JPH0541530A - Photosensor fabrication method - Google Patents

Abstract

(57) [Summary] [Object] To provide a thin film semiconductor having a high S / N and excellent uniformity. In a method for manufacturing a thin film semiconductor in which electrodes are formed on a semiconductor layer made of amorphous silicon via an ohmic contact layer, an ohmic contact layer 23 is formed on a semiconductor layer 22 made of amorphous silicon. Then, the electrodes 25 and 26 having a desired shape are formed thereon, and then the ohmic contact layer in the exposed portion is removed by the plasma etching method, followed by heat treatment at a temperature of 350 ° C. or lower. Reference numeral 21 is a substrate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photosensor used for taking out an optical signal in a photoelectric conversion device for image information processing.

[0002]

2. Description of the Related Art It is generally well known that a photosensor is used as a photoelectric conversion unit which constitutes an image reading unit for a facsimile, a digital copy or the like. As this photo sensor, chalcogenide, CdS, CdS-Se,
Planar type light produced by applying a pair of metal electrode layers facing each other so as to form a gap serving as a light receiving portion on a photoconductive layer made of amorphous silicon (hereinafter referred to as a-Si) or the like. A conductive photo sensor can be exemplified. Since photoconductive photosensors can easily form a long line sensor array, researches have been made especially in recent years. Above all, a
A photosensor using a -Si photoconductive layer is particularly excellent in photoresponsiveness and is expected as a photosensor capable of high-speed reading.

FIG. 1 is a schematic sectional view showing an example of a method for manufacturing a conventional planar type photosensor. PCV on a glass substrate such as ^# 7059 glass substrate 11 manufactured by Corning
An a-Si photoconductive layer (intrinsic layer) 12 is deposited by using the D method, an Al layer 13 is uniformly formed on the photoconductive layer 12, and then unnecessary Al is removed to remove the photoelectric conversion portion. And a pair of electrodes 15 and 16
To form. FIG. 2 shows an example of V-I characteristics during light irradiation in a photo sensor having a sensor gap width of 200 μm. According to this, when the electric field strength exceeds about 50 V / cm, the diode in the reverse direction existing at the interface between the electrodes 15 and 16 and the photoconductive layer 12 becomes dominant and the ohmic characteristics are not exhibited (non-ohmic region). At the same time, high performance cannot be obtained in this region because the response of the photosensor at the time of flashing light is extremely slow. Therefore, the a-Si photoconductive layer 12
An n ⁺ layer, which is an ohmic contact layer, is interposed at the interface between the electrode and the electrodes 15 and 16 so that the ohmic characteristics are exhibited even under a high electric field. Such n ⁺
FIG. 3 shows an example of VI characteristics of a photosensor having a layer at the time of light irradiation.

By the way, since a-Si has a lower heat resistance than crystalline silicon, ion plantation or thermal diffusion cannot be used as a doping means for forming an n ⁺ layer. Therefore, PH _{3 is used as} the source gas for PCVD,
It is general to form an n ⁺ layer which is an ohmic contact layer by a PCVD method by mixing a doping gas such as AsH ₃ . Thus since the n ⁺ layer is entirely uniformly deposited, followed must remove n ⁺ layer of a portion corresponding to the sensor gap, the case of producing a long line sensor array between adjacent bit n ⁺ The layers also need to be removed together. As means for removing the n ⁺ layer, there are a method of etching with a mixed solution of hydrofluoric acid / nitric acid / acetic acid (wet etching method) and a method of etching with plasma discharge of a gas containing carbon halide as a main component (plasma etching method). .. However, these conventionally known etching methods have the following drawbacks.

(A) Disadvantages of the wet etching method (1)
The etched surface has more dangling bonds,
The dark current, which is a noise component, increases; (2) Even with an etching solution having an etching rate of 100 Å / sec,
Etch pits generated on the surface; (3) the etching solution is too large selectivity of the n ⁺ layer and the photoconductive layer is, n present at the interface of the n ⁺ layer and the photoconductive layer ^- the layer can not be removed, a dark This causes an increase in current and an increase in variations in characteristics. (4) Since the etching solution contains hydrofluoric acid, the surface of the glass substrate becomes rough. Therefore, in the photosensor in which light is incident from the glass substrate side, the amount of light reaching the photoelectric conversion unit is reduced.

(B) Disadvantages of the plasma etching method (1)
The etched surface has more dangling bonds,
Dark current, which is a noise component, increases; (2) Implantation of cathode material such as SUS occurs.

Therefore, only the photosensor having a poor S / N and a large variation in performance can be manufactured by using either the wet etching method or the plasma etching method.

[0008]

An object of the present invention is to provide a photosensor having a high S / N and excellent uniformity in view of the above-mentioned conventional techniques.

The above object is achieved by removing the unnecessary portion of the ohmic contact layer by the plasma etching method at the time of manufacturing the photosensor and then performing the heat treatment.

[0010]

The present invention will be specifically described below with reference to examples.

FIG. 4 is a schematic sectional view for explaining a preferred embodiment of the photosensor manufacturing method according to the present invention.
FIG. 3 is a schematic partial plan view of a long line sensor array obtained by the manufacturing method of the present invention.

First, a glass substrate ( ^# 70 manufactured by Corning Incorporated)
59) A photoconductive layer (intrinsic layer) 22 made of an a-Si layer was provided on 21 by a glow discharge method. That is, SiH ₄ diluted to 10% by volume with H ₂ was used at a gas pressure of 0.50 Torr and RF (Radio Frequency).
cy) A photoconductive layer 22 having a thickness of 0.7 μm was obtained by depositing at a power of 10 W and a substrate temperature of 250 ° C. for 2 hours. Similarly, the n ⁺ layer 23 was provided by the glow discharge method. That is, H
SiH diluted to ₂ with 10% by volume ₄ and 100p with H ₂
A gas obtained by mixing PH ₃ diluted to pm at a mixing ratio of 1:10 was used as a raw material, and the other conditions were the same as the deposition conditions of the photoconductive layer 22, and the n of the thickness of 0.1 μm was continuously applied to the photoconductive layer 22.
^{A +} layer 23 is provided. Next, Al was deposited to a thickness of 0.3 μm by the electron beam evaporation method to form the conductive layer 24. Then, the part of the conductive layer 24 which will be the photoelectric conversion part was removed. That is, after forming a photoresist pattern in a desired shape using a positive type microposit 1300-27 (trade name: manufactured by Shipley) photoresist, phosphoric acid (85% by volume aqueous solution), nitric acid (60% by volume aqueous solution) ), Glacial acetic acid and water were mixed at a volume ratio of 16: 1: 2: 1 to remove the conductive layer 24 on the exposed portion using an etching solution to form a common electrode 25 and an individual electrode 26. Next, the portion of the n ⁺ layer 23 that will be the photoelectric conversion portion was removed. That is, after peeling off the microposit 1300-27 photoresist, a parallel plate type plasma etching apparatus (DEM-451 manufactured by Nichiden Anelva Co., Ltd.) is used to perform a plasma etching method (also known as a reactive ion etching method) with an RF power of 120 W and a gas. Dry etching with CF ₄ gas was performed for 5 minutes at a pressure of 0.1 Torr to remove the exposed part of the n ⁺ layer 23 and the surface layer of the photoconductive layer 22. In this embodiment, in order to prevent the implantation of the cathode material of the etching apparatus, the sputtering target of polysilicon (8 inch φ, purity 99.99) is formed on the cathode.
9%), place the sample on it, and add S of the cathode material.
The exposed US portion was covered with a Teflon sheet cut out in a donut shape, and etching was performed in a state where the SUS surface was hardly exposed to plasma. After that, heat treatment was performed at 200 ° C. for 60 minutes in an oven in which nitrogen was passed at 3 liter / min.

FIG. 6 shows data of uniformity of photocurrent when light is made incident on each of the 32 photosensors of the long photosensor array as shown in FIG. 5 thus produced so as to obtain uniform illuminance. Show. This data includes the gap width 10 μ between the common electrode 25 and the individual electrode 26 in FIG. 5, the applied voltage 10 V between the common electrode 25 and the individual electrode 26, and the photocurrent at an illuminance of 100 lx and 10 lx in the photoelectric conversion unit. Is shown. Further, the data of the photoresponse time (τ) of the above photosensor array is shown in Table 1:

[0014]

[Table 1] It should be noted that here, τ _on and τ _off are saturation values at a photocurrent of 100 lx-10% when the illuminance is increased and decreased from 10 lx to 100 lx and from 100 lx to 10 lx, respectively.
And the time to reach -90%. Generally, the optical response speed related to the reading speed is dominated by either τ _on or τ _off , whichever is slower.

For comparison, the photocurrent uniformity was measured in the same manner for the photosensor array manufactured in exactly the same manner except that the heat treatment was not performed during the manufacturing process of the above embodiment. The data is shown in FIG. In addition, the light response time (τ) was measured in the same manner. The data are shown in Table 2:

[0016]

[Table 2] From the above, it is understood that the following advantages can be obtained by performing heat treatment after plasma etching. (1) Uniformity is remarkably improved; (2) γ value, which is the rate of increase in photocurrent with increasing light amount: γ
= Log (I _photo-2 / I _photo-1 ) / log (F ₂ / F
₁ ) is improved and exceeds 1; (3) The photoresponse times τ _on and τ _off are balanced, and τ _off is significantly shortened.

As a result, it was possible to obtain a photosensor array having a high S / N ratio, excellent uniformity, and capable of reading a light beam.

Next, the temperature of the heat treatment for the photosensor performance,
The time dependence was investigated. The results are shown in FIGS. 8 and 9.
FIG. 8 shows the γ value data, and FIG. 9 shows the photocurrent value data under an illuminance of 100 lx. The γ value increases as the temperature increases and the time increases, but at the same time, the photocurrent decreases. Especially 15
30 minutes or more in an atmosphere of 0 to 200 ° C, 200 to 250 ° C
20 minutes or more, 250 to 300 ° C for 10 to 60 minutes, 30
It is preferably carried out at 0 to 350 ° C. for 5 to 30 minutes.

The gas used in the plasma etching step in the manufacturing method of the present invention is not limited to CF ₄ , but a gas containing a halogenated hydrocarbon as a main component, such as CHF ₃ , CCl ₂ F ₂ , CF ₃ Br, CF _4. + Cl
₂ , CF ₄ + O ₂ , CF ₄ + H ₂ can be used,
Similar results were obtained in this case as well.

The heat treatment atmosphere in the manufacturing method of the present invention is not limited to N ₂ , but may be H ₂ , Ar, dry air, or vacuum.

The cause of the improvement of the characteristics of the photosensor by the heat treatment in the manufacturing method of the present invention is that the stress of the film is relaxed, and dangling bonds due to halogen atoms such as F remaining on the surface of the a-Si photoconductive layer during plasma etching. Can be considered as a terminator.

A photosensor manufactured by removing the n ⁺ layer by the wet etching method also shows a slight improvement in characteristics by heat treatment, but it is not practical because the dark current is extremely large in the first place. I knew that.

[0023]

According to the method of manufacturing a photosensor of the present invention as described above, a photosensor capable of high-speed reading with high S / N and excellent uniformity is provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method for manufacturing a conventional photo sensor.

FIG. 2 is a graph of VI characteristics of a photo sensor.

FIG. 3 is a graph of VI characteristics of a photo sensor.

FIG. 4 is a cross-sectional view showing a method for manufacturing a photosensor of the present invention.

FIG. 5 is a partial plan view of a photosensor array obtained by the manufacturing method of the present invention.

FIG. 6 is a graph showing the uniformity of the photo sensor.

FIG. 7 is a graph showing the uniformity of the photo sensor.

FIG. 8 is a graph showing photosensor performance characteristics depending on temperature and time of heat treatment in the manufacturing method of the present invention.

FIG. 9 is a graph showing photosensor performance characteristics depending on temperature and time of heat treatment in the manufacturing method of the present invention.

[Explanation of symbols]

21 substrate 22 photoconductive layer 23 n ⁺ layer 24 conductive layer 25 common electrode 26 individual electrode

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 20, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for manufacturing thin film semiconductor

[Claims]

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a thin film semiconductor in which an electrode is formed on a semiconductor layer made of amorphous silicon via an ohmic contact layer. INDUSTRIAL APPLICABILITY The present invention can be applied to, for example, production of a photosensor used for taking out an optical signal in a photoelectric conversion device for image processing.

[0002]

2. Description of the Related Art It is generally well known that a photosensor is used as a photoelectric conversion unit which constitutes an image reading unit for a facsimile, a digital copy or the like. As this photo sensor, chalcogenide, CdS, CdS-Se,
Planar type light produced by applying a pair of metal electrode layers facing each other so as to form a gap serving as a light receiving portion on a photoconductive layer made of amorphous silicon (hereinafter referred to as a-Si) or the like. A conductive photo sensor can be exemplified. Since photoconductive photosensors can easily form a long line sensor array, researches have been made especially in recent years. Above all, a
A photosensor using a -Si photoconductive layer is particularly excellent in photoresponsiveness and is expected as a photosensor capable of high-speed reading.

FIG. 1 is a schematic sectional view showing an example of a method for manufacturing a conventional planar type photosensor. PCV on a glass substrate such as ^# 7059 glass substrate 11 manufactured by Corning
An a-Si photoconductive layer (intrinsic layer) 12 is deposited by using the D method, an Al layer 13 is uniformly formed on the photoconductive layer 12, and then unnecessary Al is removed to remove the photoelectric conversion portion. And a pair of electrodes 15 and 16
To form. FIG. 2 shows an example of V-I characteristics during light irradiation in a photo sensor having a sensor gap width of 200 μm. According to this, when the electric field strength exceeds about 50 V / cm, the diode in the reverse direction existing at the interface between the electrodes 15 and 16 and the photoconductive layer 12 becomes dominant and the ohmic characteristics are not exhibited (non-ohmic region). At the same time, high performance cannot be obtained in this region because the response of the photosensor at the time of flashing light is extremely slow. Therefore, the a-Si photoconductive layer 12
An n ⁺ layer, which is an ohmic contact layer, is interposed at the interface between the electrode and the electrodes 15 and 16 so that the ohmic characteristics are exhibited even under a high electric field. Such n ⁺
FIG. 3 shows an example of VI characteristics of a photosensor having a layer at the time of light irradiation.

By the way, since a-Si has a lower heat resistance than crystalline silicon, ion plantation or thermal diffusion cannot be used as a doping means for forming an n ⁺ layer. Therefore, PH _{3 is used as} the source gas for PCVD,
It is general to form an n ⁺ layer which is an ohmic contact layer by a PCVD method by mixing a doping gas such as AsH ₃ . Thus since the n ⁺ layer is entirely uniformly deposited, followed must remove n ⁺ layer of a portion corresponding to the sensor gap, the case of producing a long line sensor array between adjacent bit n ⁺ The layers also need to be removed together. As means for removing the n ⁺ layer, there are a method of etching with a mixed solution of hydrofluoric acid / nitric acid / acetic acid (wet etching method) and a method of etching with plasma discharge of a gas containing carbon halide as a main component (plasma etching method). .. However, these conventionally known etching methods have the following drawbacks.

(A) Disadvantages of the wet etching method (1)
The etched surface has more dangling bonds,
The dark current, which is a noise component, increases; (2) Even with an etching solution having an etching rate of 100 Å / sec,
Etch pits generated on the surface; (3) the etching solution is too large selectivity of the n ⁺ layer and the photoconductive layer is, n present at the interface of the n ⁺ layer and the photoconductive layer ^- the layer can not be removed, a dark This causes an increase in current and an increase in variations in characteristics. (4) Since the etching solution contains hydrofluoric acid, the surface of the glass substrate becomes rough. Therefore, in the photosensor in which light is incident from the glass substrate side, the amount of light reaching the photoelectric conversion unit is reduced.

(B) Disadvantages of the plasma etching method (1)
The etched surface has more dangling bonds,
Dark current, which is a noise component, increases; (2) Implantation of cathode material such as SUS occurs.

Therefore, only the photosensor having a poor S / N and a large variation in performance can be manufactured by using either the wet etching method or the plasma etching method.

The above-mentioned circumstances are the same for other than the photosensor as long as it is a thin film semiconductor in which an electrode is formed on a semiconductor layer made of amorphous silicon via an ohmic contact layer.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior arts.
An object of the present invention is to provide a thin film semiconductor having a high S / N and excellent uniformity, in which an electrode is formed on a semiconductor layer made of amorphous silicon via an ohmic contact layer.

[0010]

SUMMARY OF THE INVENTION According to the present invention, in order to achieve the above object, an ohmic contact layer is formed on a semiconductor layer made of amorphous silicon, and an electrode having a desired shape is formed thereon. Next, the exposed portion of the ohmic contact layer is removed by a plasma etching method, followed by heat treatment at a temperature of 350 ° C. or lower.
A method for manufacturing a thin film semiconductor is provided.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 4 is a schematic cross-sectional view for explaining a preferred embodiment of manufacturing a photosensor which is an example of a method for manufacturing a thin film semiconductor according to the present invention, and FIG. 5 is a long film obtained by the manufacturing method according to the present invention. FIG. 3 is a schematic partial plan view of a line sensor array.

First, a glass substrate ( ^# 70 manufactured by Corning Incorporated)
59) A photoconductive layer (intrinsic layer) 22 made of an a-Si layer was provided on 21 by a glow discharge method. That is, SiH ₄ diluted to 10% by volume with H ₂ was used at a gas pressure of 0.50 Torr and RF (Radio Frequency).
cy) A photoconductive layer 22 having a thickness of 0.7 μm was obtained by depositing at a power of 10 W and a substrate temperature of 250 ° C. for 2 hours. Similarly, the n ⁺ layer 23 was provided by the glow discharge method. That is, H
SiH diluted to ₂ with 10% by volume ₄ and 100p with H ₂
A gas obtained by mixing PH ₃ diluted to pm at a mixing ratio of 1:10 was used as a raw material, and the other conditions were the same as the deposition conditions of the photoconductive layer 22, and the n of the thickness of 0.1 μm was continuously applied to the photoconductive layer 22.
^{A +} layer 23 is provided. Next, Al was deposited to a thickness of 0.3 μm by the electron beam evaporation method to form the conductive layer 24. Then, the part of the conductive layer 24 which will be the photoelectric conversion part was removed. That is, after forming a photoresist pattern in a desired shape using a positive type microposit 1300-27 (trade name: manufactured by Shipley) photoresist, phosphoric acid (85% by volume aqueous solution), nitric acid (60% by volume aqueous solution) ), Glacial acetic acid and water were mixed at a volume ratio of 16: 1: 2: 1 to remove the conductive layer 24 on the exposed portion using an etching solution to form a common electrode 25 and an individual electrode 26. Next, the portion of the n ⁺ layer 23 that will be the photoelectric conversion portion was removed. That is, after peeling off the microposit 1300-27 photoresist, a parallel plate type plasma etching apparatus (DEM-451 manufactured by Nichiden Anelva Co., Ltd.) is used to perform a plasma etching method (also known as a reactive ion etching method) with an RF power of 120 W and a gas. Dry etching with CF ₄ gas was performed for 5 minutes at a pressure of 0.1 Torr to remove the exposed part of the n ⁺ layer 23 and the surface layer of the photoconductive layer 22. In this embodiment, in order to prevent the implantation of the cathode material of the etching apparatus, the sputtering target of polysilicon (8 inch φ, purity 99.99) is formed on the cathode.
9%), place the sample on it, and add S of the cathode material.
The exposed US portion was covered with a Teflon sheet cut out in a donut shape, and etching was performed in a state where the SUS surface was hardly exposed to plasma. After that, heat treatment was performed at 200 ° C. for 60 minutes in an oven in which nitrogen was passed at 3 liter / min.

FIG. 6 shows data of uniformity of photocurrent when light is made incident on each of the 32 photosensors of the long photosensor array as shown in FIG. 5 thus produced so as to obtain uniform illuminance. Show. This data includes the gap width 10 μ between the common electrode 25 and the individual electrode 26 in FIG. 5, the applied voltage 10 V between the common electrode 25 and the individual electrode 26, and the photocurrent at an illuminance of 100 lx and 10 lx in the photoelectric conversion unit. Is shown. Further, the data of the photoresponse time (τ) of the above photosensor array is shown in Table 1:

[0015]

[Table 1] Here, τ _on and τ _off are until the photocurrent reaches a saturation value of −10% and −90% of 100 lx when the illuminance increases and decreases from 10 lx to 100 lx and from 100 lx to 10 lx, respectively. Indicates the time. Generally, the optical response speed related to the reading speed is dominated by either τ _on or τ _off , whichever is slower.

For comparison, the photocurrent uniformity was measured in the same manner for a photosensor array manufactured in exactly the same manner except that the heat treatment was not performed in the manufacturing process of the above-mentioned embodiment. The data is shown in FIG. In addition, the light response time (τ) was measured in the same manner. The data are shown in Table 2:

[0017]

[Table 2] From the above, it is understood that the following advantages can be obtained by performing heat treatment after plasma etching. (1) Uniformity is remarkably improved; (2) γ value, which is the rate of increase in photocurrent with increasing light amount: γ
= Log (I _photo-2 / I _photo-1 ) / log (F ₂ / F
₁ ) is improved and exceeds 1; (3) The photoresponse times τ _on and τ _off are balanced, and τ _off is significantly shortened.

As a result, it was possible to obtain a photosensor array having a high S / N ratio, excellent uniformity and capable of reading a light beam.

Next, the temperature of the heat treatment for the photosensor performance,
The time dependence was investigated. The results are shown in FIGS. 8 and 9.
FIG. 8 shows the γ value data, and FIG. 9 shows the photocurrent value data under an illuminance of 100 lx. The γ value increases as the temperature increases and the time increases, but at the same time, the photocurrent decreases. Especially 15
30 minutes or more in an atmosphere of 0 to 200 ° C, 200 to 250 ° C
20 minutes or more, 250 to 300 ° C for 10 to 60 minutes, 30
It is preferably carried out at 0 to 350 ° C. for 5 to 30 minutes.

The gas used in the plasma etching step in the manufacturing method of the present invention is not limited to CF ₄ , but a gas containing a halogenated hydrocarbon as a main component, such as CHF ₃ , CCl ₂ F ₂ , CF ₃ Br, CF _4. + Cl
₂ , CF ₄ + O ₂ , CF ₄ + H ₂ can be used,
Similar results were obtained in this case as well.

The heat treatment atmosphere in the manufacturing method of the present invention is not limited to N ₂ , but may be H ₂ , Ar, dry air, or vacuum.

The cause of the improvement of the characteristics of the thin film semiconductor by the heat treatment in the manufacturing method of the present invention is that the stress of the film is relaxed and that F remaining on the surface of the a-Si layer during plasma etching.
Termination of dangling bonds by halogen atoms such as

It should be noted that the photosensor manufactured by removing the n ⁺ layer by the wet etching method also shows a slight improvement in the characteristics due to the heat treatment, but in the first place it is not practical because the dark current is extremely large. I knew that.

[0024]

According to the manufacturing method of the present invention as described above, high S
A thin film semiconductor capable of high-speed operation with excellent uniformity is provided at / N.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method for manufacturing a conventional photo sensor.

FIG. 2 is a graph of VI characteristics of a photo sensor.

FIG. 3 is a graph of VI characteristics of a photo sensor.

FIG. 4 is a cross-sectional view showing the fabrication of a photo sensor according to the present invention.

FIG. 5 is a partial plan view of a photosensor array obtained by the manufacturing method of the present invention.

FIG. 6 is a graph showing the uniformity of the photo sensor.

FIG. 7 is a graph showing the uniformity of the photo sensor.

FIG. 8 is a graph showing photosensor performance characteristics depending on temperature and time of heat treatment in the manufacturing method of the present invention.

FIG. 9 is a graph showing photosensor performance characteristics depending on temperature and time of heat treatment in the manufacturing method of the present invention.

[Explanation of reference numerals] 21 substrate 22 photoconductive layer 23 n ⁺ layer 24 conductive layer 25 common electrode 26 individual electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Kakimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A method for manufacturing a photosensor in which an electrode is formed on a photoconductive layer via an ohmic contact layer, the ohmic contact layer is formed on the photoconductive layer,
A method of manufacturing a photosensor, comprising forming an electrode having a desired shape on the ohmic contact layer, removing the exposed ohmic contact layer by plasma etching, and then performing heat treatment. 2. The manufacturing method according to claim 1, wherein the photoconductive layer and the ohmic contact layer are based on amorphous silicon. 3. The manufacturing method according to claim 1, wherein the plasma etching is performed using a gas mainly containing a halogenated carbon. 4. The method according to claim 1, wherein the heat treatment is performed at a temperature of 350 ° C. or lower. 5. The heat treatment is performed in an atmosphere of 150 to 200 ° C. for 30 minutes or more, at 200 to 250 ° C. for 20 minutes or more, 250 to
10 to 60 minutes at 300 ° C, or 5 to 300 to 350 ° C
The method according to claim 4, wherein the method is performed for about 30 minutes.