A wafer of float-zone material was partially subjected to prolonged annealing at 960C. The annealed and unannealed portions of the wafer were then diffused with Au for various lengths of time. The Au concentration was deduced from spreading resistance measurements. It was found that the crystal portion which was annealed before Au deposition exhibited a different Au accumulation, as a function of time, than did the as-received parts of the crystal. The Au concentration at the center of the wafer did not obey the previously reported t½ behavior. It instead followed a curve that exhibited an inflection. The results were explained in terms of vacancy clusters that were retained during the original crystal growth.

T.K.Monson, J.A.Van Vechten, Q.S.Zhang: Journal of the Electrochemical Society, 1995, 142[6], 2077-80