JPH07183540A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To previously control a solution which accelerates the crystallization of a silicon film in element concentration so as to improve the silicon film in crystallinity and to lessen the solution in element content by a method wherein an amorphous silicon film is made to retain the solution and thermally treated to form an active region. CONSTITUTION:An amorphous silicon film 12 is formed on a glass substrate 11. After a hydrofluoric acid treatment, an oxide film 13 is formed on the siicon film 12. Then, nickel is added to an acetate solution, wherein nickel is 100ppm in concentration. 2ml of the acetate solution is made to drip on the surface of the oxide film 13 on the amorphous silicon film 12, the substrate 11 is left to stand for five minutes keeping the oxide film 13 in this state, and the oxide film 13 is spin-dried up by a spinner 15. By this setup, a nickel-containing acetate solution film 14 can be formed. Thereafter, the substrate 11 is kept in this state for five minutes and then thermally treated in a nitrogen atmosphere at a temperature of 550 deg.C for four hours in a heating oven to obtain a crystalline silicon thin film 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using a crystalline semiconductor and a method for manufacturing the semiconductor device.

[0002]

2. Description of the Related Art A thin film transistor (hereinafter referred to as TFT) using a thin film semiconductor is known. This TFT is formed by forming a thin film semiconductor on a substrate and using this thin film semiconductor. This TFT is used in various integrated circuits, and is particularly noted as a switching element provided in each pixel of an electro-optical device, particularly an active matrix type liquid crystal display device, and a driver element formed in a peripheral circuit portion. .

As a thin film semiconductor used for TFT,
Although it is easy to use an amorphous silicon film, there is a problem in that its electrical characteristics are low. In order to improve the characteristics of the TFT, a crystalline silicon thin film may be used. A crystalline silicon film is referred to as polycrystalline silicon, polysilicon, microcrystalline silicon, or the like. In order to obtain this crystalline silicon film, an amorphous silicon film may first be formed and then crystallized by heating.

However, crystallization by heating requires heating at a temperature of 600 ° C. or higher for 10 hours or longer, which makes it difficult to use a glass substrate as a substrate. For example, Corning 7059 glass used in an active type liquid crystal display device has a glass strain point of 593 ° C., and there is a problem in heating at 600 ° C. or higher in consideration of increasing the area of a substrate.

BACKGROUND OF THE INVENTION According to the research conducted by the present inventors, a small amount of elements such as nickel, palladium, and lead are deposited on the surface of an amorphous silicon film, and then heated to 550. It has been found that crystallization can be performed in a treatment time of about 4 hours at ℃.

In order to introduce such a trace amount of elements (catalyst elements that promote crystallization), plasma treatment, vapor deposition, or ion implantation may be used. Plasma treatment is a parallel plate type or positive column type plasma CVD apparatus in which a material containing a catalytic element is used as an electrode, and plasma is generated in an atmosphere such as nitrogen or hydrogen to form a catalytic element on the amorphous silicon film. Is a method of adding.

However, the presence of a large amount of the above-mentioned elements in the semiconductor impairs the reliability and electrical stability of the device using these semiconductors and is not preferable.

That is, the above-mentioned element (catalyst element) that promotes crystallization, such as nickel, is necessary when crystallizing amorphous silicon, but the crystallized silicon should not be included as much as possible. Is desirable. To achieve this goal,
It is necessary to select a catalyst element that has a strong tendency to be inactive in crystalline silicon, at the same time reduce the amount of the catalyst element required for crystallization as much as possible, and perform crystallization with the minimum amount. For that purpose, it is necessary to precisely control the amount of the catalyst element added and to introduce it.

When nickel is used as a catalyst element, an amorphous silicon film is formed, nickel is added by a plasma treatment method to form a crystalline silicon film, and the crystallization process and the like are examined in detail. The following matters were found. (1) When nickel is introduced into the amorphous silicon film by the plasma treatment, nickel has already penetrated to a considerable depth in the amorphous silicon film before the heat treatment. (2) The initial nucleation of crystals occurs from the surface into which nickel is introduced. (3) Even when nickel is formed on the amorphous silicon film by the vapor deposition method, crystallization occurs as in the case of performing the plasma treatment.

From the above it is concluded that all the nickel introduced by the plasma treatment is not functioning effectively. That is, it is considered that there is nickel that does not function sufficiently even if a large amount of nickel is introduced. From this, it is considered that the point (plane) where nickel and silicon are in contact functions during low temperature crystallization.
Then, it is concluded that nickel should be dispersed as finely as possible in atomic form. That is, it is concluded that "it is necessary to disperse nickel as atomically as possible in a concentration as low as possible within the range where low temperature crystallization is possible near the surface of the amorphous silicon film."

A method of introducing a very small amount of nickel only in the vicinity of the surface of the amorphous silicon film, in other words, a very small amount of a catalytic element that promotes crystallization only in the vicinity of the surface of the amorphous silicon film is used. , Vapor deposition method can be mentioned,
The vapor deposition method has poor controllability and has a problem that it is difficult to strictly control the introduction amount of the catalyst element.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides (1) a method of controlling the amount of a catalytic element and introducing it in the production of a crystalline thin film silicon semiconductor by a heat treatment at 600 ° C. or less using a catalytic element. Minimize the amount. (2) Use a method with high productivity. The purpose is to meet such requirements.

[0013]

In order to satisfy the above object, the present invention uses the following means to obtain a crystalline silicon film. A catalyst element simple substance or a compound containing the catalyst element is held in contact with the amorphous silicon film to promote crystallization of the amorphous silicon film, and the amorphous silicon film contains the catalyst element simple substance or the catalyst element. When the compounds are in contact,
Heat treatment is performed to crystallize the amorphous silicon film.

Specifically, the above structure is realized by applying a solution containing the catalytic element to the surface of the amorphous silicon film and introducing the catalytic element. Particularly in the present invention,
The feature is 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.

Further, the crystalline silicon film is used to form an active region having at least one PN, PI, NI or other electrical junction of a semiconductor device. A thin film transistor (TFT), a diode, or an optical sensor can be used as the semiconductor device.

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.

As a method for applying a solution containing an element that promotes crystallization to 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 nickel alone 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, powder of nickel alone or a nickel compound is in a dispersion medium. A material such as an emulsion uniformly dispersed in the above may be used. 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. In addition, after forming a thin oxide film, rubbing treatment may be performed to form irregularities in the oxide film at regular intervals, widths, and directions. Such unevenness is effective in further promoting the permeation of the solvent, averaging the crystal grain sizes, and aligning the crystal grain directions. Further, forming a semiconductor element so that a current flows through the crystalline silicon film having such a directionality in an appropriate direction was effective in suppressing variations in element characteristics.

Further, by using a non-polar solvent such as a toluene solution of nickel 2-ethylhexanoate as a solution, the solution can be directly applied to 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 kind 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) based on the solution. Is desirable. This is a value determined in consideration of the nickel concentration in the film and the hydrofluoric acid resistance after completion of crystallization.

Further, the crystal growth can be selectively carried out by selectively applying the solution containing the catalytic element. In this case, in particular, crystal growth can be performed in a direction substantially parallel to the surface of the silicon film from the area where the solution is applied, toward the area where the solution is not applied. In this specification, a region in which crystal growth is performed in a direction substantially parallel to the surface of the silicon film is referred to as a lateral crystal growth region.

It has been confirmed that the concentration of the catalytic element is low in the region where the crystal growth is performed in the lateral direction.
Although it is useful to use a crystalline silicon film as the active layer region of the semiconductor device, it is generally preferable that the concentration of impurities in the active layer region is low. Therefore, forming the active layer region of the semiconductor device by using the region in which the crystal growth is performed in the lateral direction is useful for device fabrication.

In the present invention, the most remarkable effect can be obtained when nickel is used as the catalyst element, but the other usable catalyst elements are preferably Ni, Pd, Pt, Cu and Ag. Au, In, S
n, Pd, Sn, Pd, P, As, and Sb can be used. Further, one or more kinds of elements selected from Group VIII elements, IIIb, IVb, and Vb elements can also be used.

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.

[0032]

【Example】

 [Example 1]

This embodiment is an example in which a catalytic element that promotes crystallization is contained in an aqueous solution, applied on an amorphous silicon film, and then crystallized by heating.

First, referring to FIG. 1, the steps up to the introduction of the catalytic element (here, nickel is used) will be described. In this embodiment, Corning 7059 glass is used as the substrate. The size is 100mm x 100mm
And

First, an amorphous silicon film is formed into an amorphous silicon film by plasma CVD or LPCVD.
It forms from 00 to 1500Å. Here, plasma CVD
The amorphous silicon film 12 is formed to a thickness of 1000 Å by the method. (Fig. 1 (A))

Then, a hydrofluoric acid treatment is performed to remove the dirt and the natural oxide film, and then the oxide film 13 is removed by 10 to 50.
Deposit on Å. Needless to say, this step may be omitted if the stain can be ignored, and a natural oxide film may be used as it is instead of the oxide film 13. Since the oxide film 13 is extremely thin, the exact film thickness is unknown.
It is considered to be about 0Å. Here, the oxide film 13 is formed by irradiation with UV light in an oxygen atmosphere. The film formation was performed by irradiating UV for 5 minutes in an oxygen atmosphere. As a method of forming the oxide film 13,
A thermal oxidation method may be used. 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, for improving 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 100 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 (2000
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 this nickel solution coating step once to plural times. Can be formed. In this case, nickel in this layer 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 necessarily a perfect film.

After application of the above solution, the state is maintained for 5 minutes. The concentration of nickel contained in the silicon film 12 can be finally controlled also by the holding time, but the largest control factor is the concentration of the solution.

Then, in a heating furnace, heat treatment is performed in a nitrogen atmosphere at 550 ° C. for 4 hours. As a result,
It is possible to obtain the crystalline silicon thin film 12 formed on the substrate 11.

The above heat treatment can be carried out at a temperature of 450 ° 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.

[Embodiment 2] This embodiment is an example in which a 1200 Å silicon oxide film is selectively provided in the manufacturing method shown in Embodiment 1 and nickel is selectively introduced using this silicon oxide film as a mask. .

FIG. 2 shows an outline of the manufacturing process in this embodiment. First, the glass substrate (Corning 7059, 10c
A silicon oxide film 21 serving as a mask is formed on the (m square) to a thickness of 1000 Å or more, here 1200 Å. The film thickness of the silicon oxide film 21 is 5 according to experiments by the inventors.
It has been confirmed that there is no problem even with 00Å, and if the film quality is dense, it may be possible to make it thinner.

Then, the silicon oxide film 21 is patterned into a required pattern by a normal photolithographic patterning process. Then, a thin silicon oxide film 20 is formed by irradiation of ultraviolet rays in an oxygen atmosphere. This silicon oxide film 2
Production of 0 is performed by irradiating UV light for 5 minutes in an oxygen atmosphere. The thickness of the silicon oxide film 20 is considered to be about 20 to 50Å (FIG. 2 (A)). still,
The silicon oxide film for improving the wettability may be added just by the hydrophilicity of the silicon oxide film of the mask only when the size of the solution and the pattern match. However, such an example is special, and it is generally safer to use the silicon oxide film 20.

In this state, as in Example 1, 10
5 ml of an acetate solution containing 0 ppm of nickel is dropped (in the case of a 10 cm square substrate). At this time, spin coating is performed with a spinner at 50 rpm for 10 seconds to form a uniform water film on the entire surface of the substrate. In this state, 5
After holding for 2 minutes, using a spinner, 2000 rpm, 60
Perform a second spin dry. This holding may be performed while rotating the spinner at 0 to 150 rpm. (Fig. 2 (B))

Then, the amorphous silicon film 12 is crystallized by performing heat treatment at 550 ° C. (nitrogen atmosphere) for 4 hours. At this time, crystal growth is performed in the lateral direction from the region of the portion 22 into which nickel has been introduced to the region into which nickel has not been introduced, as indicated by 23. In FIG. 2C, 24 is a region in which nickel is directly introduced and crystallized, and 25 is a region in which lateral crystallization is performed. In addition, it has been confirmed that crystal growth is performed in the region of 25 in the direction of substantially the <111> axis.

In this embodiment, the concentration of nickel in the region where nickel was directly introduced is changed from 1 × 10 ¹⁶ atoms cm ^-3 to 1 by changing the solution concentration and the holding time.
The concentration can be controlled in the range of × 10 ¹⁹ atoms cm ⁻³ , and similarly, the concentration of the lateral growth region can be controlled to be lower than that.

The crystalline silicon film formed by the method shown in this embodiment is characterized in that it has good hydrofluoric acid resistance. According to the findings by the present inventors, a crystalline silicon film obtained by crystallizing nickel by plasma treatment is
Low hydrofluoric acid resistance.

For example, it is necessary to form an electrode by forming a silicon oxide film functioning as a gate insulating film or an interlayer insulating film on a crystalline silicon film and then performing a hole forming process to form an electrode. It may be said that. In such a case, a process of removing the silicon oxide film with buffer hydrofluoric acid is usually adopted. However, when the hydrofluoric acid resistance of the crystalline silicon film is low, it is difficult to remove only the silicon oxide film, and there is a problem that the crystalline silicon film is also etched.

However, when the crystalline silicon film has a hydrofluoric acid resistance, a large difference (selection ratio) between the etching rates of the silicon oxide film and the crystalline silicon film can be obtained, so that the silicon oxide film is formed. Only this can be selectively removed, which is extremely significant in the manufacturing process.

As described above, since the concentration of the catalytic element is low and the crystallinity is good in the region where the crystal has grown in the lateral direction, it is useful to use this region as the active region of the semiconductor device. For example, it is extremely useful to use it as a channel formation region of a thin film transistor.

[Embodiment 3] This embodiment is an example in which nickel, which is a catalytic element, is contained in alcohol, which is a non-aqueous solution, and is coated on an amorphous silicon film. In this embodiment, nickel acetylacetonate is used as a nickel compound, and the compound is contained in alcohol. The concentration of nickel may be the required concentration.

The subsequent steps are the same as those shown in the first or second embodiment. Further, the alcohol solution containing nickel may be applied under the amorphous silicon film. In this case, this solution may be applied using a spinner before forming the amorphous silicon film. When alcohol is used, it can be directly coated on the amorphous silicon film.

Specific conditions will be described below. First, nickel acetylacetonate is prepared as a nickel compound. Since this substance is soluble in alcohol and has a low decomposition temperature, it can be easily decomposed during heating in the crystallization step.

Further, ethanol is used as the alcohol. First, the nickel acetylacetonate is adjusted to 100 ppm in ethanol in terms of the amount of nickel to prepare a solution containing nickel.

Then, this solution is coated on the amorphous silicon film. The amorphous silicon film is a silicon oxide base film (200
1 on a 100 mm square glass substrate with 0 Å thickness)
It is formed by a plasma CVD method with a thickness of 000Å.

The coating of the solution on the amorphous silicon film is less than that of the case of using the aqueous solution of the first or second embodiment. This is because the contact angle of alcohol is smaller than that of water. Here, 2 ml is dropped on an area of 100 mm square.

Then, this state is maintained for 5 minutes. After that, it is dried using a spinner. At this time, the spinner is 1
Rotate at 500 rpm for 1 minute. After this, 550
Crystallization is performed by heating at ℃ for 4 hours. Thus, a crystalline silicon film is obtained.

[Embodiment 4] This embodiment is an example in which a simple substance of nickel which is a catalytic element is dissolved in an acid, and the acid in which the simple substance of nickel is dissolved is applied onto an amorphous silicon film.

In this embodiment, 0.1 mol of acid is used.
1 / l nitric acid is used. Dissolve nickel powder in this nitric acid so that the concentration of nickel becomes 50 ppm,
This is used as a solution. The subsequent steps are the same as those in the first embodiment.

[Embodiment 5] This embodiment is an example of manufacturing a TFT provided in each pixel portion of an active matrix type liquid crystal display device using a crystalline silicon film manufactured by using the method of the present invention. Indicates. It is needless to say that the application range of the TFT is not limited to the liquid crystal display device but can be applied to a generally-known thin film integrated circuit.

FIG. 3 shows an outline of the manufacturing process of this embodiment.
First, an underlying silicon oxide film (not shown) is formed on the glass substrate by 2
Form a film with a thickness of 000Å. This silicon oxide film is provided to prevent the diffusion of impurities from the glass substrate.

Then, an amorphous silicon film is formed to a thickness of 1000 Å by the same method as in the first embodiment. After the hydrofluoric acid treatment for removing the natural oxide film, a thin oxide film 20 is formed to a thickness of about 20Å by UV light irradiation in an oxygen atmosphere.

Then, an acetate solution containing nickel of 10 ppm is applied, held for 5 minutes, and spin-dried using a spinner. After that, the silicon oxide films 20 and 21 are removed by buffer hydrofluoric acid, and the silicon film 100 is crystallized by heating at 550 ° C. for 4 hours. (Up to this point, it is the same as the manufacturing method shown in Example 1)

The process of introducing this nickel is the same as in Example 3.
Alternatively, the method shown in Example 4 may be used. Of course, the concentration of nickel and the holding time may be appropriately selected.

Next, the crystallized silicon film is patterned to form island-shaped regions 104. This island area 10
Reference numeral 4 constitutes an active layer of the TFT. And thickness 200 ~
The silicon oxide 105 of 1500 Å, here 1000 Å, is formed. This silicon oxide film also functions as a gate insulating film. (Fig. 3 (A))

Attention must be paid to the formation of the silicon oxide film 105. Here, TEOS is used as a raw material, and the substrate temperature is 150 to 600 ° C., preferably 300 to 45, together with oxygen.
It was decomposed and deposited at 0 ° C. by the RF plasma CVD method. TE
The pressure ratio of OS and oxygen is 1: 1 to 1: 3, the pressure is 0.05 to 0.5 torr, and the RF power is 100 to 25.
It was set to 0W. Alternatively, by using TEOS as a raw material together with ozone gas by a low pressure CVD method or a normal pressure CVD method,
The substrate temperature is 350 to 600 ° C., preferably 400 to 55
It was formed as 0 ° C. After the film formation, annealing was performed at 400 to 600 ° C. for 30 to 60 minutes in an atmosphere of oxygen or ozone.

In this state, the KrF excimer laser (wavelength 248 nm, pulse width 20 nsec) or intense light equivalent thereto may be irradiated to promote crystallization of the silicon region 104. In particular, RTA using infrared light
(Rapid thermal annealing) can selectively heat only silicon without heating the glass substrate, and can reduce the interface state at the interface between the silicon and the silicon oxide film. It is useful in the fabrication of a field effect semiconductor device.

After that, an aluminum film having a thickness of 2000 Å to 1 μm is formed by electron beam evaporation, and this is patterned to form a gate electrode 106. The aluminum may be doped with scandium (Sc) in an amount of 0.15 to 0.2% by weight. Next, set the substrate pH
It is immersed in an ethylene glycol solution of 7 to 1 to 3% tartaric acid, and anodization is performed using platinum as a cathode and this aluminum gate electrode as an anode. The anodization is completed by first raising the voltage to 220 V with a constant current and then maintaining that state for 1 hour. In the present embodiment, in the constant current state, it is appropriate that the voltage rising rate is 2 to 5 V / min. In this way, the anodic oxide 109 having a thickness of 1500 to 3500Å, for example 2000Å, is formed. (Fig. 3 (B))

After that, an impurity (phosphorus) was self-alignedly injected into the island-shaped silicon film of each TFT by an ion doping method (also referred to as a plasma doping method) using the gate electrode portion as a mask. Phosphine (PH ₃ ) was used as the doping gas. The dose amount is 1 to 4 × 10
¹⁵ cm ^-2 .

Further, as shown in FIG. 3C, a KrF excimer laser (wavelength 248 nm, pulse width 20 ns) is used.
ec) is applied to improve the crystallinity of the portion where the crystallinity is deteriorated by the introduction of the impurity region. The energy density of the laser is 150 to 400 mJ / cm ² , preferably 200 to 250 mJ / cm ² . Thus, the N-type impurity (phosphorus) regions 108 and 109 are formed. The sheet resistance in these regions was 200 to 800 Ω / □.

In this step, instead of using a laser, a flash lamp is used, and 1000 to
Raise it to 1200 ° C (silicon monitor temperature),
So-called RTA (Rapid Thermal Annealing) (RTP, also called rapid thermal process) for heating the sample may be used.

After that, an interlayer insulator 110 is formed on the entire surface.
Plasma CVD with TEOS as raw material and oxygen
Method, low pressure CVD method with ozone, or atmospheric pressure CV
A silicon oxide film having a thickness of 3000 Å is formed by the D method. The substrate temperature is 250 to 450 ° C., for example 350 ° C.
After the film formation, this silicon oxide film is mechanically polished to obtain the flatness of the surface. Further, an ITO film is deposited by the sputtering method and patterned to form the pixel electrode 111. (Fig. 3 (D))

Then, the interlayer insulator 110 is etched to form contact holes in the source / drain of the TFT as shown in FIG. 1E, wirings 112 and 113 of chromium or titanium nitride are formed, and the wiring 113 is formed. Is connected to the pixel electrode 111.

Since the crystalline silicon film into which nickel is introduced by the plasma treatment has lower selectivity for buffer hydrofluoric acid than the silicon oxide film, it is often etched in the contact hole forming step. It was

However, when nickel is introduced by using an aqueous solution at a low concentration of 10 ppm as in this embodiment, since the hydrofluoric acid resistance is high, the formation of the contact hole can be stably performed with good reproducibility. it can.

Finally, in hydrogen at 300 to 400 ° C.
Anneal for 1-2 hours to complete hydrogenation of silicon. In this way, the TFT is completed. Then, a large number of TFTs manufactured at the same time are arranged in a matrix to complete an active matrix liquid crystal display device.
This TFT has source / drain regions 108/109 and a channel formation region 114. Also 115 is N
It becomes the electrical junction of I.

When the structure of this embodiment is adopted, the concentration of nickel existing in the active layer is about 3 × 10 ¹⁸ cm ⁻³ or less, 1 × 10 ¹⁶ atoms cm ^{−3 to} 3 × 10 5.
It is considered to be ¹⁸ atoms cm ^-3 .

[Embodiment 6] In this embodiment, as shown in Embodiment 2, nickel is selectively introduced, and electrons are emitted from the portion where crystals are grown laterally (parallel to the substrate). An example of forming a device is shown. When such a structure is adopted, the nickel concentration in the active layer region of the device can be further lowered, and the structure can be made extremely preferable in terms of electrical stability and reliability of the device.

The method of introducing nickel element in this embodiment may be the method shown in the third and fourth embodiments.

This embodiment relates to a process of manufacturing a TFT used for controlling pixels of an active matrix. FIG. 4 shows the manufacturing process of this embodiment. First, the substrate 20
1 is washed, and TEOS (tetra-ethoxy-silane) and oxygen are used as source gases to form a plasma-deposited film having a thickness of 2
A base film 202 of 000Å silicon oxide is formed. Then, the thickness is 500 to 1500 by the plasma CVD method.
Å, for example, 1000 Å intrinsic (I-type) amorphous silicon film 2
03 is deposited. Next, continuously thickness 500-2000
Å, for example, 1000 Å of silicon oxide film 205 with plasma C
The film is formed by the VD method. Then, the silicon oxide film 205 is selectively etched to expose the region 2 where the amorphous silicon is exposed.
06 is formed.

Then, a solution (here, an acetate solution) containing nickel element which is a catalytic element for promoting crystallization is applied by the method shown in Example 2. The concentration of nickel in the acetic acid solution is 100 ppm. In addition, the detailed process order and conditions are the same as those shown in the second embodiment.
This step may be according to the method shown in Example 3 or 4.

After that, 500 to 620 under a nitrogen atmosphere.
The silicon film 303 is crystallized by performing heat anneal at 4 ° C., for example, 550 ° C. for 4 hours. Crystallization proceeds from a region 206 where the nickel film and the silicon film are in contact with each other as a starting point, and crystal growth proceeds in a direction parallel to the substrate as indicated by an arrow. In the figure, a region 204 shows a portion crystallized by direct introduction of nickel, and a region 203 shows a portion crystallized laterally. The crystal in the lateral direction indicated by 203 is 2
It is about 5 μm. The crystal growth direction is roughly <11.
It has been confirmed that the direction is 1> axial. (Fig. 4
(A))

Next, the silicon oxide film 205 is removed. At this time, the oxide film formed on the surface of the region 206 is also removed at the same time. Then, after patterning the silicon film 204, dry etching is performed to form an island-shaped active layer region 208.
At this time, the region indicated by 206 in FIG. 4A is a region into which nickel is directly introduced, and is a region in which nickel is present at a high concentration. It has also been confirmed that nickel also exists at a high concentration at the tip of crystal growth. It has been found that the nickel concentration in these regions is higher than that in the intermediate region. Therefore, in this embodiment, in the active layer 208, these regions having a high nickel concentration are prevented from overlapping the channel formation region.

Thereafter, 10% by volume containing 100% steam
The surface of the active layer (silicon film) 208 is oxidized by leaving it in the atmosphere of 500 to 600 ° C., typically 550 ° C. for 1 hour to oxidize the surface of the silicon oxide film 209.
To form. The thickness of the silicon oxide film is 1000Å. After forming the silicon oxide film 209 by thermal oxidation, the substrate is placed in an ammonia atmosphere (1 atm, 100%) at 400 ° C.
To hold. Then, in this state, the substrate is irradiated with infrared light having a peak at a wavelength of 0.6 to 4 μm, for example, 0.8 to 1.4 μm for 30 to 180 seconds, and the silicon oxide film 20 is irradiated.
A nitriding process is performed on 9. At this time, the atmosphere was 0.
1-10% HCl may be mixed.

A halogen lamp is used as the infrared light source. The intensity of infrared light is adjusted so that the temperature on the monitor's single crystal silicon wafer is between 900 and 1200 ° C. Specifically, the temperature of the thermocouple embedded in the silicon wafer is monitored, and this is fed back to the infrared light source. In this embodiment, the temperature rise is constant, the speed is 50 to 200 ° C./sec, and the temperature fall is 20 to 100 by natural cooling.
℃. Since this infrared light irradiation selectively heats the silicon film, the heating of the glass substrate can be minimized. (Fig. 4 (B))

Subsequently, by the sputtering method,
A film of aluminum (containing 0.01 to 0.2% scandium) having a thickness of 3000 to 8000Å, for example, 6000Å is formed. Then, the aluminum film is patterned to form the gate electrode 210. (Fig. 2 (C))

Further, the surface of the aluminum electrode is anodized to form an oxide layer 211 on the surface. This anodic oxidation is performed in an ethylene glycol solution containing 1-5% tartaric acid. The resulting oxide layer 211 has a thickness of 2
It is 000Å. Since the oxide 211 has a thickness to form the offset gate region in the subsequent ion doping process, the length of the offset gate region can be determined by the anodic oxidation process. (Fig. 4
(D))

Next, the gate electrode portion, that is, the gate electrode 210 and the oxide layer 211 around it is used as a mask in the active layer region (which constitutes a source / drain and a channel) by an ion doping method (also called a plasma doping method). An impurity (phosphorus here) which imparts N conductivity type is added in a self-aligning manner. Phosphine (PH ₃ ) is used as the doping gas, and the acceleration voltage is set to 60 to 90 kV, for example, 80 kV. Dose amount is 1 × 10 ¹⁵ to 8 × 10
^{It is set to 15} cm ^-2 , for example, 4 × 10 ¹⁵ cm ^-2 . As a result, N-type impurity regions 212 and 213 can be formed. As is clear from the figure, the impurity region and the gate electrode are in an offset state separated by a distance x. Such an offset state is particularly effective in reducing a leak current (also referred to as an off current) when a reverse voltage (negative in the case of an N-channel TFT) is applied to the gate electrode.
In particular, in the TFT for controlling the pixels of the active matrix as in the present embodiment, it is desired that the leak current is low so that the charges accumulated in the pixel electrode do not escape in order to obtain a good image, and therefore an offset is provided. That is valid.

After that, annealing was performed by irradiation with laser light. As the laser light, a KrF excimer laser (wavelength 248 nm, pulse width 20 nsec) is used, but other laser may be used. The laser beam irradiation condition is such that the energy density is 200 to 400 mJ / cm.
² , for example, 250 mJ / cm ² and 2 per place
Irradiation was performed for 10 shots, for example, 2 shots. The effect may be increased by heating the substrate to about 200 to 450 ° C. during the irradiation of the laser light. (Fig. 4
(E))

Then, a silicon oxide film 21 having a thickness of 6000Å is formed.
4 as an interlayer insulator is formed by the plasma CVD method. Further, a transparent polyimide film 215 is formed by spin coating to flatten the surface. A thickness of 80 is formed on the flat surface thus formed by the sputtering method.
A 0 Å transparent conductive film (ITO film) is formed and patterned to form a pixel electrode 216.

Then, contact holes are formed in the interlayer insulators 214 and 215, and the electrodes / wirings 217 and 218 of the TFT are formed from a metal material, for example, a multilayer film of titanium nitride and aluminum. Finally, annealing is performed at 350 ° C. for 30 minutes in a hydrogen atmosphere of 1 atm to complete an active matrix pixel circuit having TFTs. (Fig. 4
(F))

[Embodiment 7] FIG. 5 shows a cross-sectional view of a manufacturing process of this embodiment. First, the substrate (Corning 7059) 50
A base film 102 of silicon oxide having a thickness of 2000 Å was formed on 1 by a sputtering method. The substrate is annealed at a temperature higher than the strain temperature before or after the formation of the base film, and then gradually cooled to the strain temperature or less at 0.1 to 1.0 ° C./min. The shrinkage of the substrate in the accompanying steps (including the thermal oxidation step of the present invention and the subsequent thermal annealing step) is small, and mask alignment is ready. For Corning 7059 substrates, 1-4 at 620-660 ° C
After annealing for an hour, it is gradually cooled at 0.03 to 1.0 ° C./min, preferably 0.1 to 0.3 ° C./min, and 400 to 500.
It is recommended to take out when the temperature has dropped to ℃.

Next, a thickness of 5 is formed by plasma CVD.
An intrinsic (I-type) amorphous silicon film having a thickness of 00 to 1500 Å, for example 1000 Å, was formed. Then, the amorphous silicon film was crystallized by the method shown in Example 1. Then, it is annealed in a nitrogen atmosphere (atmospheric pressure) at 600 ° C. for 48 hours to be crystallized, and the silicon film is patterned into a size of 10 to 1000 μm square to form an island-shaped silicon film (active layer of TFT) 50.
Formed 3. (Figure 5 (A))

After that, a pyrogenic reaction method was carried out in an oxygen atmosphere containing 70 to 90% of steam at 500 to 750 ° C., typically 600 ° C. at a hydrogen / oxygen ratio of 1.5 to 1.9. Formed using. By leaving it in such an atmosphere for 3 to 5 hours, the surface of the silicon film was oxidized to form a silicon oxide film 504 having a thickness of 500 to 1500 Å, for example, 1000 Å. Notable teeth, such oxidation reduces the surface of the initial silicon film by 50 Å or more, and as a result, the contamination of the outermost surface portion of the silicon film is
This means that the silicon oxide interface was not reached, that is, a clean silicon-silicon oxide interface was obtained. Since the thickness of the silicon oxide film is twice that of the silicon film to be oxidized, 10
When a silicon film having a thickness of 00Å is oxidized to obtain a silicon oxide film having a thickness of 1000Å, the remaining silicon film has a thickness of 500.
It means Å.

Generally, the thinner the silicon oxide film (gate insulating film) and the active layer are, the better the mobility is and the better the off current is. On the other hand, in the initial crystallization of the amorphous silicon film, the thicker the film, the easier the crystallization. Therefore, conventionally, regarding the thickness of the active layer, there is a contradiction in terms of characteristics and processes. The present invention solves this contradiction for the first time, that is, a thick amorphous silicon film is formed before crystallization to obtain a good crystalline silicon film. Then, next, the silicon film is thinned by oxidizing the silicon film to improve the characteristics as a TFT. Further, in this thermal oxidation, the amorphous component in which recombination centers are likely to exist and the crystal grain boundaries are easily oxidized, and as a result, the recombination centers in the active layer are reduced. Therefore, the product yield is increased.

After the silicon oxide film 504 is formed by thermal oxidation, the substrate is placed in an atmosphere of dinitrogen monoxide (1 atm, 100 atm).
%), And annealed at 600 ° C. for 2 hours. (FIG. 5 (B)) Subsequently, a thickness of 3000 to 8 is formed by a low pressure CVD method.
000Å, for example, 6000Å polycrystalline silicon (0.01 to
(Containing 0.2% phosphorus). Then, the silicon film was patterned to form a gate electrode 505. Further, by using the silicon film as a mask, an impurity (phosphorus in this case) which imparts N conductivity type to the active layer region (which constitutes a source / drain and a channel) is self-aligned by an ion doping method (also referred to as plasma doping method). ) Was added. Phosphine (PH ₃ ) as doping gas
And the acceleration voltage was set to 60 to 90 kV, for example, 80 kV. The dose amount was set to 1 × 10 ¹⁵ to 8 × 10 ¹⁵ cm ⁻² , for example, 5 × 10 ¹⁵ cm ⁻² . As a result, N-type impurity regions 506 and 507 were formed.

After that, annealing was performed by irradiation with laser light. As the laser light, a KrF excimer laser (wavelength 248 nm, pulse width 20 nsec) was used, but another laser may be used. The laser light irradiation conditions are energy density of 200 to 400 mJ / cm ² ,
For example, 250 mJ / cm ² and ² to 10 per place
Shot, for example, 2 shots were irradiated. The effect may be increased by heating the substrate to about 200 to 450 ° C. during the irradiation of the laser light. (Fig. 5 (C))

Further, this step may be performed by lamp annealing with near infrared light. Near-infrared rays are more easily absorbed by crystallized silicon than by amorphous silicon, and effective annealing comparable to thermal annealing at 1000 ° C. or higher can be performed. On the other hand, a glass substrate (far infrared light is absorbed by the glass substrate, but visible / near infrared light (wavelength 0.5 to 4
(μm) is hard to be absorbed to), so the glass substrate does not have to be heated to a high temperature and can be processed in a short time, so it is an optimal method in the process where shrinkage of the glass substrate is a problem. Can be said.

Then, a silicon oxide film 50 having a thickness of 6000Å is formed.
8 was formed by the plasma CVD method as an interlayer insulator. Polyimide may be used as the interlayer insulator. Further, a contact hole is formed, and a TF is formed by a metal material, for example, a multilayer film of titanium nitride and aluminum.
T electrodes / wirings 509 and 510 were formed. Finally, 1
The TFT was completed by annealing at 350 ° C. for 30 minutes in a hydrogen atmosphere at atmospheric pressure. (Figure 5 (D))

The TFT obtained by the above method has a mobility of 110 to 150 cm ² / Vs and an S value of 0.2 to 0.5.
It was V / digit. Further, when a P-channel TFT in which the source / drain is doped with boron was manufactured by the same method, the mobility was 90 to 120 cm ² / Vs,
The S value is 0.4 to 0.6 V / digit, and the mobility is 20% or more higher than the case where the gate insulating film is formed by the known PVD method or the CVD method, and the S value is 20% or more. Diminished. In addition, in terms of reliability, the T
FT is a TF produced by high temperature thermal oxidation at 1000 ° C.
It showed good results comparable to T.

[Embodiment 8] This embodiment shows an example in which the present invention is applied to an active matrix type liquid crystal display device. FIG. 7 is a top view showing an outline of one substrate of the active matrix type liquid crystal display device of FIG. 6.

In the figure, 61 is a glass substrate, and 6
Reference numeral 2 is a pixel region configured in a matrix, and several hundreds × several hundreds of pixels are formed in the pixel region. A TFT is arranged as a switching element in each of the pixels. The driver TFT for driving the TFT in this pixel area is arranged in the peripheral driver area 6
It is 2. The pixel region 63 and the driver region 62 are integrally formed on the same substrate 61.

The TFT arranged in the driver region 62 needs to flow a large current, and high mobility is required.
Further, since the TFT arranged in the pixel region 63 needs to have a fixed retention rate for the charge of the pixel electrode, a characteristic that the off current (leakage current) is small is required. For example, as the TFT arranged in the pixel region 63, the TFT shown in the fifth embodiment can be used.

[Embodiment 9] In this embodiment, in the manufacturing method shown in Embodiment 1, before the step of applying the nickel acetate aqueous solution, the surface of the silicon oxide film is rubbed to obtain the surface of the silicon oxide film. Forming fine scratches on the
This is an example in which nickel is introduced into the amorphous silicon film with a certain direction, width, and interval.

First, a silicon oxide film was formed on the substrate (Corning 7059) as a base film by sputtering.
00Å formed. Then, the amorphous silicon film is subjected to plasma CV.
The film was formed by the method D at 300 to 800Å, for example, 500Å. Then, hydrofluoric acid treatment was performed to remove the stain and the natural oxide film, and then UV light irradiation was performed in an oxygen atmosphere to form a silicon oxide film of 10 to 100 liters. At this time, the silicon oxide film may be formed by treatment with hydrogen peroxide or thermal oxidation.

After the silicon oxide film was formed, the surface of the silicon oxide film was rubbed to form fine scratches on the film surface as shown in FIG. 7 (A). This rubbing treatment was performed using diamond paste, but it is also possible to use cotton cloth, rubber or the like. Here, the abrasion has a constant direction, width,
The intervals are preferable.

After the unevenness due to scratches was formed on the film surface as described above, a nickel acetate film was formed by the spin coating method as in Example 1. At this time, the nickel acetate aqueous solution uniformly permeates the concave portion of the scratch formed in the previous step.

Then, in the same manner as in Example 1, heat treatment was performed at 550 ° C. for 4 hours in a nitrogen atmosphere in a heating furnace. As a result, a crystalline silicon film (crystalline silicon film) could be obtained. In this example, since the silicon oxide film was rubbed to introduce the nickel into the amorphous silicon film with a constant direction, width, and interval, as shown in FIG. 7B. This crystalline silicon film was obtained in which the directions of crystal grain boundaries and the sizes thereof were uniform to some extent. That is, like a rectangle or an ellipse,
Many crystal grains long in one direction were obtained. In FIG. 7B, the shape of the crystal is shown to be elliptical, but crystals of other shapes were obtained at the same time. The longitudinal direction of the crystal grains was roughly the rubbing direction.

The width and interval of the irregularities may be optimized by changing the rubbing time, the density of the diamond paste and the like. However, since the width and the interval cannot be clearly measured by microscopic observation, the conditions were determined so that the size of the crystal grains of the obtained crystalline silicon film, the density of the amorphous silicon residue, and the like were optimized. In this embodiment, the size (major axis) of the remaining amorphous silicon (uncrystallized region) is 1 μm or less, preferably,
It was set to 0.3 μm or less.

When nickel acetate was applied and crystallization was performed without rubbing treatment as in Example 1, nickel was not soaked uniformly and crystallization was not performed uniformly. A circular uncrystallized region having a size of about 10 μm was observed. However, in this embodiment,
The number of such uncrystallized regions was remarkably reduced, and the size thereof could be reduced.

[Embodiment 10] This embodiment is an example in which a pixel TFT is manufactured using the crystalline silicon film manufactured in Embodiment 9. FIG. 8 shows the manufacturing process of this embodiment. First, the substrate 8
01 (Corning 7059, 10 cm square), a silicon oxide film 802 as a base film is formed by plasma CVD
A film was formed at 000Å. Then, the amorphous silicon film is formed by plasma CVD to 300 to 1000 Å, for example, 500
Film was formed on Å.

Then, as in Example 9, a silicon oxide film was formed in the form of an amorphous silicon film, subjected to rubbing treatment, and a nickel acetate film was formed by spin coating. Then, in a nitrogen atmosphere, heat treatment was performed at 550 ° C. for 4 hours to crystallize. Most crystals were long in one direction.

Then, laser light was irradiated to further improve the crystallinity. At this time, KrF excimer laser light (wavelength 248 nm) was applied at 200 to 350 mJ / cm ^2.
Then, a good crystalline silicon film 803 was obtained. Further, as a result, the slightly crystallized uncrystallized region was completely crystallized. (Figure 8 (A))

Next, the crystalline silicon film 803 thus obtained was patterned to form an island region 804 (island silicon film). When forming this island-shaped region, two directions can be taken in the vertical direction and the parallel direction with respect to the crystal grain boundary as shown in FIGS.

At this time, when the current flowing through the TFT crosses the grain boundary, the resistance of the grain boundary is large. In addition, current easily flows along the grain boundaries. Therefore, depending on the number of grain boundaries included in the channel region and the direction thereof, the leak current of the TFT (the drain current in a state where a reverse bias voltage is applied to the gate electrode. For example, in the case of an N-channel TFT, the gate electrode Drain voltage with a negative voltage applied to
Is greatly affected. In particular, when a plurality of TFTs are present, if the number and direction of crystals (grain boundaries) present in the channel of each TFT vary greatly, this causes variation in leak current.

This is a serious problem when the size of the crystal grains is about the same as or smaller than the size of the channel. When the channel is sufficiently larger than the crystal grain, such variations are averaged and are not observed as a phenomenon. For example, in the situation where one grain boundary exists in the channel or not, if no grain boundary exists, the same characteristics as a single crystal TFT can be expected. On the other hand, when the grain boundary exists in parallel with the drain current, the leak current becomes large. On the contrary, when the grain boundary exists at right angles to the drain current, the leak current becomes small.

In this example, since the crystal grows elongated in the rubbing direction, the drain current flowing in the channel region is parallel to that direction (FIG. 9A). The number of existing grain boundaries (crystals) is difficult to average, and the leak current tends to vary. And, in general,
Since the drain current direction is the grain boundary direction, the leak current is large. On the other hand, when taken vertically as shown in FIG. 9B, in the present invention, since the width of the crystal grain 901 is almost constant, the grain boundary 903 existing in the channel region 902 is present.
, And the stable I _off can be expected. Therefore, as shown in FIG. 9B, the island-shaped silicon film 804 is preferably formed in a direction in which the drain current flows perpendicular to the grain boundary direction (that is, substantially perpendicular to the rubbing direction).
This island-shaped silicon film 804 forms an active layer of the TFT.

In this example, in addition to the above, there was a drop due to the averaging of the crystal grains by the rubbing treatment. For example, a large change in the size of the crystal grain causes a large change in the number of crystals that can exist in the channel.
In particular, this caused variations in leak current. In the case of Example 1, since the diffusion of nickel was non-uniform, the size of the crystal grains may vary, and 10 μm
Even if the large uncrystallized region was crystallized by laser irradiation, the crystallinity was extremely poor.

However, when the rubbing treatment is performed as in this embodiment, the crystal sizes become relatively uniform, and the uncrystallized region is crystallized by the laser irradiation, so that the crystallinity in the vicinity of the crystal is increased. Since it was strongly influenced by epitaxial growth, it showed good crystallinity. Thus, the effect obtained by performing the rubbing treatment was observed. Next, as the gate insulating film 805, a film thickness of 20
A silicon oxide film of 0 to 1500 Å, for example, 1000 Å, was formed by the plasma CVD method.

After that, an aluminum (containing 1 wt% Si or 0.1-0.3 wt% Sc) film having a thickness of 1000 Å to 3 μm, for example 5000 Å, is formed by a sputtering method and patterned. hand,
A gate electrode 806 was formed. Next, set the substrate to pH ≈ 7,
It was immersed in an ethylene glycol solution of 1 to 3% tartaric acid and anodized using platinum as a cathode and an aluminum gate electrode 806 as an anode. The anodization was completed by first raising the voltage to 220 V with a constant current and then maintaining that state for 1 hour. In this way, the thickness 1500-3500
Å, for example, 2000 Å of anodic oxide 807 was formed. (Fig. 8 (B))

After that, impurities were implanted into the island-shaped silicon film 804 by the ion doping method in a self-aligned manner using the gate electrode 806 as a mask. Here, diborane (B
Boron was implanted using ₂ H ₆ ) as a doping gas to form a P-type impurity region 808. In this case, the dose amount of boron was 4 to 10 × 10 ¹⁵ cm ^-2 and the acceleration voltage was 65 kV. (Fig. 8 (C))

Furthermore, a KrF excimer laser (wavelength 2
The doped impurity region 808 was activated by irradiation with 48 nm and a pulse width of 20 nsec. Laser energy density is 200-400 mJ / c
m ^2, and a preferably suitably 250~300mJ / cm ^2. Next, as the interlayer insulating film 809, plasma C is used.
A silicon oxide film was formed to a thickness of 3000Å by the VD method.

Then, the interlayer insulating film 809 and the gate insulating film 805 were etched to form a contact hole in the source. After that, an aluminum film is formed by a sputtering method and patterned to form the source electrode 8
Formed 10. (Figure 8 (D))

Finally, as the passivation film 811, a silicon nitride film having a thickness of 2000 to 6000Å, for example, 3000Å is formed by the plasma CVD method, and this, the interlayer insulating film 809 and the gate insulating film 805 are etched,
A contact hole was formed for the drain. Then, an indium tin oxide film (ITO film) was formed and this was etched to form a pixel electrode 812. (FIG. 8 (E)) The pixel TFT was formed as described above.

[0129]

[Effect] By manufacturing a semiconductor device using a crystalline silicon film in which a catalytic element is introduced and crystallized at low temperature in a short time, a device with high productivity and excellent characteristics can be obtained.

[Brief description of drawings]

FIG. 1 shows a process of an example.

FIG. 2 shows a process of an example.

FIG. 3 shows the relationship between the nickel concentration in the solution and the crystal growth distance in the lateral direction.

FIG. 4 shows a manufacturing process of an example.

FIG. 5 shows a manufacturing process of an example.

FIG. 6 shows a configuration of an example.

FIG. 7 shows crystal growth of Example.

FIG. 8 shows a manufacturing process of an example.

FIG. 9 shows an arrangement of active layers of a TFT of an example.

[Explanation of symbols]

 11 ... Glass substrate 12 ... Amorphous silicon film 13 ... Silicon oxide film 14 ... Acetic acid solution film containing nickel 15 ... Spinner 21 ... For mask Silicon oxide film 20 ... Silicon oxide film 11 ... Glass substrate 104 ... Active layer 105 ... Silicon oxide film 106 ... Gate electrode 109 ... Oxide layer 108 ... Source / Drain region 109 ... Drain / source region 110 ... Interlayer insulating film (silicon oxide film) 111 ... Pixel electrode (ITO) 112 ... Electrode 113 ... Electrode

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 21/26 21/268 Z 27/12 R (72) Inventor Hiroya Zhang Hase, Atsugi, Kanagawa Prefecture No. 398 Inside Semiconductor Energy Laboratory Co., Ltd.

Claims (22)

[Claims] 1. A semiconductor device in which a crystalline silicon film is used to form an active region on a substrate having an insulating surface, the active region being in contact with an amorphous silicon film. A semiconductor device, which is formed by dissolving a catalytic element that promotes the crystallization of (1) in a solvent and holding it, and performing heat treatment. 2. A semiconductor device in which a crystalline silicon film is used to form an active region on a substrate having an insulating surface, the active region being in contact with an amorphous silicon film. A semiconductor device, which is formed by holding a compound containing a catalytic element that promotes the crystallization of, and performing heat treatment. 3. The catalyst element according to claim 1 or 2, wherein Ni, Pd, Pt, Cu, Ag, and A are used as the catalyst element.
A semiconductor device, wherein one or more elements selected from u, In, Sn, Pd, Sn, Pd, P, As, and Sb are used. 4. The semiconductor according to claim 1 or 2, wherein one or more kinds of elements selected from Group VIII, IIIb, IVb and Vb elements are used as the catalytic element. apparatus. 5. The semiconductor device according to claim 1, wherein the semiconductor device formed in the active region is a thin film transistor, a diode, or an optical sensor. 6. The concentration of the catalyst element in the active layer region according to claim 1 or 2,
A semiconductor device characterized in that it is ¹⁶ atoms cm ⁻³ to 1 × 10 ¹⁹ atoms cm ⁻³ . 7. The semiconductor device according to claim 1, wherein the active region has at least one junction represented by PI, PN, and NI. 8. A catalyst element simple substance or a compound containing the catalyst element which promotes crystallization of the amorphous silicon film is held in contact with the amorphous silicon film, and the catalyst element simple substance or the compound containing the catalyst element is held in the amorphous silicon film. A method for manufacturing a semiconductor device, characterized in that heat treatment is performed to crystallize the amorphous silicon film in a state where the compound containing the catalytic element is in contact with the compound. 9. A step of applying on the amorphous silicon film a solution in which a simple catalytic element that promotes crystallization of the amorphous silicon film is dissolved or dispersed, and the amorphous silicon film is heat-treated. And a step of crystallizing the semiconductor device. 10. The catalyst element according to claim 8 or 9, wherein Ni, Pd, Pt, Cu, Ag and A are used as the catalyst element.
A method of manufacturing a semiconductor device, wherein one or more kinds of elements selected from u, In, Sn, Pd, Sn, Pd, P, As, and Sb are used. 11. The semiconductor device according to claim 8 or 9, wherein one or more elements selected from the group VIII, IIIb, IVb, and Vb elements are used as the catalyst element. Manufacturing method. 12. A step of applying a solution in which a compound containing a catalytic element that promotes crystallization of the amorphous silicon film is dissolved or dispersed in a polar solvent onto the amorphous silicon film, and the amorphous silicon film. And a step of crystallizing the same by heat treatment, the method for manufacturing a semiconductor device. 13. The polar solvent according to claim 12,
A method for manufacturing a semiconductor device, wherein one or more selected from water, alcohol, acid, and ammonia water is used. 14. A method of manufacturing a semiconductor device according to claim 12, wherein nickel is used as a catalyst element and the nickel is used as a nickel compound. 15. The nickel compound according to claim 14, which is nickel bromide, nickel acetate, nickel oxalate, nickel carbonate, nickel chloride, nickel iodide, nickel nitrate, nickel sulfate, nickel formate, nickel acetylacetonate, A method for manufacturing a semiconductor device, wherein at least one selected from nickel 4-cyclohexylbutyrate, nickel oxide, and nickel hydroxide is used. 16. A step of applying a solution in which a compound containing a catalytic element that promotes crystallization of the amorphous silicon film is dissolved or dispersed in a non-polar solvent onto the amorphous silicon film, and the amorphous silicon film is formed. A method for manufacturing a semiconductor device, comprising the step of crystallizing a film by heat treatment. 17. The method of manufacturing a semiconductor device according to claim 16, wherein at least one selected from benzene, toluene, xylene, carbon tetrachloride, chloroform, and ether is used as the nonpolar solvent. 18. A method of manufacturing a semiconductor device according to claim 16, wherein nickel is used as a catalyst element and the nickel is used as a nickel compound. 19. The nickel compound according to claim 18, which is nickel acetylacetonate, nickel 4-cyclohexylbutyrate, nickel oxide, nickel hydroxide, 2-
A method for manufacturing a semiconductor device, wherein at least one selected from nickel ethylhexanoate is used. 20. A step of mixing and coating a surface active agent on a solution in which a single element of a catalytic element that promotes crystallization of the amorphous silicon film is dissolved or dispersed on the amorphous silicon film, and coating the amorphous silicon film. A method for manufacturing a semiconductor device, comprising the step of crystallizing a film by heat treatment. 21. A semiconductor device in which an active region is formed on a substrate having an insulating surface by using a crystalline silicon film, the active region being in contact with an amorphous silicon film. The catalyst element that promotes crystallization is dissolved in a solvent and selectively retained, and heat treatment is performed to cause crystal growth from the retained region to its peripheral region. Semiconductor device. 22. A semiconductor device in which an active region is formed on a substrate having an insulating surface by using a crystalline silicon film, the active region being in contact with an amorphous silicon film. A semiconductor characterized in that a compound containing a catalytic element that promotes crystallization is selectively retained, and a crystal is grown from the retained region to its peripheral region by heat treatment. apparatus.