Mass transport in Ti0.5Sb2Te3 phase-change nanobridge

Investigation of atomic migration behavior in nanoscale phase-change material is very valuable for phase-change memory applications. In this work, Ti0.5Sb2Te3-based phase-change nanobridges were fabricated and mass transport by atomic migration was studied. A 3-D finite-element simulation on the electrothermal field was introduced to describe the electrothermal environment in the phase-change region. During the nanosecond operation, an obvious compositional distribution resulting from atomic migration was observed in the Ti0.5Sb2Te3 phase-change nanobridge. Based on the mass continuity equation, a physical model for mass transport is proposed to illustrate that the density variation during the amorphous-to-crystalline structural transformation is the main reason for the atomic migration in nanoscale Ti0.5Sb2Te3 phase-change material. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.