Research on functional electronic devices based on straind-Si on SiGe alloy substrates

本研究的目的是在自制的锗成分均匀的硅基衬底上实现具有优异电子性能的应变控制硅基异质结构。首先，我们尝试在现场监测系统的基础上开发一种晶体-熔体界面位置和温度的反馈控制系统。通过对CCD图像的二值化和微分，实现了接口位置的自动识别。利用新开发的系统，我们成功地生长出了成分均匀的SiGe。为了提高晶体质量，我们系统地改变了晶体-熔体界面周围的温度梯度。结果证实了x射线摇摆曲线线宽的系统性减小和强度的增加，这可能是由于抑制了本构过冷。此外，发现晶体质量强烈依赖于种子晶体的取向。在自制的SiGe上，采用分子束外延的方法生长出具有应变锗通道的调制掺杂结构。虽然载流子迁移率没有得到改善，但菌株的可控性得到了证实。

The purpose of this research is to realize strain-controlled Si-based heterostructures with superior electronic properties on homemade SiGe substrates wish uniform Ge composition.Firstly, we tried to develop a feedback control system of the crystal-melt interface position and temperature based on in-situ monitoring system. Automatic recognition of the interface position was successful by binarization and differentiation of the CCD image. By utilizing newly developed system, we succeeded in growing SiGe with uniform composition. To improve the crystal quality, we systematically changed the temperature gradient at around the crystal-melt interface. At a result, systematic decrease of the line-width of the X-ray rocking curve and increase of the intensity were confirmed presumably due to the suppression of constitutional supercooling. In addition, crystal quality was found to be strongly dependent on the orientation of the seed crystal.On homemade SiGe, modulation doped structure with strained-Ge channel was grown by molecular beam epitaxy. Although improved carrier mobility was not achieved, controllability of strain was confiemed.