Heterointerface effects on the charging energy of shallow D- ground state in silicon: the role of dielectric mismatch

TL;DR

This paper investigates how heterointerface effects, including dielectric mismatch and metallic gates, influence the charging energy of shallow donor states in silicon nanostructures, revealing significant reductions compared to bulk values.

Contribution

It combines experimental measurements with theoretical modeling to elucidate the impact of dielectric mismatch and metallic proximity on donor charging energies in silicon devices.

Findings

Experimental reduction in charging energy of As dopants in Si FinFETs

Theoretical explanation involving insulator screening and metallic gate effects

Identification of heterointerface effects as key factors in device behavior

Abstract

Donor states in Si nanodevices can be strongly modified by nearby insulating barriers and metallic gates. We report here experimental results indicating a strong reduction in the charging energy of isolated As dopants in Si FinFETs relative to the bulk value. By studying the problem of two electrons bound to a shallow donor within the effective mass approach, we find that the measured small charging energy may be due to a combined effect of the insulator screening and the proximity of metallic gates.