Ultrasmooth epitaxial Ge grown on (001) Si utilizing a thin B-doped SiGe buffer layer

摘要

With the introduction of an intermediate ultrathin B-doped Si_(0.70)Ge_(0.30) buffer layer, an epitaxial Ge layer with a surface root-mean-square roughness of 0.43 nm and a threading dislocation density of 3.5 × 10~6cm~(-2) has been directly grown on Si using a reduced-pressure chemical vapor deposition system. The obtained micro-Raman spectra show the uniform distribution of tensile strain in the Ge layer at room temperature. Furthermore, the effect of the ultrathin low-temperature B-doped Si_(0.70)Ge_(0.30) buffer layer on the quality of the Ge epilayer is investigated. Our research reveals that the increase in the B concentration in the buried Si_(0.70)Ge_(0.30) buffer layer significantly improves the quality of the Ge epilayer.