Patent ID: 6855981

Claim:
A silicon carbide power device comprising: a silicon carbide power transistor including a normally-off junction field effect transistor, both gates of which are voltage controlled; a protective diode, which prevents the silicon carbide power transistor from being destroyed and protects a circuit that controls a gate of the transistor; a substrate, which is substantially made of SiC and has a first conduction type; a drift layer, which is substantially made of SiC and has the first conduction type; a first JFET impurity layer, which is substantially made of SiC and has a second conduction type; and a source layer, which is substantially made of SiC and has the first conduction type, wherein the drift layer has an impurity concentration lower than those of the substrate and the source layer, wherein the drift layer, the first JFET impurity layer, and the source layer are sequentially layered in this order on a surface of the substrate, and wherein the junction field effect transistor includes: a part of the substrate; a part of the drift layer; a part of the first JFET impurity layer; a part of the source layer, wherein a trench extends from a surface of the part of the source layer to the part of the drift layer through the part of the first JFET impurity layer; a channel layer, which is substantially made of SiC, has the first conduction type, and is located on a surface defining the trench; and a second JFET impurity layer, which is substantially made of SiC, has the second conduction type, and located on the channel layer.