We have systematically examined electrical characteristics of ultra-thin body (UTB) (111) Ge-on-insulator (GOI) n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs) fabricated by the smart-cut process and have compared their electrical properties with those of (100) ones. The (111) GOI thickness was varied from 29.4 to 7.3 nm. The normal MOSFET operation of a 7.3 nm-thick (111)-oriented GOI nMOSFET has been demonstrated with a reasonable ON/OFF ratio of 10 ⁴ . However, degradation in the effective electron mobility and subthreshold swing (SS) of the (111) GOI nMOSFETs with decreasing the GOI thickness ( $\text{T}_{\mathrm{ GOI}}$ ) was observed. Raman analyses and electrical characteristics of GOI nMOSFET under back-gate operation has suggested that a high interface state density at (111) GOI/buried oxide interfaces as well as low GOI film quality near the back interfaces can be an origin of this degradation of the electrical properties with thin body channels.

中文翻译：

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通过智能切割工艺制造的超薄体 (111) Ge-On-Insulator n 沟道 MOSFET 的电气特性

我们系统地研究了通过智能切割工艺制造的超薄体 (UTB) (111) 绝缘体上锗 (GOI) n 沟道金属氧化物半导体场效应晶体管 (nMOSFET) 的电气特性，并进行了比较它们的电性能与 (100) 相同。(111) GOI 厚度从 29.4 到 7.3 nm 不等。7.3 nm 厚 (111) 取向的 GOI nMOSFET 的正常 MOSFET 操作已被证明具有 10 ⁴的合理开/关比 。然而，随着 GOI 厚度的降低，（111）GOI nMOSFET 的有效电子迁移率和亚阈值摆动（SS）会降低（ $\text{T}_{\mathrm{ GOI}}$ ） 被观测到。背栅操作下 GOI nMOSFET 的拉曼分析和电气特性表明，(111) GOI/掩埋氧化物界面处的高界面态密度以及背界面附近的低 GOI 膜质量可能是造成这种退化的原因。具有薄体通道的电气特性。