Novel SiC Power Devices utilizing a Si/4H-SiC Heterojunction

Abstract

We have developed novel SIC devices, both a diode and a transistor, utilizing a Si/4H-SiC heteroj unction. A heterojunction diode (HJD) was fabricated with P+ polycrystalline silicon on an N- epitaxial layer of 4H-SiC. The HJD achieved lower Von and higher reverse blocking voltage than a commercial Schottky barrier diode (SBD) of SiC. Switching charcteristics of the HJD indicated almost zero reverse recovery similar to that of a SBD. A hetero junction tunneling transistor (HETT) was driven by an insulated gate electrode. The width of the heterojunction barrier was controlled by the gate bias to allow tunneling current to flow. The HETT was fabricated with N+ polycrystalline silicon on an N- 4H-SiC epitaxial layer. The channnel length of the HETT was almost zero and was expected to have low on-resistance.