Abrupt SiGe and Si Profile Fabrication by Introducing Carbon Delta Layer

High quality and steep Si/Si 0.5 Ge 0.5 /Si profile is fabricated by introducing a C delta layer at the interface using reduced pressure chemical vapor deposition system. The Si 0.5 Ge 0.5 and Si layers are deposited by H 2 -SiH 4 -GeH 4 at 500°C and H 2 -Si 2 H 6 at 500°C to 575°C, respectively. By introducing a C delta layer at the surface, roughening of the Si 0.5 Ge 0.5 surface is maintained at 575°C due to suppressed surface migration of Si and Ge as well as defect injection into the Si 0.5 Ge 0.5 layer resulting in high crystallinity Si cap layer growth. Adsorbed CH 3 species at the surface are preventing the epitaxial Si cap layer growth at 500°C, but it is possible to deposit high quality epitaxial Si at higher temperature because of hydrogen-desorption from adsorbed CH 3 . Interdiffusion of Si and Ge at the interface is observed at 525°C in the case of sample without C delta layers, but the interdiffusion is suppressed even at 575°C by introducing C delta layers.