Effects of nitrogen deficiency on electronic properties of AlGaN surfaces subjected to thermal and plasma processes
Effects of nitrogen deficiency on electronic properties of AlGaN surfaces subjected to thermal and plasma processes
复制标题
DOI：
10.1016/j.apsusc.2004.05.091
复制
发表时间：
2004-07-15
影响因子：
6.7
通讯作者：
Hasegawa, H
中科院分区：
文献类型：
--
作者：
Hashizume, T;Hasegawa, H
研究了器件工艺对AlGaN表面化学和电学性质的影响。X射线光电子能谱分析表明，经过高温退火、H2-等离子体清洗、CH 4/H2/Ar等离子体干法刻蚀和SiO2沉积处理后的AlGaN表面出现了严重的化学计量无序和氮缺陷（N缺陷）。这导致在处理的AlGaN表面处的表面态的高密度。此外，N缺陷在AlGaN表面引入了与N空位（V-N）相关的局部深施主能级。这种由V-N相关的深施主和表面态连续体控制的电子态可以导致AlGaN表面处的强费米能级钉扎、AlGaN肖特基界面处的势垒高度和过量漏电流的降低以及AlGaN/GaN异质结构场效应晶体管中的严重漏电流崩溃。发现SiNx或Al 2 O3基钝化方案与远程N-2等离子体处理的组合在抑制AlGaN表面处形成VN相关的表面缺陷方面是有效的。(C)2004 Elsevier B. V.保留所有权利。
Effects of device processing on chemical and electronic properties of AlGaN surfaces were investigated. The X-ray photoelectron spectroscopy analysis showed serious deterioration such as stoichiometry disorder and nitrogen deficiency (N deficiency) at the AlGaN surfaces processed by high-temperature annealing, H-2-plasma cleaning, dry etching in CH4/H-2/Ar plasma and deposition Of SiO2. This resulted in high density of surface states at the processed AlGaN surface. Furthermore, the N deficiency introduced a localized deep donor level related to N vacancy (V-N) at AlGaN surfaces. Such electronic states governed by a V-N-related deep donor and surface state continuum can cause strong Fermi level pinning at the AlGaN surface, reduction of the barrier height and excess leakage currents at the AlGaN Schottky interface and serious drain current collapse in AlGaN/GaN heterostructure field effect transistors. The SiNx- or Al2O3-based passivation scheme with a combination of a remote N-2-plasma treatment was found to be effective in suppressing formation Of VN-related surface defects at AlGaN surfaces. (C) 2004 Elsevier B.V. All rights reserved.