| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device having a trench gate structure, which can relax stress generated in the trench gate structure.SOLUTION: A semiconductor device comprises trenches 3 each of which includes a first trench 3a having an opening on a surface of a base layer 2, and a second trench 3b which communicates with the first trench 3a, has a clearance between opposite side walls longer than a clearance between opposite side walls of the first trench 3a and has a bottom located in a drift layer 1. The opening is covered with a gate electrode 5. The gate electrode 5 includes a cavity 6 inside. With this configuration, even when use environment changes to have a high temperature and stress occurs due to a difference between a linear expansion coefficient of a gate insulation film 4 and a linear expansion coefficient of the gate electrode 5, the cavity can relax the stress. Accordingly, degradation in characteristics and deterioration in reliability of a trench gate structure can be inhibited. |
