Ion bombardment effects on elemental incorporation probabilities during sputter deposition of GaSb and InSb

Abstract

The relative elemental incorporation probability of Sb in GaSb and InSb films deposited by multitarget sputtering has been measured as a function of growth temperature Ts, the ratio r of elemental Sb to Ga (or In) impingement fluxes, and substrate bias during deposition. The average film composition was determined by electron microprobe measurements. The application of a negative substrate bias, Vs, during film growth was found to result in preferential resputtering of second phase precipitates formed in the film whenever JSbφSb≠JIIIφIII where J and φ are the elemental impingement rates and thermal sticking probabilities, respectively. At any value of r investigated, a value of Vs could be found such that for negative substrate biases greater than this value, the films were single phase. No preferential resputtering was observed for Vs up to 250 V in films in which JSbφSb=JIIIφIII. Thus, the range of r and Ts values over which single-phase stoichiometric films could be deposited from the vapor phase was extended by low energy ion bombardment of the growing film.