Patent ID: 8896025
Filing Date: 2014-11-25
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor device comprising: forming a recess to an AlGaN layer by etching, the AlGaN layer having an Al composition ratio of 0.2 or greater, the recess having a bottom having an RMS roughness less than 0.3 nm; forming a first Ta layer having a thickness of 4 nm to 8 nm on the bottom of the recess; and annealing the first Ta layer to make an ohmic contact in the AlGaN layer, wherein the etching is performed by plasma etching using an etching gas that is one of a mixed gas of boron chloride gas and chlorine gas, a mixed gas of boron chloride gas, silicon chloride gas and chloride gas, and a mixed gas of silicon chloride gas and chlorine gas.