| 摘要 |
PROBLEM TO BE SOLVED: To prevent the channel leak of a trench-gate type MOSFET. SOLUTION: First, a source diffusion layer is formed through ion implantation and thermal diffusion. Then, by the RIE, after a trench for a trench gate is formed, sacrificial oxidation and gate one are carried out. At this point, ion implantation for a base diffusion layer has not been carried out yet. Trench gate is formed by the formation and etchback of a polysilicon film. Then, an interlayer insulating film is formed, and in addition, the trench is formed in the interlayer insulating film with a resist as a mask. Successively, with the same resist as the mask, ion implantation is carried out, and furthermore, the base diffusion layer is formed by thermal diffusion. Then, a trench contact is formed, and a base contact layer is formed.
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