Self-diffusion experiments were performed on undoped 69Ga121Sb/71Ga123Sb heterostructures, at 571 to 708C, under Sb-rich (table 12) or Ga-rich ambients. The Ga and Sb profiles, as measured using secondary ion mass spectrometry, revealed that Ga diffused faster than Sb by several orders of magnitude. This strongly suggested that the 2 self-atom species diffused independently on their own sub-lattices. The results led to the conclusion that Ga and Sb diffusion was mediated by Ga vacancies and Sb interstitials, respectively, rather than by the formation of a triple defect. The extremely slow diffusion of Sb, up to the melting point of GaSb, was suggested to be a result of amphoteric transformations between native point defects which suppressed the formation of the native defects which controlled Sb diffusion. Experiments on the effect of Zn in-diffusion at 550C, upon Ga and Sb diffusion, revealed enhanced intermixing of the Ga isotope layers; as compared with undoped GaSb. However, the diffusion of Sb was not significantly affected under the same conditions.

Self-Diffusion in 69Ga121Sb/71Ga123Sb Isotope Heterostructures. H.Bracht, S.P.Nicols, E.E.Haller, J.P.Silveira, F.Briones: Journal of Applied Physics, 2001, 89[10], 5393-9

Table 12

Diffusivity of Sb in GaSb

* Ga-rich conditions, § Sb-rich conditions