An extremely fast, energy-efficient RESET process in Ge2Sb2Te5 phase change memory device revealed by the choice of electrode materials and interface effects

Abstract

Phase change memory (PCM) offers promising features such as high speed, non-volatility for 'universal memory', however, achieving low-power RESET process in sub-ns timescale is a key challenge. In this study, we display a trade-off between speed and power to enable an ultrafast (sub-ns) and yet, low-power (sub-mW) RESET operation in a nanoscale pore-type Ge2Sb2Te5 (GST) PCM device by means of the choice of electrode materials and their interface effects on a well-designed device architecture using TCAD simulation. The miniaturized device with 20 nm contact diameter (CD) is investigated by employing three different bottom electrode materials, namely TiAlN, TiW and TiN, where the latter is found to be efficient for low-power RESET (159 μW) using a pulse-length of 40 ns showing 63% and 44% power reduction as compared to TiW and TiAlN respectively. A strong interface effect that exists between GST/TiN and GST/SiO2 helps to achieve low-power RESET operation. Furthermore, low-energy RESET is realized using ultrafast (400 ps) pulse with IRESET of 529 μA leads to ∼100× reduction in energy consumption (578 fJ). Moreover, an extremely fast RESET operation in 200 ps is displayed by the simulated device with TiN and TiAlN electrode materials. Hence, our simulation results of ultrafast (200 ps), ultralow-energy (578 fJ) and low-power (159 μW) RESET process with the significant role of interface effects would be highly useful towards designing ultralow-energy PCM device for future electronics. © 2019 IOP Publishing Ltd.