We investigated a high electron mobility Ge FinFET fabricated by defect-free and roughness-free atomic layer neutral beam etching (NBE) compared with one fabricated by conventional plasma etching (PE). The etching interface roughness and defect were estimated by high-resolution transmission electron microscopy (TEM). In the case of using atomic layer defect-free NBE, the root-mean-square roughness of the Ge Fin sidewall surface is 1/3 times smaller than that using PE. Then, the electron mobility of Ge FinFET was improved by 1.65 times compared with that of a PE etched FinFET sample. For the subthreshold swing, the defect density of the interface between the Ge and gate dielectric film was improved by NBE. Ioff average currents of NBE and PE were around 18.1 and 57.6 nA/μm, respectively. As a result, NBE reduces the off-leakage current to 1/3 times less than PE. This corresponded to the differences in surface roughness and defect generation between NBE and PE. Therefore, we found that NBE could achieve a good performance by defect-free and atomically-flat etching the surface.

中文翻译：

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通过原子层无缺陷和无粗糙度蚀刻制造的高电子迁移率FinFET

我们研究了通过无缺陷和无粗糙度的原子层中性束刻蚀（NBE）与通过常规等离子刻蚀（PE）制备的高电子迁移率Ge FinFET。蚀刻界面的粗糙度和缺陷通过高分辨率透射电子显微镜（TEM）估算。在使用无原子层无缺陷的NBE的情况下，Ge Fin侧壁表面的均方根粗糙度是使用PE的1/3倍。然后，与PE蚀刻的FinFET样品相比，Ge FinFET的电子迁移率提高了1.65倍。对于亚阈值摆幅，通过NBE改善了Ge和栅极介电膜之间界面的缺陷密度。NBE和PE的Ioff平均电流分别约为18.1和57.6 nA /μm。因此，NBE将截止泄漏电流降低到PE的1/3倍。这对应于NBE和PE之间的表面粗糙度和缺陷产生的差异。因此，我们发现NBE可以通过无缺陷和原子平面蚀刻表面获得良好的性能。