Patent ID: 9178016
Filing Date: 2015-11-03
Classification: H01L

Abstract:
1. A semiconductor device, comprising: a III-nitride semiconductor substrate having a two-dimensional charge carrier gas at a depth from a main surface of the III-nitride semiconductor substrate; a surface protection layer on the main surface of the III-nitride semiconductor substrate, the surface protection layer having charge traps in a band gap which exist at room temperature operation of the semiconductor device; a contact in electrical connection with the two-dimensional charge carrier gas in the III-nitride semiconductor substrate; and a charge protection layer on the surface protection layer, the charge protection layer comprising an oxide and shielding the surface protection layer under the charge protection layer from radiation with higher energy than the bandgap energy of silicon nitride, wherein the charge protection layer has a stepwise or continuously-graded composition of oxygen and corresponding graded band gap energy, wherein the composition of oxygen decreases in the charge protection layer heading toward the III-nitride semiconductor substrate in a direction perpendicular to the main surface of the III-nitride semiconductor substrate.