Thin relaxed SiGe layer grown on Ar~+ ion implanted Si substrate by ultra-high vacuum chemical vapor deposition

摘要

Thin strain-relaxed Si_(0.81)Ge_(0.19) films (95 nm) on the Ar~+ ion implanted Si substrates with different energies (30 keV, 40 keV and 60 keV) at the same implanted dose (3 x 10~(15) cm~(-2)) were grown by ultra high vacuum chemical vapor deposition (UHVCVD). Rutherford backscattering/ion channeling (RBS/C), Raman spectra as well as atomic force microscopy (AFM) were used to characterize these SiGe films. Investigations by RBS/C demonstrate that these thin Si_(0.81)Ge_(0.19) films were epitaxially grown on the Ar~+ ion implanted Si substrates, although there existed lots of crystal defects. The relaxation extent of Si_(0.81)Ge_(0.19) films on the Ar~+ implanted Si substrates is larger than that in the unimplanted case, which were verified by Raman spectra. Considering the relaxation extent of strain, surface roughness and crystal defects in these SiGe films, the thin relaxed SiGe film on the 30 keV Ar~+ implanted Si substrate is optimal.