Patent ID: 7750438
Filing Date: 2010-07-06
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first conductivity type drift region; a first conductivity type emitter region formed on one side of said drift region; a second conductivity type base region arranged between said drift region and said emitter region; a gate electrode layer arranged to be electrically isolated from and opposed to said base region held between said drift region and said emitter region; a second conductivity type collector region formed on another side of said drift region; and a first conductivity type buffer region arranged between said drift region and said collector region with a higher impurity concentration than that of said drift region, wherein the ratio (D (where ∈ S represents the dielectric constant of silicon, ∈ 0 represents the dielectric constant of a vacuum, q represents the charge quantity of electrons, Nd represents the impurity concentration of said drift region and V represents the avalanche voltage) and the thickness WTB of said drift region held between said base region and said buffer region.