Patent ID: 9224730
Filing Date: 2015-12-29
Classification: H01L

Abstract:
1. A semiconductor device including a cell region and a peripheral region, the cell region having a freewheeling diode and a vertical insulated gate bipolar transistor surrounded by the freewheeling diode, the peripheral region having a peripheral dielectric-strength structure that surrounds the cell region, the semiconductor device comprising: a first conductivity type drift layer; a second conductivity type collector region located on a back side of the drift layer in the cell region and peripheral region; a first conductivity type cathode region located on the back side of the drift layer in the cell region at a position where the collector region is not located; a second conductivity type base region located in a superficial part of a front side of the drift layer in the cell region at positions where the insulated gate bipolar transistor and the freewheeling diode are located; a first conductivity type emitter region located in a superficial part of the base region; a gate insulating film located on a surface of the base region between the emitter region and the drift layer; a gate electrode located on the gate insulating film; a second conductivity type deep well layer located in the superficial part of the front side of the drift layer in the cell region at the position where the freewheeling diode is located, the deep well layer located to surround a periphery of the base region and connected to the base region, the deep well layer being deeper than the base region and having an impurity concentration greater than that of the base region; an upper electrode electrically connected to the emitter region, the base region, and the deep well layer; and a lower electrode electrically connected to the collector region and the cathode region, wherein the emitter region is not formed in at least one region between a plurality of gate structures to define a first region and a second region, the emitter region is formed in the first region so that the first region acts as the insulated gate bipolar transistor, the emitter region is not formed in the second region so that the second region acts as the freewheeling diode, a portion located to surround the insulated gate bipolar transistor is defined as a third region acting as the freewheeling diode, each of the first region and the second region has a longitudinal direction in a planar surface of the drift layer parallel to the longitudinal direction in the planar surface of the drift layer of the plurality of gate structures and, the first region is divided in the longitudinal direction into multiple regions, the second region is located adjacent to the first region, W denotes a distance between the multiple regions L1 denotes a thickness of the drift layer, k1 denotes a parameter that depends on structures of the insulated gate bipolar transistor and the freewheeling diode, and K denotes a value calculated by multiplying the parameter k1 by a ratio of a snapback voltage to a built-in potential between the deep well layer and the drift layer.