ZINC DIFFUSION IN TELLURIUM DOPED GALLIUM ANTIMONIDE

Zinc diffusion into tellurium doped gallium antimonide, GaSb, has been carried out as a function of time, temperature, and antimony over-pre ssure. Total zinc profiles as well as carrier concentration profiles h ave been measured. Results favor a substitutional-interstitial vacancy (Frank-Turnbull)(1) or kick-out (Gosele-Morehead)(2) mechanism, altho ugh there is insufficient evidence to conclusively distinguish between them. There is also an inverse dependence of the diffusivity on antim ony over-pressure, this is discussed in terms of zinc diffusion superi mposed on gallium vacancy diffusion. Tellurium doping seems to have li ttle effect on the fusion because of its low level in comparison to th at of zinc. Furthermore, at high zinc concentrations, the profiles ind icate an additional component associated with a non-electrically activ e zinc species which has a small, strongly temperature dependent diffu sion coefficient.