To provide a semiconductor device and a manufacturing method thereof which is excellent in its on-voltage and switching characteristics whereby the generation of its anode shorting state is prevented.
The semiconductor device has a second conductivity type drain layer, a first conductivity type buffer layer formed on the second conductivity type drain layer, a first conductivity type higher-resistance layer formed on the first conductivity type buffer layer, each second conductivity type base layer formed on the surface of the first conductivity type high-resistance layer, each first conductivity type source layer formed on the surface of each second conductivity type base layer, each insulation film formed on the inner wall of each trench reaching the first conductivity type high-resistance layer from the surface of each first conductivity type source layer, each gate electrode formed in the inside of each trench, each source electrode formed on the surfaces of each second conductivity type base layer and each first conductivity type source layer, and a drain electrode formed on the surface of the second conductivity type drain layer. Further, the impurity concentration of the first conductivity type buffer layer is made low relatively in the vicinity of the surface present on the side of the second conductivity type drain layer.
Hidetoshi Tachibana
Yasukazu Sato
Hiroshi Yoshimoto
Yasushi Kawasaki
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