Patent ID: 7525133
Filing Date: 2009-04-28
Classification: H01L

Abstract:
1. A semiconductor device, comprising: a first semiconductor layer of a first conduction type; a second semiconductor layer of the first conduction type formed on a surface of said first semiconductor layer; a semiconductor base layer of a second conduction type formed on said second semiconductor layer; a semiconductor diffusion layer of the first conduction type formed on a surface of said semiconductor base layer; a trench formed from a surface of said semiconductor diffusion layer to a depth reaching said second semiconductor layer; a gate electrode formed of a conductor film buried in said trench with a gate insulator interposed therebetween; a first main electrode brought into contact with said semiconductor diffusion layer and said semiconductor base layer; and a second main electrode formed on a rear surface of said first semiconductor layer, wherein said conductor film includes a first conductor film formed along an inner wall of said trench covering the trench at its bottom and side to have a recess inside said trench, the recess formed to reach the second semiconductor layer, and a second conductor film formed to fill said recess, said first and second conductor films being composed of the same material but being different in crystal grain.