Enhanced stress relaxation in ultrathin SiGe-on-insulator by H+-implantation-assisted oxidation

Abstract

Effects of H+ implantation (⩽5×1016cm−2) on stress relaxation in an oxidation-induced Ge condensation method have been investigated to form stress-relaxed ultrathin (∼30nm) SiGe-on-insulator (SGOI) virtual substrates. High-dose (⩾1015cm−2) implantation enhanced stress relaxation, which was attributed to bond breaking at the SiGe∕buriedSiO2 interface. However, oxidation velocity was also enhanced due to irradiation defects. Two-step annealing (500 °C for 30 min and 850 °C for 60 min) before oxidation was proposed to remove irradiation defects. This achieved enhanced stress relaxation in ultrathin SGOI without changing oxidation velocity.