Interlayer diffusion in InSb/GaSb superlattice structure grown by multitarget rf sputtering

Abstract

The rate of interlayer diffusion during annealing of InSb/GaSb superlattice structures with layer thicknesses ranging from 12.5 to 50 Å has been investigated. The films were grown by multitarget rf sputtering on InSb‐coated Corning 7059 glass slides. The InSb underlayers were deposited at 320 °C and were approximately 300 Å thick. The multilayer films had a total thickness of ∼1 μm and were grown at either 200 or 250 °C in an Ar sputtering pressure of 15 mTorr (2 Pa). Prior to annealing the samples were encapsulated in a 1000‐Å‐thick rf sputtered overlayer of In₂O₃. InSb/GaSb interlayer diffusion was investigated using x‐ray diffraction techniques in which the intensity of satellite peaks around the Bragg reflection peaks were monitored as a function of annealing time. A diffusion coefficient of 4.5×10⁻²¹ cm²/sec was determined for an annealing temperature of 320 °C.