, nickel carbonate, nickel chloride, nickel iodide, nickel nitrate, nickel sulfate, nickel formate, nickel acetylacetonate, 4-cyclohexyl butyric acid. A material selected from nickel, nickel oxide, and nickel hydroxide is used.

Further, as a solvent containing a catalytic element, benzene, toluene, xylene, carbon tetrachloride, which are nonpolar solvents,
It is possible to use one selected from chloroform and ether.

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

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

When elemental nickel is used as the catalytic element, it must be dissolved in acid to form a solution.

The above description is an example of using a solution in which nickel, which is a catalytic element, is completely dissolved. However, even if nickel is not completely dissolved, a powder of nickel alone or a nickel compound is in the dispersion medium. A material such as an emulsion uniformly dispersed in the above may be used. Alternatively, a solution for forming an oxide film may be used. Examples of such a solution include OCD (Ohka Diffusion) of Tokyo Ohka Kogyo Co., Ltd.
Source) can be used. Using this OCD solution, 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, it is also possible to add impurities so that it can be utilized 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 containing nickel, when these solutions are directly applied to the amorphous silicon film, the solution becomes elastic. You may get burned. In this case, a thin oxide film having a thickness of 100 Å or less is first formed, and a solution containing a catalytic element is applied thereon, whereby the solution can be applied uniformly. A method of improving wetting by adding a material such as a surfactant to the solution is also effective.

Further, by using a non-polar solvent such as a toluene solution of nickel 2-ethylhexanoate as a solution, it is possible to directly coat the surface of the amorphous silicon film. In this case, it is effective to pre-apply a material such as an adhesive used when applying the resist. However, if the coating amount is too large, the addition of the catalytic element into the amorphous silicon will be hindered, and therefore caution must be exercised.

The amount of the catalytic element contained in the solution depends on the type of the solution, but the general tendency is to set the amount of nickel to 200 ppm to 1 ppm, preferably 50 ppm to 1 ppm (weight conversion) relative to the solution. Is desirable. This is a value determined in consideration of the nickel concentration in the film after the crystallization is completed.

The amorphous silicon film to which the catalytic element has been added is heat-treated to form crystal nuclei and then irradiated with laser light to uniformly form the entire surface of the amorphous silicon film into a crystalline silicon film. It can be crystallized. A very specific phenomenon has been observed in this laser crystallization process. Compared with the laser power required to perform crystallization on the whole surface when crystal nuclei are not introduced, the same degree of crystallization can be achieved with a considerably smaller laser power. Generally, in order to crystallize a microcrystallized amorphous film,
A higher laser power than that required to crystallize a film containing no crystal component is required (because the laser power absorbed is small due to the different transmittance), while the opposite tendency is observed. This is also one of the great merits of the present invention.

By adjusting the introduction amount of the catalytic element,
The density of crystal nuclei can be controlled. The state in which the crystal nuclei are formed can be said to be a state in which a crystalline component and an amorphous component are mixed as a whole. By irradiating with laser light here, crystal growth can be performed from crystal nuclei present in the component having crystallinity, and a silicon film with high crystallinity can be obtained. That is, it is possible to grow small crystal grains into large crystal grains. Therefore, the crystal growth distance, the size of the accompanying crystal grains, the number of crystal grains, and the like can be controlled by appropriately setting the amount of the catalytic element initially introduced and the laser power.

Instead of irradiating with laser light, a method of irradiating with intense light, especially infrared light may be adopted. Infrared light is difficult to be absorbed by glass and easily absorbed by a silicon thin film, so that the silicon thin film formed on the glass substrate can be selectively heated, which is useful. This method using infrared light is called rapid thermal annealing (RTA) or rapid thermal process (RTP).

The method of introducing the catalyst 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 catalyst element can be used.
For example, a metal compound or oxide containing a catalytic element can be used.

[0048]

The action of the catalytic element forms crystal nuclei on one surface of the amorphous silicon film and in the vicinity thereof, and further artificially forms a large number of dangling bonds in the amorphous silicon film. By subsequently irradiating the surface on which the crystal nuclei are formed with laser light or intense light, crystals can be grown from the crystal nuclei, and a crystalline silicon film having good crystallinity can be obtained.

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

[0050]

【Example】

[Embodiment 1] This embodiment shows the effect of a heat treatment for hydrogen extraction when an amorphous silicon film is crystallized by laser light irradiation based on experimental results.

First, the silicon oxide film which is the base protection film
Glass substrate with a film thickness of 00Å (Corning 705
9) an amorphous silicon film (a-
A Si film) was formed to a thickness of 1000Å 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 manufactured. One type was not heat-treated, and the other type was heat-treated for 1 hour at a temperature of 500 ° C. in a nitrogen atmosphere which is an inert gas. This heat treatment is for discharging hydrogen from the amorphous silicon film to artificially form dangling bonds in the film. And for both, in a vacuum, the Kr of wavelength 248 nm
Crystallization was performed by irradiation with F excimer laser. This step was performed only for one shot by changing the energy density of laser light. Further, the substrate was irradiated with laser light without heating.

Raman spectra were measured to examine the crystallinity of the two types of samples produced as described above. The curve indicated by A in FIG. 1 is the wave number (cm ⁻¹ ) of the peak of the Raman spectrum of the sample heat-treated at a temperature of 500 ° C. for 1 hour before the laser light irradiation and the energy density (mJ / mJ / 3 is a graph showing a relationship with cm ² ). The curve indicated by B is the relationship between the peak and wave number (cm ^-1 ) of the Raman spectrum of the sample that was not heat-treated before laser light irradiation, and the energy density (mJ / cm ² ) of the laser light irradiated. It is a graph showing.

As can be seen from the curve A in FIG. 1, by performing the heat treatment before the irradiation of the laser beam, the peak of the single crystal silicon is 521 even at a low laser energy density.
It can be seen that a value close to cm ^-1 can be obtained. Generally, the peak of Raman spectrum of a film obtained by crystallizing an amorphous silicon film is 521 cm which is the peak of 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, 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 discharging hydrogen.

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

Generally, the energy density of an excimer laser is apt to fluctuate and lacks stability, which is a drawback. However, when the relationship such as the curve A is obtained, the crystallinity has little dependence on the intensity of the laser beam,
A crystalline silicon film having uniform crystallinity can be obtained without being affected by the instability of the excimer laser.

However, in the case of the curve B, that is, when the heat treatment for discharging hydrogen 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, how to manufacture a device having uniform characteristics is a big problem. Therefore, as shown by the curve A, it is useful to obtain a crystalline silicon film which is stable and has good crystallinity independent of the energy density of laser light.

Further, as shown in FIG. 1, it is concluded that the sample heat-treated for hydrogen generation is crystallized by a laser beam having a low energy density as shown by the curve A. From this, it is concluded that the minimum energy density (threshold energy density) for causing crystallization can be lowered by performing the heat treatment for dehydrogenation.

From this, it can be concluded that the threshold energy density for crystallization can be lowered by thoroughly discharging hydrogen into the amorphous silicon film and forming a large amount of dangling bonds. .

Example 2 In this example, a step of incorporating a catalytic element that promotes crystallization into an aqueous solution, coating the solution on an amorphous silicon film, and introducing a catalytic element that promotes crystallization,
The heat treatment step for forming crystal nuclei, the heat treatment step for dehydrogenation, and the crystallization step by laser light irradiation will be described.

The steps up to the introduction of the catalytic element (here, nickel is used) will be described with reference to FIG. 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 subjected to plasma CVD.
Method and LPCVD method to form a film having a thickness of 100 to 1500 Å. Here, the amorphous silicon film 12 is formed to a thickness of 1000 Å by the plasma CVD method. (Fig. 1
(A))

Then, a hydrofluoric acid treatment is performed to remove dirt and a natural oxide film, and then the oxide film 13 is removed by 10 to 50.
Deposit on Å. If dirt can be ignored, oxide film 13
Instead of the above, a natural oxide film may be used as it is.

Since the oxide film 13 is extremely thin, the exact film thickness is unknown, but it is considered to be about 20Å.
Here, the oxide film 1 is formed by irradiation with UV light in an oxygen atmosphere.
3 is deposited. The film forming conditions are UV in an oxygen atmosphere.
Is irradiated for 5 minutes. This oxide film 13
A thermal oxidation method may be used as the film forming method. Alternatively, treatment with hydrogen peroxide may be used.

This oxide film 13 is provided to spread the acetate solution over the entire surface of the amorphous silicon film in the later step of applying the acetate solution containing nickel, that is, to improve the wettability. Is. For example, when the acetate solution is directly applied to the surface of the amorphous silicon film, the amorphous silicon repels the acetate solution, so that nickel cannot be introduced to the entire surface of the amorphous silicon film. 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 (200
0 rpm, 60 seconds). (Fig. 1 (C), (D))

The concentration of nickel in the acetic acid solution is 1
Practical use is achieved when the content is at least ppm, preferably at least 10 ppm. 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 the catalyst element can be directly introduced onto the amorphous silicon film.

A layer containing nickel having an average film thickness of several Å to several hundred Å is formed on the surface of the amorphous silicon film 12 after spin drying by performing the coating process of this nickel solution once to plural times. 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. Note that this layer is not always a perfect film.

After application of the above solution, the state is maintained for 1 minute. The concentration of nickel contained in the silicon film 12 can be finally controlled also by the holding time. The nickel concentration can be controlled by the nickel concentration in the solution.

Then, heat treatment is performed in a heating furnace in a nitrogen atmosphere at 550 ° C. for 1 hour. 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, in this step, dangling bonds are formed in the silicon thin film 12. A view schematically showing this state is shown in FIG. FIG. 3A shows a state in which crystal nuclei 21 formed by introducing nickel are formed on the surface of the amorphous silicon film 12 formed on the glass substrate 11. A photograph of a cross section of the silicon thin film corresponding to FIG. 3A is shown in FIG. FIG. 4 shows a state in which crystal nuclei are formed on the surface of an amorphous silicon film formed on a glass substrate by introducing nickel and the crystal nuclei are slightly grown. In FIG. 4, this slightly grown crystal component is indicated by a black square. Although a silicon oxide film is formed on the surface of the glass substrate, as shown in FIG.
It cannot be distinguished from the glass substrate in the photograph shown in.

The above heat treatment can be carried out at a temperature of 500 ° C. or higher, but if the temperature is low, the heating time must be lengthened and the production efficiency will be reduced. Further, if the temperature is 550 ° C. or more, the problem of heat resistance of the glass substrate used as the substrate is exposed.

Although the method of introducing the catalytic element onto the amorphous silicon film has been described in this embodiment, the method of introducing the catalytic element below the amorphous silicon film may be adopted. in this case,
The catalyst element may be introduced onto the base film using a solution containing the catalyst element before forming the amorphous silicon film.

After the formation of crystal nuclei, heat treatment is further performed at 400 ° C. for 3 hours in a nitrogen atmosphere to thoroughly dehydrogenate the hydrogen. In this step, a large number of dangling bonds are formed in the film. Thus, a partially crystalline silicon film 12 in which crystal nuclei are introduced and dangling bonds are formed is obtained. Next, a KrF excimer laser (wavelength: 248 nm, pulse width: 30 nsec) was applied for 200 to 200 in a nitrogen atmosphere.
The silicon film 12 is completely crystallized by irradiation with a power density of 350 mJ / cm ² for several shots. This process is
In particular, irradiation with infrared light may be used. In this process,
It is important to irradiate the laser light from the upper surface side of the silicon film 12 in which the catalytic element is introduced and crystal nuclei are formed.

FIG. 3 (B) schematically shows a state in which the crystal growth as shown by 22 is performed from the crystal nucleus shown by 21 by being irradiated with the laser beam 20. . Crystallization grows around the crystal nucleus 21 as shown by the arrows in FIGS. 3 (A) and 3 (B). By the progress of this crystallization, a polycrystalline structure as shown by 23 in FIG. 3C can be obtained.

Example 2 In this example, a catalyst element was introduced into the surface of an amorphous silicon film formed on a glass substrate, hydrogen was further extracted, and crystal nuclei were further formed. An example in which crystallization is performed by irradiation with laser light will be shown.

The process of this embodiment is shown in FIG. First, a silicon oxide film 52 as a base film is formed on the glass substrate 51 by 1000 Å
To a film thickness. Then, an amorphous silicon film 53 is formed in a thickness of 1000Å by plasma CVD method or low pressure thermal CVD method. Next, as shown in Example 2, nickel is introduced as a catalytic element using a solution. The conditions such as the nickel concentration are the same as in Example 2. In this step, nickel is brought into contact with the surface of the amorphous silicon film 53 and held. (Figure 5 (A))

Next, heat treatment is performed at 400 ° C. for 2 hours,
Hydrogen is extracted from 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 dehydrogenating is carried out at 350 ° C to 50 ° C.
It is preferably carried out at a temperature of 0 degrees. When the catalyst element is not introduced, it is effective to carry out hydrogen desorption at a temperature of about 500 to 550 degrees, but when the catalyst element is introduced, the crystallization temperature of the amorphous silicon film is 550. Since it is less than 100 degrees Celsius, it is necessary to discharge hydrogen at a temperature of less than 500 degrees Celsius.

Next, heat treatment for forming crystal nuclei 54 is performed. The heat treatment for forming the crystal nucleus 54 is 5
It is carried out in an inert atmosphere at 50 ° C. for 1 hour. (Fig. 5 (C))

This crystal nucleus forming step needs to be performed at a temperature equal to or higher than the crystallization temperature. However, it is important to carry out crystallization to the extent that crystal nuclei are formed without proceeding completely.

Then, the KrF excimer laser beam 55 is irradiated to grow crystals from the crystal nuclei.
It is important that this laser light irradiation is performed from the surface side of the amorphous silicon film on which the crystal nuclei are formed. In this step, crystal growth is performed from the crystal nuclei, and the crystalline silicon film 5
6 can be obtained. (Figure 5 (D))

[Embodiment 3] In this embodiment, after introducing a catalytic element, a heat treatment for forming crystal nuclei is performed, a heat treatment for dehydrogenating is further performed, and a crystal by irradiation with laser light is further added. This is an example of conversion. FIG. 6 shows a manufacturing process of this example. The reference numerals shown in FIG. 6 are the same as those shown in FIG.

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

Next, a heat treatment for forming crystal nuclei is performed. The heat treatment for forming the crystal nucleus 54 is 550
1 hour in a nitrogen atmosphere. (Fig. 6
(B))

Next, heat treatment is performed at 400 ° C. for 2 hours,
Hydrogen is extracted from 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 the KrF excimer laser beam 55, crystal growth from the crystal nuclei is performed.
It is important that this laser light irradiation is performed from the surface side of the amorphous silicon film on which the crystal nuclei are formed. In this step, crystal growth is performed from the crystal nuclei, and the crystalline silicon film 5
6 can be obtained. (Figure 6 (D))

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

FIG. 7 shows the 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 500Å to 30
00Å, for example, 1500Å. Next, as shown in Example 2, nickel is introduced into the surface of the base film 72 as a catalytic element using a solution. By this step, the state in which the catalytic element is provided in contact with the surface of the base film is realized.

Next, an amorphous silicon film 73 is formed in a thickness of 1000Å by plasma CVD method or low pressure thermal CVD method. Next, heat treatment for hydrogen discharge is performed to release hydrogen in the film and form a large number of dangling bonds. The heat treatment for this hydrogen discharge is performed in a nitrogen atmosphere.
It is performed under the condition of 350 to 500 degrees, for example, 450 degrees and 2 hours. (Fig. 7 (B))

Next, a 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 is 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 the base film 72 and the amorphous silicon film and in the vicinity thereof. (Fig. 7
(C))

Next, laser light is irradiated from the glass substrate 71 side to crystallize the amorphous silicon film 75. In this step, the crystal nuclei 74 are crystal-grown by the energy of the laser beam, and the crystalline silicon film 75 can be obtained.
(Figure 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 catalyst element is introduced to the surface of an underlayer film on which an amorphous silicon film is formed, an amorphous silicon film is formed thereafter, and a base film is formed by heat treatment. Crystal nuclei are 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 surface side on which the crystal nuclei are formed.

FIG. 8 shows the 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 by a sputtering method to a thickness of 1000 Å. Next, nickel, which is a catalytic element, is applied to the surface of the base film 72 using a solution by the method shown in the second embodiment. (Figure 8 (A))

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

Next, a heat treatment for discharging hydrogen is performed. This step is performed in a nitrogen atmosphere at 450 ° C. for 2 hours. 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 crystal nuclei 74 and obtain a crystalline silicon film 75.
(Figure 8 (D))

In this case, it is important to irradiate the laser beam from the substrate 71 side. In this step, if the laser light 76 is applied from the surface side of the amorphous silicon film, that is, the surface side where the crystal nuclei are not 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 with an underlying film interposed therebetween, and then a heat treatment step for discharging hydrogen is performed, and then an amorphous silicon film is formed. A catalytic element that promotes crystallization is introduced into the surface of the silicon film, and then heat treatment is performed to form crystals, and the surface side where the crystal nuclei are finally formed (exposed amorphous silicon film surface side) Is irradiated with laser light from the above to grow crystals from the crystal nuclei.

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

Next, nickel, which is a catalytic element, is introduced to the surface of the amorphous silicon film 93 by the method shown in the second embodiment.
The conditions are the same as in the second embodiment. (Fig. 9 (B))

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

Next, as shown in FIG. 9D, crystal nuclei 9
A crystalline silicon film 96 is obtained by irradiating a KrF excimer laser beam from the surface side on which 4 is formed.

[Embodiment 7] In this embodiment, a thin film transistor (generally referred to as a TFT) is formed by using a crystalline silicon film on a glass substrate manufactured by the method described in Embodiments 1 to 6. Is to be manufactured. The thin film transistor described in this embodiment can be used for a pixel of a liquid crystal display device, a peripheral circuit, and other integrated circuits. A method for manufacturing a thin film crystalline silicon semiconductor used in this example is as follows.
Any of the crystalline silicon films shown in Examples 1 to 6 may be used.

FIG. 10 shows a manufacturing process of a thin film transistor. In FIG. 10A, a silicon oxide film 102 serving as a base film and a crystallized crystalline silicon film 10 are formed over a glass substrate 101.
The state where 3 is provided is shown. Silicon oxide film 102
Has a thickness of 1500Å, and the crystalline silicon film has a thickness of 10
It is 00Å.

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

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

Next, the silicon oxide film 1 forming the gate insulating film
05 is formed to a thickness of 1000Å by a sputtering method. Then, an N-type crystalline silicon film for forming a gate electrode is formed to a thickness of 5000Å 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,
The gate electrode 106 is formed. (Figure 10 (C))

Next, as shown in FIG. 10D, phosphorus ion doping is performed by the ion implantation method (or plasma doping method). This doping is gate electrode 1
06 is used as a mask. And 107 and 10
Region 9 is N-typed. 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 irradiating laser light or intense 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, the interlayer insulating film 110 is formed with silicon oxide or polyimide. Then, the electrode hole patterning is performed to form the source / drain electrode 111 and the drain / source electrode 112 with aluminum or other metal. At the same time, a gate wiring (not shown) is formed.
Thus, a thin film transistor using a 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 crystalline silicon film is obtained by forming crystal nuclei using the catalyst element, and irradiating a laser beam from the surface side on which the crystal nuclei are formed.

The reason why the nitride film is formed is to reduce the roughness of the interface with the amorphous silicon film and improve the flatness thereof by forming the nitride film. By forming crystal nuclei at the interface having this flatness, the crystal nuclei can be formed uniformly. Then, uniform crystal growth can be performed in the subsequent crystallization step by irradiation with laser light. Further, since the silicon nitride (SiN _x ) film functions as an antireflection film, when the nitride film is formed on the surface of the amorphous silicon film, the laser power is effectively utilized by irradiating the laser beam from the surface side. It can be configured.

The manufacturing process of this embodiment will be described with reference to FIGS. 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 1000Å.
A silicon nitride film or an aluminum nitride film may be used as the base film 122.

Next, the amorphous silicon film 123 is subjected to plasma CVD.
Method or low pressure thermal CVD method to form a film having a thickness of 1000Å. Then, according to the method described in Example 2, nickel is used as the catalyst element for promoting crystallization, and the nickel is used as the amorphous silicon film 12.
3 surface. (Figure 11 (A))

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

Next, as shown in FIG. 11C, heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C. for 1 hour. In this step, crystal nuclei 120 are formed.

Next, as shown in FIG. 11D, a heat treatment for discharging hydrogen is performed. This step is performed in a nitrogen atmosphere at 400 ° C. 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, laser light (KrF excimer laser) 125 is irradiated to grow crystals from the crystal nuclei 120. Thus, the crystalline silicon film 126 is obtained.

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

FIG. 12 shows the manufacturing process of this embodiment. First, a base film 122 is formed on a glass substrate by sputtering 1
Form a film with a thickness of 000Å. Next, the amorphous silicon film 123 is formed by plasma CVD or low pressure thermal CVD to 100
Form to a thickness of 0Å. Then, nickel, which is a catalytic element, is introduced to the surface of the amorphous silicon film 123 by the method shown in the second embodiment.

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

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

Next, as shown in FIG. 12D, a heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C. for 1 hour. In this step, crystal nuclei 120 are formed at and near the interface between the nitride film 124 and the amorphous silicon film 123.

Next, the crystal nuclei 120 are crystal-grown by irradiating a laser beam (KrF excimer) 125 from the surface side of the amorphous silicon film on which the crystal nuclei are formed, that is, the surface side on which the nitride film 124 is formed. Then, the 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 heat treatment for dehydrogenation,
Next, a catalytic element is introduced on the surface of the amorphous silicon film, then a nitride film is formed on the surface of the amorphous silicon film on which the catalytic element is introduced, and then heat treatment for forming crystal nuclei is performed. The amorphous silicon film is crystallized by irradiating a laser beam from the side where the crystal nuclei are formed.

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

Next, a heat treatment for discharging hydrogen is performed.
This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. Through this step, the amorphous silicon film 123
Hydrogen desorption is carried out therein, and dangling bonds are formed in the film. (Fig. 13 (A))

Then, nickel, which is a catalytic element, is introduced to the surface of the amorphous silicon film 123 by the method shown in the second embodiment. (Fig. 13 (B))

Next, the nitride film 124 is formed by the plasma nitriding method.
Is deposited to a thickness of about 200Å. (Figure 13 (C))

Next, as shown in FIG. 12D, a heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C. for 1 hour. In this step, crystal nuclei 120 are formed at and near the interface between the nitride film 124 and the amorphous silicon film 123.

Next, the crystal nuclei 120 are crystal-grown by irradiating a laser beam (KrF excimer) 125 from the side where the crystal nuclei of the amorphous silicon film are formed, that is, the side where the nitride film 124 is formed. Then, the 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 substrate having a light-transmitting property, and thereafter, crystallization is promoted on the surface of the nitride film. Is introduced, and then an amorphous silicon film is formed, followed by heat treatment for forming crystal nuclei,
Further, heat treatment is performed to remove hydrogen from the amorphous silicon film, and finally, a laser beam is irradiated from the substrate side to grow crystal nuclei and 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 by plasma CVD to a thickness of about 500 to 3000 Å, for example, 2000 Å.

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

Next, the amorphous silicon film 133 is subjected to plasma CVD.
Method or low pressure thermal CVD method to form a film with a thickness of 1000 Å. Then, as shown in FIG.
A heat treatment for forming the. This step is performed in a nitrogen atmosphere at 550 ° C. for 1 hour. The crystal nucleus as referred to herein means a region having a monocrystalline crystal seed in at least a nucleus portion in an amorphous semiconductor provided with dehydrogenation or dangling bonds.

Next, a heat treatment for discharging hydrogen is performed to form a large amount of dangling bonds in the amorphous silicon film 133. This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. (Figure 14 (C))

Next, laser light 1 is applied from the glass substrate 131 side.
By irradiating 34, crystal nuclei 130 are 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 through the glass substrate 131. When a quartz substrate is used as the substrate, laser light in the ultraviolet region, for example, KrF excimer laser (wavelength 248 nm) can be used. Alternatively, a XeCl excimer laser with a wavelength of 308 nm that transmits a silicon nitride film may be used. Alternatively, RTA by irradiation of infrared light may be used. Furthermore, strong light equivalent to that of the 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 thereafter the surface of the nitride film is promoted to be crystallized. Is introduced, and then an amorphous silicon film is formed, followed by heat treatment for dehydrogenating the amorphous silicon film, and further heat treatment for forming crystal nuclei. Finally, by irradiating a laser beam 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 the glass substrate 131 by a plasma CVD method at 500 to 3000 Å
The film is formed to a thickness of, for example, 2000 Å.

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

Next, the amorphous silicon film 133 is subjected to plasma CVD.
Method or low pressure thermal CVD method to form a film with a thickness of 1000 Å.

Next, a heat treatment for discharging hydrogen is performed to form a large amount of dangling bonds in the amorphous silicon film 133. This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. (Fig. 15 (B))

Then, as shown in FIG. 15C, a heat treatment for forming crystal nuclei is performed. This step is performed in a nitrogen atmosphere at 550 ° C. for 1 hour. In this step, crystal nuclei 130 are formed at the interface between the nitride film 132 and the amorphous silicon film 133 and its vicinity.

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

At this time, it is necessary to use, as the laser beam 134, a laser beam having a wavelength that transmits the glass substrate 131.

[Embodiment 13] In Embodiment 2, the catalyst element is introduced into the surface of the amorphous silicon film by including the catalyst element in the solution and applying this solution to the surface of the amorphous silicon film. In the method, a method of forming an extremely thin oxide film on the surface of the amorphous silicon film was adopted 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 this 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 catalytic element. (2) To improve crystallinity during crystal growth from crystal nuclei formed on the surface of the amorphous silicon film and in the vicinity thereof.

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

Then, nickel, which is a catalytic element, is introduced into the surface of the nitride film 154 by the same steps as those shown in the second embodiment. Here, an acetate solution in which nickel is added to the acetate solution (the nickel concentration is 25 pp in terms of weight)
Nickel is introduced by applying m) to the amorphous silicon film 153 on which the nitride film 154 is formed. Detailed conditions are the same as those described in the second embodiment. In this step, nickel is added to the amorphous silicon film 1 through the nitride film.
It will be introduced on the surface of 53. (Fig. 16 (B))

Next, a heat treatment for forming crystal nuclei is carried out so that the crystal nuclei 150 are converted into 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 1 hour. (Figure 15 (C))

Next, a heat treatment for discharging hydrogen is performed.
This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. (Figure 16 (D))

Next, crystallization is performed by irradiating the KrF excimer laser beam 155 from the side where the crystal nuclei 150 are formed, that is, the side where the nitride film 154 is formed. In this step, the crystal nuclei 150 grow crystals and a crystalline silicon film 156 can be obtained. (Fig. 16 (E))

[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 onto the nitride film to form the amorphous silicon film 153. A catalytic element is introduced to the surface of the film, and then heat treatment for hydrogen removal is carried out. Then, by heat treatment, crystal nuclei are formed at the interface between the amorphous silicon film and the nitride film and in the vicinity thereof. A crystalline silicon film is obtained by irradiating a laser beam from the surface side on which crystal nuclei are formed.

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

Then, nickel, which is a catalytic element, is introduced into the surface of the nitride film 154 by the same steps as those shown in the second embodiment. Here, an acetate solution in which nickel is added to the 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. Detailed conditions are the same as those described in the second embodiment. In this step, nickel will be introduced to the surface of the amorphous silicon film 153 through the nitride film 154. (Fig. 17 (B))

Next, a heat treatment for discharging hydrogen is performed.
This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. (Fig. 17 (C))

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

Next, a KrF excimer laser beam 155 is irradiated from the side of the nitride film 154, so that the crystal nucleus 150 is irradiated.
Can be grown to obtain a crystalline silicon film 156.
(Fig. 17 (E))

[Embodiment 15] In this embodiment, an amorphous silicon film is formed on a substrate having an insulating surface, and a heat treatment for discharging hydrogen is further performed. An ultrathin nitride film is provided on the surface, and a catalyst element-containing solution is applied onto the nitride film to introduce the catalytic element into the surface of the amorphous silicon film. A crystalline silicon film is obtained by forming crystal nuclei at the interface between the film and the nitride film and in the vicinity thereof, and then irradiating laser light from the surface side where the crystal nuclei are finally formed.

The fabrication process of this example is shown in FIG. First, a silicon oxide film is formed as a base film 152 on the glass substrate 151 to a thickness of 1000 Å by a sputtering method. Next, an amorphous silicon film 153 is formed to a thickness of 1000Å by plasma CVD method or low pressure thermal CVD method. Next, heat treatment for discharging hydrogen is performed. This step is performed in a nitrogen atmosphere at 400 ° C. for 2 hours. (Fig. 18
(A))

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

Then, nickel, which is a catalytic element, is introduced into the surface of the nitride film 154 by the same steps as those shown in the second embodiment. Here, an acetate solution in which nickel is added to the 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. Detailed conditions are the same as those described in the second embodiment. In this step, nickel will be introduced to the surface of the amorphous silicon film 153 through the nitride film 154. (Fig. 18 (C))

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

Next, a KrF excimer laser beam 155 is irradiated from the side of the nitride film 154 to form crystal nuclei 150.
Can be grown to obtain a crystalline silicon film 156.
(Fig. 18 (E))

[0168]

EFFECTS OF THE INVENTION With respect to an amorphous silicon film in which crystal nuclei are formed on one surface by introduction of a catalytic element and hydrogen is desorbed to form dangling bonds, the catalytic element is By irradiating laser light or intense light from the side of the formed surface, the crystal nuclei are crystal-grown to obtain a crystalline silicon film.

[Brief description of drawings]

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

FIG. 2 shows a manufacturing process of an example.

FIG. 3 shows a state of crystal growth.

FIG. 4 shows a photograph of a cross section of a silicon thin film.

FIG. 5 shows a manufacturing process of an example.

FIG. 6 shows a manufacturing process of an example.

FIG. 7 shows a manufacturing process of an example.

FIG. 8 shows a manufacturing process of an example.

FIG. 9 shows a manufacturing process of an example.

FIG. 10 shows a manufacturing process of an example.

FIG. 11 shows a manufacturing process of an example.

FIG. 12 shows a manufacturing process of an example.

FIG. 13 shows a manufacturing process of an example.

FIG. 14 shows a manufacturing process of an example.

FIG. 15 shows a manufacturing process of an example.

FIG. 16 shows a manufacturing process of an example.

FIG. 17 shows a manufacturing process of an example.

FIG. 18 shows a manufacturing process of an 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 light 51 ... Glass substrate 52 ... Underlayer film (silicon oxide film) 53 ... Amorphous silicon film 54 ... Crystal nucleus 55 ... Laser light 56 ... Crystalline silicon film 71 ... Glass substrate 72 ... Underlayer film 73 ... Amorphous silicon film 74 ... -Crystal nucleus 76-Laser light 75-Crystalline silicon film 91-Glass substrate 92-Base film 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 forming region 110..interlayer insulating film 111..source / drain electrode 112 .. ..Drain / source electrodes

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Takeyama, 398 Hase, Atsugi, Kanagawa Prefecture, Semiconducting Energy Laboratory Co., Ltd. (72) Inventor, Shoji Miyanaga, 398, Hase, Atsugi, Kanagawa, Ltd., Semiconducting Energy Laboratory, Ltd.

Claims (14)

[Claims] 1. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, and a step of forming crystal nuclei on the surface side of the amorphous silicon film on which the catalytic element is introduced. And a step of dehydrogenating the amorphous silicon film, irradiating laser light or strong light equivalent thereto from the surface side of the amorphous silicon film on which crystal nuclei are formed, A method for manufacturing a semiconductor, comprising the step of crystallizing a film. 2. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, a step of dehydrogenating the amorphous silicon film, and a step of dehydrogenating the amorphous silicon film. A step of forming crystal nuclei on the surface side on which the catalytic element is introduced; and irradiating laser light or strong light similar to the laser light from the surface side on which the crystal nuclei of the amorphous silicon film are formed. A method for manufacturing a semiconductor, comprising the step of crystallizing a film. 3. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, and a step of forming crystal nuclei on the surface side of the amorphous silicon film on which the catalytic element is introduced. And a step of forming dangling bonds in the amorphous silicon film, irradiating laser light or strong light equivalent thereto from the surface side of the amorphous silicon film on which crystal nuclei are formed, And a step of crystallizing a crystalline silicon film, the method comprising: 4. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, a step of forming dangling bonds in the amorphous silicon film, A step of forming crystal nuclei on the side of the silicon film on which the catalytic element is introduced; and irradiating laser light or strong light equivalent thereto from the surface side of the amorphous silicon film on which the crystal nuclei are formed, And a step of crystallizing a crystalline silicon film, the method comprising: 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; A step of forming crystal nuclei on the side where the catalytic element is introduced; and irradiating a laser beam or strong light equivalent thereto from the surface side where the crystal nuclei of the amorphous silicon film are formed to produce the amorphous silicon. A method for manufacturing a semiconductor, comprising the step of crystallizing a film. 6. A step of forming dangling bonds in the amorphous silicon film; a step of introducing a catalytic element that promotes crystallization into one surface of the amorphous silicon film; A step of forming crystal nuclei on the side of the silicon film on which the catalytic element is introduced; and irradiating laser light or strong light equivalent thereto from the surface side of the amorphous silicon film on which the crystal nuclei are formed, And a step of crystallizing a crystalline silicon film, the method comprising: 7. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, a step of forming a nitride film in contact with the one surface of the amorphous silicon film, A step of dehydrogenating the amorphous silicon film; a step of forming crystal nuclei on the surface of the amorphous silicon film on which the catalytic element is introduced; and a step of forming crystal nuclei of the amorphous silicon film. And irradiating laser light or strong light equivalent thereto from the surface side to crystallize the amorphous silicon film. 8. A step of introducing a catalyst element that promotes crystallization to one surface of the amorphous silicon film, a step of forming a nitride film in contact with one surface of the amorphous silicon film, Forming a crystal nucleus on the side of the amorphous silicon film on which the catalytic element is introduced; dehydrogenating the amorphous silicon film; and forming a crystal nucleus of the amorphous silicon film. And irradiating laser light or intense light equivalent thereto to crystallize the amorphous silicon film. 9. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, a step of forming a nitride film in contact with the one surface of the amorphous silicon film, Forming dangling bonds in the amorphous silicon film, forming crystal nuclei on the surface of the amorphous silicon film on which the catalytic element is introduced, and crystal nuclei of the amorphous silicon film Irradiating a laser beam or strong light equivalent thereto from the surface side on which is formed to crystallize the amorphous silicon film. 10. A step of introducing a catalytic element that promotes crystallization to one surface of the amorphous silicon film, a step of forming a nitride film in contact with the one surface of the amorphous silicon film, Forming a crystal nucleus on the side of the amorphous silicon film on which the catalytic element is introduced; forming a dangling bond in the amorphous silicon film; and forming a crystal nucleus of the amorphous silicon film. Irradiating a laser beam or strong light equivalent thereto from the surface side on which is formed to crystallize the amorphous silicon film. 11. The catalyst element according to claim 1, wherein Ni, Pt, Cu, Ag, Au, In and S are used as the catalyst element.
A method for manufacturing a semiconductor, which comprises using one or more kinds of elements selected from n, Pb, P, As, and Sb. 12. A semiconductor manufacturing method according to claim 1, wherein one or more elements selected from the group VIII, IIIb, IVb and Vb elements are used as the catalyst element. 13. An amorphous silicon film having crystal nuclei formed on one surface side and having been dehydrogenated, is irradiated with laser light or an intense light equivalent thereto from the surface side on which the crystal nuclei are formed. A method for manufacturing a semiconductor, which comprises irradiating light to grow crystals from the crystal nuclei. 14. For an amorphous silicon film having crystal nuclei formed on one surface side and having dangling bonds, laser light or a laser beam equivalent to the laser light is applied from the surface side on which the crystal nuclei are formed. A method for manufacturing a semiconductor, which comprises irradiating strong light to grow crystals from the crystal nuclei.