Growth and phase stability of epitaxial metastable InSb1−xBix films on GaAs. II. Phase stability

Abstract

Single-crystal metastable InSb1−xBix films have been grown on GaAs substrates by multitarget sputtering. The films were metastable in two directions on the In-Sb-Bi ternary phase diagram—the solid solubility of tetragonal InBi in zinc blende structure InSb was increased by more than a factor of 4, and the width of the InSb-InBi pseudobinary phase field was increased from ∼10−3% to ?0.5%. The transition from the single-phase metastable state M1 to the equilibrium state occurred through the intermediate metastable state M2. The thermal stability of single-phase films was found by high-temperature growth and post-annealing experiments to depend on film orientation in the following order: (110), (111), and (100). The metastable phase diagram was established for (110) oriented films in which it was found that the transition temperature from the M1 state to the M2 state ranged from 150 to 300 °C, depending on film composition, above the equilibrium eutectic temperature at ∼100 °C and to be only about 125 °C less than the liquidus temperature.