It was found that, after exposure to SF6/CHF3 plasma, the sheet resistance of Si-doped layers had increased. This was due to carrier reduction near to the surface. The carrier reduction could be almost entirely restored by annealing (450C, 0.5h). Exposure to He plasma or CHF3 plasma caused more extreme carrier reduction than did exposure to SF6 plasma; thus indicating that carrier reduction in the damaged layers was due mainly to bombardment with low-mass fragments such as H and He. The low-temperature (4.2K) photoluminescence of plasma-exposed material exhibited a complicated broad spectrum (1.25 to 1.43eV) that was related to defect complexes which resulted from the incorporation of H.

K.Mitani, H.Oda, J.Kasai, Y.Imamura: Japanese Journal of Applied Physics, 1995, 34[1-8A], 3970-5