Strain in GaN／Si〈111〉by RBS／Channeling

GaN film grown on Si substrate was characterized by Rutherford backscattering /Channeling(RBS/C).The experimental results show that the thickness of GaN epilayer is about 2.5μm and the GaN film has a good crystalline quality (Xmin=3.3%).By using channeling angular scanning,the 0.35% of average tetragonal distortion in GaN layer is observed.I addition,the depth profiles of strain in GaN film layer reveal that the strain in GaN film nonlinearly decreases with the increase of film thickness,The strain-free thickness(above 2.5μm) of GaN film on Si substrate is far below that(150μm) of GaN film on Sapphire.     

The property of Si/SiGe/Si heterostructure during thermal budget characterized by HRXRD

Si/SiGe/Si heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD) were characterized by Rutherford backscattering/Channeling (RBS/C) together with high resolution X ray diffraction (HRXRD). High quality SiGe base layer was obtained. The Si/SiGe/Si heterostructures were subject to conventional furnace annealing and rapid thermal annealing with temperature between 750℃ and 910℃. Both strain and its relaxation degree in SiGe layer are calculated by HRXRD combined with elastic theory, which are never reported in other literatures. The rapid thermal annealing at elevated temperature between 880℃ and 910℃ for very short time had almost no influence on the strain in Si0.84Ge0.16 epilayer. However, high temperature (900℃@) furnace annealing for 1h prompted the strain in Si0.84Ge0.16 layer to relax.