Low threading-dislocation-density Ge film on Si grown on a pitting Ge buffer layer

A Ge layer with a pitting surface can be obtained when the growth temperature is lowered to 290degC. On the low temperature Ge buffer layer with pits, high quality Ge layer was grown at 600degC with a threading dislocation density of ~1times10⁵cm^-2. According to channeling and random Rutherford backscattering spectrometry spectra, a chi_min value of 10% and 3.9% was found, respectively, at the Ge/Si interface and immediately under the surface peak. The root-mean-square surface roughness of Ge film was 0.33 nm.