It was recalled that the rapid diffusion of Zn into GaAs had recently been attributed to the fact that a small fraction of the Zn interstitials changed to Ga sites, thereby producing interstitial Ga (IGa). This kick-out reaction led to the possibility of determining the IGa transport properties from Zn diffusion experiments on essentially perfect GaAs. However, previous attempts had been impeded by the diffusion-induced generation of microstructural defects which acted as IGa sinks. In the present study, this was prevented by using Zn-doped GaAs powder as a diffusion source. The measured 2-stage profiles showed that, under these conditions, Zn diffusion at 906C was controlled by IGa3+ in addition to IGa2+. Analysis of the profiles yielded quantitative data on the Ga- and Zn-related diffusivities, and on the concentration of IGa.

G.Bösker, N.A.Stolwijk, H.G.Hettwer, A.Rucki, W.Jäger, U.Södervall: Physical Review B, 1995, 52[16], 11927-31