Physical origin of the resistance drift exponent in amorphous phase change materials

The resistance of amorphous chalcogenides used in phase change memory devices increases over time due to structural relaxation (SR). The resistance drift usually follows a power law with time described by an exponent nu. Understanding the origin of may lead to engineering methods to improve the stability in memory devices. This work presents an analytical model to describe the activation energies for conduction and SR based on the Meyer-Neldel rule. The model accounts for the observed temperature and time dependence of resistance, and highlights that nu is related to the ratio between conduction and SR activation energies at any given time during drift. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3599559]