Molecular-beam epitaxy of (100) InSb for CdTe/InSb device applications

Abstract

Interest in InSb and InSb-based heterostructures has recently been renewed in view of their important potential applications in infrared, logic, and novel quantum-well devices. Our work to date has concentrated on the growth of CdTe/InSb multilayer structures in which the properties of the InSb constituent layers have a very significant influence on subsequent device performance. The present paper describes data obtained during a systematic investigation of the growth, using molecular-beam epitaxy (MBE), of (100) InSb homoepitaxial layers, specifically for CdTe/InSb device applications. Modulated-beam mass spectrometry experiments have shown that polycrystalline InSb can be used as an MBE source of antimony, and the properties of InSb epilayers grown using either elemental antimony or polycrystalline InSb as the group-V source are compared. Cross-sectional transmission electron microscope analysis indicates that very high structural quality layers can be produced and has also identified the mechanisms which give rise to structural breakdown in layers grown under nonoptimum conditions. All unintentionally doped InSb layers grown to date have exhibited n-type conductivity (n≳3×1015 cm−3) and secondary ion mass spectrometry data has indicated the presence of tellurium, sulfur, and selenium contamination. The mechanisms by which tellurium and sulfur become incorporated in the grown layers are identified.