Effects of Cl2-Based Inductively Coupled Plasma Etching of AlGaN on Interface Properties of Al2O3/AlGaN/GaN Heterostructures

The effects of the inductively coupled plasma (ICP) etching of AlGaN on the interface properties of the Al 2 O 3 /AlGaN/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 AlGaN surface significantly increased the interface state density up to 8×10 12 cm -2 eV -1 at the Al 2 O 3 /AlGaN interface. The transmission electron microscopy and X-ray photoelectron spectroscopy analyses indicated that the monolayer-level roughness, disorder of the chemical bonds at the AlGaN surface caused poor C – V characteristics due to high-density interface states at the Al 2 O 3 /ICP-etched AGaN interface.