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 Al2O3/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 8×1012 cm-2 eV-1 at the Al2O3/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 Al2O3/ICP-etched AGaN interface.

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