ABSTRACT - AlGaN/GaN high electron mobility transistors (HEMTs) on Silicon (111) substrates are grown by using multi-stacked strained superlattices layer structures. Atomic force microscopy, X-ray diffraction and cross-sectional transmission electron microscopy are employed to investigate the structural properties of these AlGaN/GaN HEMT structures. The insertion of AlGaN/AlN strained superlattices layer modified with different numbers of GaN layers is revealed to reduce the pit density and threading dislocation density, resulting in the improvement of epilayer quality. The temperature dependent Hall effect measurements show that the two-dimensional electron gas characteristics are greatly improved by the employed modified superlattices layers in AlGaN/GaN HEMT structures throughout the whole measured temperature range. The superlattices layer engineering is shown to be important for achieving higher carrier mobility (>2340 cm2/Vs) and sheet carrier density (>8.22 × 1012 cm−2) at room temperature in AlGaN/GaN HEMTs.

中文翻译：

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采用多层应变层超晶格结构的硅 (111) 衬底上的 AlGaN/GaN 高电子迁移率晶体管的研究

摘要 - 硅 (111) 衬底上的 AlGaN/GaN 高电子迁移率晶体管 (HEMT) 是通过使用多层堆叠应变超晶格层结构生长的。采用原子力显微镜、X 射线衍射和横截面透射电子显微镜来研究这些 AlGaN/GaN HEMT 结构的结构特性。揭示了用不同数量的GaN层改性的AlGaN/AlN应变超晶格层的插入降低了凹坑密度和穿透位错密度，从而提高了外延层质量。温度相关的霍尔效应测量表明，在整个测量温度范围内，在 AlGaN/GaN HEMT 结构中采用改性超晶格层大大改善了二维电子气特性。