Increase of doping efficiency by light soaking in boron-doped hydrogenated amorphous silicon

Boron-doped hydrogenated amorphous silicon deposited at 100°C exhibits a decrease of dark conductivity and an increase of doping efficiency, simultaneously, during band-gap light illumination. We prove that these two effects are bulk effects and that their origins are different. The decrease in dark conductivity is due to the creation of dangling bonds. On the other hand, the increase in doping efficiency anneals out with an activation energy of 1.66 eV. The increase in stretching mode absorption of boron-hydrogen has been observed after light soaking for the amorphous silicon-boron alloy film, and this appears to be related with the increase in doping efficiency of boron.