Opto-electronic device with self-aligned ohmic contact layer
AssigneeOki Data Corporation
InventorsMasaharu Nobori, Hiroyuki Fujiwara, Masumi Koizumi
Life of this patent
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Abstract
An opto-electronic device has a diffusion area of one conductive type formed in a semiconductor substrate of another conductive type, an ohmic contact layer making contact with the diffusion area, and an electrode making contact with the ohmic contact layer. The diffusion area is formed by solid-phase diffusion. The same mask is used to define the patterns of both the diffusion source layer and the ohmic contact layer, so that the ohmic contact layer is self-aligned with the diffusion area.
Claims14
A method of fabricating an opto-electronic device, comprising the steps of:
- (a) forming an ohmic contact layer on a surface of a semiconductor substrate of a first conductive type;
- (b) forming a diffusion source layer on the ohmic contact layer;
- (c) forming a mask on the diffusion source layer;
- (d) etching the diffusion source layer, using said mask as an etching mask;
- (e) diffusing impurity atoms from the diffusion source layer into the ohmic contact layer and the semiconductor substrate, thereby forming at least one diffusion area of a second conductive type in the semiconductor substrate;
- (f) etching the ohmic contact layer, using at least one of the diffusion source layer and said mask as an etching mask, thereby removing all parts of the ohmic contact layer disposed outside said at least one diffusion area;
- and
- (g) forming at least one electrode making ohmic contact with the ohmic contact layer.
An opto-electronic device having a semiconductor substrate of a first conductive type, with at least one diffusion area of a second conductive type formed in the semiconductor substrate, comprising:
- an ohmic contact layer disposed on a surface of the semiconductor substrate within said at least one diffusion area, self-aligned with said at least one diffusion area;
- a diffusion source layer disposed on the ohmic contact layer, self-aligned with the ohmic contact layer, the diffusion source layer being penetrated by at least one contact hole extending to the ohmic contact layer;
- a diffusion cap film disposed on the diffusion source layer and said surface of the semiconductor substrate, said at least one contact hole also penetrating the diffusion cap film;
- and
- at least one electrode disposed on the diffusion cap film, electrically isolated from the semiconductor substrate by the diffusion cap film, making electrical contact with the ohmic contact layer through said at least one contact hole.
An opto-electronic device having a semiconductor substrate of a first conductive type, with at least one diffusion area of a second conductive type formed in the semiconductor substrate, comprising:
- an ohmic contact layer disposed on a surface of the semiconductor substrate within said at least one diffusion area, self-aligned with said at least one diffusion area;
- an isolation film disposed on the ohmic contact layer and said surface of the semiconductor substrate, penetrated by at least one contact hole extending to the ohmic contact layer;
- and
- at least one electrode disposed on the isolation film, electrically isolated from the semiconductor substrate by the isolation film, making electrical contact with the ohmic contact layer through said at least one contact hole.
Dependencies are inferred from the claim text.