JPH0563196A - Thin film semiconductor device, manufacture thereof and liquid crystal display device - Google Patents

Abstract

PURPOSE:To increase a field effect mobility and to decrease an OFF current by forming a channel layer of a two-layer structure of a poly-Si and a hydrogenated amorphous silicon film having a special thickness in a reversely staggered structure thin film transistor. CONSTITUTION:A gate electrode 2 is first formed on a glass substrate, an SiN insulating film 3 is deposited, and a hydrogenated amorphous silicon film (H film) is deposited in thickness of 10 to 40nm. Thereafter, it is irradiated with an excimer laser to modify the H film to a poly-Si film 4. Then, the H film 5 is deposited on the upper part, the Si film of a part for forming a thin film transistor(TFT) having a reversely staggered structure is insularly formed, source/drain electrodes 7 are then formed, and with both the electrodes as masks the n-type silicon film on the part corresponding to a channel is removed. Thus, the TFT having a high mobility and a low OFF current can be formed, and a driving peripheral circuit can be contained in a liquid crystal display substrate or an image processing substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film semiconductor device,
In particular, the present invention relates to a thin film transistor having an inverted stagger structure used for a liquid crystal display device and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a reverse staggered thin film transistor (hereinafter abbreviated as TFT) has a gate insulating film, a semiconductor thin film, and a high-concentration impurity layer which can be successively formed by a plasma CVD method, so that a manufacturing process is easy and a light-shielding film. It is widely used as an active matrix substrate for liquid crystal displays because of the advantage that it is unnecessary. FIG. 2 shows a process flow and a structural sectional view of an inverted stagger structure a-Si TFT. As described above, the plasma CVD film (gate insulating film, semiconductor thin film, high-concentration impurity layer) can be continuously formed in three layers, so that the characteristic variation is small. However, when a hydrogenated amorphous silicon film (hereinafter abbreviated as a-Si: H film) is used for the channel layer, the field effect mobility is 0.5 cm ² / V · s.
Since it is small in size, it is sufficient for use in a pixel portion of a liquid crystal display device, but the a-SiT film is formed on the same substrate as the pixel portion.
It is very difficult to configure a driving peripheral circuit with FT.

Therefore, in order to overcome the above problems, aS
A method of irradiating the i: H film with a laser beam to improve the field effect mobility has been considered. In particular, the excimer laser whose oscillation wavelength is in the ultraviolet region has a large absorption coefficient for the a-Si: H film and has a small thermal influence on the glass substrate. Therefore, inexpensive low-melting glass can be used, and local crystallization is also possible by using a laser.

An example of a conventional method of manufacturing a polycrystalline silicon thin film transistor (hereinafter abbreviated as poly-Si TFT) using the above process is shown below.

After forming a gate electrode of chromium (Cr), aluminum (Al) or the like formed on a glass substrate by a sputtering method, a gate insulating film and an a-Si: H film are sequentially deposited by a plasma CVD method. After that, XeCl excimer laser is irradiated to convert the a-Si: H film into a poly-Si film. A structural sectional view at this time is shown in FIG. Next, an n-type silicon film is deposited as an ohmic contact layer by the plasma CVD method, and the Si film in the portion where the TFT is formed is processed into an island shape by a photo-etching process. After that, a source electrode and a drain electrode are formed of Cr or Al formed by a sputtering method, and the n-type silicon film on the portion corresponding to the channel portion is selectively removed by a dry etching method or the like using both electrodes as a mask. Finally, a passivation film is deposited on the entire surface to manufacture the target poly-Si TFT.
(Described in JP-A-2-130913).

As a method different from the above-mentioned conventional example, a method of irradiating a XeCl excimer laser after depositing a passivation film on the entire surface as shown in FIG. 4 is considered. According to this method, the laser irradiation is performed after the conventional manufacturing process of the a-Si TFT is completed, so that the process is changed the least (described in JP-A-60-245124).

Further, as a method and structure for irradiating the a-Si: H film with a laser beam to increase the mobility of the inverted stagger structure TFT, the following can be considered. Generally a-Si TFT
In this case, since the etching of the n-type silicon film and the a-Si: H film has a low selectivity, a-Si: H which will become the channel layer is formed.
It is necessary to make the film thick to some extent. However, a-S
When the i: H film is thickened, it is difficult to crystallize the entire film even if the excimer laser is irradiated with high energy.
In reality, the improvement of crystallinity in the vicinity of the interface with the gate insulating film through which the on-current flows becomes insufficient. Therefore, the improvement of the field effect mobility of the TFT is small. Therefore, first, after thinly depositing an a-Si: H film, a laser beam is irradiated to the a-Si: H film.
The H film is modified into a poly-Si film, and then an a-Si: H film is deposited on the poly-Si film. In this way, by forming the channel layer into a two-layer structure of poly-Si and a-Si: H, it is possible to improve the field effect mobility and to allow the etching of the n-type silicon film to have a margin.

[0008]

In the above prior art, the film thickness of the Si film to be crystallized, the energy when the laser beam is irradiated, the influence of the heating on the gate insulating film when the laser beam is irradiated, etc. Is not considered.

Since the TFT has an inverted staggered structure, when the a-Si: H film to be crystallized is thick, the vicinity of the interface with the gate insulating film where the on-current actually flows even when the high energy laser beam is irradiated. It is difficult to improve the crystallinity. Therefore, it is difficult to improve the field effect mobility. However, by setting the film thickness of the a-Si: H film to 100 nm or less, the entire a-Si: H film can be crystallized. Therefore, when the gate insulating film is composed of the SiO ₂ film, the field effect mobility can be improved by limiting the film thickness as described above.

However, when the gate insulating film is composed of the SiN film, the TFT obtained is different from the case of the above-mentioned SiO ₂ film.
Have different characteristics. When the a-Si: H film is irradiated with a laser beam, the Si film has latent heat, and this latent heat is a-Si:
The thicker the H film, the larger. Therefore, the thicker the a-Si: H film, the greater the influence of heating on the gate insulating film. Further, the higher the energy of the laser to be irradiated, the greater the influence. When hydrogen is not contained in the film like the SiO ₂ film, the deterioration of the film quality due to the influence of heating does not occur. However, when a large amount of hydrogen is contained in the film such as the SiN film, the contained hydrogen is released due to the effect of this heating, and the film quality is significantly deteriorated. Therefore, the electrical characteristics when the TFT is formed are also deteriorated.

Further, in the above-mentioned prior art, the off current (hereinafter I
_OFF ) and reverse leakage current (hereinafter abbreviated as I _REV )
However, there was a problem that the driving peripheral circuit could not be built in the active matrix substrate for the liquid crystal display finally.

According to the present invention, a TFT having a large field effect mobility and a low off current is formed without deteriorating the film quality of the gate insulating film, and finally the driving peripheral circuit is formed on the same substrate as the display section. Intended to be built-in.

[0013]

In order to achieve the above object, the present invention employs an inverted staggered structure TFT as follows. After forming the gate electrode and the SiN film on the insulative substrate, the channel layer is made of poly-S from the side in contact with the SiN film.
i, a-Si: H has a two-layer structure and poly-Si
The reverse staggered structure TFT has a film thickness of 10 nm or more and 40 nm or less.

In order to achieve the above object, the present invention uses a method of manufacturing an inverted stagger structure TFT as follows. First, after forming a gate electrode and a SiN film on an insulating substrate, a-
A Si: H film is deposited with a film thickness of 10 nm or more and 40 nm or less. After that, use an excimer laser of 130 mJ / cm ² or more 2
Irradiation with an energy of 00 mJ / cm ² is carried out, and the a-Si:
The H film is converted into a poly-Si film. The irradiation atmosphere at that time is preferably in an inert gas such as He or Ar or in a vacuum. After forming the poly-Si film, a-Si:
The H film is deposited, and the Si film in the portion forming the TFT is processed into an island shape. Next, source / drain electrodes are formed, and the n-type silicon film on the portion corresponding to the channel portion is selectively removed by a dry etching method or the like using both electrodes as a mask. Finally, a passivation film is formed on the entire surface to form a target high mobility TFT.

[0015]

In the inverted stagger structure TFT of the present invention manufactured as described above, the latent heat of the Si film is small because the film thickness of the a-Si: H film is 40 nm or less when the laser is irradiated, and therefore the SiN film is formed. The effect of heating on is small. On the other hand, a-S
When the film thickness of the i: H film exceeds 40 nm, the latent heat becomes large and the SiN film is heated. Therefore, S in the SiN film
The i-H bond is broken, the contained hydrogen is released, and the film quality is significantly deteriorated. When formed in such a state, the field effect mobility is low, the threshold voltage is high, and the off current is high.
It becomes FT. However, forming the TFT by the means of the present invention does not deteriorate the film thickness of the gate insulating film. In addition, since the a-Si: H film is deposited on the crystallized Si film, the channel layer can be thickened, increasing the process margin when selectively removing the n-type silicon film by the dry etching method or the like. be able to. In the TFT thus formed, when a forward voltage is applied to the gate electrode to turn on the transistor, the inversion layer is formed in a poly-Si film having high carrier mobility and has a staggered structure. There is a large overlap between the inversion layer and the source / drain.
A large on-current can be obtained even in the two-layer structure of the ly-Si film and the a-Si: H film. Note that the thickness of the poly-Si film needs to be larger than the thickness of the inversion layer, and further, considering the stability of the film formation, the thickness of the poly-Si film is preferably 10 nm or more.

Further, since the a-Si: H film is present at the junction with the source / drain region where the electric field is concentrated, the electric field is relaxed, and the off current and the reverse leakage current can be suppressed. In addition, the thickness of the Si layer on the side in contact with the gate insulating film is 40
Even if the thickness is less than or equal to nm, when an excimer laser having an energy of more than 200 mJ / cm ² is irradiated, the SiN film is heated, hydrogen contained in the film is released, and the film quality deteriorates. However, by setting the irradiation energy of the excimer laser to 200 mJ / cm ² or less, the Si film can be crystallized without degrading the film thickness of the SiN film. Also, when the irradiation energy is 130 mJ / cm ² or less, a
Since the crystallization of the —Si: H film does not occur stably, the lower limit of the irradiation energy is 130 mJ / cm ² .

With the above TFT structure and manufacturing method, a target liquid crystal display device with a built-in driving circuit can be realized.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is a structural sectional view of a thin film transistor showing the constitution of the present invention. First, the gate electrode 2 is formed of Cr on the glass substrate 1, and then the gate insulating film 3 is deposited. After that, an a-Si: H film is deposited with a film thickness of 10 to 80 nm, and a XeCl excimer laser is set to 200 m in a He atmosphere.
Irradiation was performed with an energy of J / cm ² . At this time, a-Si:
If the H film contains a large amount of hydrogen, the Si film is peeled off by irradiation with an excimer laser. Therefore, heat treatment is performed at 400 ° C. or higher as a pretreatment for laser annealing, or irradiation with an energy beam such as an Ar laser is performed. It is necessary to control the amount of hydrogen contained in the a-Si: H film. By irradiating the excimer laser as described above, the a-Si: H film is modified into the poly-Si film 4. Next, an a-Si: H film 5 is deposited on the poly-Si film 4 so that the total film thickness of the Si film is 220 nm, and then an n-type silicon layer 6 is deposited to 35 nm. Next, the Si film in the portion for forming the TFT is processed into an island shape by a photo-etching process, and then the source / drain electrodes 7 are formed of Al or the like. The n-type silicon film on the portion corresponding to the channel portion is removed by dry etching using both electrodes as a mask, and finally, a passivation film is deposited on the entire surface to complete the target TFT. In FIG. 5, the gate insulating film is a SiN film or SiO.
The relationship between the film thickness of the poly-Si film and the field effect mobility in the case of being composed of _two films is shown. When the gate insulating film is composed of the SiO ₂ film, a TFT having a field effect mobility of about 20 cm ² / V · s can be obtained in the range of 10 to 80 nm for the poly-Si film. However, when the gate insulating film is made of the SiN film and the film thickness of the poly-Si film exceeds 40 nm, the field effect mobility remarkably decreases. When the SiN film is used as the gate insulating film as described above, the film thickness of the poly-Si film needs to be 40 nm or less. However, by limiting the film thickness as described above, the SiO ₂ film is used as the gate insulating film. TF with a field effect mobility of 20 cm ² / V · s as in the case of using the film
T can be formed.

Example 2 Next, the case where the energy of the excimer laser for irradiating the a-Si: H film was changed will be described below. Cr is deposited to a thickness of 120 nm on a glass substrate by a sputtering method, and a gate electrode is formed by a photo-etching process. Next, a SiN film and an a-Si: H film are each formed by plasma CVD to form 3 films each.
Deposit 50 nm and 30 nm. Then, heat treatment is performed in a nitrogen atmosphere at 400 ° C. for 15 minutes as a pretreatment for irradiating the excimer laser to reduce the amount of hydrogen contained in the a-Si: H film. In this pretreatment, an energy beam such as an Ar laser may be irradiated. Next, the excimer laser 100-
Irradiation with an energy of 250 mJ / cm ²
The i: H film is modified into the poly-Si film 4. After that, the a-Si: H film 5 and the n-type silicon film 6 are formed by the plasma CVD method.
Of 190 nm and 35 nm respectively are deposited, and the Si film of the portion forming the TFT is processed into an island shape by a photo-etching process. Next, after forming a source / drain electrode with Al formed by a sputtering method, the n-type silicon film on a portion corresponding to the channel portion is selectively removed by a dry etching method or the like using both electrodes as a mask. Finally, a passivation film is formed on the entire surface to complete the TFT. The relationship between the field effect mobility of the TFT thus formed and the irradiation energy of the excimer laser is shown in FIG. When the irradiation energy of the excimer laser is 130 mJ / cm ² or less, the a-Si: H film is not crystallized and the field effect mobility is not improved. Further, when the irradiation energy of the excimer laser exceeds 200 mJ / cm ² , hydrogen in the SiN film is released due to the temperature rise, so that the field effect mobility is significantly reduced. Further, the off-current also increases as the field effect mobility decreases. However, by setting the irradiation energy of the excimer laser to 130 to 200 mJ / cm ² , a TFT having a field effect mobility of 20 cm ² / Vs and an off current of 2 pA could be manufactured without variation.

Embodiment 3 Next, an embodiment in which the gate insulating film has a two-layer structure of an anodic oxide film and a SiN film will be described with reference to FIG.

An Al film 10 is sputtered on the glass substrate 1 to have a pressure of 54 μPa, a power of 2.1 kW and a substrate temperature of 10.
250 nm is deposited under the condition of 0 ° C. After forming a gate electrode pattern by a photo-etching process, the surface of Al is anodized. The film thickness of the Al ₂ O ₃ film 11 formed at this time is 200 nm. After that, the SiN film 3 is formed by plasma CVD at a pressure of 0.6 Torr, a power of 60 W, a substrate temperature of 350 ° C., and a gas flow rate of SiH ₄ 8 sccm NH ₃ 48 sccm N _2.
An a-Si: H film having a thickness of 160 nm, a pressure of 0.6 Torr, a power of 40 W, a substrate temperature of 300 ° C., and a gas flow rate of SiH ₄ 14 sccm H ₂ 40 sccm are continuously formed for 30 nm, and then an Ar laser is output at 6.0 W. , Beam diameter 2.0
Irradiation is performed on the a-Si: H film on the part where the TFT is formed under the conditions of mmφ and scanning speed of 3.0 mm / s. This gives a
-Reduce the amount of hydrogen in the Si: H film and prevent the film from peeling off when irradiated with a maximer laser. After irradiating with Ar laser, XeCl excimer laser is irradiated with energy of 170 mJ / cm ² to modify the a-Si: H film into poly-Si film 4. Next, a-Si: H is formed by a plasma CVD method.
The film 5 is 190 nm under the same conditions as the a-Si: H film, the n-type silicon film 6 is pressure 0.6 Torr, power 40 W, substrate temperature 250 ° C., gas flow rate SiH ₄ 20 sccm PH ₃ 20 sccm.
35 nm is continuously formed under the condition of H ₂ 50 sccm. After that, the Si film is processed into an island shape by a photo-etching process, and then a Cr film 12 and an Al film 10 are formed by a sputtering method under the same conditions as the gate Al film to have a thickness of 60 nm and 400 nm, respectively, and are patterned into source / drain electrodes. The n-type silicon film on the portion corresponding to the channel portion is selectively removed by dry etching using both electrodes as a mask, and then a passivation film 8 of 1 μm is formed on the entire surface to complete the target TFT.
As a result, a TFT having a field effect mobility of 20 cm ² / Vs, a threshold voltage of 2 V and an off current of 2 pA (W / L = 10) could be formed. Further, by irradiating an energy beam such as an excimer laser after anodizing, the adhesion with the SiN film is improved, and the variation in TFT characteristics is further reduced.

Embodiment 4 FIG. 8 shows an embodiment of the present invention and is a schematic view of an active matrix substrate with a built-in driving peripheral circuit.
In the present embodiment, the display unit 100 realizes a video display terminal (hereinafter abbreviated as VDT) including a peripheral circuit 101 for driving the display unit with a diagonal of 10 inches. In this case, the number of pixels of the display unit 100 is 480 × 640 × (3), the TFT used in the display unit 100 is a normal a-Si TFT having an inverted stagger structure, and the TFT used in the peripheral circuit unit has a poly-channel region. It has a two-layer structure of an -Si film and an a-Si: H film.

First, a Cr film having a thickness of 120 nm is deposited as a gate electrode on a 12-inch diagonal glass substrate by a sputtering method. After patterning the Cr film by the photo-etching process, the SiN film 3 is formed by the plasma CVD method.
A 0-nm a-Si: H film is successively formed in a thickness of 30 nm.
Here, He is formed on a portion of the substrate where the driving peripheral circuit is formed.
170 mJ / cm ² of XeCl excimer laser in the atmosphere
Irradiation of the a-Si: H film to poly-Si
Convert to Membrane 4. Then, a-
The Si: H film 5 is deposited to a thickness of 190 nm. As a result, the peripheral circuit section has a-Si: H (190 nm) / poly-Si (3
The pixel portion 100 is a-Si: H.
A single layer structure of (220 nm) is obtained. The cross-sectional structure diagram of each is shown in FIG. Next, an n-type silicon layer is deposited to a thickness of 35 nm by the plasma CVD method, the Si film is processed into an island shape by a photo-etching step, ITO that is a transparent electrode is deposited by the sputtering method, and patterning is performed by the photo-etching step. Thereafter, a Cr film and an Al film are deposited by sputtering to 60 nm and 400 nm, respectively, and a source / drain electrode is formed by a photo-etching process. After selectively removing the n-type silicon film on the portion corresponding to the channel portion by a dry etching method using both electrodes as a mask, a passivation film is formed on the entire surface to complete the intended active matrix substrate for liquid crystal display. The characteristics of the TFT provided on the active matrix substrate are as follows: field effect mobility in the peripheral circuit part: 20 cm ² / Vs, threshold voltage: 2 V, off current: 2 pA, reverse leakage current: 3 p
A (W / L = 10), field effect mobility in the pixel portion: 0.4 cm ² / Vs, threshold voltage: 1.5 V, off current: 1 pA (W / L = 10). On the other hand, the other one
A polarizing plate, a color filter, and a transparent electrode are formed on a 2-inch glass substrate, and liquid crystal is sealed between the active matrix substrate and the active matrix substrate to complete a 10-inch size VDT liquid crystal display device.

[0025]

According to the present invention, the a-Si: H film formed on the gate insulating film is irradiated with a laser beam without deteriorating the film quality of the gate insulating film and poly-Si.
There is an effect that it can be converted into a film, and a TFT having high mobility and low off-current can be formed. Further, finally, there is an effect that the driving peripheral circuit can be built in the liquid crystal display substrate or the image processing substrate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a two-layer structure TFT.

FIG. 2 is a process flow diagram of an a-Si TFT.

FIG. 3 is a cross-sectional structure diagram at the time of laser annealing of a conventional technique.

FIG. 4 is a cross-sectional structural diagram at the time of laser annealing of a conventional technique.

FIG. 5 is a relationship diagram between a gate insulating film and TFT characteristics.

FIG. 6 is a relationship diagram between laser irradiation energy and field effect mobility.

FIG. 7 is a cross-sectional structure of a two-layer structure TFT.

FIG. 8 is a diagram showing an active matrix substrate with built-in driving peripheral circuits.

FIG. 9 is a TFT structure diagram of a pixel portion and a circuit portion.

[Explanation of symbols]

1 ... Glass substrate, 2 ... Gate electrode, 3 ... Gate insulating film,
4 ... Polycrystalline silicon film, 5 ... Hydrogenated amorphous silicon film,
6 ... N-type silicon film, 7 ... Source / drain electrodes, 8 ...
Passivation film, 10 ... Aluminum film, 11 ... Alumina film, 12 ... Chrome film, 100 ... Liquid crystal display device pixel portion, 101 ... Liquid crystal display device driving peripheral circuit portion.

Claims (11)

[Claims] 1. A reverse staggered thin film semiconductor device having a gate electrode, a gate insulating film, a channel region, a source region, and a drain region on an insulating substrate, wherein the channel region is polycrystalline from the side in contact with the gate insulating film. silicon,
A thin film semiconductor device having a two-layer structure of amorphous silicon in this order, and the film thickness of the polycrystalline silicon is 10 nm or more and 40 nm or less. 2. A thin film semiconductor device according to claim 1, wherein at least a side of the gate insulating film which is in contact with the channel region is made of silicon nitride. 3. A method of manufacturing a thin film semiconductor device having an inverted stagger structure, comprising a gate electrode, a gate insulating film, a channel region, a source region, and a drain region on an insulating substrate, after forming the gate electrode and the gate insulating film. , Film thickness is 10n
A method for manufacturing a thin film semiconductor device, comprising depositing a polycrystalline silicon layer having a thickness of m or more and 40 nm or less, and then depositing an amorphous silicon layer to form a source region and a drain region. 4. The method according to claim 3, wherein after forming the gate insulating film, an amorphous silicon layer is deposited, and the amorphous silicon layer is converted into a polycrystalline silicon layer by an energy beam such as a laser. A method of manufacturing a thin-film semiconductor device characterized. 5. A method of manufacturing a thin film semiconductor device according to claim 4, wherein at least a side of the gate insulating film in contact with the channel region is made of silicon nitride. 6. A liquid crystal display device in which a liquid crystal is sealed between transparent insulating substrates, and a thin film transistor is provided as a switching element on one side of the transparent insulating substrate, in a pixel region serving as a display portion and a peripheral circuit region for driving the pixels. And an inverted staggered structure having a gate electrode, a gate insulating film, a channel region, a source region, and a drain region on an insulating substrate, and at least one side of the gate insulating film in contact with the channel region is made of silicon nitride. A thin film transistor having a double-layered structure, in which polycrystalline silicon and amorphous silicon are formed in this order from the side where the channel region contacts the gate insulating film, and the polycrystalline silicon has a film thickness of 10 nm or more and 40 nm or less. A liquid crystal display device characterized by being used. 7. A liquid crystal display device in which liquid crystal is sealed between transparent insulating substrates, and a thin film transistor is provided as a switching element on one side of the transparent insulating substrate, a gate electrode and a silicon nitride film are deposited on the insulating substrate. After that, the film thickness is 1
Deposit an amorphous silicon layer of 0 nm or more and 40 nm or less,
At least one of a pixel region which becomes a display portion and a peripheral circuit region which drives a pixel is irradiated with an energy beam such as a laser to convert the amorphous silicon layer into a polycrystalline silicon layer, and then the amorphous silicon layer. And a source region and a drain region are formed next, and a method for manufacturing a liquid crystal display device. 8. A liquid crystal display device in which liquid crystal is sealed between transparent insulating substrates, and a thin film transistor is provided as a switching element on one side of the transparent insulating substrate, a gate electrode is formed on the insulating substrate, and the gate electrode is formed. Is anodized, a silicon nitride film is deposited, and then the film thickness is 10n.
An amorphous silicon layer having a thickness of m or more and 40 nm or less is deposited, and at least one of a pixel region serving as a display portion and a peripheral circuit region for driving the pixel is irradiated with an energy beam such as a laser to form the amorphous silicon layer. After converting to a polycrystalline silicon layer, an amorphous silicon layer is formed, and then a source region,
A method of manufacturing a liquid crystal display device, which comprises forming a drain region. 9. The method of manufacturing a thin film semiconductor device according to claim 5, wherein the energy beam is an excimer laser. 10. The irradiation energy of the excimer laser according to claim 9, wherein the irradiation energy is 130 mJ / cm ² or more and 200 m.
A method for manufacturing a thin film semiconductor device, wherein the method is J / cm ² or less. 11. The method according to claim 4, wherein the gate insulating film has a two-layer structure of a film in which a part of the gate electrode is anodized and a silicon nitride film, and a laser beam is irradiated after forming the anodized film. A method of manufacturing a thin-film semiconductor device characterized.