Increasing the thickness of the SiO 2 dielectric layer used to electrically isolate AlGaN/GaN high-electron-mobility transistors led to a gradual increase in the sheet carrier density of the two-dimensional electron gas (2DEG) at the AlGaN/GaN interface. An increase of approximately 33% in sheet carrier density was observed after depositing 125 nm of SiO 2 by plasma-enhanced chemical vapor deposition. The observed dependency of the sheet carrier density in 2DEG on SiO 2 thickness was attributed to strain accumulation to AlGaN and improved surface passivation effect, based on analyses by Raman spectroscopy and dielectric capacitance measurement.

中文翻译：

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SiO 2钝化对在AlGaN / GaN界面中形成的二维电子气的薄层载流子密度的影响

用于电隔离AlGaN / GaN高电子迁移率晶体管的SiO 2介电层的厚度增加导致在AlGaN / GaN界面处的二维电子气（2DEG）的薄层载流子密度逐渐增加。通过等离子体增强化学气相沉积沉积125 nm的SiO 2之后，观察到片状载体密度增加了约33％。基于拉曼光谱和介电电容测量的分析，观察到的2DEG中薄层载流子密度对SiO 2厚度的依赖性归因于AlGaN的应变积累和改善的表面钝化效果。