Manufacture of solar cells
First Claim
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1. A method of making a photovoltaic semiconductor solar cell comprising the steps of:
- (1) providing a semiconductor body of a first conductivity type and having first and second opposite surfaces;
(2) forming on said first surface a continuous layer of a material containing a dopant capable upon diffusion into said body of forming a region of a second opposite conductivity type in said body;
(3) removing said layer from selected portions of said surface so as to form a grid-like pattern of apertures defined by intervening non-removed sections of said layer;
(4) heating said body in an atmosphere containing said dopant at a temperature at which said dopant will diffuse into said body from said layer and said atmosphere so as to form in said body relatively deep diffused regions of opposite conductivity type in line with said apertures and relatively shallow diffused regions of said opposite conductivity type in line with said intervening layer sections, said regions establishing a junction within said body; and
(5) forming conductive contacts on said surfaces with the contacts on said first surface conforming to and overlying said deep diffused regions.
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Abstract
The invention provides a method of producing solar cells having a composite shallow/deep junction device construction. The solar cells have grid-like contacts on their front energy-receiving sides, with each portion of each contact being coincident, i.e., aligned with, the deep junction regions while the shallow junction regions are exposed to incident radiation. The composite junction and contacts are formed by a novel method which employs conventional techniques, notably the use of doped oxide films as diffusion sources.
126 Citations
19 Claims
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1. A method of making a photovoltaic semiconductor solar cell comprising the steps of:
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(1) providing a semiconductor body of a first conductivity type and having first and second opposite surfaces; (2) forming on said first surface a continuous layer of a material containing a dopant capable upon diffusion into said body of forming a region of a second opposite conductivity type in said body; (3) removing said layer from selected portions of said surface so as to form a grid-like pattern of apertures defined by intervening non-removed sections of said layer; (4) heating said body in an atmosphere containing said dopant at a temperature at which said dopant will diffuse into said body from said layer and said atmosphere so as to form in said body relatively deep diffused regions of opposite conductivity type in line with said apertures and relatively shallow diffused regions of said opposite conductivity type in line with said intervening layer sections, said regions establishing a junction within said body; and (5) forming conductive contacts on said surfaces with the contacts on said first surface conforming to and overlying said deep diffused regions. - View Dependent Claims (2, 3, 4)
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5. Method of making a solar cell comprising the steps of:
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(a) providing a substrate in the form of a semiconductor body of a first type conductivity; (b) depositing on one surface of said body a diffusion source in the form of a film doped with a diffusion impurity of a second conductivity type; (c) removing said film from only selected areas of said surface so as to form a pattern of apertures defined by intervening sections of said film; (d) diffusing said second conductivity type impurity out of said film and through said surface into said body and also diffusing additional second conductivity type impurity into said body via the apertures in said film so as to form a diffused second conductivity type region in said body which is separated from the first conductivity type bulk region of said body by a P/N junction and which has a greater depth measured from said surface along the areas of said apertures than along the areas of said intervening sections; and (e) forming a metal contact on said one surface only in the areas thereof coincident with said apertures. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification