JP2000188408A - Photovoltaic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the use of any dielectric separation of elements from each other even when the element is integrated with other elements. SOLUTION: An SOI(silicon on insulator) substrate is configured out of a semiconductor substrate 1, an insulation film 2 formed on the semiconductor substrate 1, and a semiconductor layer 3 comprising a plurality of photodiode cells C formed on the insulation film 2. In the SOI substrate, one of the adjacent photodiode cells C to each other of the plurality of the photodiode cells C is formed out of an n-type impurity separation layer extended from the surface of the semiconductor layer 3 to the insulation film 2 and a p-type silicon layer 30 surrounded by the n-type impurity separation layer 31. Further, the other of the foregoing adjacent photodiode cells C to each other is formed out of another n-type impurity separation layer 31 surrounding at an interval the foregoing n-type impurity separation layer 31 and another p-type silicon layer 30 sandwiched between the other and foregoing n-type impurity separation layers 31. Then, the plurality of photodiode cells C are connected in series with each other by a plurality of surface electrodes 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device (photovoltaic element) for converting light energy into electric energy.
In particular, the present invention relates to a multi-junction type photovoltaic device using an SOI (silicon on insulator) structure.

[0002]

2. Description of the Related Art Photovoltaic devices are well known and are commonly used to generate control signals for solid state relays (SSRs). In such a device, LEDs that are turned on / off in response to a drive signal input to an input terminal are spaced and insulated so as to irradiate the photosensitive surface light of the photovoltaic device. The output of the photovoltaic device can be used as the input of a MOS gate device, typically a switching device such as a power MOSFET, which switching device is switched on in response to driving the LED. have. Generally, a photovoltaic device consists of a number of photovoltaic cells connected in series to generate a voltage high enough to turn on a power switching device.

[0003] A photovoltaic device comprising a large number of photovoltaic cells connected in series can be manufactured in many different ways, but the photovoltaic devices used in the SSR are mutually separated by dielectric separation. In general, a photodiode array (hereinafter referred to as a PDA) in which photodiodes isolated from each other are connected in series by a surface electrode.

FIG. 3A shows an example of a cross-sectional structure of a PDA in which each photodiode cell is separated using dielectric isolation.
However, in order to clarify the specification of each part of the PDA, reference numerals in parentheses shown in FIG. 3 are appropriately used. Silicon oxide film 120
And a plurality of lightly doped silicon islands 130 with p-type impurities are formed on the polycrystalline silicon substrate 110. Each silicon island 130 has an n-type impurity diffusion layer 140 having a shallow diffusion of about 0.5 μm. The silicon island 130 and the n-type impurity diffusion layer 140 are formed as photodiode cells. And, for example, the silicon island 13
0 (131) and the impurity diffusion layer 140 (141).
31) is connected to the n-type impurity diffusion layer 140 (142) of the next photodiode cell including the silicon islands 130 (132) and the impurity diffusion layers 140 (142) by the surface electrode 150, and each photodiode cell Are connected in series.

FIG. 3B shows a part of the surface structure of a PDA in which a plurality of photodiode cells are connected in series using dielectric isolation. Since each photodiode cell is dielectrically separated, it can be understood that photodiode cells having different potentials can be freely arranged, and there is no restriction on the surface layout.

However, such a dielectric isolation method requires complicated steps such as etching, embedding, and planarization polishing to form an isolation portion, which increases the production cost of the substrate and increases the production cost of the substrate. There is a problem that it takes a long time.

In order to avoid this problem, a junction separation is known as a separation method that enables a series connection of many cells without using the above-described dielectric separation.

An example of connecting a plurality of photodiode cells in series using this junction separation is shown in FIG.
(Silicon on sapphire) disclosed by Mr. Yutaka Hayashi at the IEICE General Conference 2007
Method of isolating a photodiode connected in series formed on a substrate by junction separation, and 1998
SOI disclosed on 29p-P-13 by Hidetaka Takato at the 45th Annual Conference of the Japan Society of Applied Physics at the 45th Annual Meeting of the Japan Society of Applied Physics
There is a method of isolating photodiodes connected in series formed on a substrate by junction separation.

FIG. 4A shows an example of a cross-sectional structure of a conventional SOI substrate on which a series-connected photodiode isolated by junction separation is formed. An n-type impurity diffusion layer 232 having a shallow diffusion of about 0.5 μm is formed in the p-type silicon layer 230 of the SOI substrate so as to be connected to the n-type impurity separation layer 231. The layer 231 and the n-type impurity diffusion layer 232 form a photodiode cell. A part of the n-type impurity isolation layer 231 of the photodiode cell and a part of the p-type silicon layer 230 of the next photodiode cell are connected by the surface electrode 250, and the respective photodiode cells are connected in series. Here, 1 is a semiconductor support substrate and 2 is an insulating film.

Japanese Patent Laid-Open No. Hei 5-267635 discloses that a first impurity diffusion layer is formed on an insulating film formed on a semiconductor substrate, and the first impurity diffusion layer is formed in a vertical direction in the layer. There is disclosed a photodiode array that is separated by a high-concentration second impurity diffusion layer.

[0011]

However, in the conventional example using the above-described junction separation, as can be seen from the surface view of the SOI substrate shown in FIG. 4A, the photodiode cells are connected in series. Since the outermost periphery 200 of the photovoltaic device is not junction-separated, there is a problem that it must be separated by a dielectric separation or an air gap. The reason is, for example, FIG.
If the outermost periphery of the photovoltaic device is the same as the n-type impurity separation layer 231 as shown in FIG. 4A, all the n-type impurity diffusion layers 232 are connected by the n-type impurity separation layer 231. . Alternatively, as shown in FIG. 5B, even if the n-type impurity diffusion layer 232 is formed in the p-type silicon layer 230 and is not connected to the outermost n-type impurity separation layer 231, the n-type impurity separation layer 231 may be formed. Is in a floating state, carriers generated in the n-type impurity isolation layer 231 at the time of light irradiation cause a current to flow between the photodiode cells in a direction opposite to the photocurrent, which causes a reduction in the electromotive voltage of the photovoltaic device. That is, in the case of junction separation, the separation layer cannot be shared, and the separation layer must be at the same potential as the anode and the force sword of the next stage.

The present invention has been made in view of the above points, and an object of the present invention is to provide a photovoltaic device which does not need to use dielectric isolation even when integrated with other elements. To provide.

[0013]

According to a first aspect of the present invention, there is provided a photovoltaic device comprising: a semiconductor substrate;
An SOI substrate formed of an insulating film formed on the semiconductor substrate and a semiconductor layer forming a plurality of photovoltaic cells formed on the insulating film, and a connection for electrically connecting the plurality of photovoltaic cells Means, wherein one of the plurality of photovoltaic cells adjacent to each other is a first conductivity type impurity region extending from the surface of the semiconductor layer to the insulating film, and the first conductivity type. The other photovoltaic cell, which is constituted by a second conductivity type impurity region surrounded by an impurity region, has another first conductivity type surrounding the first conductivity type impurity region at a distance from the first conductivity type impurity region. Type impurity region, and a second conductivity type impurity region sandwiched between the other first conductivity type impurity region and the first conductivity type impurity region of the one photovoltaic cell. Next to each other The first of the one photovoltaic cell
The conductive type impurity region is electrically connected to the second conductive type impurity region of the other photovoltaic cell.

In this structure, the first of the inner photovoltaic cells
Since the conductivity type impurity region and the second conductivity type impurity region of the outer photovoltaic cell are electrically connected, the first conductivity type impurity region of the inner photovoltaic cell is separated from the photovoltaic cell by a separation layer. Will function as As described above, in the above-described structure in which the plurality of photovoltaic cells are electrically connected in series, the first conductivity type impurity region functioning as a separation layer between the photovoltaic cells does not float electrically. In addition, current does not flow between photovoltaic cells in the direction opposite to the photocurrent during light irradiation. This eliminates the need to use dielectric isolation even when integrating with other elements.

The connecting means is formed of a light-transmitting conductive film, and the first conductive type impurity region of the one adjacent photovoltaic cell and the second conductive type impurity region of the other photovoltaic cell are adjacent to each other. A structure may be provided on the upper surface of the semiconductor layer at the boundary with the region and formed almost all around the boundary (claim 2). In this structure, since the conductive film is translucent, there is no possibility that light is short-circuited by the conductive film and the short-circuit current is reduced. Further, the potential of the first conductivity type impurity region functioning as a separation layer between the photovoltaic cells is stabilized, and the open voltage does not drop.

Further, the connecting means may be provided in the semiconductor layer corresponding to a boundary between the first conductivity type impurity region of the one photovoltaic cell and the second conductivity type impurity region of the other photovoltaic cell adjacent to each other. It is a light-shielding conductive film provided on the upper surface, and the light-shielding conductive film may have a structure in which at least two of the light-shielding conductive films are provided on a part of the boundary for each of the boundaries. In this structure, since at least two light-shielding conductive films are provided at a part of each boundary at each boundary, the light-shielding area is smaller than when all of the conductive films are provided. The decrease amount is reduced. By arranging the light-shielding conductive films at appropriate intervals, the potential of the first conductivity type impurity region functioning as a separation layer between photovoltaic cells is stabilized. Further, inexpensive aluminum or the like can be used as the light-shielding conductive film.

Further, each of the plurality of photovoltaic cells may have a structure having the same volume. In this structure, the amount of carriers generated in each photovoltaic cell becomes equal, so that the same photo-short current can be obtained in each photovoltaic cell. This makes it possible to prevent loss due to uneven optical short-circuit current.

[0018]

1A and 1B are a schematic plan view showing a part of a photovoltaic device according to a first embodiment of the present invention and a line XX 'in FIG. 1A, respectively. The first embodiment will be described with reference to this schematic sectional view. However, FIG. 1A shows a portion corresponding to the second quadrant when X ′ is the origin. Further, in order to clarify the specification of each part of the photovoltaic device, reference numerals in parentheses in FIG. 1 are appropriately used.

This photovoltaic device is a PDA, which is a semiconductor substrate 1 made of single crystal silicon or the like, an insulating film 2 made of a silicon oxide film or the like formed on one main surface of the semiconductor substrate 1, and a PDA. An SOI substrate formed of a semiconductor layer 3 which is formed on the insulating film 2 and constitutes a plurality (three in the example of FIG. 1) of photodiode cells (photovoltaic cells) C, a surface electrode 4, and a plurality of photodiode cells C It comprises a surface electrode 5 and a surface electrode 6 which are electrically connected.

Of the plurality of photodiode cells C, one of the photodiode cells C adjacent to each other has a semiconductor layer 3
N-type impurity separation layer (first conductivity type impurity region) 31 extending from the surface of the substrate to insulating film 2 and n-type impurity separation layer 3
1, the other photodiode cell C surrounds the n-type impurity isolation layer 31 at a distance from the n-type impurity isolation layer 31. Another n-type impurity separation layer 3
1 and a p-type silicon layer 30 sandwiched between the other n-type impurity isolation layer 31 and the n-type impurity isolation layer 31 of the one photodiode cell C.

That is, in the example shown in FIG. 1B, one of the photodiode cells C1 adjacent to each other has an n-type impurity isolation layer 31 extending from the surface of the semiconductor layer 3 to the insulating film 2.
1 and a p-type silicon layer 301 surrounded by the n-type impurity isolation layer 311, while the other photodiode cell C 2 includes an n-type impurity isolation layer 311.
Is separated from the n-type impurity isolation layer 311, and the n-type impurity isolation layer 312
And an n-type impurity separation layer 311. Similarly, also in the photodiode cells C2 and C3 adjacent to each other, the photodiode cell C3 includes the n-type impurity isolation layer 313 surrounding the n-type impurity isolation layer 312 at a distance from the n-type impurity isolation layer 312, and the n-type impurity isolation layer 313. P-type silicon layer 303 sandwiched between isolation layer 313 and n-type impurity isolation layer 312
It consists of.

The surface electrode 4 is formed in a square shape by a light-transmitting conductive film, and is provided at the center of the upper surface of the p-type silicon layer 301 in the photodiode cell C1. In the first embodiment, this surface electrode 4 becomes the anode electrode of the PDA.

The surface electrode (connection means) 5 is connected to the n-type impurity isolation layer 31 of one of the photodiode cells C adjacent to each other.
And electrically connects to the p-type silicon layer 30 of the other photodiode cell C. In the first embodiment, it is made of a light-transmitting conductive film, and is adjacent to each other as shown in FIG. 1A is provided on the upper surface of the semiconductor layer 3 at the boundary between the n-type impurity separation layer 31 of one photodiode cell C and the p-type silicon layer 30 of the other photodiode cell C, as shown in FIG. , Formed all around the boundary.

The surface electrode 6 is made of a light-transmitting conductive film, and is provided on the upper surface of the n-type impurity isolation layer 31 in the photodiode cell C3. This surface electrode 6 is a PDA
Of the cathode electrode.

The photovoltaic device thus constructed will be described in further detail. In the first embodiment, the p-type silicon layer 30 has a thickness of about 3 μm and an impurity concentration of 1 × 10
It is about ¹⁵ to 1 × 10 ¹⁶ cm ⁻³ .

The SOI substrate can be formed by an SOI growth method in which single-crystal silicon is grown on the insulating layer in each of a gas phase, a liquid phase, and a solid phase.
SIMOX (separation by impla
nted oxygen) method.

A triple n-type impurity isolation layer 31 surrounding the p-type silicon layer 30 with X 'as the center is formed on the SOI substrate. These triple n-type impurity isolation layers 31 are separated from each other, and the p-type silicon layers 30 sandwiched between the n-type impurity isolation layers 31 each constitute a photodiode cell C. P-type silicon layer 30 of each photodiode cell C
Is connected to n-type impurity isolation layer 31
An n-type impurity diffusion layer 32 having a shallow diffusion of about μm is formed. Thereby, the p-type silicon layer 30 functions as an anode of the photodiode cell C, and the n-type impurity separation layer 31 and the n-type impurity diffusion layer 32 connected to each other function as a force source of the photodiode cell C.

A part of the n-type impurity isolation layer 31 of the photodiode cell C and the p-type
Each photodiode cell C is connected in series by connecting a part of the mold silicon layer 30 by the surface electrode 5.

The surface electrode 5 has a thickness of about 100 nm.
It is made of TO (indium tin oxide) and is formed all around the boundary (the boundary and the vicinity thereof) between the p-type silicon layer 30 and the n-type impurity separation layer 31. These surface electrodes 5 are formed by first removing a portion corresponding to the above boundary portion in the silicon oxide film 33 formed on the semiconductor layer 3, and then depositing ITO in a groove obtained by the removal by, for example, electron beam evaporation. Formed by embedding. In addition, the above-mentioned surface electrode 4,
6 is formed in the same manner.

Since the p-type silicon layer 30 and the n-type impurity separation layer 31 of the adjacent photodiode cell form a pnp transistor, the surface electrode 5 is
It is desirable to form it almost all around the boundary between the 0 and n-type impurity isolation layers 31. This is due to p
If the connection between the n-type impurity isolation layer 31 and the n-type silicon layer 30 is insufficient, the n-type impurity isolation layer 31 corresponding to the base region of the pnp transistor is in an electrically floating state,
This is because a transistor current may flow to lower the electromotive voltage of the photodiode cell.

The reason why the transparent electrodes 4 to 6 are used is to prevent a decrease in the amount of light incident on the p-type silicon layer 30 and the n-type impurity separation layer 31 due to light shielding by the opaque electrode.

Further, the volume of the photodiode cell including the p-type silicon layer 30, the n-type impurity separation layer 31, and the n-type impurity diffusion layer 32 is equal in the three photodiode cells. When the diffusion length of the carrier is sufficiently large when the volume is made equal in this manner, the carrier generated by light in the p-type silicon layer 30, the n-type impurity separation layer 31 and the n-type impurity diffusion layer 32 in the photodiode cell can be reduced. The total amount is equal for each photodiode cell. Then, since the optical short-circuit current generated in the photodiode cells is determined by the total amount of the carriers, the optical short-circuit current generated in each photodiode cell becomes equal. In a series-connected photodiode cell, if at least one photo-short current is small, the photo-short current of the entire series-connected photo-diode cell is rate-determined by the small photo-short current. As a result, the optical short-circuit current generated in each photodiode cell can be equalized, and the rate-limiting of the entire optical short-circuit current due to the small optical short-circuit current can be prevented. This makes it possible to prevent loss due to uneven optical short-circuit current.

As described above, according to the first embodiment, the structure shown in FIG. 1 does not cause the n-type impurity separation layer 31 functioning as a separation layer between photodiode cells to be in an electrically floating state. Sometimes the current does not flow between the photodiode cells in the direction opposite to the photocurrent, and it is not necessary to use dielectric isolation even when integrating with other elements.

FIGS. 2A and 2B are a schematic plan view showing a part of a photovoltaic device according to a second embodiment of the present invention and a schematic sectional view taken along line XX 'in FIG. ,
Hereinafter, the second embodiment will be described with reference to FIG.

This photovoltaic device includes a semiconductor substrate 1 and an insulating film 2 in the same manner as in the first embodiment, and differs from the first embodiment in that the surface electrodes 4a, 5a, 6
a, and a semiconductor layer 3a formed in the same manner as the semiconductor layer 3 except for an upper silicon oxide film 33a whose structure is different from that of the first embodiment due to each of these surface electrodes.

The surface electrode 4a is formed in a rectangular shape by a light-shielding conductive film, and is provided at the center of the upper surface of the p-type silicon layer 301 in the photodiode cell C1.
This surface electrode 4a becomes an anode electrode of the PDA.

The surface electrode (connection means) 5a is connected to the n-type impurity separation layer 3 of one of the photodiode cells C adjacent to each other.
The p-type silicon layer 30 of the first and the other photodiode cells C
In the second embodiment, the semiconductor layer which corresponds to the boundary between the n-type impurity isolation layer 31 of one of the adjacent photodiode cells C and the p-type silicon layer 30 of the other photodiode cell C is provided. The light-shielding conductive film is provided on the upper surface of the substrate 3. The four light-shielding conductive films are provided at a part of each of the boundaries.

The surface electrode 6a is connected to the photodiode cell C3.
Is formed of a light-shielding conductive film provided on the upper surface of the n-type impurity separation layer 31, and is formed at four corners of the photodiode cell C3. This surface electrode 6a becomes a cathode electrode of the PDA.

The photovoltaic device thus configured will be described in further detail. In the second embodiment, the p-type silicon layer 30 has a thickness of about 3 μm and an impurity concentration of 1 × 10
It is about ¹⁵ to 1 × 10 ¹⁶ cm ⁻³ .

A triple n-type impurity isolation layer 31 surrounding the p-type silicon layer 30 with X 'as the center is formed on the SOI substrate. These triple n-type impurity isolation layers 31 are separated from each other, and the p-type silicon layers 30 sandwiched between the n-type impurity isolation layers 31 each constitute a photodiode cell C. P-type silicon layer 30 of each photodiode cell C
Is connected to n-type impurity isolation layer 31
An n-type impurity diffusion layer 32 having a shallow diffusion of about μm is formed. Thereby, the p-type silicon layer 30 functions as an anode of the photodiode cell C, and the n-type impurity separation layer 31 and the n-type impurity diffusion layer 32 connected to each other function as a force source of the photodiode cell C.

Then, a part of the n-type impurity isolation layer 31 of the photodiode cell C and the p-type
A part of the silicon mold layer 30 is connected by the surface electrode 5a, and the photodiode cells C are connected in series.

The surface electrode 5a is made of aluminum having a thickness of about 1 μm, and is located at the boundary between the p-type silicon layer 30 and the n-type impurity isolation layer 31 and is located at the photodiode cell C.
1, and C2 are formed at the four corners. These surface electrodes 5a
Is formed by first removing portions corresponding to the four corners of the silicon oxide film 33a formed above the semiconductor layer 3, and then embedding aluminum in a groove obtained by the removal, for example, by a sputtering method. .
The above-mentioned surface electrodes 4a and 6a are formed in the same manner.

The reason why the surface electrodes 5a and 6a are arranged at the four corners is that the area shielded by the light-shielding electrode is reduced as much as possible and that the n-type impurity isolation layer 31 as the base region is in an electrically floating state. In order to prevent the open-circuit voltage from lowering.

Furthermore, in order to prevent the photo-short current obtained from the PDA from being limited by a photodiode cell smaller than the others, a photodiode in which the p-type silicon layer 30, the n-type impurity separation layer 31 and the n-type impurity diffusion layer 32 are combined. The cell volume is equivalent for the three photodiode cells. This makes it possible to prevent loss due to uneven optical short-circuit current.

As described above, according to the second embodiment, the structure shown in FIG. 2 does not cause the n-type impurity separation layer 31 functioning as a separation layer between photodiode cells to be in an electrically floating state. Sometimes the current does not flow between the photodiode cells in the direction opposite to the photocurrent, and it is not necessary to use dielectric isolation even when integrating with other elements.

In the first and second embodiments, the first
The second conductivity type is n-type and p-type, respectively, but may be p-type and n-type. In this case, the relationship between the anode and the cathode is reversed.

[0047]

As is apparent from the above description, according to the first aspect of the present invention, a semiconductor substrate, an insulating film formed on the semiconductor substrate, and a plurality of photovoltaic devices formed on the insulating film. SOI comprising a semiconductor layer constituting a power cell
A substrate, and a connecting means for electrically connecting the plurality of photovoltaic cells, and among the plurality of photovoltaic cells, one of the photovoltaic cells adjacent to each other is formed from the surface of the semiconductor layer. The other photovoltaic cell includes the first conductivity type impurity region extending to the insulating film and the second conductivity type impurity region surrounded by the first conductivity type impurity region. Another first conductivity type impurity region surrounding the first conductivity type impurity region at a distance from the first conductivity type impurity region, and between the another first conductivity type impurity region and the first conductivity type impurity region of the one photovoltaic cell. The second conductive type impurity region is sandwiched between the first conductive type impurity region of the one photovoltaic cell and the second conductive type impurity region of the other photovoltaic cell. Electrically connect In, also in the case of integration with other elements, it is not necessary to use a dielectric isolation.

According to the second aspect of the present invention, the connecting means is made of a light-transmitting conductive film, and the first conductive type impurity region of the one photovoltaic cell and the other photovoltaic cell adjacent to each other. It is provided on the upper surface of the semiconductor layer at the boundary with the impurity region of the second conductivity type of the power cell, and is formed almost all around the boundary, thereby preventing a decrease in optical short-circuit current due to shading by the conductive film. It becomes possible. In addition, it is possible to stabilize the potential of the first conductivity type impurity region functioning as a separation layer between photovoltaic cells, and to prevent a drop in open-circuit voltage.

According to the third aspect of the present invention, the connecting means includes the first conductive type impurity region of the one photovoltaic cell and the second conductive type impurity region of the other photovoltaic cell adjacent to each other. And a light-shielding conductive film provided on the upper surface of the semiconductor layer at the boundary between the light-shielding layer and the light-shielding conductive film. The amount of decrease in the optical short circuit current can be reduced. Further, it is possible to stabilize the potential of the first conductivity type impurity region functioning as a separation layer between photovoltaic cells. Further, inexpensive aluminum or the like can be used as the light-shielding conductive film.

According to the fourth aspect of the present invention, since the plurality of photovoltaic cells each have the same volume, it is possible to obtain the same optical short circuit current in each of the photovoltaic cells. Loss due to uneven current can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are a schematic plan view showing a part of a photovoltaic device according to a first embodiment of the present invention and a schematic sectional view taken along line XX ′ in FIG. .

FIGS. 2A and 2B are a schematic plan view showing a part of a photovoltaic device according to a second embodiment of the present invention and a schematic sectional view taken along line XX ′ in FIG. .

FIGS. 3A and 3B are diagrams each showing an example of a cross-sectional structure of a PDA in which each photodiode cell is separated by using dielectric isolation, and a diagram showing a part of the surface structure of the PDA shown in FIG. It is.

4 (a) and 4 (b) are views showing an example of a cross-sectional structure of a conventional SOI substrate forming a series-connected photodiode isolated by junction isolation, and FIG. 4 (a) shows a surface structure of the SOI substrate. It is a figure which shows a part.

5 (a) and 5 (b) are explanatory diagrams showing that the outermost peripheral isolation structure shown in FIG. 4 (b) is limited to a dielectric isolation or an air gap.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 insulating film 3, 3a semiconductor layer 4, 5, 6 surface electrode 4a, 5a, 6a surface electrode 30, 301-303 p-type silicon layer 31, 311-313 n-type impurity separation layer 32, 321-323 n -Type impurity diffusion layer 33, 33a Silicon oxide film C Photodiode cell

Continued on the front page (72) Inventor Masahiko Suzumura 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor Yuji Suzuki 1048 Odaka Kazuma Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. Person Yoshifumi Shirai 1048 Kadoma Kadoma, Kadoma-shi, Osaka Prefecture (72) Inventor Takashi Kishida Takashi Kishida 1048 Kadoma Kadoma, Kadoma-shi, Osaka (72) Inside the Matsushita Electric Works, Ltd. 1048 Kadoma Matsushita Electric Works Co., Ltd. F-term (reference) 5F051 AA02 BA05 BA14 DA16 DA20 GA04 GA06

Claims (4)

[Claims] An SOI substrate including a semiconductor substrate, an insulating film formed on the semiconductor substrate, and a semiconductor layer forming a plurality of photovoltaic cells formed on the insulating film; Connecting means for electrically connecting cells, wherein one of the plurality of photovoltaic cells adjacent to each other is a first conductive type impurity extending from the surface of the semiconductor layer to the insulating film. A second conductive type impurity region surrounded by the first conductive type impurity region, and the other photovoltaic cell separates the first conductive type impurity region from the first conductive type impurity region. And a second conductivity type impurity region sandwiched between the other first conductivity type impurity region and the first conductivity type impurity region of the one photovoltaic cell. Composed It said connection means is electrically connected to photovoltaic devices and a second conductive type impurity region of the first conductivity type impurity region and the other photovoltaic cells of the one photovoltaic cells adjacent to each other. 2. The method according to claim 1, wherein the connecting unit is formed of a light-transmitting conductive film, and the first conductive type impurity region of the one photovoltaic cell and the second conductive type impurity of the other photovoltaic cell adjacent to each other. The photovoltaic device according to claim 1, wherein the photovoltaic device is provided on an upper surface of the semiconductor layer corresponding to a boundary with a region, and is formed substantially all around the boundary. 3. The semiconductor device according to claim 2, wherein said connecting means includes a first conductive type impurity region of said one photovoltaic cell and a second conductive type impurity region of said other photovoltaic cell which are adjacent to each other. A light-shielding conductive film provided on the upper surface, and the light-shielding conductive film has at least two
The photovoltaic device according to claim 1, wherein the photovoltaic device is provided at a part of the boundary. 4. The photovoltaic device according to claim 1, wherein each of the plurality of photovoltaic cells has the same volume.