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US 2013/0240905 A1Published application
Silicon Carbide Rectifier
AssigneeThe Government of the United States of America, as represented by the Secretary of the Navy
InventorsKarl D. Hobart, Francis J. Kub, Mario Ancona, Eugene A. Imhoff
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Abstract
Silicon carbide PiN diodes are presented with reduced temperature coefficient crossover points by limited p type contact area to limit hole injection in the n type drift layer in order to provide a lower current at which the diode shifts from negative temperature coefficient to a positive temperature coefficient of forward voltage for mitigating thermal runaway.
Claims31
A rectifier, comprising:
- an n type drift layer disposed over an n type silicon carbide substrate, the n type drift layer having a dopant concentration less than a dopant concentration of the n type silicon carbide substrate;
- a p type anode layer disposed on the n type drift layer and having an upper surface;
- a plurality of p type anode contact structures disposed on the upper surface of the p type anode layer, individual p type anode contact structure being laterally spaced from one another and having a higher dopant concentration than the p type anode layer, the plurality of p type anode contact structures having a total upper surface area less than a surface area of the upper surface of the p type anode layer;
- a plurality of electrical contacts individually disposed along an upper surface of a corresponding one of the p type anode contact structures;
- an anode metal layer connected to upper surfaces of the plurality of electrical contacts;
- and
- a cathode metal layer connected to a lower surface of the n type silicon carbide substrate.
4 more elements
A rectifier, comprising:
- a drift layer disposed over a silicon carbide substrate, the drift layer having a dopant concentration of a first conductivity type less than a dopant concentration of the first conductivity type of the silicon carbide substrate;
- an anode layer of a second conductivity type disposed on the drift layer and having an upper surface;
- a plurality of anode contact structures of the second conductivity type disposed on the upper surface of the anode layer, individual anode contact structures being laterally spaced from one another and having a higher dopant concentration than the anode layer, the plurality of anode contact structures having a total upper surface area less than a surface area of the upper surface of the anode layer;
- a plurality of electrical contacts individually disposed along an upper surface of a corresponding one of the anode contact structures;
- an anode metal layer connected to upper surfaces of the plurality of electrical contacts;
- and
- a cathode metal layer connected to a lower surface of the n type silicon carbide substrate.
4 more elements
A rectifier, comprising:
- a semiconductor substrate;
- a first layer disposed over the semiconductor substrate, the first layer having a dopant concentration of a first conductivity type less than a dopant concentration of the first conductivity type of the semiconductor substrate;
- an anode layer of a second conductivity type disposed on the first layer and having an upper surface;
- an anode contact structure of the second conductivity type disposed on the upper surface of the anode layer, the anode contact structure having a higher dopant concentration than the anode layer, the anode contact structure having a total upper surface area less than a surface area of the upper surface of the anode layer;
- an electrical contact disposed along an upper surface of the anode contact structure;
- an anode metal layer connected to an upper surface of the electrical contact;
- and
- a cathode metal layer connected to a lower surface of the n type silicon carbide substrate.
5 more elements
A method of making a rectifier, comprising:
- providing a semiconductor substrate;
- disposing a first layer over the semiconductor substrate;
- ensuring the first layer has a dopant concentration of a first conductivity type less than a dopant concentration of the first conductivity type of the semiconductor substrate;
- disposing an anode layer of a second conductivity type having an upper surface on the first layer;
- disposing an anode contact structure of the second conductivity type on the upper surface of the anode layer;
- ensuring the anode contact structure has a higher dopant concentration than the anode layer and the anode contact structure has a total upper surface area less than a surface area of the upper surface of the anode layer;
- disposing an electrical contact along an upper surface of the anode contact structure;
- connecting an anode metal layer to an upper surface of the electrical contact;
- and
- connecting a cathode metal layer to a lower surface of the n type silicon carbide substrate.
7 more elements
Dependencies are inferred from the claim text.