Inside Submicron MOSFETS

Abstract

ABSTRACTNanofabrication techniques allow us to carve out narrow (40 nm) conducting channels and multiple voltage probes inside a submicron portion of a “conventional” silicon MOSFET. The repeated capture and emission of single electrons at a particular interface trap can be observed, because this changes the number of scatterers, producing sudden switching of the conductance. The dependence of capture and emission rates on lattice temperature, electron temperature, and gate voltage are consistent with a simple “configuration coordinate” model of the coupling between the trapped electron and the surrounding lattice. At low temperatures, the electrons being scattered diffuse considerable distances Lϕ before losing quantum phase information. When measured at scale Lϕ, random quantum interference causes a typical (rms) conductance change of e2/h = (25.8 kΩ)−1 (“universal conductance fluctuations”). From this, the resistance fluctions at longer and shorter voltage probe spacings can be predicted. Each scatterer substantially affects the quantum interference throughout a region of size Lϕ.