Monte Carlo simulation of charge transport in amorphous chalcogenides

Abstract

The I(V) characteristics of amorphous GST devices show a peculiar S-shape behavior, that is a swift rise of the current along with a voltage snap-back. This type of characteristics led to a growing research interest in view of the future application of such materials to the manufacturing of phase-change memory devices. In this work we adopt a generalization of the variable-range hopping theory to simulate charge transport in a layer of amorphous Ge 2Sb2Te5 sandwiched between two planar metallic electrodes. The numerical implementation of a current-driven Monte Carlo code allows one both to provide a complete microscopic particle picture of electrical conduction in the device and to better analyze the mechanisms governing the snap-back effect. © 2009 IOP Publishing Ltd.