By using B- and Si-doped (100) doping superlattices as monitors of native point defect behavior, it was shown that vacuum annealing at 810C led to a depletion of self-interstitials, with their lowest concentration being at the surface, but did not affect the vacancy population. At a given depth, the interstitial concentration fell with increasing annealing time. For a given time, the interstitial concentration increased as a function of depth. Annealing of a B-doping superlattice in Ar produced flat interstitial profiles. It was proposed that vacuum annealing made the surface a better sink for interstitials than did annealing in Ar. This led to an equilibrium interstitial concentration that was below the bulk value, and established a net out-flux of interstitials to the surface. The absence of a response of the vacancy population put a lower limit, on the interstitial-vacancy recombination time, of 104s at 810C.

H.J.Gossmann, C.S.Rafferty, F.C.Unterwald, T.Boone, T.K.Mogi, M.O.Thompson, H.S.Luftman: Applied Physics Letters, 1995, 67[11], 1558-60