Toyota Central R&D Laboratories Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan.
J Synchrotron Radiat. 2019 Nov 1;26(Pt 6):1951-1955. doi: 10.1107/S1600577519012827. Epub 2019 Oct 16.
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.
氮化镓是用于下一代车辆的功率半导体器件有前途的材料。其载流子迁移率和阈值电压等电特性受氧化物和半导体之间的界面影响，因此确定界面态对于改善这些特性很重要。提出了一种通过检测源自 Ga K 壳层吸收的 Ga LMM Auger 电子的 Ga K 边扩展 X 射线吸收精细结构（EXAFS）的表面敏感测量方法，用于 GaN。检测到低能量的 LMM Auger 电子，并确认了 EXAFS 振荡，从而提供了表面处 Ga 原子的信息。对具有定义厚度的氧化层的热氧化 GaN 的研究表明，分析深度小于 10nm，这与 GaN 中 LMM Auger 电子的估计非弹性平均自由程 2.3nm 一致。
