Direct determination of surface stress during Bi-mediated Ge growth on Si

Asaoka, Hidehito  ; Yamazaki, Tatsuya; Filimonov, S.*; Shamoto, Shinichi  

We report stress evolutions during Bi adsorption on Si(111) 77 and initial stages of Bi-mediated Ge growth on Si(111). Surface stress is determined by using a real-time measurement of the substrate curvature. We find a difference in the surface stress between clean Si(111) 77 surface and Si(111) surface covered with one monolayer of Bi, and an increase in the surface stress accompanied by RHEED intensity oscillation of the specular beam during ideal pseudomorphic Ge layer growth with Bi. For Ge coverage of up to 2 bilayers, the stress evolution shows a clear stress relaxation due to formation of trenches on the Ge surface and injection of misfit dislocations into the Ge/Si interface.