Patent ID: 7777249
Filing Date: 2010-08-17
Classification: H01L

Abstract:
1. A semiconductor device comprising: a plurality of MOSFETs each having a channel of a first conductivity type formed in a stripe on the first major surface of a wafer; a buffer layer of a first conductivity type formed on the second major surface of said wafer, wherein highly activated portions and lowly activated portions are alternately formed in a stripe, an impurity concentration of the highly activated portions is the same as an impurity concentration of the lowly activated portions, an activation rate of impurities in the highly activated portions is higher than an activation rate of impurities in the lowly activated portions; a collector layer of a second conductivity type formed on the second major surface side of said wafer than said buffer layer; an emitter electrode formed on the first major surface of said wafer; and a collector electrode formed on the second major surface of said wafer.