Experimental evidence of both interstitial- and vacancy-assisted diffusion of Ge in Si

We present the first experimental identification of the diffusion mechanisms of Ge in Si. Using thermal nitridation reactions to create either excess self-interstitials or vacancies, it is established that under equilibrium conditions at 1050°C Ge diffusion takes place by both substitutional- interstitial interchange and vacancy mechanisms, with comparable contributions from each. If previous conjectures that Ge diffusion in Si is similar to Si self-diffusion are correct, our findings support the idea that Si self-diffusion takes place by both interstitial and vacancy mechanisms.