JPH11284193A - Manufacture of thin-film semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin-film semiconductor device by which crystal defect can be repaired securely and in a short time and the boundary condition be improved by effecting an appropriate hydrogenation to a semiconductor thin film and a gate insulation film. SOLUTION: This method includes at least a step to form on the gate insulation film 3 above a substrate (glass board 1) such a metallic thin-film 4 that can prevent the escape of hydrogen, chlorine, or fluorine from the semiconductor film and the gate insulation film, and a step to apply heat treatment so as to activate the hydrogen, chlorine, or fluorine which is injected into the semiconductor thin film and gate insulation film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a thin film semiconductor device.

[0002]

2. Description of the Related Art A polysilicon semiconductor film (p-Si film: polycrystalline silicon film) or an amorphous silicon semiconductor film (a-Si film: amorphous silicon film) as a silicon semiconductor film (semiconductor thin film) is, for example, TFT (Thin Film Transisto) on the active matrix substrate of a liquid crystal device
r: a thin film transistor) and the like.

Here, a low-temperature p-type, which is a kind of the above-mentioned TFT, is used.
An example of the manufacturing process of the SiTFT will be briefly described with reference to the process chart shown in FIG.

First, an a-Si film is deposited on a glass substrate 1 by LPCVD (low pressure CVD) using disilane gas or PECVD (plasma CVD) using monosilane gas, and an excimer film is formed on the entire surface of the a-Si film. Laser annealing with a laser for crystallization results in p-S
An i film 2 is formed (step (a) in FIG. 10).

After the p-Si film 2 is patterned by etching, a gate insulating film 3 is formed by a CVD method (step (b) in FIG. 10).

Next, polysilicon, Ta, Cr, Al or the like is deposited at predetermined positions on the gate insulating film 3 to form the gate electrode 4, and then impurities are implanted by ion doping to form the source / drain regions 2a. , 2b are formed in a self-aligned manner (step (c) in FIG. 10).

After that, an interlayer insulating film 5 is formed by depositing SiO2 or the like by a CVD method, a contact hole 6 is opened, and an ITO film 7 of a pixel electrode and an Al film serving as a data line are formed.
The wiring layer 8 is formed (step (d) in FIG. 10).

Next, a passivation film 9 made of SiO 2 or the like is provided, necessary portions are opened (step (e) in FIG. 10), and the entire manufacturing process of the TFT element substrate is completed.

[0009]

However, the p-Si film formed in the step (a) of FIG.
Due to various factors, dangling bonds are formed in the film 2 and the gate insulating film 3 formed on the p-Si film 2 in the step (a) of FIG. 10 and the interface between the p-Si film 2 and the gate insulating film 3. Crystal defects D are generated based on the existence of Si atoms having (dangling bonds) (see FIG. 2A).

[0010] The crystal defects D adversely affect the interface state between the p-Si film 2 and the gate insulating film 3 and increase the surface leakage current or generate impurity levels to lower the reliability of the TFT. Had a problem. Further, the crystal defect D has also been a factor for lowering the dielectric breakdown voltage characteristics of the gate insulating film 3.

Therefore, hydrogen (H) is added to the Si atom having a dangling bond to terminate the dangling bond with hydrogen, thereby repairing the crystal defect D (see FIG. 2 (b)), and various electric Attempts have been made to improve the properties.

The conventional hydrogenation method is as follows:
After the steps (a) to (e) in FIG. 10 are completed, the entire substrate on which the thin film semiconductor device is formed is exposed to hydrogen plasma,
hydrogen is diffused into the p-Si film 2 and the gate insulating film 3,
Thereafter, annealing is performed at 300 ° C. for about 3 hours to repair crystal defects.

However, the above-mentioned conventional method has a problem that the thin-film semiconductor device formed on the substrate accumulates charges due to hydrogen plasma.

It has been found that the higher the temperature of the annealing, the more effective the recovery of crystal defects is. However, if the temperature is too high, the thin film semiconductor device may be damaged. I had to keep it to the extent.
Therefore, it has been difficult to say that the degree of recovery of crystal defects by the annealing is sufficient to improve the interface state.

In the hydrogen addition method of exposing to the hydrogen plasma, the p-Si film 2 and the gate insulating film 3
Since the amount of hydrogen added to hydrogen is basically governed by the natural diffusion of hydrogen atoms, it has been difficult to achieve uniform hydrogenation.

When excessive hydrogen is added by, for example, hydrogen plasma, SiH ₂ bonds or SiH ₃ bonds are generated in addition to SiH bonds effective for repairing crystal defects, thereby deteriorating the electric conduction characteristics. Or a volatile reaction product such as SiH ₄ may be generated to cause an etching reaction.

The present invention has been devised in view of the above-described problems, and has as its object the purpose of appropriately adding hydrogen (or adding chlorine or fluorine) to a semiconductor thin film and a gate insulating film. It is an object of the present invention to provide a method of manufacturing a thin film semiconductor device capable of improving a boundary state by reliably repairing crystal defects in a short period of time.

[0018]

In order to achieve the above object, a method of manufacturing a thin film semiconductor device according to the present invention is a method of manufacturing a thin film semiconductor device in which a thin film transistor is formed on a substrate. Forming a semiconductor thin film on the semiconductor thin film, forming a gate insulating film of the thin film transistor on the semiconductor thin film, and implanting hydrogen, chlorine or fluorine ions into the semiconductor thin film and the gate insulating film. Forming a metal thin film on the gate insulating film to prevent the escape of ions, and activating hydrogen, chlorine or fluorine implanted at the interface between the semiconductor thin film and the gate insulating film and the semiconductor film. And a step of forming a gate electrode by etching the metal thin film.

According to this, the crystal defect based on the existence of dangling atoms in the semiconductor thin film and the gate insulating film is caused by hydrogen ions, chlorine ions or fluorine ions in the ion implanting step. It is injected into the film, activated by the heat treatment, and repaired by adding hydrogen, chlorine or fluorine.

In particular, since the metal thin film prevents the escape of hydrogen, chlorine or fluorine from the semiconductor thin film and the gate insulating film, the amount of hydrogen, chlorine or fluorine added can be made uniform and reliable. By repairing crystal defects, the interface state between the semiconductor thin film and the gate insulating film can be improved. Since the metal thin film is used to form a gate electrode by being etched, it is possible to prevent the number of steps from being increased unnecessarily.

According to another aspect of the present invention, there is provided a method of manufacturing a thin film semiconductor device having a thin film transistor formed on a substrate, comprising the steps of: forming a semiconductor thin film on a substrate; A step of forming a gate insulating film of the thin film transistor, a step of subjecting the semiconductor thin film and the gate insulating film to steam annealing, and a step of forming a metal thin film on the gate insulating film to prevent the escape of moisture, hydrogen or hydroxyl groups. Performing a heat treatment for decomposing or activating moisture, hydrogen or hydroxyl groups introduced into the semiconductor thin film and the gate insulating film, and forming a gate electrode by etching the metal thin film. At least.

According to this, the crystal defect based on the presence of dangling atoms in the semiconductor thin film and the gate insulating film is caused by introducing moisture, hydrogen or a hydroxyl group into the semiconductor thin film and the gate insulating film in the steam annealing step. It is repaired by being decomposed or activated by the heat treatment in the annealing step and hydrogenated.

In particular, since the metal thin film formed in the metal thin film forming step prevents water, hydrogen or hydroxyl groups from being released from the semiconductor thin film and the gate insulating film, the amount of added hydrogen is made uniform. Thus, crystal defects can be surely repaired, and the interface state between the semiconductor thin film and the gate insulating film can be improved. Since the metal thin film is used to form a gate electrode by being etched in the gate electrode forming step, it is possible to avoid an unnecessary increase in the number of steps.

The metal thin film is made of Ta, Al, A
1 or Cr, and can be formed by a sputtering method, and a general gate electrode material can be used.

The heat treatment can be performed by irradiating a laser beam from above the metal thin film. Thereby, crystal defects in the semiconductor thin film and the gate insulating film can be repaired in a short time, and manufacturing efficiency can be improved. It is to be noted that such laser annealing was made possible by forming a metal thin film as described above to remove hydrogen, chlorine, fluorine, moisture, hydrogen, or a hydroxyl group from the semiconductor thin film and the gate insulating film. Is effectively prevented and activated.

Further, the heat treatment can be performed by irradiating infrared rays from above the metal thin film under a heating condition of 350 ° C. or more, so that a conventional lamp annealing apparatus can be effectively utilized.

The heat treatment may be performed in an N ₂ gas atmosphere at a temperature of 350 ° C. or higher.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a low-temperature p-type TFT, which is a kind of TFT, by a method of manufacturing a thin-film semiconductor device according to this embodiment.
FIG. 9 is a process diagram illustrating an example of a manufacturing process when manufacturing a -SiTFT. FIG. 2 is an explanatory view showing a state before and after hydrogenation is performed in the manufacturing method according to the present embodiment. FIGS. 3 and 4 are diagrams respectively illustrating a state manufactured by performing hydrogenation in the manufacturing method according to the present embodiment. N-channel TFT
5 is a graph showing Ids-Vgs (drain-source current-gate-source voltage) characteristics of a TFT and a p-channel TFT.

FIG. 5 is a schematic diagram showing a configuration example of a liquid crystal panel to which an active matrix substrate AM using TFTs manufactured by applying the method of manufacturing a thin film semiconductor device according to the present invention, and FIG. Substrate AM
FIG. 3 is a schematic diagram showing the configuration of FIG.

In FIG. 1, the same parts as those in FIG. 10 are denoted by the same reference numerals.

In the step (a) of FIG. 1, first, a base SiO ₂ film 10 is formed on a glass substrate 1 by a thermal oxidation method or a CVD method, and then LPCVD using disilane gas is performed.
(Low pressure CVD) method or PECVD using monosilane gas
A-Si (amorphous silicon) film is deposited by a (plasma CVD) method, and laser annealing is performed by irradiating the entire surface of the a-Si film with excimer laser.
The i-film is crystallized to form a p-Si (polysilicon) film 2.

At this time, many crystal defects D are generated in the p-Si film 2 due to the presence of Si atoms having dangling bonds (see FIG. 2A). ).

Next, after the p-Si film 2 is patterned by etching, SiO
₂ is formed (step (b) in FIG. 1).

Then, hydrogen ions (H ⁺ ) are formed from above the gate insulating film 3 at a dose of, for example, 5 × 10 ¹⁴ / cm ^−2.
Is implanted (step (b) of FIG. 1). At this time, hydrogen ions penetrate the gate insulating film 3 and become
-Si film is injected into the p-Si film from the interface.

Subsequently, Ta, A is formed on the entire surface of the gate insulating film 3.
1 is deposited to a thickness of, for example, 5000 ° by a sputtering method to form a metal thin film 4 (step (c) in FIG. 1).

Then, laser annealing is performed by scanning the substrate surface with infrared laser (eg, CO ₂ laser or YAG laser) light from above the metal thin film 4 (step (c) in FIG. 1).

By this laser annealing, hydrogen ions implanted at the p-Si film 2 and the gate insulating film 3 and at the interface of the p-Si film are activated, and the p-Si film 2 and the gate insulating film 3 and the p-Si film are activated. S with dangling bonds existing at the interface
Repairs crystal defect D by bonding with i atom (FIG. 2 (b)
reference).

At this time, since the entire surface of the gate insulating film 3 is covered with the metal thin film 4, it is ensured that hydrogen ions implanted in the p-Si film 2 and the gate insulating film 3 evaporate and escape. This prevents the activated hydrogen ions from bonding with the Si atoms having dangling bonds effectively.

In addition, by performing laser annealing by infrared laser irradiation in the step (c), locally high-density energy can be applied in a short time.
The crystal defect D can be repaired efficiently in a short time, and the production efficiency of the low-temperature p-Si TFT can be improved.

In this embodiment, the case where hydrogen ions are implanted in the step (b) as described above is described. However, the present invention is not limited to this, and chlorine ions or fluorine ions may be implanted. In such a case, the laser annealing in the step (c) is performed, so that the Si
A crystal defect D due to the combination of atoms and chlorine or fluorine ions
Is repaired.

Further, in this embodiment, the case where the laser annealing is performed by the infrared laser in the step (c) has been described. However, the present invention is not limited to this. The laser annealing is performed at 600 ° C. for 1 minute or 400 ° C. using an infrared lamp. C, 5
Lamp annealing may be performed under the condition of
Even if N ₂ annealing is performed at 350 ° C. for 3 hours, the crystal defect D can be similarly repaired.

After completion of the laser annealing in the step (c), the metal thin film 4 is etched to form a gate electrode G (step (d) in FIG. 1). Thus, the metal thin film 4
Can be used to form a gate electrode, so that it is possible to avoid increasing the number of TFT manufacturing steps.

Then, using the gate electrode G as a mask, impurities are implanted by ion doping to form the source / drain regions 2a and 2b in a self-aligned manner (step (d) in FIG. 1).

Thereafter, an interlayer insulating film 5 is formed by depositing SiO ₂ or the like by a CVD method, a contact hole 6 is opened, and an ITO film 7 of a pixel electrode and an Al film serving as a data line are formed.
The wiring layer 8 is formed (step (e) in FIG. 1).

Next, a passivation film 9 made of SiO ₂ or the like is provided, necessary portions are opened (step (f) in FIG. 1), and the manufacturing process of the low-temperature p-Si TFT element substrate is completed.

With respect to the TFT device thus manufactured, Ids-Vgs (drain-source current-gate
The source voltage) characteristics were measured. As shown in the graph of FIG. 3, for the n-channel type (for example, when P was implanted as an impurity at 3 × 10 ¹⁵ / cm ² ), no hydrogen was added (A ) When hydrogen is added compared to (B)
It can be seen that the Ids-Vgs characteristics of the sample are improved.

[0048] Further, p-channel type (e.g., if you 1 × 10 ¹⁵ / cm ² implanted B as impurity) as for shown in the graph of FIG. 4, hydrogen compared with the case without addition of hydrogen (A) Ids-Vg of (B) when is added
It can be seen that the s characteristic is improved.

Therefore, it was confirmed that the method for manufacturing a thin film semiconductor device according to the present invention is effective for improving the characteristics of a low-temperature p-Si TFT element.

FIG. 5 shows a configuration example of a liquid crystal panel P to which an active matrix substrate AM having a low-temperature p-Si TFT manufactured as described above is applied. As shown in the figure, the active matrix substrate (TF
On a T array substrate) AM, the two substrates are bonded together around a pixel region (a region of a liquid crystal panel where an image is actually displayed due to a change in the orientation state of the liquid crystal layer 52) regulated by the plurality of pixel electrodes 52. As an example of a sealing member surrounding the liquid crystal layer 53, a sealing material 54 made of a photocurable resin
Are provided along the pixel region. Further, a light-shielding peripheral parting layer 57 is provided on a portion of the incident-side counter substrate 56 having the color filter layer 55 corresponding to the inner region of the above-mentioned pixel region outer sealing material 54.

When the active matrix substrate AM is set in a light-shielding case having an opening corresponding to the pixel region later, the peripheral parting layer 57 may have an opening in the case due to a manufacturing error or the like. Formed of a band-shaped light-shielding material having a width of about 500 μm to 1 mm around the pixel area so as not to be hidden by the edge, that is, for example, to allow about several hundred μm as a shift of the liquid crystal panel substrate 50 from the case. Is done. Such a light-shielding peripheral parting layer 57 is made of, for example, Cr (chrome) or N
The counter substrate 31 is formed by sputtering, photolithography, and etching using a metal material such as i (nickel) and Al (aluminum). Instead of the metal material, the peripheral parting layer 57 may be formed of a material such as resin black in which carbon or Ti (titanium) is dispersed in a photoresist.

A peripheral circuit (scanning line driving circuit) 58 and a pad 59 as an external terminal are provided along the lower side of the pixel region in a region outside the sealing material 54, and are provided on both sides of the pixel region (two on the left and right in the figure). A peripheral circuit (signal line driving circuit) 60 is provided along the side. Further, a wiring 61 for electrically connecting the peripheral circuits 60 provided on both sides of the pixel region is provided on the upper side of the pixel region.
Further, columns 62 made of a conductive source voltage material for establishing electrical continuity between the active matrix substrate 51 and the counter substrate 56 are provided at the four corners of the sealing material 54. Then, a counter substrate 56 having substantially the same contour as the sealing material 54 is fixed to the active matrix substrate AM by the sealing material 54, and the liquid crystal panel P is formed.

The low-temperature p-Si in this embodiment is
The formation process of the TFT includes any of a transistor for controlling the pixel electrode 52 on the active matrix substrate ON and OFF, a transistor for forming the scanning line driving circuit 58, a transistor for forming the peripheral circuit (signal line driving circuit) 60, and the like. It can also be applied to the case of forming (see FIG. 6).

Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 7 shows a low-temperature p-type TFT, which is a kind of TFT, by the method of manufacturing a thin-film semiconductor device according to this embodiment.
FIG. 8 is a process chart showing another example of a manufacturing process when manufacturing a -Si TFT, and FIG. 8 shows Ids-Vgs when steam annealing is performed in the manufacturing method according to the present embodiment.
FIG. 9 is a graph showing Ids-Vgs characteristics when steam annealing was not performed.

In step (a) of FIG. 7, the glass substrate 1
After an underlying SiO ₂ film 10 is formed thereon by a thermal oxidation method or a CVD method, an a-Si (amorphous silicon) film is formed by an LPCVD (low pressure CVD) method using a disilane gas or a PECVD (plasma CVD) method using a monosilane gas. Is deposited, and laser annealing is performed by irradiating the entire surface of the a-Si film with an excimer laser, and the a-Si film is crystallized to form a p-Si (polysilicon) film 2.

At this time, many crystal defects D are generated in the p-Si film 2 due to the presence of Si atoms having dangling bonds (see FIG. 2A). ).

Next, after the p-Si film 2 is patterned by etching, TEOS (Tetra Ethy
l OrthoSilicate) SiO ₂ generated by the pyrolysis method
Is formed (step (b) in FIG. 7).

Then, steam annealing (wet annealing) is performed on the substrate on which the gate insulating film 3 is formed at 350 ° C. for 3 hours. At this time, water (H ₂ O), hydrogen (H) and hydroxyl group (OH) in the steam are
It is introduced and diffused into the gate insulating film 3 and the p-Si film 2. In particular, S produced by the pyrolysis method of TEOS
Since the gate insulating film 3 made of iO ₂ has a characteristic of easily absorbing moisture, moisture and the like are easily introduced and diffused.

Subsequently, Ta, A is formed on the entire surface of the gate insulating film 3.
1 and the like are deposited to a thickness of, for example, 5000 ° by a sputtering method to form a metal thin film 4 (step (c) in FIG. 7).

The metal thin film 4 is irradiated with infrared rays from an infrared lamp to perform lamp annealing at 600 ° C. for 1 minute or 400 ° C. for 5 minutes (FIG. 7).
Step (c)).

By this lamp annealing, the moisture (H) introduced and diffused into the p-Si film 2 and the gate insulating film 3
₂ O) is decomposed into hydrogen (H) and oxygen (O ₂ ), and hydrogen (H) and hydroxyl (OH) are activated to form p-Si
Film 2 and bonded to Si atoms having dangling bonds present in the gate insulating film 3 to repair the crystal defects D ((b), see FIG. 2), also, the coupling of the SiO ₂ gate insulating film 3 Can be more robust.

With respect to the degree of the repair of the crystal defect D, the present inventor has determined that the p-Si film 2 and the gate insulating film 3
(Electron spin resonance method) As a result of the measurement, the spin density at the E ′ center was reduced by two orders of magnitude from 1E ¹⁸ to 1E ¹⁶ , and the spin density at the Pb center was 1E ¹³
We can see that reduced an order of magnitude to E ^12, the manufacturing method according to the present invention was confirmed to be very effective in the repair of crystal defects D.

Then, by repairing the crystal defect D, p
-The interface state between the Si film 2 and the gate insulating film 3 can be improved, and the electrical characteristics can be improved.

In this embodiment, the case where the lamp annealing is performed by the infrared lamp in the step (c) has been described. However, the present invention is not limited to this, and the laser annealing is performed in the same manner as in the first embodiment. Alternatively, the crystal defect D can be similarly repaired by performing N ₂ annealing at 400 ° C. for 3 hours.

After completion of the lamp annealing in the step (c), the metal thin film 4 is etched to form a gate electrode G (step (d) in FIG. 7). Thus, the metal thin film 4
Can be used to form a gate electrode, so that it is possible to avoid unnecessarily increasing the number of TFT manufacturing steps.

Then, using the gate electrode G as a mask, impurities are implanted by ion doping to form the source / drain regions 2a and 2b in a self-aligned manner (step (d) in FIG. 7). Thereafter, an interlayer insulating film 5 is formed by depositing SiO ₂ or the like by a CVD method, a contact hole 6 is opened, and an ITO film 7 of a pixel electrode and an Al serving as a data line are formed.
The wiring layer 8 is formed (step (e) in FIG. 7).

Next, a passivation film 9 made of SiO ₂ or the like is provided, necessary portions are opened (step (f) in FIG. 7), and the manufacturing process of the low-temperature p-Si TFT element substrate is completed.

As shown in the graph of FIG. 8, Id of the TFT element manufactured by performing the steam annealing as described above.
The s-Vgs characteristics were measured.

In FIG. 8, the measurement curve A shows a train source voltage (V) in a normal state (a state in which no voltage stress is applied).
The measurement curve B shows the Ids-Vgs characteristics when ds) is 4 V and the Ids-Vgs characteristics when Vds is 8 V in the same state.
The Vgs characteristic and the measurement curve C show the Ids-Vgs characteristic when Vds is 4 V in a state where a voltage stress is applied,
The measurement curve D is Id when Vds is 8 V in the same state.
The respective s-Vgs characteristics are shown.

From the graph of FIG. 8, the measurement curves A, B,
It can be seen that the curves of C and D substantially coincide with each other, and the change in the characteristics is extremely small, and it can be confirmed that the characteristics of the TFT element are stable.

On the other hand, FIG. 9 shows the same Ids-Vg for a TFT element manufactured without performing steam annealing.
5 is a graph showing the results of measuring the s-characteristics, but the curves of the measurement curves A ′, B ′, C ′, and D ′ do not match and the TFT
It can be seen that the characteristics of the element vary.

From the comparison of the characteristics of the TFT elements, it can be confirmed that the steam annealing in this embodiment is effective for repairing the crystal defect D.

In the first and second embodiments, the metal thin film 4 is etched to form the gate electrode G.
However, the present invention is not limited to this, and the metal thin film 4 is entirely removed once, and another material (for example, p-S
A gate electrode may be formed according to i).

[0075]

As described above, the method of manufacturing a thin film semiconductor device according to the present invention provides a method for manufacturing a thin film semiconductor device which eliminates crystal defects based on the presence of dangling atoms at the interface between the semiconductor thin film and the gate insulating film and the semiconductor thin film. In the ion implantation step,
An effect that hydrogen ions, chlorine ions or fluorine ions are implanted into the semiconductor thin film and the gate insulating film, activated by heat treatment in the annealing step, and can be repaired by adding hydrogen, chlorine or fluorine. There is.

[Brief description of the drawings]

FIG. 1 is a process diagram showing an example of a manufacturing process when a low-temperature p-Si TFT is manufactured by applying the method for manufacturing a thin-film semiconductor device according to the present invention.

FIG. 2 is an explanatory view showing a state of crystal defects before and after hydrogenation is performed by a method of manufacturing a thin film semiconductor device according to the present invention.

FIG. 3 shows Ids-Vg of an n-channel TFT manufactured by performing hydrogenation in the manufacturing method according to the first embodiment.
4 is a graph showing s characteristics.

FIG. 4 shows the Ids-Vg of a p-channel TFT manufactured by performing hydrogenation in the manufacturing method according to the first embodiment.
4 is a graph showing s characteristics.

FIG. 5 is a schematic view of a liquid crystal panel using an active matrix substrate using a TFT manufactured by applying the method of manufacturing a thin film semiconductor device according to the present invention.

FIG. 6 is a schematic view of an active matrix substrate using a TFT manufactured by applying the method of manufacturing a thin film semiconductor device according to the present invention.

FIG. 7 is a process chart showing another example of a manufacturing process when a low-temperature p-Si TFT is manufactured by applying the method of manufacturing a thin-film semiconductor device according to the present invention.

FIG. 8 is a graph showing Ids-Vgs characteristics of a TFT manufactured by performing steam annealing in the manufacturing method according to the second embodiment.

FIG. 9 is a graph showing Ids-Vgs characteristics of a TFT manufactured without performing steam annealing.

FIG. 10 is a process diagram showing an example of a conventional low-temperature p-Si TFT manufacturing process.

[Explanation of symbols]

Reference Signs List 1 glass substrate 2 p-Si film 2a source region 2b drain region 3 gate insulating film 4 metal thin film 5 interlayer insulating film 6 contact hole 7 ITO film 8 Al wiring layer 9 passivation film 10 base SiO ₂ film G gate electrode D crystal defect AM Active matrix substrate

Claims (6)

[Claims] 1. A method of manufacturing a thin film semiconductor device having a thin film transistor formed on a substrate, comprising: forming a semiconductor thin film on the substrate; and forming a gate insulating film of the thin film transistor on the semiconductor thin film. Hydrogen for the semiconductor thin film and the gate insulating film,
A step of ion-implanting ions of chlorine or fluorine; a step of forming a metal thin film on the gate insulating film to prevent the escape of the ions; and an interface between the semiconductor thin film and the gate insulating film and the semiconductor film. A method for manufacturing a thin film semiconductor device, comprising: at least a step of performing a heat treatment for activating implanted hydrogen, chlorine, or fluorine; and a step of forming a gate electrode by etching the metal thin film. 2. A method of manufacturing a thin film semiconductor device comprising a thin film transistor formed on a substrate, comprising: forming a semiconductor thin film on the substrate; and forming a gate insulating film of the thin film transistor on the semiconductor thin film. Performing a steam anneal on the semiconductor thin film and the gate insulating film; forming a metal thin film on the gate insulating film to prevent the escape of the moisture, hydrogen, or hydroxyl group; At least a step of performing a heat treatment for decomposing or activating moisture, hydrogen, or a hydroxyl group introduced into the gate insulating film; and a step of etching the metal thin film to form a gate electrode. A method for manufacturing a thin film semiconductor device. 3. The manufacturing method of a thin film semiconductor device according to claim 1, wherein said metal thin film is made of Ta, Al, an alloy of Al or Cr, and is formed by a sputtering method. Method. 4. The heat treatment according to claim 1, wherein a laser beam is irradiated from above the metal thin film.
The method for manufacturing a thin-film semiconductor device according to any one of the above. 5. The method of manufacturing a thin film semiconductor device according to claim 1, wherein said heat treatment includes irradiating infrared rays from above said metal thin film under a heating condition of 350 ° C. or more. Method. 6. The heat treatment is performed in an N2 gas atmosphere at 350.degree.
The method of manufacturing a thin film semiconductor device according to claim 1, wherein the method is performed under a condition of not less than ° C. 7.