| 摘要 |
PROBLEM TO BE SOLVED: To form an element isolation structure by trench isolation, a well region with small variation in depth, and a trench with small variation in depth in a trench gate type semiconductor device. SOLUTION: An element isolation oxide film 3 is formed on an n drift layer 1. The element isolation oxide film 3 is removed such that a region for forming an element isolation structure by trench isolation and a region for forming a trench gate structure remain. A p well region 4 is epitaxially grown on the removed portion to a position lower than the front surface of the element isolation oxide film 3, and then an n<SP>+</SP>source region 5 is epitaxially grown on the p well region 4 to a position higher than the front surface of the element isolation oxide film 3. After planarization of the front surface, the region for forming the trench gate structure of the element isolation oxide film 3 is removed and a trench 9 is formed. The trench 9 is deepend by isotropic etching, and then a gate insulating film 10 and a gate electrode 11 are formed. COPYRIGHT: (C)2005,JPO&NCIPI
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