Heteroepitaxy on Compliant Substrates for Vertical and Horizontal Integration of Multi-Functional Devices

摘要

This report presents the results of research on compliant substrate behavior in III-V semiconductors grown by molecular beam epitaxy (MBE) on thin (50-80A) InGaAs layers on GaAs, and in II-VI semiconductors (HgCdTe, CdTe, ZnTe) grown on thin Si(211) layers on Si(100). A comprehensive experimental study was conducted utilizing spectroscopic ellipsometry, transmission electron microscopy, and atomic force microscopy at various stages in the fabrication and processing of the compliant layers and during MBE growth on those layers. Contrary to earlier reports by other investigators, we obtained no evidence for defect reduction or solid phase atomic rearrangement due to substrate compliancy in either of the III-V or II-V systems studied here. We conclude that the early reports of compliancy may have been erroneous interpretation of limited experimental data. Indeed, a theoretical consideration of stress relief mechanics in semiconductor thin films suggests that many of the proposed compliancy mechanisms are not feasible. Although no evidence of substrate compliancy was obtained, we were nevertheless successful in growing high quality II-VI layers by MBE on thin Si(211) layers bonded to Si(100) substrates. This has important implications for monolithic integration of HgCdTe infrared focal plane arrays with readout circuitry fabricated in Si(100) substrates.