ICP etching of high Al concentration AlGaN

The etching effect on the surface and electrical characteristics of high Al mole fraction Al_xGa_1-xN (x=0.65) was characterized by X-ray photoelectron spectroscopy(XPS) and transfer length method (TLM). The measured inductively coupled plasma (ICP) etching rates increased with the increasing RF power. XPS results show the Ga3d and Al2p peaks moved to lower energy after ICP etchings. And the integrated intensities of O1s peaks show a reduced oxygen concentration for the etched material comparing the unetched sample, while the oxide slightly increased with the increasing RF power. The extracted sheet resistance of the layer from TLM increases gradually after ICP etching, from approximately 1278Omega/square to 3205Omega/square with the increasing RF power. The possible etch defect is N deficiency and its damage to the performance of devices has been discussed.