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US 7,732,293 B2Granted
Tunable semiconductor diodes
AssigneeInternational Business Machines Corporation
InventorSteven H. Voldman
Life of this patent
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Abstract
A diode structure fabrication method. In a P− substrate, an N+ layer is implanted. The N+ layer has an opening whose size affects the breakdown voltage of the diode structure. Upon the N+ layer, an N− layer is formed. Then, a P+ region is formed to serve as an anode of the diode structure. An N+ region can be formed on the surface of the substrate to serve as a cathode of the diode structure. By changing the size of the opening in the N+ layer during fabrication, the breakdown voltage of the diode structure can be changed (tuned) to a desired value.
Claims11
A semiconductor fabrication method, comprising:
- providing a semiconductor diode structure, wherein the semiconductor diode structure comprises:
- (a) a substrate layer comprising a semiconductor material and first dopants of a first doping polarity,
- (b) a first layer having an opening, the first layer being on top of and in direct physical contact with the substrate layer, the first layer consisting of only one piece of continuously distributed semiconductor material and second dopants of a second doping polarity, the second doping polarity being opposite to the first doping polarity, and
- (c) a second layer being on top of and in direct physical contact with the first layer, the second layer comprising the semiconductor material and third dopants of the second doping polarity, the first layer having a higher doping concentration than the second layer, wherein the second layer is in direct physical contact with the substrate layer through the opening of the first layer;
- and
- forming an electrode structure being on top of and in direct physical contact with the second layer, the electrode structure including at least an anode and a cathode, wherein both the anode and the cathode are (i) in direct physical contact with the second layer and (ii) not in direct physical contact with the first layer.
3 more elements
Dependencies are inferred from the claim text.