Upper limit of two-dimensional electron density in enhancement-mode Si/SiGe heterostructure field-effect transistors
Journal
Applied Physics Letters
Journal Volume
99
Journal Issue
15
Date Issued
2011
Author(s)
Abstract
In this paper, we present our study of the maximum electron density, nmax, accessible via low-temperature transport experiments in enhancement-mode Si/Si1?xGex heterostructure field-effect transistors. Experimentally, we find that nmax is much higher than the value obtained from self-consistent Schr?dinger-Poisson simulations and that nmax can be changed only by changing the Ge concentration in the Si1?xGex barrier layer, not by varying the barrier layer thickness. The discrepancy between experiments and simulations is explained by a non-thermal-equilibrium tunneling-limited model.
Type
journal article