Laser induced interface reactions in Sb/Ge multilayer thin films: a study by RBS and CS-TEM

Abstract

Thin films consisting of alternate layers of Ge and Sb are laser irradiated by single nanosecond pulses from an excimer laser. RBS and CS-TEM are used to characterize the induced transformations upon irradiation. It is shown that the interdiffusion process occurs within the liquid phase and causes, by reactions at the first interface, the growth of a buried amorphous GeSb layer with a nonconstant stoichiometry. The high cooling rates (2 × 1010 K s-1) and liquid/solid interface velocities (0.8 ms-1) achieved during solidification, together with the absence of a crystalline nucleus at the interface to initiate crystallization, explain this behaviour. © 1992.