Valley splitting by extended zone effective mass approximation incorporating strain in silicon

TL;DR

This paper investigates how strain, especially shear strain near the buried oxide interface, influences valley splitting in silicon MOSFETs using an extended zone effective mass approximation, revealing strain as a key factor.

Contribution

It demonstrates that shear strain around 5% can cause significant valley splitting, providing a theoretical explanation for experimental observations.

Findings

Shear strain near the BOX interface significantly affects valley splitting.

Extended zone EMA predicts strain as a major factor in valley splitting.

Large valley splitting observed in annealed SIMOX substrates can be explained by strain effects.

Abstract

Silicon metal-oxide-semiconductor field effect transistors (MOSFETs) fabricated on a SIMOX (001) substrate, which is a kind of silicon on insulator (SOI) substrate, that is annealed at high temperature for a long time are known to exhibit large valley splitting, but the origin of this splitting has long been unknown. Extended zone effective-mass approximation (EMA) predicts that strain significantly affects valley splitting. In this study, we analyzed valley splitting based on this theory and found that the shear strain along <110> of approximately 5% near the buried oxide (BOX) interface is a promising source for large valley splitting.