Method of making light-receiving diode
First Claim
1. A method of manufacturing a light-receiving diode comprising the steps of:
- (a) forming on one principal surface, of a pair of principal surfaces of a semiconductor substrate of a first conductivity type, an oxide film having a window at an electrode forming part;
(b) implanting impurity ions of a second conductivity type into said one principal surface through said oxide film;
(c) selectively forming a layer of aluminum on the other principal surface, of the pair of prinicpal surfaces of the semiconductor substrate; and
(d) heat-treating (1) said substrate to activate the implanted ions in the one principal surface, thereby producing an impurity-doped region having a low sheet resistance at said electrode forming part but having a relatively high sheet resistance at the remaining part, and (2) the layer of aluminum on the other principal surface of the substrate to diffuse aluminum into the other principal surface.
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Accused Products
Abstract
In a method of manufacturing a solar cell including a p-n junction formed in a semiconductor substrate, impurity ions are implanted through a mask in the form of an oxide film covering a light receiving surface of the semiconductor substrate except an electrode forming part, thereby forming a p-n junction which is deep in an area beneath the electrode forming part but shallow in the remaining area. Formation of the shallow p-n junction improves the spectral sensitivity in a short wavelength range. Further, utilization of the oxide film as a passivation film can prevent shortening of the life time of minority carriers in the substrate due to heat treatment, thereby retarding the electron-hole recombination rate at the light receiving surface of the substrate.
40 Citations
18 Claims
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1. A method of manufacturing a light-receiving diode comprising the steps of:
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(a) forming on one principal surface, of a pair of principal surfaces of a semiconductor substrate of a first conductivity type, an oxide film having a window at an electrode forming part; (b) implanting impurity ions of a second conductivity type into said one principal surface through said oxide film; (c) selectively forming a layer of aluminum on the other principal surface, of the pair of prinicpal surfaces of the semiconductor substrate; and (d) heat-treating (1) said substrate to activate the implanted ions in the one principal surface, thereby producing an impurity-doped region having a low sheet resistance at said electrode forming part but having a relatively high sheet resistance at the remaining part, and (2) the layer of aluminum on the other principal surface of the substrate to diffuse aluminum into the other principal surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of manufacturing a light-receiving diode comprising the steps of:
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(a) forming, on one principal surface of a pair of principal surfaces of a semiconductor substrate of a first conductivity type, an oxide film having a window at an electrode forming part; (b) implanting impurity ions of a second conductivity type into said one principal surface through said oxide film; (c) selectively forming a layer of aluminum on the other principal surface of the pair of principal surfaces; and (d) heat-treating said substrate to activate the implanted ions, thereby forming a pn-junction which is deep beneath said electrode forming part but shallow beneath the remaining part, and to diffuse aluminum into the other principal surface. - View Dependent Claims (13, 14, 15)
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16. A method of manufacturing a light-receiving diode comprising the steps of:
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(a) forming, on one principal surface of a pair of principal surfaces of a semiconductor substrate of a first conductivity type, a film having a window at an electrode forming part and exerting a retarting action to implanting ions; (b) implanting impurity ions of a second conductivity type into said one principal surface through said film; (c) selectively forming a layer of aluminum on the other principal surface of the pair of principal surfaces; and (d) heat-treating said substrate to activate the ions implanted into said one principal surface, thereby producing an impurity-doped region having a lower sheet resistance and a deeper depth at said electrode forming part than at the remaining part, and to diffuse aluminum to form an aluminum-doped region in the other principal surface. - View Dependent Claims (17, 18)
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Specification