Semiconductor device

摘要

A trench gate MOS structure is provided on one main surface of a semiconductor substrate which will be an n− drift region. An n shell region is provided in the n− drift region so that it contacts a surface of a p base region close to the n− drift region forming the trench gate MOS structure. The n shell region has a higher impurity concentration than the n− drift region. The effective dose of n-type impurities in the n shell region is equal to or less than 5.0×1012 cm−2. The n− drift region has a resistivity to prevent a depletion layer, which is spread from a p collector region on the other main surface when reverse rated voltage is applied with an emitter as positive electrode, from reaching either n shell region or the bottom of a first trench, whichever is closer to the p collector region.

主权项

1. A semiconductor device comprising:
a drift region that is a semiconductor substrate of a first conductivity type; a base region of a second conductivity type that is selectively provided in a surface layer of a first main surface of the semiconductor substrate; an emitter region of the first conductivity type that is selectively provided in the base region; a trench that extends from the first main surface of the semiconductor substrate to the drift region through the emitter region and the base region; an insulating film that is provided along an inner wall of the trench; a gate electrode that is embedded in the trench through the insulating film; an emitter electrode that comes into contact with the emitter region and the base region; a shell region of the first conductivity type that is provided in the drift region so as to come into contact with a surface of the base region close to the drift region; and a collector region of the second conductivity type that is provided in a surface layer of a second main surface of the semiconductor substrate, wherein: the shell region has a higher impurity concentration than the drift region, an effective dose of a first-conductivity-type impurity in the shell region is equal to or less than 5.0×1012 cm−2, and the drift region has a resistivity to prevent a depletion layer, which is spread from the collector region when a reverse rated voltage with the emitter electrode as a positive electrode is applied, from reaching either the shell region or the bottom of the trench, whichever is closer to the collector region than the other.