Abstract
ABSTRACTInvestigation of Interfacial Strains in Si0.8Ge0.2/SiUsing Three-Beam Bragg-Surface DiffractionYong-Cheng Wei, Advisor : Professor Shih-Lin ChangMaster of Physics,National Tsing Hua University, Hsinchu, TaiwanIn the manufacturing processes of semiconductor, interface strains play an important role in changing the device characteristics. Most importantly, strain is used to improve the device performance and yet broaden their applications. Therefore, here we focus on interfacial strains in Si0.8Ge0.2/Si using three-beam Bragg-surface diffraction(BSD).This experiment was carried out in the National Synchrotron Radiation Research Center at BL17B1 beam line. The energy of incident X-rays used is 12KeV. First, we study the crystalline quality of Si0.8Ge0.2/Si samples using grazing incidence X-ray diffraction and Bragg’s diffraction. Afterwards, we measure the interfacial strains of Si0.8Ge0.2/Si using three-beam Bragg-surface diffraction(BSD). By slightly changing the azimuth angle ?±?0.02?^° of the selected second-order surface diffraction, variation of interfacial strains are obtained.The sample is a germanium silicide film grown on a silicon substrate, where the SiGe films are about 47.24nm and 75.55nm thick and Si V.S. Ge is 0.8:0.2. It is found that when the germanium silicide film becomes thicker, the interfacial strains along the c-axis increases. In comparison of the previous results Ting-Wei Wu[4], the undulating intensity signals in between SiGe and Si peaks is due to the interference of the surface diffraction at the interface in Three-Beam Bragg-Surface Diffraction experiment.