Effects of Cl_2-Based Inductively Coupled Plasma Etching of AIGaN on Interface Properties of Al_2O_3/AIGaN/GaN Heterostructures

摘要

The effects of the inductively coupled plasma (ICP) etching of AIGaN on the interface properties of the Al_2O_3/AIGaN/GaN structures prepared by atomic layer deposition were investigated. It was found from the photoassisted capacitance-voltage (C-V) results that the ICP etching of the AIGaN surface significantly increased the interface state density up to 8 × 10~(12) cm~(-2) eV~(-1) at the Al_2O_3/AIGaN interface. The transmission electron microscopy and X-ray photoelectron spectroscopy analyses indicated that the monolayer-level roughness, disorder of the chemical bonds at the AIGaN surface caused poor C-V characteristics due to high-density interface states at the Al_2O_3/ICP-etched AGaN interface.