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

Effects of H + implantation ( ⩽ 5 × 10 16 cm − 2 ) on stress relaxation in an oxidation-induced Ge condensation method have been investigated to form stress-relaxed ultrathin ( ∼ 30 nm ) SiGe-on-insulator (SGOI) virtual substrates. High-dose ( ⩾ 10 15 cm − 2 ) implantation enhanced stress relaxation, which was attributed to bond breaking at the SiGe ∕ buried SiO 2 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.