| 摘要 |
PROBLEM TO BE SOLVED: To prevent large variation arising in channel resistance without making the average value of channel resistance increase substantially, in a semiconductor device such as a vertical type trench MOSFET made from SiC. SOLUTION: There are used a 4H-SiC substrate 31 where the principal surface is composed of ä0001} surfaces in general with off-angleα, and a trench formation device where the standard deviation is set up atσin the variation of the angle settled by the trench side wall surface and the substrate principal surface in the wafer. The designed value of the angle settled by the trench side wall surface and the substrate principal surface in the wafer is set up at any angle within the range of "60°+2σ" or more and "90°-tan<SP>-1</SP>(0.87×tanα)-2σ" or less, and thus, a semiconductor device where the angle settled by the trench side wall surface and the substrate principal surface is set up within 60°or more and "90°-tan<SP>-1</SP>(0.87×tanα)" or less is obtained by forming a trench 38 in a SiC substrate 31. COPYRIGHT: (C)2007,JPO&INPIT
|
