GROWTH AND CHARACTERIZATION OF INDIUM-ANTIMONIDE DOPED WITH LEAD-TELLURIDE

A PbTe dopant source has been used to grow n-type InSb using the molecular beam epitaxy growth technique. From Auger electron spectroscopy studies, no surface segregation of tellurium is observed up to approximately 10(19) cm-3 doping levels. The correlation between the PbTe flux used during growth and the electron density in the grown films is very good, suggesting that the incorporation of tellurium is near unity. From secondary-ion mass spectroscopy (SIMS) studies, no lead could be detected in the films, even when grown at temperatures as low as 280-degrees-C. This suggests that the lead rapidly re-evaporates from the surface during growth. SIMS depth profiles of tellurium show evidence of solid-state diffusion at 360-degrees-C with a diffusion coefficient approximately 10(-13) cm2 s-1. Six-probe Hall measurements of carrier transport gave room-temperature mobilities as high as 51 300 cm2V-1 s-1 at an electron density of 2.9 x 10(16) cm-3 (54 300 at an electron density of 1.9 x 10(16) cm-3 at 110 K) for a film of 4.0-mu-m thickness on an InP substrate. Our experiences with selenium contamination from previous PbSe evaporations in the same chamber and from impure Sb source material are described as well as the technique used to make the PbTe source material.