Highly strained-SiGe-on-insulator p-channel metal-oxide-semiconductor field-effective transistors fabricated by applying Ge condensation technique to strained-Si-on-insulator substrates

Abstract

High hole mobility enhancement of strained SiGe-on-insulator (sSGOI) p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) has been achieved by utilizing strained-SOI (sSOI) substrates in Ge condensation. The initial tensile strain in the sSOI substrates alleviates strain relaxation during Ge condensation process, because of smaller lattice mismatch to Ge than conventional unstrained SOI substrates. In addition, generation of hole carrier concentration and degradation of bottom interface are suppressed. Mitigation in strain relaxation is shown to effectively increase strain in SGOI layers and resulting hole mobility in the SGOI pMOSFETs in high Ge content region. The observed high mobility enhancement can be quantitatively explained by the combination of high Ge content and a large amount of compressive strain, through comparison of experimental data with theoretical calculations.