JPS5868965A - Manufacture of light-receiving element - Google Patents

Abstract

PURPOSE:To increase the speed of an optical response characteristic by forming a transparent conductive film onto a photoconductive film, which contains hydrogen and consists of silicon amorphous, and heating the surface at 140 deg.C or higher. CONSTITUTION:Electrodes 21, 22 in metal chromium are formed onto a glass substrate 1, and the N type conductive layers 31, 41, which contain hydrogen and are composed of silicon amorphous, I type conductive layers 32, 42 and P type conductive layers 33, 43 are shaped. An insulating film 5 is formed onto a substrate 1, and the transparent electrode of an In2O3-SnO2 group is shaped through a sputtering method. The element is heated in air within the range of the temperature of 170-250 deg.C. A photo diode 3 formed by the condactive layers 31, 32, 33 is an element, in which secondary photocurrents are dominant and optical response speed thereof is slow, and optical response speed can be increased by thermally treating the element.

Description

Detailed Description of the Invention The present invention relates to a lower electrode formed on a substrate, a photoconductive film made of an amorphous material mainly composed of silicon and containing hydrogen, and a transparent electrode formed by sputtering. The present invention relates to a method of manufacturing a light receiving element. For example, non-transparent metal electrodes are arranged one-dimensionally on an insulating substrate, and an amorphous material mainly composed of silicon and containing hydrogen is placed on the metal electrodes in one-to-one correspondence. N9 type conductive layer from the side.

A photoconductor layer in which an i- or n-type ring is formed in this order, a p-type conductive layer (hereinafter referred to as an amorphous hydrogenated silicon photodiode), and a photoconductor layer in one-to-one correspondence on the photoconductor layer. The present invention is useful when applied to a method for manufacturing a one-dimensional optical sensor in which transparent electrodes are laminated.

It is also useful to apply the present invention to a method of manufacturing a solid-state image sensor in which a photoconductor layer such as the amorphous hydrogenated silicon photodiode and a transparent electrode are laminated on a scanning 5S-IC substrate. It goes without saying that the present invention can also be applied to other light-receiving elements having the above structure, such as solar cells. .

The method of the present invention is useful after forming photoconductor layers and transparent electrodes such as amorphous hydrogenated silicon photodiodes.

In the example of the one-dimensional optical sensor mentioned above, a plurality of solid-state elements having a photoelectric conversion function and a signal accumulation function are arranged in a one-dimensional manner, and each solid-state element corresponds to one pixel to form a one-dimensional optical signal reading element array. It is an element that converts one-dimensional image information into an electrical signal by forming and non-order scanning each solid-state element within this array of elements. It is formed into.

Such a transparent electrode is formed so as to cover the two photoconductor layers.
A one-dimensional optical sensor based on this method has been reported so far.

This technique will be briefly explained below using a one-dimensional sensor shown in FIG.

As shown in FIG. 1, a non-transparent metal electrode 2 is formed on an insulating substrate 1, and an amorphous hydrogenated silicon photodiode 3 and an amorphous hydrogenated silicon isolation diode 4 are further formed on the electrode 2. Ru. At this time, diodes 3 and 4
are the n□ conductive layers 31, 41 . from the mold metal 21 side. i or n type conductive layer 32, 42. p-type trench'#M, jI of layer 33.43
It is formed in I. Photodiode 3 and isolation diode 4 are usually formed at the same time. The photodiode 3 is electrically connected to the transparent electrode 7 through a contact hole 62 made at a desired position in the insulating layer 5, and the transparent electrode 7 is connected to the metal electrode 22 for two-layer wiring through the contact hole 62. Further, the metal wiring 81 is connected to the row driving IC via the contact hole 64. On the other hand, the separation diode 4 is connected to the photodiode 3 through a common electrode 21,
The other side is connected to the column driving IC from the metal wiring 82 via the contact hole 61. The operating principle will be explained with reference to FIG. 1. Incident light 10 reaches photodiode 3 through transparent electrode 7.

In this case, the carriers are absorbed and generate electron-hole pairs, and these carriers are accumulated in the metal electrode 21 by the inverse I (Iasumi pressure V!) applied to the photodiode.

At this time, the isolation diode is biased in the opposite direction and is in an OFF state with respect to the wiring 82. The accumulated carriers forward bias the isolation diode 4 provided on the same metal electrode 21 to turn it on, and the accumulated carriers are read out to the outside through the wiring 82. By sequentially performing the above storage and readout operations for each photodiode using a non-matrix drive in which the wiring 82 is selected using a column driving IC and the wiring 81 is selected using a row driving IC, -dimensional image information can be obtained. can be exposed to the outside. The one-dimensional optical sensor with this structure divides all pixels into a plurality of consecutive groups and scans each group together, so the scanning circuit can be greatly simplified. In addition, photodiode 3
Since the isolation diode 4 and the isolation diode 4 can be formed in the same process, the fabrication process is simplified compared to that in which a photodiode array fabricated by the conventional 5i-IIC process is mounted.

However, after forming a desired pattern of '1121 and a photodiode 3 made of amorphous silicon hydride on a substrate 1, a transparent electrode made of indium oxide-tin oxide or a translucent electrode made of platinum or the like is placed on top of the photodiode 3 made of amorphous silicon hydride. When the photodiode is formed using a sputtering method, the photoresponse characteristics of the photodiode deteriorate.

A photodiode such as amorphous silicon hydride is used to form transparent electrodes of indium oxide-silver oxide metal oxide and semi-transparent gold electrodes of gold and platinum on the photoconductive film by sputtering. This is to improve adhesion with the material. This problem is particularly required in the above-mentioned one-dimensional optical sensor.

It is also possible to form transparent oxide electrodes or semi-transparent metal electrodes using the vacuum evaporation method, but in general, films formed using the #containing method have poorer bonding with the base film than films formed using the sputtering method. Poor adhesion.

When the one-dimensional sensor whose pixel section is shown in cross section in Fig. 1(a) is used as a facsimile optical sensor, it is transparent because it moves in close contact with the above-mentioned surface! It is necessary to form a transparent protective layer on the top of the pole and other sensor surfaces to prevent wear. Alternatively, when performing the process of bonding a thin glass plate with a transparent adhesive sufficiently to the extent that the protective layer does not lose its dissolving power, if the adhesiveness between the photodiode 3 and the transparent electrode 7 is weak, the transparent electrode 7 may peel off. The problem often arises. In this respect, it is preferable to form the transparent electrode 7 by sputtering instead of forming it by vacuum evaporation.

In addition, indium oxide-tin oxide-based transparent electrodes can be replaced with indium-tin oxide-based halides or organometallic salts.
V]) (Chemfcal Vapor pep
It is also known to create an image using the o-aiti'on) method.

However, in this method, in order to obtain a film with low specific resistance, no change in resistance over time, and good adhesion to the underlying film, the substrate temperature must be set to 300 t:' or higher. On the other hand, a photoconductive film such as amorphous hydrogenated silicon has a
When heated above 0.00, the photosensitivity in the visible light region decreases significantly. Therefore, a transparent electrode for a one-dimensional optical sensor using an amorphous hydrogenated silicon photodiode as a photoconductive film cannot be produced by the CVD method.

In the one-dimensional optical sensor shown in FIG.
C
A method (referred to as an accumulation operation method) is adopted in which the wiring 82 is set in the ON state and read out.

The light-receiving element shown in FIG. 2 is a test light-receiving element for measuring optical response characteristics. A 7L lower electrode 12 provided on a substrate 11 and a fourth photo-die made of amorphous hydrogenated silicon.
A reverse bias voltage νT is always applied to the photoconductive film, and the light dL generated in the photomeionide 13 by the light pulse 15
The direction of +&d can be measured with an ammeter 16. Here, 131 is an n0 type conductive layer, 132 is an i or n type conductive layer, and 133 is a p type conductive layer. The photoresistance of the light-receiving element shown in FIG. 2 in which the transparent conductor r is formed by sputtering is as shown in FIG. 3 when the surname is -shill. In Fig. 3, the characteristic a is the incident light pulse, and the curve is the photodiode 1.
3 shows the photoresponse characteristics when a reverse bias is applied, that is, the transparent electrode side is negatively biased (generally KVy=0 to -1 OV is used). It can be seen from the characteristic curve □ in FIG. 3 that the photoresponse characteristics are extremely poor, especially when a negative bias is applied to the transparent electrode side. In other words, in Figure 3, when the transparent electrode side is made negative and a light pulse is irradiated, a phenomenon in which negative charges are injected from the transparent electrode (also called secondary photocurrent) occurs, and even after the light is turned off, This shows that a large amount of decay current flows over a long period of time, and that it takes a long time to return to the dark current level. In a one-dimensional optical sensor, this phenomenon appears as an expansion or contraction of the pattern width of a reproduced image in the sub-scanning direction (original feeding direction). In extreme cases, a reproduced image may not be obtained at all. Further, since the photoresponse characteristic in which the secondary photocurrent is dominant has a large time constant of several tens of milliseconds or more, it is difficult to realize a high-speed facsimile device using such a light receiving element. The above-mentioned phenomena are extremely serious practical drawbacks for one-dimensional optical sensors.

The present invention is extremely effective in obtaining an integrated optical sensor using an amorphous hydrogenated silicon photodiode which eliminates the above-mentioned drawbacks.

In order to achieve the above object, the present invention forms an amorphous photoconductive film mainly made of silicon containing hydrogen on a substrate with desired wiring using a reactive sputtering method or a glow emission method.
After film formation by the CVD method, transparent electrodes are formed on the photoconductive film by sputtering from the substrate side to the n0 type conductive layer, the i or n type ring conductive layer, and the p type conductive layer 111. Thereafter, the present dimensional optical sensor is heat-treated in a temperature range of 170C to 250C to improve the deterioration of the photoresponse characteristics of the present solid-state image sensor that occurred due to the transparent electrode being formed on the photoconductive film by sputtering method. It is something. According to the present invention, it is possible to obtain an element with good photoresponse characteristics, which is an advantage of the present dimensional optical cell, and high sensitivity, and a high-speed facsimile device can be realized. In addition, an n4 type conductive layer, i
The reason why it is used as a photodiode by depositing a type or n-type ring layer, a p-type four-layer, and a transparent electrode in this order is that most of the incident light is absorbed near the transparent electrode, and the photocarrier electrons are absorbed. This is because when using a photodiode with a reverse bias, it is advantageous to have a structure in which electrons move from the vicinity of the transparent electrode to the metal electrode side, since the photoconductive film has excellent mobility. For the reactive sputtering method of the front-shadow photoconductive film, a general sputtering device may be used, or a magnetron type high-speed sputtering device may also be used. A one-dimensional optical sensor in which polycrystalline silicon is installed as a sputtering target on one of the cathodes (target-side electrodes) and the other anode (substrate-side electrodes) with the desired wiring. Install the board for

After degassing the sputtering chamber by heating it to 250 to 300C' while keeping the sputtering chamber at a high vacuum below lXl0'''@Torr, hydrogen and a rare gas such as argon and a small amount of doping gas are used as discharge gas. A mixed gas of 13.56 MH-0 was introduced into the sputtering chamber, and a 13.56 MH-0 high frequency wave was applied.

An amorphous photoconductive film mainly composed of silicon containing hydrogen is deposited on a substrate. The substrate temperature during film formation is 100~
350C, discharge gas pressure is 8×10-' Torr
~2 x 10-'' Torr, and the composition of hydrogen gas in the discharge gas is within the range of 10-60 mo4%.

During deposition of the photoconductive film, a trace amount of nitrogen gas i0.01 is added as a doping gas to the above-mentioned mixed gas of argon and hydrogen.
By mixing about 0.01% to 1% or a trace amount of phosphorus hydride (for example, phosphine (P)Tm) about 0.01 to 5%, an n0 type conductive layer can be obtained. A p-type conductive layer can be obtained by mixing about 0.01 to 5% of boron hydride such as diborane (nuHs) into the mixed gas. If these doping gases are not added, an i- or n-type conductive layer is generally obtained. Using the above sputtering conditions, an n+ type ring layer, i or n
A photoconductive film is deposited in the order of a type 4 conductive layer and a p-type ring conductive layer to form a conductive film for a photodiode and a separation diode.

In addition, the glow discharge CV f) (Chemical
There are two types of methods: RF cocoil method and bipolar discharge method. In both cases, a mixture of silane gas such as 5il (, etc.) and a rare gas such as argon or hydrogen gas is used to perform glow discharge, and a decomposition reaction of the silane gas causes the above-mentioned -dimensional optical sensor substrate to be This is a method of depositing an amorphous photoconductive film mainly made of silicon containing hydrogen, and is distinguished from reactive sputtering, which uses a reaction of adding hydrogen to silicon.

RF cocoil method A reaction chamber was placed in an RF cocoil, and a high frequency of 13.56 MH2 was applied to the RF coil to cause a glow discharge of the mixed gas of siH and argon introduced into the reaction chamber. This is a method of depositing an amorphous photoconductive film mainly made of silicon containing hydrogen on a substrate for a dimensional optical sensor. In addition, in the bipolar discharge method, a normal sputtering device is used, and 13
．． A high frequency of 56λfz was applied and introduced into the reaction chamber.
This is a method of causing a glow discharge of a mixed gas of iH4 and argon or hydrogen, and depositing an amorphous photoconductive film mainly made of silicon containing hydrogen on the above-mentioned -dimensional optical sensor substrate installed in a reaction chamber. .

The substrate temperature during film formation is 100 to 300C, and the discharge gas pressure is the same as that of the reversible sputtering method. M<5X11)-
2')'orr to 2']'Orr, O in the discharge gas
Similar to the 81H4 gas, a trace amount of phosphorus hydride, such as phosphine (PHI), is added as a doping gas to a mixed gas of 8iH4 and argon gas or hydrogen.
When about 0.001 to 5% is mixed, an n9 type conductive layer is obtained,
In addition, a trace amount of boron hydride such as diborane (B*He) is mixed as a doping gas in the above mixed gas of S t H4 and argon or hydrogen in an amount of about 0.01 to 5%.
For example, a palJ2N electric layer can be obtained. If these doping gases are not added, generally a 11 or i type conductive layer cannot be obtained. Using the above glow discharge CVI5 conditions, a photoconductive film is deposited in the order of the n0 type conductive layer, the i or n type conductive layer, and the p type ring conductive layer to form a conductive ridge film for the photodiode and isolation diode. .

When the amorphous hydrogenated film is processed into a desired pattern on the r-dimensional sensor using the above method, a single row of photodiodes and separation diodes is completed. Further, after forming the insulating layer in a desired pattern, a transparent electrode is formed on the insulating layer by sputtering. As this transparent electrode, (1)
Indium oxide.

A transparent electrode mainly composed of one selected from a mixture of tin oxide and a mixture of tin oxide and the like is used. Also, [(2) gold.

platinum, tantalum, molybdenum, aluminum, chromium,
It is also possible to use a translucent metal electrode whose main component is one selected from the group consisting of nickel and mixtures thereof.

・To form a +1) transparent electrode, there is a method of performing reactive RF sputtering in argon gas containing oxygen gas using an indium-tin metal as a target, but usually indium oxide-tin oxide is used. In a rare gas such as argon gas, using a sintered target of
A method of sputtering is used. In this case, an indium oxide-tin oxide based sintered body is installed as a sputtering target on one cathode (target side electrode) of the counter electrodes in the sputtering device, and the other anode (substrate antistatic HP
) is equipped with a one-dimensional optical sensor substrate on which a photoconductive film made of amorphous hydrogenated silicon is deposited. Inside the sputtering room 5
After evacuating the cylinder to a vacuum of less than ×10""l'orr, a rare gas such as argon was introduced into the sputtering school as a discharge gas, and high-frequency sputtering of 13.56 M)lx was performed. A transparent electrolyte of indium 5-tin oxide thread in a predetermined pattern is deposited on the electrolytic film.The substrate temperature during film formation is 80C to 22(1'), and the pressure of the emitted gas is 3 x 10°s. '1'orr to 5 x 10”
” TOrr. When a transparent electrode is formed and processed into a desired pattern, and Kanasu wiring for two-layer wiring is provided in a desired pattern, a one-dimensional light beam with a shape as shown in Fig. 1 is produced. A sensor is obtained.

Regarding the transparent electrode in (2), the cathode (target side electrode) in the sputtering device is made of aluminum, platinum, tantalum, %
If a metal whose main component is one different from the group consisting of aluminum, chromium, nickel, and their mixtures is set as a sputtering target, it will be the same as the transparent electrode in (1) above. A translucent gold F4 electrode can be deposited by a non-transparent sputtering method. In this case, the film thickness of the #-transparent metal electrode must be made as thin as possible in order to improve light transmittance. Usually, the film thickness is 40
It is 0 Å or less.

The m-body image sensor obtained by the method described above is an element with deteriorated photoresponse characteristics, as explained in FIG. In particular, in FIG. 1, a negative bias voltage V! is applied to the transparent IIt pole 7.
When , the photoresponse characteristics are dominated by the secondary photocurrent, and the time constant of the photoresponse becomes thicker. However, when this element is heat-treated at 170C to 250C for about 15 minutes to several hours, the slowness of the photoresponse is improved to such an extent that it does not pose a problem at all. The manner in which the contrast is improved can be expressed by the photoresponse characteristics of the light-receiving element shown in FIG. 2, and an example thereof is shown in FIG. Comparing FIG. 4- with FIG. 2, it can be seen that the photoresponse characteristics have been significantly improved. FIG. 5 is a diagram quantitatively comparing an example of an improved example in terms of attenuation current after the light is turned off. Curve a represents the attenuation current before heat treatment, and curve bFi represents the attenuation current after heat treatment. Before heat treatment, as shown in curve a, the initial value (photocurrent just before turning off the light) is large (
Photoelectric gain G:=4), decay time constant also τ,=39mSI
``A: response characteristic'' in which a large so-called secondary photocurrent is dominant.On the other hand, after heat treatment, as shown in the curve, the initial value of photoelectric gain G- is such that the secondary photocurrent is suppressed. However, the attenuation Li,'I constant τb is '10μ
The process speed has been improved to S and 3000 minutes. Since the curve is added with the time constant of the measurement circuit system, it becomes even larger during actual improvement. This phenomenon is observed in exactly the same way in the six-dimensional optical sensor shown in FIG.

In the one-dimensional optical sensor shown in FIG. As is clear from Fig. 6, as the heat and processing temperature are gradually increased from room temperature to room temperature, the afterimage gradually becomes larger, and after reaching a maximum value between 100 and 120C,
It shows a small value before 15°OC, and has a tendency to increase again.

The heat treatment time reaches the saturation value of the afterimage at the hillside temperature in 20 to 60 minutes at each temperature. Therefore, there is no specific point in carrying out the heat treatment for a longer time than necessary.

Although heat treatment is normally performed in the atmosphere, similar effects were confirmed when it was performed in a rare gas such as argon gas or an inert gas such as nitrogen. A general one-dimensional optical sensor can be used sufficiently if the afterimage after 3 ms is 4% or less. As shown in Fig. 6, the effect starts to appear at least above 140C, but if heat treatment is performed in the range of 170C to 250C, the afterimage after the one-dimensional optical sensor Vi3 ms shown in Fig. 1 will be reduced to 4%.
The following can be used very conveniently as a -dimensional optical sensor.

The effects of the present invention shown in FIGS. 5 and 6 are limited to
Amorphous silicon hydride was deposited using a sputtering method on a photodiode in which an n+ type conductive layer, an i or n type conductive layer, and a p type trench conductive layer were deposited in this order as shown in Figures 1 and 2. It's transparent! This improves the problem of electrical contact between the photodiode and the transparent conductor caused by depositing the electrode. Immediately after amorphous hydrogenated silicon is deposited by the above-mentioned reactive sputtering method or glow discharge method, it is kept in a photoconductive film deposition apparatus at 220 to 270 C in vacuum for the purpose of greatly improving photosensitivity. This is a different technology from heat treatment.

Furthermore, the present invention is applicable not only to the one-dimensional optical sensor shown as an example in FIG. In principle, it is also effective for all light receiving elements having the configuration shown in FIG. For example, a solar cell or a semiconductor substrate (scanning 5
A photoconductive film made of amorphous hydrogenated silicon is deposited on a 00-type conductive layer, an i- or n-type conductive layer, and a p-type conductive layer on an i-rc substrate).
A photodiode is formed by depositing electrical layers in this order, and further,
Of course, it is also useful to apply the present invention to a solid-state imaging device having a so-called two-story structure, on which a transparent electrode is deposited by sputtering.

Further, the present invention is effective even if the photoconductive film mainly composed of amorphous hydrogenated silicon used here contains an appropriate amount of carbon or germanium.

The present invention will be explained in detail below using examples.

Embodiment 1 FIGS. 7 to 11 are cross-sectional views of a pixel portion showing a method of manufacturing a one-dimensional optical sensor of the present invention. Metal chromium is deposited on an insulating glass substrate 1 to a thickness of 20 mm by sputtering.
A desired electrode pattern 2 is formed by a photo-etching process using a ceric ammonium nitrate-based etching solution (FIG. 7). Here, 2
1 is an electrode for a photodiode and a separation diode, 22
is the lower electrode for two-layer wiring. Next, this substrate was placed in a two-electrode glow electric CVD apparatus, and a reaction chamber containing 10% BAH and H gas as a discharge gas.

Introduce a gas l'l''Off, and use P as a doping gas.
By introducing H gas at a volume ratio (PH, /5i) (, ) of 1% and performing a high frequency discharge of 13.56 MHz, an n0 type conductive cell mainly made of amorphous hydrogenated silicon was formed. was deposited on the substrate to a thickness of 250 mm.

Furthermore, P)1. After stopping on the scum, high-frequency discharge was continued using only +90% H1 mixed gas, and an i-type groove conductor layer mainly composed of amorphous hydrogenated silyran was deposited to a thickness of 5,500 mm. urge Furthermore, in addition to the above-mentioned discharge gas, B, H, and gases as doping gases are deposited at a volume ratio (B!Ha1 layer is deposited to a thickness of 400 nm.
1) When an amorphous silicon hydride film with the structure is patterned into a predetermined shape by a plasma etching method using CH gas, a photodiode (3) and a separation diode (4) are formed.
(Figure 8).

Here, 31.41 is a no-type conductive layer, 32.42 is an i-type conductive layer, and 33.43 is a p-type conductive layer.

Next, a film of 2 μm thick was deposited on the substrate using a Corning Co., Ltd. jM7059 gas scale sputtering method, and then deposited at a predetermined location using a photoetching method using an HF HNOs 1#*O-based etching solution. When contact holes 61, 62, 63, and 64 are drilled at the top of the second part: tn,
o, -5no, system transparent electrode by sputtering method 5
The film is deposited to a thickness of 00OA. At this time, the sputtering target was In containing 5m01% of sno,
o. The sintered body is placed in the negative (cathode) and used.

High frequency sputtering was performed at a gas pressure of 13.56 MH2 using Ar gas as a discharge gas and a gas pressure of 1X10"" TOrr. After forming the transparent electrode, the transparent electrode is patterned into a predetermined shape 7 by photo-etching using an HCeHNOs'HtO-based etching solution, resulting in an element having a cross-sectional structure as shown in FIG. The photodiode in the above device has deteriorated photoresponse characteristics.For example, as shown in FIG.
When the heat treatment was performed for 160 minutes, the response speed was significantly faster as shown in FIG. 4, and the characteristics were improved. next,
After this patterned lTO film is completely covered with a protective film such as photoresist or the like, a shim 1 film is deposited to a thickness of 2 μm on the substrate by vacuum evaporation. moreover,
A-e electrode patterns 81 and 82 for two-layer wiring are formed by photoetching using H, p04-HNO, -IJ, 0-based etching solution. At this time, 1. The TO film is coated with photoresist to prevent electrochemical elution of the ITO film caused by contact with the pAI3 etching solution. After forming the AAt electrode pattern, the protective film of I'l'0 is removed by the plasma asher method.
A one-dimensional optical sensor with a high reading speed as shown in FIG. 1 can be obtained. Using this -dimensional optical sensor, it is possible to realize a very fast facsimile.

Embodiment 2 The present invention is also suitable for use in a method for manufacturing a thick V# battery. In this case, in addition to improving the photoresponse characteristics, the voltage-current characteristics of the amorphous hydrogenated silicon photodiode upon irradiation with light are improved.

H+ type and i type thick'w/L layers are formed on a desired stainless steel substrate in the same manner as in Example 1. Furthermore, CH and gas were added to the 10% qiH, +90% mountain mixture gas as a doping gas at a volume ratio (("H.

/5iH4) at 3%, "B*Hs gas at volume ratio (
Amorphous silicon carbide (a-
A p-type ring conductive layer mainly composed of sir2H) is deposited to a thickness of 350 nm. Next, on top of this, In, 0. -5no
The transparent electrode of the system was deposited to a thickness of 1,000 mm using the tuttering method. Suba tooling conditions were the same as in Example 1. In this way, a solar cell having a cross-sectional structure as shown in FIG. 2 was obtained. However, the characteristics of this solar cell have deteriorated, and it hardly exhibits photodiode characteristics. For example, as shown by curve a in FIG. 12, the open circuit voltage during light irradiation
ltago, ■oc) and short circuit current (5hort
circuit cu'rrent l5h) is small. Next, when this element is heat-treated in air at 230C for 20 minutes, the voltage-current characteristics are greatly improved, and the solar cell has good characteristics as shown in the curves in Figure 1-2. can be obtained.

Example 3 It was also possible to apply the present invention to an n-1-p multilayer heterojunction solar cell. 'First, on a stainless steel substrate, an n0 type conductive layer (200 layers) such as amorphous hydrogenated silicon, amorphous silicon germanium containing hydrogen gold (a-81o, a (3) 'o)o'
: H) i'ms electric layer mainly composed of f (4000 people)
- and a p-type conductive layer made of amorphous hydrogenated silicon (
250 people), and furthermore, on top thereof, in the same manner as in Example 1, an n''-
After forming a photodiode with an i-p structure (however, the thickness of the i layer was 800 nm), transparent electrode formation and heat treatment were performed in the same manner as in the example, and a solar cell with good performance was obtained.

As explained using the main embodiment, it is possible to improve the deterioration of the photoresponse characteristics of the photodiode that often occurs when a transparent electrode is deposited by sputtering on the photodiode made of monolithic silicon of the present invention. , -dimensional,
It is possible to read image information at high speed and obtain a multi-dimensional sensor or a highly efficient solar cell.

A similar effect can be obtained using .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view (a) and a plan view showing the basic structure of a one-dimensional optical sensor according to the present invention. FIG. 2 is a sectional view of a general light receiving element of the present invention. FIG. 3 is a diagram showing an example of the photoreaction characteristics of a light-receiving element when a transparent electrode is formed by sputtering. FIG. 4 is a diagram showing an example of the photoresponse characteristics of the effect improved by the heat treatment method of the present invention. Figure 5 shows before heat treatment (
a) A diagram comparing the attenuation characteristics of the photocurrent after the light is turned off. FIG. 6 is a diagram showing the heat treatment effect of the present invention in terms of the relationship between heat treatment temperature and afterimage after 3'ms. FIGS. 7 and 11 are sectional views of main parts showing the manufacturing process of the one-dimensional optical sensor of the present invention. FIG. 12 is a diagram showing an example of improvement when the manufacturing method of the present invention is applied to a solar cell. 1... Substrate, 2... Non-transparent gold maple electrode, 21...
Metal electrode for photodiode and isolation diode, 22
... Gold bullion electrode for two-layer wiring, 3 ... Photodiode mainly made of amorphous hydrogenated silicon, 4 ... Amorphous hydrogen 41 ... N9 type mainly made of amorphous hydrogenated silicon 32.42... n-type or i-type conductive layer mainly composed of amorphous hydrogenated silicon, 33.43... dil
=, W, p-type conductive layer mainly composed of hydrogenated silicon,
5... Insulating layer, 61, 62, 63.64... Contact hole, 7.14... Transparent electrode or translucent metal wire, 81.82... Metal wiring, 10... Incident light, 1
1... Board, 12... Lower part'i! Extreme, 13...Amorphous hydrogenation! n mainly composed of hydrogenated silicon
9-type conductive layer, 132... N-type or i-type exclusive layer mainly composed of amorphous hydrogenated silicon, 133... P-type conductive layer mainly composed of amorphous hydrogenated silicon, 14 ...transparent*polar,<)u translucent gold-striped gable, 15...light pulse, 16...' ) n (1)) ■3 figure ¥3 4 figure 'f36 figure f winter place five! L5jL leak (C)
-Ku'7 Figure fJ g Figure vi q Figure 10 Figure ￥J12 Figure

Claims (1)

[Claims] l. A photoconductive film made of an amorphous material mainly composed of silicon and containing hydrogen is formed on a desired substrate in the order of an n0-type conductive layer, an i- or n-type conductive layer, and a p copper conductive layer. In the method for manufacturing a light receiving element, the method includes a step of forming a transparent conductive film on the photoconductive film and a step of forming a transparent conductive film on the photoconductive film by a sputtering method: After forming the transparent conductive film, the light receiving element is A method for manufacturing a light receiving element, comprising a step of heating at 140C or higher. 2. The method of manufacturing a light receiving element according to claim 1, wherein the heating temperature is in a range of 170C to 250C. 3. The substrate has at least non-transparent metal electrodes arranged in one dimension, and after forming the photoconductive film and the transparent electrode in one-to-one correspondence on the metal electrodes, 2. The method of manufacturing a light receiving element according to claim 1, wherein the substrate is an insulating substrate with wiring so that an image signal can be extracted. 4. The substrate has at least two-dimensionally arranged switches and a scanning element that transfers photoelectric charges corresponding to an optical image taken out through the switches. 2. The method of manufacturing a light receiving element according to claim 1, wherein the semiconductor substrate is a semiconductor substrate. 5. Claims characterized in that the above-mentioned transparent conductive film is a transparent conductive film formed by a sputtering method and whose main component is one selected from indium oxide, tin oxide, and a mixture thereof. 2. A method for manufacturing a light-receiving element according to item 1. 6. The above-mentioned transparent conductive film is multi-formed by a sputtering method and has a translucent shape mainly composed of one selected from the group consisting of gold, platinum, tantalum, molybdenum, aluminum, chromium, nickel, and mixtures thereof. 2. The method of manufacturing a light-receiving element according to claim 1, wherein the light-receiving element is a metal film.