Oxygen profile engineering in silicon by germanium addition and high-temperature annealing

The formation of multilayer structures in oxygen-implanted silicon by the introduction of germanium is reported. Our results show that the oxygen distribution can be split under carefully controlled annealing conditions. The typical annealing process consists of first raising the furnace temperature from 600 to 1200 °C within 30 min and then holding the temperature at 1200 °C for 2 h. The faster crystallization rate of amorphous silicon germanium (SiGe) and germanium rejection from the oxide contribute to the final multilayer structure. Our findings suggest that oxygen profile engineering is possible and single-energy ion implantation can be utilized to fabricate multilayer structures containing multiple buried oxide layers. In addition, our results suggest that, in SiGe-on-insulator fabrication, the annealing step at a moderate temperature or a slow temperature ramp-up rate during the high-temperature annealing step is much more critical than in conventional silicon-on-insulator fabrication.