PHASE-DIAGRAMS OF RHEED INTENSITY OSCILLATIONS ACCOMPANYING THE INCORPORATION OF AS INTO VERY THIN AL FILMS - POSSIBLE MELTING-POINT LOWERING OF THIN AL FILM

We report experiments for recovery of the specular beam intensity in reflection high-energy electron diffraction (RHEED) after exposure to As flux over a pre-deposited Al film of thickness equivalent to several monolayers on a GaAs or AlAs substrate in a temperature range between room temperature and 700-degrees-C. Four types of recoveries have been found. They form a phase diagram with the substrate temperature and the Al film thickness as parameters. The phase diagram suggests that the thinner Al film on a substrate has lower melting temperature than the bulk melting point of Al if we assume that As atoms do not enhance diffusion of Al atoms in a solid Al film.