Schottky rectifier with surge-current ruggedness

1. A Schottky rectifier device, comprising:

a Silicon Carbide (SiC) layer;

a channel region of a first conductivity type formed on the SiC layer;

a metal contact formed on the channel region; and

an active region including an array of unit cells of multi-layer bodies formed within the channel region in parallel with one another and extending from the metal contact in a direction of the SiC layer, and having a period that is less than a length of the channel region between the metal contact and the SiC layer, each of the multi-layer bodies including

a multi-layer body of a second conductivity type, with a first layer adjacent to the metal contact and having a first doping concentration, a second layer adjacent to the first layer and having a second doping concentration less than the first doping concentration, and a third layer adjacent to the second layer and having a third doping concentration less than the second doping concentration.

2. The Schottky rectifier device of claim 1 , wherein the second layer has a doping concentration between 1×10 18 cm −3 and 1×10 19 cm −3 .

3. The Schottky rectifier device of claim 1 , wherein the first layer is degenerately doped and provides a tunnel contact between the metal contact and the second layer.

4. The Schottky rectifier device of claim 1 , wherein each multi-layer body extends at least thirty percent of a distance between the metal contact and the SiC layer.

5. The Schottky rectifier device of claim 1 , wherein the metal contact extends over the active region,

and further comprising

a p-n diode rim that surrounds the active region with a continuous body of the second conductivity type and an array of deep rim bodies of the second conductivity type that are parallel to each multi-layer body.

6. The Schottky rectifier device of claim 5 , wherein the metal contact layer overlaps the active region and at least a portion of the p-n diode rim.

7. The Schottky rectifier device of claim 5 , comprising a junction termination region outside of the p-n diode rim, the junction termination region comprising:

a junction termination (JT) body surrounding the p-n diode rim and connected to a plurality of deep JT bodies extending parallel to each multi-layer body and the deep rim bodies.

8. The Schottky rectifier device of claim 7 , wherein a width of each of the deep JT bodies decreases with distance from the p-n diode rim.

9. The Schottky rectifier device of claim 1 , wherein each multi-layer body extends an entire distance from the metal contact to the SiC layer.

10. A method of making a Schottky rectifier device, the method comprising:

forming a Silicon Carbide (SiC) substrate;

forming an epitaxial layer of a first conductivity type on the SiC substrate;

performing ion implantation of donors of a second conductivity type, to thereby form a posrtion of a charge-balancing body;

repeating the forming of the epitaxial layer and the performing the ion implantation until the charge-balancing body reaches a specified thickness;

forming an injection layer on the charge-balancing body, the injection layer having a doping concentration of the second conductivity type that is higher than a doping concentration of the charge-balancing body;

forming a contact layer on the injection layer; and

forming a metal contact over the contact layer and the epitaxial layer.

11. The method of claim 10 , wherein the contact layer, the injection layer, and the charge-balancing body extend at least thirty percent of a distance from the metal contact to the SiC substrate.

12. The method of claim 10 , wherein the doping contact layer has a doping concentration that is higher than the doping concentration of the injection layer.

13. A Schottky rectifier device, comprising:

a Silicon Carbide (SiC) layer;

a channel region of a first conductivity type formed on the SiC layer;

a metal contact formed on the channel region;

a multi-layer body of a second conductivity type formed within the channel region and extending from the metal contact in a direction of the SiC layer, the multi-layer body including a tunnel contact layer adjacent to the metal contact, an injection layer adjacent to the tunnel contact layer, and a deep layer adjacent to the injection layer;

a p-n diode rim surrounding an active region of the Schottky rectifier device that includes the channel region and the multi-layer body; and

a junction termination region outside of the p-n diode rim, the junction termination region including a junction termination (JT) body surrounding the p-n diode rim and connected to a plurality of deep JT bodies extending parallel to the multi-layer body and the deep rim bodies.

14. The Schottky rectifier device of claim 13 , wherein the multi-layer body extends an entire distance from the metal contact to the SiC layer.

15. The Schottky rectifier device of claim 13 , wherein the metal contact extends over the active region, and

wherein the p-n diode rim that surrounds the active region with a continuous body of the second conductivity type and an array of deep rim bodies of the second conductivity type that are parallel to the multi-layer body.

16. The Schottky rectifier device of claim 13 , comprising a silicide Ohmic contact between the tunnel contact layer and the metal contact.

17. The Schottky rectifier device of claim 13 , wherein the multi-layer body extends at least thirty percent of a distance between the metal contact and the SiC layer.