Patent ID: 7244974
Filing Date: 2007-07-17
Classification: H01L

Abstract:
1. A power semiconductor device comprising: a first semiconductor layer having a band gap of 3 eV or more; a second semiconductor layer of a first conductivity type formed on the first semiconductor layer, the second semiconductor layer having a band gap of 3 eV or more; first and second main electrodes formed on the second semiconductor layer separately from each other; a control electrode formed on the second semiconductor layer between the first main electrode and the second main electrode; and a third semiconductor layer formed on the second semiconductor layer between the control electrode and the second main electrode, the third semiconductor layer having a band gap of 3 eV or more, a fourth semiconductor layer of a second conductivity type formed on the third semiconductor layer, the fourth semiconductor layer having a band gap of 3 eV or more; and a field plate electrode formed on the fourth semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer form a heterojunction, the second semiconductor layer has a band gap that is wider than that of the first semiconductor layer, the third semiconductor layer has a band gap that varies in a depth direction thereof, and the third semiconductor layer has a band gap that is wider than that of the fourth semiconductor layer.