GOLD AND PLATINUM DIFFUSION - THE KEY TO THE UNDERSTANDING OF INTRINSIC POINT-DEFECT BEHAVIOR IN SILICON

The study of gold and platinum diffusion is found to allow the separate observation of the intrinsic point defects, i.e., of silicon self-interstitials and of vacancies. The diffusion of gold in float zone (FZ) silicon is found to be dominated by the kick-out mechanism for temperatures of 800-degrees-C and higher. The diffusion of platinum in FZ silicon is described by the kick-out mechanism for temperatures above approximately 900-degrees-C, whereas for temperatures below approximately 850-degrees-C the dissociative mechanism governs platinum diffusion. As a result of numerical simulations, we suggest a complete and consistent set of parameters which describes the diffusion of platinum in silicon in the temperature range from 700-degrees-C to 950-degrees-C and the diffusion of gold in the temperature range from 800-degrees-C to 1100-degrees-C. The generation or recombination of self-interstitials and vacancies is found to be ineffective at least below 850-degrees-C. The concentration of substitutional platinum is determined by the initial concentration of vacancies at diffusion temperatures below 850-degrees-C. Platinum diffusion below 850-degrees-C can be used to measure vacancy distributions in silicon quantitatively.