EP0455360A1
Expired / Lapsed
EP
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Method of manufacturing a solar cell
Assignee: Mitsubishi Electric Corp
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Filing: 1991-04-10
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Granted: —
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Expires: 2011-04-10
Abstract
Abstract A method for manufacturing a solar cell which includes at least a first GaAs layer of a first conductivity type and a second GaAs layer of a second conductivity type sequentially formed on a first main surface of an Si substrate of the first conductivity type, a first electrode formed on a second main surface opposite to the first main surface of the Si substrate and a second electrode formed on the second GaAs layer. The method includes a first step of forming a layer comprising a material having a thermal expansion coefficient smaller than that of Si on the second main surface of the Si substrate at a temperature close to the room temperature and a second step of sequentially forming the first and second GaAs layers on the first main surface of the Si substrate.
Inventors
- 👤 Takahiko Oohara
- 👤 Yoshiro Ohmachi
- 👤 Yoshiaki Kadota
- 👤 Kotaro C/O Mitsubishi Denki K.K. Mitsui
- 👤 Nobuyoshi C/O Mitsubishi Denki K.K. Ogasawara
- 👤 Takashi C/O Mitsubishi Denki K.K. Nishimura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 08:40
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/14; H10F10/144; H10F19/00; H10F19/20; H10F71/00; H10F71/127; H10F71/1276; H10F77/00; H10F77/20; H10F77/206; H10F77/211; H10F77/215; H10P; H10P14/00; H10P14/20; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/32; H10P14/3202; H10P14/3214; H10P14/3221; H10P14/3242; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3421; H10P14/36; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S438/00; Y10S438/933
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
137 words
A method for manufacturing a solar cell which comprises at least a first GaAs layer of a first conductivity type and a second GaAs layer of a second conductivity type sequentially formed on a first main surface of an Si substrate of the first conductivity type, a first electrode formed on a second main surface opposite to the first main surface of said Si substrate and a second electrode formed on said second GaAs layer, said method comprising: a first step of forming a layer comprising a material having a thermal expansion coefficient smaller than that of Si on said second main surface of the Si substrate at a temperature close to the room temperature; and a second step of sequentially forming said first and second GaAs layers on said first main surface of the Si substrate.
Claim 2
Dependent Claim
39 words
A method for manufacturing a solar cell in accordance with claim 1, wherein said material having the thermal expansion coefficient smaller than that of Si comprises any one of SiO₂, SiN, BN or C or a combination of those.
Claim 3
Dependent Claim
115 words
A solar cell comprising: at least a first GaAs layer of a first conductivity type and a second GaAs layer of a second conductivity type sequentially formed on a first main surface of an Si substrate of the first conductivity type; a first electrode formed on a second main surface opposite to the first main surface of said Si substrate; and a second electrode formed on said second GaAs layer, said first electrode being formed of a conductive material having a thermal expansion coefficient smaller than that of Si on said second main surface of the Si substrate at a temperature close to the room temperature before said first and second GaAs layers are formed.
Claim 4
Dependent Claim
31 words
A solar cell in accordance with claim 3, wherein said material having the thermal expansion coefficient smaller than that of Si comprises BN to which C is applied in high concentration;
Claim 5
Dependent Claim
64 words
A solar cell in accordance with claim 3, wherein a metal layer is connected to said second main surface of the Si substrate and the layer comprising the material having the thermal expansion coefficient smaller than that of the Si substrate through a hole formed at a part of the layer comprising the material having the thermal expansion coefficient smaller than that of Si.
Claim 6
Independent Claim
111 words
A method for manufacturing a solar cell having an active layer formed of GaAs on an Si substrate, said method comprising: a first step of forming a GaAs buffer layer to which an impurity of a first conductivity type of high concentration is applied, on a first main surface of said Si substrate; a second step of forming a layer comprising a material having a thermal expansion coefficient smaller than that of Si on a second main surface of said Si substrate at a temperature close to the room temperature; and a third step of sequentially forming first and second GaAs layers on said first main surface of said Si substrate.
Claim 7
Dependent Claim
23 words
A method for manufacturing a solar cell in accordance with claim 6, wherein a thickness of said buffer layer is 1 to 2µm.
Claim 8
Dependent Claim
89 words
A method for manufacturing a solar cell in accordance with claim 6, wherein after said buffer layer is formed on said first main surface of said Si substrate and then said buffer layer is selectively removed, active layers comprising the first conductivity type GaAs layer and the second conductivity type GaAs layer are formed on said buffer layer and then said active layer and said buffer layer at a peripheral part of the region in which said buffer layer remains and on a little inner side thereof are removed.
Claim 9
Dependent Claim
39 words
A method for manufacturing a solar cell in accordance with claim 8, wherein an angle formed between the side of said selectively removed active layer and said first main surface of said Si substrate is 90 degrees or less.
Claim 10
Dependent Claim
70 words
A method for manufacturing a solar cell in accordance with claim 9, wherein an angle formed between the side of said buffer layer which is selectively removed after said active layer is formed and said first main surface of said Si substrate is 90 degrees or more at an interface between said buffer layer and said Si substrate and it is gradually decreased as it gets away from said interface.
Claim 11
Independent Claim
121 words
A method for manufacturing solar cell having an active layer formed on GaAs on an Si substrate comprising: a first step of forming a GaAs buffer layer, to which an impurity of a first conductivity type of high concentration is applied, on said first main surface of said Si substrate; a second step of forming a wedge-shaped notched part on the side of said buffer layer or a pinhole of a predetermined configuration on said buffer layer; and a third step of forming an active layer comprising a first conductivity type GaAs layer and a second conductivity type GaAs layer on said buffer layer and having a crack generated from the end of said wedge-shaped notched part or from said pinhole.
Claim 12
Dependent Claim
35 words
A method for manufacturing a solar cell in accordance with claim 11, wherein said wedge-shaped notched part is positioned almost at the center of collecting electrodes to be arranged later which form the second electrode.
Claim 13
Dependent Claim
32 words
A method for manufacturing a solar cell in accordance with claim 11, wherein the direction of said crack is not in parallel with said collecting electrodes nor crosses it at right angles.
Claim 14
Dependent Claim
30 words
A method for manufacturing a solar cell in accordance with claim 11, wherein a pn junction which is exposed when said crack is generated is covered with an insulating film.
Claim 15
Dependent Claim
28 words
A method for manufacturing a solar cell in accordance with claim 14, wherein said step of covering said insulating film is performed before the second electrode is formed.
Claim 16
Dependent Claim
33 words
A method for manufacturing a solar cell in accordance with claim 15, wherein said second electrode is formed on said insulating film at a region in which said crack crosses the second electrode.
Claim 17
Dependent Claim
45 words
A method for manufacturing a solar cell in accordance with claim 11, wherein a configuration of said pinhole is a rhomb or formed of two circular arcs circumscribed on the rhomb and the angle formed between said two circular arcs is 90 degrees or less.
Claim 18
Dependent Claim
33 words
A method for manufacturing a solar cell in accordance with claim 17, wherein said pinhole is positioned almost at the center of the collecting electrodes forming the second electrode to be arranged later.
Claim 19
Dependent Claim
54 words
A method for manufacturing a solar cell in accordance with claim 17, wherein a diagonal line connected to vertexes of the acute angle-parts of said rhomb is in parallel with the direction of cleavage of a GaAs crystal and it is not in parallel to said collecting electrode nor crosses it at right angles.
Claim 20
Dependent Claim
28 words
A method for manufacturing a solar cell in accordance with claim 19, wherein the angle formed between said diagonal line and said collecting electrode is approximately 45 degrees.
Claim 21
Dependent Claim
32 words
A method for manufacturing a solar cell in accordance with claim 17, wherein said active layer and buffer layer in the vicinity of said pinhole are removed after said crack is generated.
Claim 22
Dependent Claim
118 words
A solar cell having an active layer comprising GaAs on an Si substrate comprising: a plurality of island-shaped buffer layers formed in one element region by dividing the GaAs buffer layer, to which an impurity of a first conductivity type of high concentration is applied and which is formed on a first main surface of the first conductivity type Si substrate, by checkered mesa grooves; and active layers comprising a first conductivity type GaAs layer and a second conductivity type GaAs layer which are sequentially formed on each island-shaped buffer layer, in which at least one second conductivity type collecting electrode connected to the common electrode is connected to the second conductivity type GaAs layer in each island.
Claim 23
Dependent Claim
52 words
A solar cell on an Si substrate having a plurality of island-shaped active layers formed by the method in accordance with claim 8, in which at least one of the second conductivity type collecting electrodes connected to the common electrode is connected to said second conductivity type GaAs layer in the island.
Claim 24
Dependent Claim
91 words
A solar cell comprising: at least a GaAs layer of a first conductivity type and a GaAs layer of a second conductivity type formed on a first main surface of a first conductivity type Si substrate; a first electrode formed on a second main surface opposite to the first main surface of said Si substrate; and a second electrode formed on said second conductivity type GaAs layer, at least one of said first and second electrodes being formed of metal which is likely to be plastically deformed as the base material.
Claim 25
Dependent Claim
20 words
A solar cell in accordance with claim 24, wherein said metal which is likely to be plastically deformed is gold.
Claim 26
Dependent Claim
82 words
A solar cell comprising: at least a GaAs layer of a first conductivity type and a GaAs layer of a second conductivity type formed on a first main surface of a first conductivity type Si substrate; a first electrode formed on a second main surface opposite to the first main surface of said Si substrate; and a second electrode formed on said second conductivity type GaAs layer, said first electrodes being separately arranged on said second main surface of said Si substrate.
Claim 27
Dependent Claim
108 words
A solar cell comprising: at least a GaAs layer of a first conductivity type and a GaAs layer of a second conductivity type formed on a first main surface of a first conductivity type Si substrate; a first electrode formed on a second main surface opposite to the first main surface of said Si substrate; and a second electrode formed on said second conductivity type GaAs layer, said second electrode being patterned into a configuration in which a state where the collecting electrode is not connected to a region divided by another active region is not likely to occur when a crack is generated in the active layer.
Claim 28
Dependent Claim
16 words
A solar cell in accordance with claim 27, wherein said second electrode forms a closed-loop configuration.
Claim 29
Dependent Claim
15 words
A solar cell in accordance with claim 28, wherein said closed-loop configuration is grid shape.
Claim 30
Dependent Claim
46 words
A solar cell in accordance with claim 27, wherein said second electrode comprises a plurality of collecting electrodes and the common electrode electrically connected to said plurality of collecting electrodes and the angle formed between said collecting electrode and said common electrode is not 90 degrees.
Claim 31
Dependent Claim
27 words
A solar cell in accordance with claim 30, wherein said collecting electrode is arranged in the direction which crosses the direction of cleavage of said active layer.
Claim 32
Dependent Claim
27 words
A solar cell in accordance with claim 31, wherein said first main surface mostly forms 100 surface and said common electrode is arranged in the <100> direction.
Claim 33
Dependent Claim
19 words
A solar cell in accordance with claim 30, wherein at least two common electrodes are formed on one element.
References Cited (Backward Citations)
EP0328405A2
Cited
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