Evidence for electrically induced drift of threshold voltage in Ge2Sb2Te5

Threshold voltage (V-T) is an important parameter in phase change memory (PCM), marking the minimum voltage needed to program the memory device. In this work, we demonstrate that subthreshold pulses at V < V-T can induce an increase of V-T. The pulse-induced modification of V-T is explained primarily due to the Joule heating during V-T measurement accelerating the structural relaxation in the amorphous phase-change material. Our results demonstrate that V-T can be adjusted through applied voltage pulses in the subthreshold regime, allowing the stabilization of programmed PCM states. (C) 2013 AIP Publishing LLC.