The effect of doping type and concentration on optical absorption via implantation induced defects in silicon-on-insulator waveguides

The influence of the charge state of ion implantation induced defects in SOI waveguides on the absorption of sub-bandgap wavelengths is described. It is found that waveguides pre-doped with boron absorb with significantly greater efficiency than those pre-doped with phosphorus. Following annealing at 300degC this difference is approximately 8 dBcm^-1, while the intrinsic loss of the waveguides is limited to 2 dBcm^-1. These results have significant ramifications for a number of integrated optical devices fabricated in silicon.