Interdiffusion study of HgTe–HgCdTe superlattice. I. Low‐temperature Auger sputter depth profiling

Abstract

It has been suggested that some discrepancies between theoretical and experimentally measured band‐gap values may arise from interdiffusion which occurs during superlattice growth. Previously, no analytical technique had been sufficiently developed to provide compositional depth profiling with high enough depth resolution to characterize superlattice structures. We report the development of Auger sputter depth profiling (SDP) of HgCdTe superlattices at cryogenic temperatures and the subsequent investigation of superlattice interdiffusion using this technique. First, we studied Hg desorption, sputter rates, and preferential sputtering on molecular‐beam epitaxy (MBE) and liquid phase epitaxy grown HgTe and CdTe standards as well as HgCdTe samples at room temperature and at −126 °C to understand the effect of electron and ion beams on these materials and subsequent analysis. Next, we were successful in obtaining a high‐resolution Auger SDP of an MBE grown ‘‘square‐wave’’ HgTe–Hg0.15Cd0.85Te (52 A/80 A) and a...