Silicon carbide power device having protective diode
First Claim
1. 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.
1 Assignment
0 Petitions
Accused Products
Abstract
A silicon carbide power device includes a junction field effect transistor and a protective diode, which is a Zener or PN junction diode. The PN junction of the protective diode has a breakdown voltage lower than the PN junction of the transistor. Another silicon carbide power device includes a protective diode, which is a Schottky diode. The Schottky diode has a breakdown voltage lower than the PN junction of the transistor by adjusting Schottky barrier height or the depletion layer formed in the semiconductor included in the Schottky diode. Another silicon carbide power device includes three protective diodes, which are Zener diodes. Two of the protective diodes are used to clamp the voltages applied to the gate and the drain of the transistor due to surge energy and used to release the surge energy. The last diode is a thermo-sensitive diode, with which the temperature of the JFET is measured.
-
Citations
20 Claims
-
1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification