DIFFUSION, SOLUBILITY, AND THERMODYNAMIC PROPERTIES OF GOLD IN SOLID GERMANIUM STUDIED BY MEANS OF RADIOTRACER AND SPREADING-RESISTANCE ANALYSIS

Diffusion profiles of gold in germanium were measured using the radiotracer as well as the spreading-resistance technique. Diffusion coefficients from both experimental methods show a good agreement and are described by an activation energy of 147 +/- 2 kJ mol-1 and a preexponential factor in the range (1-2) x 10(-6) m2 s-1. The results are interpreted within a generalized dissociative model allowing for interstitial-substitutional exchange with the aid of vacancies or interstitial Au-vacancy pairs. Solubility data taken from the boundary concentration of the penetration profiles reveal nonsignificant differences between the total Au concentration and that of substitutional Au atoms. Basic thermodynamic quantities were calculated from the temperature dependence of the solid solubility using data from the Au-Ge phase diagram.