Formation Kinetics of Thermal Donors in Silicon

ABSTRACTThe kinetics of thermal donor formation in Czochralski-silicon at ca. 450° C are explained by a simple model based on the work of Suezawa and Sumino which derives forward and reverse reaction rates for each electrically active species from the general features of the infrared electronic absorption spectra. The model, which is independent of the chemical nature of the thermal donor core, assumes that all thermal donors beyond the first donor species are chemically stable at the donor formation temperature, and approximates the reactions for species smaller than the first thermal donor as being in chemical equilibrium. The model is shown to be consistent with both sets of the available IR spectra of thermal donors (Oeder-Wagner and Suezawa-Sumino) when differences in the annealing temperature and initial oxygen concentration are taken into account.