Local atomic structure analysis of GaN surfaces via X-ray absorption spectroscopy by detecting Auger electrons with low energies

GaN is a promising material for power semiconductor devices used in next-generation vehicles. Its electrical properties such as carrier mobility and threshold voltage are affected by the interface between the oxide and the semiconductor, and identifying the interface states is important to improve these properties. A surface-sensitive measurement of Ga K-edge extended X-ray absorption fine structure (EXAFS) by detecting Ga LMM Auger electrons that originate from Ga K-shell absorption is proposed for GaN. LMM Auger electrons with low energies were detected and the EXAFS oscillation was confirmed, providing information on the Ga atoms at the surface. Investigation of thermally oxidized GaN with an oxide film of defined thickness showed that the analysis depth was less than 10   nm, which is consistent with the inelastic mean free path of 2.3   nm estimated for LMM Auger electrons in GaN.

Source: Journal of Synchrotron Radiation - October 15, 2019 Category: Physics Authors: Isomura, N. Kikuta, D. Takahashi, N. Kosaka, S. Kataoka, K. Tags: extended X-ray absorption fine structure Auger electron yields surface sensitivity gallium nitride K-shell absorption research papers Source Type: research