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

サーファクタントを利用したGe/Si成長過程におけるストレス測定

朝岡 秀人  ; 山崎 竜也*; 山口 憲司; 社本 真一  ; Filimonov, S.*; 末光 眞希*

Asaoka, Hidehito; Yamazaki, Tatsuya*; Yamaguchi, Kenji; Shamoto, Shinichi; Filimonov, S.*; Suemitsu, Maki*

Biサーファクタントを利用したGe/Si(111)ヘテロ成長過程において、レーザーによる基板のたわみを実測したストレス遷移と、電子線を利用したRHEEDの同時測定を行った。その結果、Bi終端構造と比較したSi再構成構造に内在する表面ストレス,層状成長過程で、原子層1層ごとに圧縮,緩和を繰り返すストレス遷移を捉えることに成功した。

We have focused on stress measurements during Bi termination of Si(111) and Ge growth on this Bi-mediated Si(111). In order to obtain information on both the surface stress and the surface structure simultaneously, we have combined the surface-curvature and the reflection-high-electron-energy-diffraction instrumentations in an identical ultrahigh vacuum system. We find the Bi-terminated Si(111) - surface releases 1.8 N/m (=J/m), or (1.4 eV/(11 unit cell)), of the surface energy from the strong tensile Si(111) 77 reconstruction. Subsequent Ge deposition on the Bi-terminated Si surface develops a compressive stress, which oscillates with a period corresponding to the growth of a single bilayer. The real-time stress measurement provides a direct evidence for this oscillatory stress relaxation in the layer-by-layer growth.