Tunable semiconductor diodes
AssigneeInternational Business Machines Corporation
InventorSteven H. Voldman
Life of this patent
Estimating the term…
Abstract
A diode structure that facilitates tuning the breakdown voltage of the diode structure, and a method for forming and operating the diode structure. In a P− substrate, a 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 implanted in the substrate. 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.
Claims20
A diode structure, comprising:
- a substrate layer comprising a semiconductor material and first doping impurities with a first doping polarity;
- 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 doping impurities with a second doping polarity, the second doping polarity being opposite to the first doping polarity;
- 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 doping impurities with 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
- 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 of the diode structure, 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.
A method for forming a diode structure, the method comprising the steps of:
- providing a substrate comprising a semiconductor material and first doping impurities with a first charge polarity;
- implanting in the substrate second doping impurities with a second charge polarity to form a first layer with an opening, the opening comprising the semiconductor material and not comprising the second doping impurities;
- implanting in the substrate third doping impurities with the second charge polarity to form a second layer on top of and in direct physical contact with the first layer, the first layer having a higher doping concentration than the second layer;
- and
- forming en electrode structure on top of and in direct physical contact with the second layer, the electrode structure including at least an anode and a cathode.
A diode structure, comprising:
- a substrate layer comprising a semiconductor material;
- 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 first doping impurities with a first doping polarity;
- a second layer being on top of the first layer, the second layer comprising the semiconductor material and second doping impurities with the first doping polarity, wherein the second layer is in direct physical contact with the substrate layer through the opening of the first layer;
- and
- 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 of the diode structure, 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.
Dependencies are inferred from the claim text.