Irregular growth of AlSb in solid aluminum-solid antimony diffusion couples

Abstract

An investigation was made of the growth of the intermediate phase aluminum antimonide (AlSb) in solid aluminum-solid antimony diffusion couples, AlSb being the only intermediate phase present in the equilibrum phase diagram. Most diffusion couples were assembled from polycrystalline aluminum and antimony, but a few were made from single crystals; the diffusion couple surfaces were prepared in a variety of ways and the couples were isothermally annealed at temperatures between 450° and 615°C. It was found in all cases that AlSb nucleates at the original interface and after sufficient time coalesces into a highly irregular layer, irrespective of the details of the surface treatment. In several cases in which limited nucleation of AlSb took place, the morphology of the crystals was such as to suggest that the observed anisotropic growth was related to the zinc-blende crystal structure of the AlSb.