Selective electrochemical process for creating semiconductor nano-and micro-patterns
First Claim
1. A method of selectively creating a patterned semiconductor by electrochemical etching, comprising the steps of:
- a) treating selected regions of a semiconductor to create crystal defects in said selected regions and thereby reduce the threshold potential at which pore formation occurs during an electrochemical etch; and
b) carrying out an electrochemical etch on said semiconductor at an anodic potential that is at least equal to said reduced threshold potential for said selected regions and less than the threshold potential for untreated regions to selectively form patterns in said selected regions.
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Abstract
A porous semiconductor is created by electrochemical etching. Selected regions of a semiconductor are first treated to reduce the threshold potential at which pore formation occurs, and then an electrochemical etch is carried out on the semiconductor at a potential at least equal to the reduced threshold potential for the selected regions and less than the threshold potential for untreated regions. The selective treatment preferably involves implantation with the same ions as the semiconductor, i.e. Si ions for silicon. The treatment results in the formation of highly defined etch patterns or patterns of porous material depending on the process conditions.
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Citations
21 Claims
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1. A method of selectively creating a patterned semiconductor by electrochemical etching, comprising the steps of:
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a) treating selected regions of a semiconductor to create crystal defects in said selected regions and thereby reduce the threshold potential at which pore formation occurs during an electrochemical etch; and
b) carrying out an electrochemical etch on said semiconductor at an anodic potential that is at least equal to said reduced threshold potential for said selected regions and less than the threshold potential for untreated regions to selectively form patterns in said selected regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of selectively creating a porous semiconductor by electrochemical etching, comprising the steps of:
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a) creating crystal defects in selected regions of a semiconductor to reduce the threshold potential at which pore formation occurs during an electrochemical etch; and
b) carrying out an electrochemical etch on said semiconductor at an anodic potential that is at least equal to said reduced threshold potential for said selected regions and less than the threshold potential for untreated regions to selectively form pores in said selected regions. - View Dependent Claims (19, 20)
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21. A method of selectively creating a porous semiconductor by electrochemical etching, comprising the steps of:
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a) implanting ions in selected regions of a semiconductor to selectively create crystal defects and thereby reduce the threshold potential at which pore formation occurs during an electrochemical etch in said selected regions; and
b) carrying out an electrochemical etch in dark conditions on said semiconductor at an anodic potential that is stepped in value at intervals over a range lying between said reduced threshold potential for said selected regions and the threshold potential for untreated regions to selectively form pores in said selected regions.
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Specification