Effects of the surface condition of the substrates on the electrical characteristics of 4H-SiC MOSFETs

Oshima, Takeshi; Onoda, Shinobu; Kamada, Toru*; Hotta, Kazutoshi*; Kawata, Kenji*; Eryu, Osamu*

Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) were fabricated on p-type epitaxial 4H-SiC substrates with different surface conditions. These electrical characteristics were compared from a point of view of the surface condition. The MOSFETs on Chemical Mechanical Polished substrates showed the drain current of the order of 10 A at a gate voltage of zero. The drain current increased with increasing the surface roughness of substrates. With decreasing the surface roughness of substrates, the values of the threshold voltage decreased and the quality of gate oxide became better.