Short-Period Superlattice Materials for Heterojunction Bipolar Transistors.

摘要

This is the final report of the project Short-period Superlattice Materials for Heterojunction Bipolar Transistors , for the period 5/01/89-12/31/92. The goal of this project was to investigate the usefulness of short-period superlattices (SPSL) of InAs/GaAs and InAs/AlAs for heterojunction bipolar transistors (HBTs). Because of difficulties encountered early in the project in growing high structural quality SPSLs, the emphasis of the project was shifted to attempting to understand the growth of HBT material at low temperatures using migration-enhanced epitaxy and the incorporation of that material into HBTs. To summarize our technical results, we have grown InAs/GaAs SPSL on InP and GaAs and determined their surface roughening behavior with thickness and InAs content; correlated x-ray line widths with RHEED observations of roughening; developed methods to use migration-enhanced epitaxy to grow doped GaAs on (111) and (100) substrates, with material on both orientations having good mobilities; studied the properties of low-temperature conducting GaAs, determining Schottky barrier heights; and applied the migration-enhanced epitaxy technique to the low temperature growth of Be-doped base materials for HBTs with usable gain and no Be diffusion during growth....Molecular beam epitaxy, Short-period superlattices, Heterojunction bipolar transitions.