Open AccessLocal atomic structure analysis of GaN surfaces via X‐ray absorption spectroscopy by detecting Auger electrons with low energies
Author(s) -
Isomura Noritake,
Kikuta Daigo,
Takahashi Naoko,
Kosaka Satoru,
Kataoka Keita
Publication year - 2019
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577519012827
Subject(s) - extended x ray absorption fine structure , auger effect , auger electron spectroscopy , auger , materials science , atomic physics , electron , absorption (acoustics) , semiconductor , spectroscopy , surface extended x ray absorption fine structure , analytical chemistry (journal) , absorption spectroscopy , molecular physics , optoelectronics , chemistry , optics , physics , quantum mechanics , chromatography , nuclear physics , composite material
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.