Patent ID: 9257550
Filing Date: 2016-02-09
CPC Classification: H01L

Claim Text:
1. A method for making a semiconductor device comprising: providing a first semiconductor layer having a first bandgap; forming a second semiconductor layer over the first semiconductor layer and having a second bandgap that is wider than the first bandgap, the second semiconductor layer comprising in stacked relation a first buffer semiconductor layer having a first thickness, a second buffer semiconductor layer having the first thickness, and a drift semiconductor layer having a second thickness; forming a third semiconductor layer over the second semiconductor layer and having the first bandgap; forming a trench in the third semiconductor layer defining first and second opposing walls; forming a P+ type first semiconductor region spaced from the first wall and extending from a bottom surface of the third semiconductor layer into the second semiconductor layer a first depth; and forming a P+ type second semiconductor region spaced from the second wall and extending from the bottom surface of the third semiconductor layer into the second semiconductor layer the first depth.