Nitride semiconductor device comprising bonded substrate and fabrication method of the same

Abstract

A substratefor growing nitride semiconductor has a first and second face and has a thermal expansion coefficient that is larger than that of the nitride semiconductor. At least n-type nitride semiconductor layersto, an active layerand p-type nitride semiconductor layerstoare laminated to form a stack of nitride semiconductor on the first face of the substrate. A first bonding layer including more than one metal layer is formed on the p-type nitride semiconductor layer. A supporting substrate having a first and second face has a thermal expansion coefficient that is larger than that of the nitride semiconductor and is equal or smaller than that of the substratefor growing nitride semiconductor. A second bonding layer including more than one metal layer is formed on the first face of the supporting substrate. The first bonding layerand the second bonding layerare faced with each other and, then, pressed with heat to bond together. After that, the substratefor growing nitride semiconductor is removed from the stack of nitride semiconductor so that a nitride semiconductor device is provided.