Low-pressure chemical vapour deposition of silicon and germanium on silicon using contamination-minimized processing

Low-pressure Si and Ge chemical vapour deposition (CVD) was investigated using contamination-minimized processing. A drastic decrease of Si epitaxial temperature compared with conventional CVD was obtained due to the reduction of native oxide by clean reactive gases. It was also found that Si CVD can be partly selective on Si/SiO₂ during a certain incubation period using only SiH₄ and H₂ gases, without addition of HCl. For Ge CVD, perfect selectivity and epitaxy on Si was obtained at low temperatures such as 400°C. The via-hole filling behaviour of Ge shows that there are two epitaxial growth mechanisms; step flow and dangling-bond dominated growth.