Diffusion of Ir into Si was investigated by annealing of front-side deposited floating-zone Si wafers at between 1000 and 1200C. Concentration-depth profiles were measured by means of neutron activation analysis in conjunction with mechanical sectioning. The observed deep penetrations and anomalous profile shapes pointed to a diffusion process involving both highly mobile interstitial Iri as the diffusion vehicle and immobile substitutional Irs as the dominant species. The experimental findings were best reproduced by making allowance for Iri-Irs exchanges that simultaneously took place via Si self-interstitials (kick-out mechanism) and Si vacancies (dissociative mechanism). As a unique property it was found that the Si:Ir system was subject to a gradual transition from a Iri-controlled diffusion mode at higher temperatures to a self-interstitial-controlled diffusion mode at lower temperatures.

Diffusion of Iridium in Silicon - Changeover from a Foreign-Atom-Limited to a Native-Defect-Controlled Transport Mode. S.Obeidi, N.A.Stolwijk: Physical Review B, 2001, 64[11], 113201 (4pp)