The co-precipitation of O and C in Czochralski-type material was studied in terms of a diffusion-limited growth model. Interfacial energy increases which occurred upon C incorporation into oxide precipitates, as well as changes in the O and C concentrations of the Si matrix as a function of annealing time, were taken into account. A comparison of the model predictions with available experimental data led to the conclusion that, regardless of the C content of the crystal, it was necessary to introduce sinks for precipitation-induced excess Si self-interstitials in the matrix at high annealing temperatures. At annealing temperatures below about 1000C, the enhancement effect of C upon O precipitation resulted mainly from an increase in the precipitate density. A transition in the C precipitation behavior, that was observed in C-rich Si crystals at annealing temperatures of about 800C, was related to a change in the availability of effective Si self-interstitial sinks in the Si matrix at these temperatures. An enhancement of the C diffusivity in the presence of excess Si self-interstitials played an important role in increasing the precipitate growth rate; especially at low temperatures, where no efficient Si self-interstitial sinks were available in the Si matrix.

J.Y.Huh, U.Gösele, T.Y.Tan: Journal of Applied Physics, 1995, 78[10], 5926-35