Variation in thermal stability of Ge1−xSnx films for infrared device applications

Abstract

We report on changes in Ge1−xSnx films (0.065 ≤ x ≤ 0.144) after short high-temperature anneals. Films were grown by molecular beam epitaxy on (001) Ge wafers, rapidly annealed, and characterized by x-ray diffraction, Raman spectroscopy, and optical microscopy. Sn segregated to the surface after a maximum temperature is inversely related to the Sn content. Lower content films showed little to no improvement in crystal quality below segregation temperatures, while higher content and partially relaxed films demonstrated improved uniformity for moderate annealing.