Basic research for development of electronics devices with strain-Si

针对目前的高分辨率卢瑟福后向散射光谱（HRBS）系统，研制了新的测角仪和负载锁定室。利用改进的HRBS系统进行通道角扫描，并将扫描结果与通道离子轨迹模拟结果进行对比，测量了离子注入后应变si试样和离子注入后退火后应变si试样在SiGe层上生长的应变。结果表明，退火后的应变恢复了。将锗外延生长在菌株si的清洁（001）表面，并利用HRBS原位观察生长过程。通过原位HRBS观察，研究了应变对Si（001）初始氧化过程的影响。结果表明，与普通Si相比，Ge与应变-Si之间的相互扩散增强。在室温（RT）和640℃下，应变Si的饱和氧覆盖率与普通Si相同。在RT下更详细的观察发现，在12 L的氧暴露下没有差异，但在30 L时，应变- si的氧覆盖面积更大。这一结果与第一性原理计算表明，应变对氧化的影响取决于氧的吸附位置。

New goniometers and load lock chambers were developed for the present high-resolution Rutherford backscattering spectroscopy (HRBS) system. By performing the channeling angular scan with the improved HRBS system and comparing the result with a trajectory simulation of channeling ions, the strain in the strain-Si grown on a SiGe layer was measured for both ion-implanted strain-Si samples and strain-Si samples annealed after ion implantation. It was found that the strain was recovered after annealing.Germanium was epitaxially grown on a clean (001) surface of strain-Si and the growth process was observed in situ with HRBS. For comparison a similar measurement was done with normal Si It was hind that the interdiffusion between Ge and strain-Si is enhanced as compared with the normal Si The effect of strain on the initial oxidation process of Si(001) was also studied by in-situ HRBS observation. The saturation oxygen coverage on the strain-Si was hind to be the same as the normal Si at room temperature (RT) as well as at 640℃. More detailed observation at RT revealed that there is no difference at the oxygen exposure of 12 L but oxygen coverage for the strain-Si is larger at 30 L. This result together with the first principles calculation suggests that the effect of the strain on the oxidation depends on the adsorption site for oxygen.