Patent ID: 7705396

Claim:
A Trench MOSFET, comprising: a semiconductor substrate including a highly-doped drain region of a first conductivity type, a lightly-doped drain region of the first conductivity type, a channel body region of a second conductivity type, and a source region of the first conductivity type; a trench region being formed on the semiconductor substrate; a channel region of a first conductivity type formed on a bottom surface and on first and second side walls of the trench region so as to line an entire surface of the trench region; and a gate electrode provided within the trench region, the highly-doped drain region, the lightly-doped drain region, the channel body region, and the source region being adjacently formed in this order, and the channel region being a SiGe layer whose thickness and doping is adjusted such that it becomes fully depleted if a polarity of a voltage applied to the gate electrode is a first polarity with respect to the source region, and does not become depleted if the polarity is opposite to the first polarity.