Amorphous silicon produced by ion implantation: Effects of ion mass and thermal annealing

Characterization of the two optical states of amorphous Si produced by ion implantation is extended to include electron paramagnetic resonance, fundamental absorption edge, and density measurements in addition to infrared reflection. It is found that the properties of the two a-Si states are not dependent upon the mass of the incident ion (12C, 29Si, 31P, 120Sn) or upon the anneal temperature for 400 °≤TA≤600 °C. The dangling-bond density drops about a factor of 2 when the a-Si makes a transition between the two states. The absorption coefficient also drops by more than a factor of 5, but the density of the a-Si does not change when the transition occurs. The transition between states was not completed at TA=300 °C, so the annealing mechanism may be temperature dependent.