Diffusion mask and fabrication method for forming pn-junction elements in a compound semiconductor substrate
AssigneeOki Electric Industry Co., Ltd.
InventorsMitsuhiko Ogihara, Yukio Nakamura, Masumi Koizumi, Masumi Taninaka
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Abstract
A pn-junction element is formed in a compound semiconductor substrate by depositing an aluminum-nitride film on the surface of the substrate, patterning the aluminum-nitride film to form a diffusion mask, depositing a diffusion source film on the diffusion mask, diffusing an impurity from the diffusion source film into the substrate, and removing the diffusion source film with buffered hydrofluoric acid. Electrode lines can then be formed directly on the aluminum-nitride diffusion mask, which is not etched by buffered hydrofluoric acid.
Claims20
A method of fabricating a pn-junction element in a compound semiconductor substrate, comprising the steps of:
- forming an aluminum-nitride film on said compound semiconductor substrate;
- patterning said aluminum-nitride film to create a diffusion mask with windows;
- forming a diffusion source film comprising an impurity on said diffusion mask and windows;
- diffusing said impurity from said diffusion source film into said compound semiconductor substrate through said windows by annealing;
- and
- removing said diffusion source film entirely from said diffusion mask and windows, by etching with hydrofluoric acid.
A method of fabricating an electrical element which includes a doped diffusion region, said method comprising the steps of:
- (a) forming a film that is impervious to hydrofluoric acid above a III-V compound semiconductor substrate, the film comprising aluminum nitride;
- (b) patterning the film to create a diffusion mask with a window;
- (c) forming a diffusion source film comprising a doping agent on the diffusion mask and the window;
- (d) diffusing doping agent from the diffusion source film into the III-V compound semiconductor substrate through the window to create the doped diffusion region;
- and
- (e) removing the diffusion source film entirely by etching it away with hydrofluoric acid without altering the diffusion mask.
A method of fabricating an electrical element which includes a doped diffusion region, said method comprising the steps of:
- (a) forming a film consisting essentially of aluminum nitride on a gallium arsenide substrate;
- (b) patterning the film to create a diffusion mask with a window;
- (c) forming a diffusion source film comprising a doping agent on the diffusion mask and the window;
- (d) diffusing doping agent from the diffusion source film into the gallium arsenide substrate through the window to create the doped region;
- (e) removing the diffusion source film entirely by etching it away with hydrofluoric acid without altering the diffusion mask;
- and
- (f) forming an electrode line on the diffusion mask, the electrode line extending through the window and contacting the doped region.
Dependencies are inferred from the claim text.