R&D: Scheme for Enabling Ultimate Speed of Threshold Switching in Phase Change Memory Devices

Nature Scientific Reports has published an article written by Nishant Saxena, Phase Change Memory Lab, Advanced Memory and Computing Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India, Rajamani Raghunathan, UGC-DAE Consortium for Scientific Research, DAVV Campus, Khandwa Road, Indore, Madhya Pradesh, 452001, India, and Anbarasu Manivannan, Phase Change Memory Lab, Advanced Memory and Computing Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.

Abstract: “Phase change materials exhibit threshold switching (TS) that establishes electrical conduction through amorphous material followed by Joule heating leading to its crystallization (set). However, achieving picosecond TS is one of the key challenges for realizing non-volatile memory operations closer to the speed of computing. Here, we present a trajectory map for enabling picosecond TS on the basis of exhaustive experimental results of voltage-dependent transient characteristics of Ge₂Sb₂Te₅ phase-change memory (PCM) devices. We demonstrate strikingly faster switching, revealing an extraordinarily low delay time of less than 50 ps for an over-voltage equal to twice the threshold voltage. Moreover, a constant device current during the delay time validates the electronic nature of TS. This trajectory map will be useful for designing PCM device with SRAM-like speed.“