JPH0644620B2 - Substrate for thin film photoelectric conversion element and method for manufacturing the same - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film photoelectric conversion element substrate used in a photoelectric conversion device corresponding to a document in a reading system such as a facsimile, and a manufacturing method thereof. .

Structure of Conventional Example and Problems Thereof A cross-sectional view of FIGS. 1A to 1D shows a manufacturing method of a substrate for a thin film photoelectric conversion element used in a conventional photoelectric conversion device of a reading system such as a facsimile. .

As shown in FIG. 1 (a), on a glass substrate 1 such as Corning 7059 manufactured by Dow Corning Co., Ltd., which has a coefficient of expansion matched with that of a photoelectric conversion element such as a II-VI group compound semiconductor such as CdS or CdSe,
A high-melting point material such as Si, Cr, Ti, or Ta is deposited by vacuum deposition or sputtering, and is 0.5 to 0.7 in the case of Si.
In the case of Cr and Cr, a film thickness of 0.1 to 0.3 μm is deposited on the entire surface, and light from the back surface of the glass substrate 1 has a transmittance of 0.
The light shielding layer 2 that shields light to 5% or less is formed. Next, Fig. 1
As shown in (b), in order to take in the illumination light from the back surface of the glass substrate 1, after applying a resist on the entire surface, a resist pattern 3 is formed using a photolithography method, and a chemical etching method or a plasma etching method is used. An illumination window 4 as shown in FIG. 1 (c) is formed. Furthermore, as shown in FIG. 1 (d),
A substrate for a thin film photoelectric conversion element is manufactured by forming the translucent insulating layer 5 having a film thickness of 0.1 to 0.7 μm by using the same material as the glass substrate 1, for example, Corning 7059 or the like, by a sputtering method or the like. .

However, the following problems occur in the method of manufacturing a substrate for a thin film photoelectric conversion element as described above.

First, when Si is used for the light shielding layer 2, the film thickness is 0.
Even if it is as thick as 6 μm, it has a transmittance of 5% or more for light having a wavelength of 650 nm or more, and cannot be used as a photoelectric conversion element substrate for reading a color original. A crack is generated due to the difference in expansion coefficient between the transparent conductive layer and the insulating layer, which leads to a decrease in productivity and reliability. Further, a step difference corresponding to the film thickness of Si is generated in the illumination window 4 when the transparent insulating layer is formed. When a lead-out electrode of the photoelectric conversion element is formed on the electrode 5, step breakage occurs, which causes a decrease in yield.

Secondly, when the light-shielding layer 2 is formed of a metal film such as Cr or Ta, the material of the light-shielding layer 2 causes thermal diffusion in the light-transmissive insulating layer 5 due to heat treatment during the formation of the photoelectric conversion element. Since the insulating property and the breakdown voltage of the optical insulating layer 5 are lowered and the impurities are also introduced into the photoelectric conversion element as an impurity, there arises a problem that characteristics are deteriorated and variations are increased.

When the translucent insulating layer 5 is formed of SiO ₂ or the like, II-VI
There is a problem that peeling occurs due to a difference in expansion coefficient when forming a photoelectric conversion element of a group compound semiconductor.

An object of the present invention is to solve the above-mentioned conventional problems, and in a photoelectric conversion device in a reading system such as a facsimile, the uniformity and stability of the characteristics are high, and the productivity is high. It is an object of the present invention to provide an excellent substrate for thin film photoelectric conversion element and a method for manufacturing the same.

According to the present invention, a light-shielding layer having an illumination window is formed on a light-transmitting insulating substrate, a layer for preventing diffusion of the light-shielding layer is formed thereover, and a light-transmitting insulating layer is further stacked. By the substrate for a thin film photoelectric conversion element to be formed and the manufacturing method thereof, the reliability is high, the productivity of the photoelectric conversion device and the like can be improved, and the characteristics can be made uniform.

Description of Examples Hereinafter, the structure of the substrate for a thin film photoelectric conversion element and the manufacturing method thereof according to the present invention will be described in detail with reference to Examples.

2 (a) to 2 (d) are cross-sectional views showing the structure of the substrate for a thin film photoelectric conversion element and the method for manufacturing the same in the first embodiment of the present invention.

In FIG. 2 (a), for example, a photoelectric conversion element film made of a II-VI group compound semiconductor such as CdS or CdSe, which has a matching expansion coefficient,
In order to remove thermal strain, the insulating glass substrate 1 such as Corning 7059 manufactured by Dow Corning Co. is used at 600 to 650 ° C.
Heat treatment. Cr, Ta, Ti, W, Mo, etc. are formed on the entire surface of the glass substrate 1 by a vacuum deposition method, a sputtering method or the like, and the transmittance of visible light is 0.
800-4000Å preferably 1 to keep it below 5%
The light-shielding layer 21 is formed by applying a film having a thickness of 000 to 2500Å. Next, as shown in FIG. 2B, a resist pattern of the illumination window 4 is formed on the light shielding layer 21 by a photolithography method or the like, and the light shielding layer 21 is etched by a chemical etching method or a plasma etching method to form the illumination window 4. After the formation, the resist is removed. Next, as shown in FIG. 1 (c), the light shielding layer 2 having the illumination window 4
1 is, for example, Cr, thermal oxidation is performed at 500 ° C.
In the case of a, the metal oxide film of the light-shielding layer 21 is formed on the surface of the light-shielding layer 21 in the form of, for example, Cr ₂ O ₃ or Ta ₂ O _{5 to} a film thickness of 100 to 1000 Å or a nitrogen atmosphere by anodization. By forming the metal nitride film by the heat treatment in the inside, the layer 6 for preventing the diffusion of the material of the light shielding layer 21 is formed. Further, as shown in FIG. 2 (d), a transparent insulating layer 5 made of the same material as the glass substrate 1 is formed on the diffusion-preventing layer 6 by a sputtering method or the like at 500Å to 1 μm, preferably at 500 to 50 μm.
A film thickness of 00Å is formed.

As described above, according to the present embodiment, since the layer 6 for preventing the diffusion of the material of the light shielding layer 21 can be formed of the metal oxide film or the nitride film of the light shielding layer 21, a simple structure and complicated steps are not required. In addition, since the glass substrate 1 and the translucent insulating layer 5 are the same substance in the illumination window 4, there is no difference in the refractive index at the boundary surface, and the illumination light is lost due to reflection. Can be reduced, and the light utilization efficiency can be significantly improved.

The second embodiment of the present invention will be described below with reference to FIG.

FIGS. 3 (a) to 3 (d) are cross-sectional views showing the structure of a substrate for a thin film photoelectric conversion element and a method for manufacturing the same, showing a second embodiment of the present invention.

In FIG. 3, what differs from FIG. 2 in the manufacturing method is the difference in the structure of the layer for preventing the diffusion of the material of the light shielding layer 21 in FIGS. 3 (c) and 2 (c) and the manufacturing method thereof. The other structure and manufacturing method are the same as in FIG. That is, the third
As shown in FIG. 3C, the softening point is 1000 on the light shielding layer 21.
SiO ₂ , Si ₃ N ₄ , which is a high melting point insulating material of ℃ or higher,
SiC or the like is formed on the entire surface by a sputtering method, a plasma CVD method or the like so as to have a film thickness of 500 to 3000 Å to form a layer 7 for preventing diffusion.

As described above, according to this embodiment, the layer 7 for preventing diffusion is
By forming the light-transmitting insulating film with a high melting point insulating material, the film thickness of the light-shielding layer 21 is good because it does not require the formation of an oxide film or a nitride film, and the light-shielding unevenness does not occur. It can stabilize. Further, the layer 7 for preventing diffusion and the translucent insulating layer 5 can be formed in the same process, so that the productivity is high and the process can be simplified.

Finally, it is obvious that a more reliable diffusion prevention effect can be obtained by combining the first and second embodiments as in the third embodiment shown in FIGS. 4 (a) to (e). is there.

FIG. 5 is a cross-sectional view of a photoelectric conversion device in which the substrate formed by using the third embodiment is applied to a one-dimensional line sensor,
Reference numeral 8 is an illumination light, 9 is a thin film photoelectric conversion element such as CdS or CdSe, 10 is a protective layer, and 11 is a read document. As a second application example, FIG. 6 shows a sectional view of a photoelectric conversion device used in a pressure-sensitive sensor. The pressure 12 detects the amount of deformation 14 of the silicone rubber 13 or the like by the incidence of the light 15 on the photoelectric conversion element 9. As described above, various applications are possible by using the substrate for the thin film photoelectric conversion element.

EFFECTS OF THE INVENTION As described above, according to the present invention, a layer for preventing the diffusion of the light shielding layer material by the metal oxide film, the nitride film or the high melting point insulating material of the light shielding layer into the transparent insulating film is complicated. It does not require any steps, can be easily formed, has a great industrial effect, and has a wide range of applications. Further, by providing a layer for preventing diffusion, the light-shielding layer is formed of a thin metal film such as Cr having a high light-shielding property against visible light without using Si or the like, which requires a certain thickness, and There is no concern about step breaks or cracks in the light-shielding film, and it is possible to easily support colorization, which is one of the high-performance functions of facsimiles and other light-receiving sensors.

Furthermore, since the light shielding layer material does not diffuse into the translucent insulating layer, it is possible to form a film having excellent insulating properties and good withstand voltage,
In addition, since the introduction of impurities into the photoelectric conversion element formed on the translucent insulating layer is hindered, the characteristics of the element are not adversely affected, and a substrate for a thin film photoelectric conversion element having excellent reliability and productivity is provided. It can be realized.

[Brief description of drawings]

1 (a) to (d) are cross-sectional views showing a conventional method for manufacturing a substrate for a thin film photoelectric conversion element, and FIGS. 2 (a) to (d) are thin film photoelectric conversions in the first embodiment of the present invention. 3A to 3D are sectional views showing a method for manufacturing a device substrate, and FIGS. 3A to 3D are sectional views showing a method for manufacturing a thin film photoelectric conversion device substrate according to a second embodiment of the present invention. ) To (e) are sectional views showing a method for manufacturing a substrate for a thin film photoelectric conversion element in a third embodiment of the present invention, and FIG. 5 is a principle sectional view of a photoelectric conversion device using the third embodiment of the present invention. Figure,
FIG. 6 is a principle sectional view of a pressure-sensitive sensor using the third embodiment of the present invention. 1 ... Translucent insulating substrate, 21 ... Shading layer, 3 ... Resist pattern, 4 ... Illumination window, 5 ... Translucent insulating layer, 6,
7 ... Layer for preventing diffusion, 8 ... Illumination light, 9 ... Photoelectric conversion element, 10 ... Protective layer, 11 ... Read original.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noboru Yugami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kiyotaka Wasa 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Kosuke Ikeda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 59-151456 (JP, A) JP 58-40856 (JP, A) Special Kaisho 58-56363 (JP, A)

Claims (8)

[Claims] 1. A C having an illumination window on a translucent insulating substrate.
Translucency for reducing adhesion strain between a light-shielding layer made of at least one of r, Ta, W, and Ti, a layer preventing diffusion of the light-shielding layer, and a photoelectric conversion element made of a II-VI group compound. A thin film photoelectric conversion element, characterized in that an insulating layer and a photoelectric conversion element made of a II-VI group compound are sequentially formed. 2. The thin film photoelectric conversion element according to claim 1, wherein the light shielding layer is made of Cr. 3. The thin-film photoelectric conversion device according to claim 1, wherein the layer for preventing diffusion of the light-shielding layer comprises an oxide film or a nitride film of the light-shielding layer. 4. The layer for preventing diffusion of the light shielding layer is made of SiO ₂ ,
The thin film photoelectric conversion element according to claim 1 or 2, wherein the thin film photoelectric conversion element is made of a high melting point insulating material such as Si ₃ N ₄ or SiC. 5. Cr, Ta, W, T on a transparent insulating substrate.
i) a step of forming a light-shielding layer made of at least one of i, a step of forming an illumination window in the light-shielding layer, and a reduction in adhesion strain between the light-shielding layer and a photoelectric conversion element made of a II-VI group compound. A step of forming a layer for preventing diffusion of the light-shielding layer between the translucent insulating layers, a step of forming the translucent insulating layer, and a II-VI group compound on the translucent insulating layer. A method of manufacturing a thin film photoelectric conversion element, comprising: 6. The method of manufacturing a thin film photoelectric conversion element according to claim 5, wherein the light shielding layer is formed of Cr. 7. The thin film photoelectric conversion device according to claim 5, wherein the layer for preventing diffusion of the light shielding layer is formed of an oxide film or a nitride film of the light shielding layer. Production method. 8. A layer for preventing diffusion of a light-shielding layer is made of SiO ₂ ,
7. The method for manufacturing a thin film photoelectric conversion element according to claim 5, wherein the thin film photoelectric conversion element is formed of a high melting point insulating material such as Si ₃ N ₄ or SiC.