Cryogenic Operation of Phase Change Memory Down to 4 K

Understanding and realizing the memory operations of non-volatile memory cell under extreme conditions such as cryogenic environment is scientifically and technologically crucial. In this work, we demonstrate the cyrogenic operation of phase change memory (PCM) at 4 K and extensively investigate its SET/RESET programming characteristics over a wide range of temperatures. On the fundamental side, the temperature dependent behavior of phase transition and its dynamics of Ge₂Sb₂Te₅, a textbook example of phase change material, is monitored with the key device metrics including the voltage shift of RESET/SET operation and with varying input pulses (width, fall time, etc), respectively. It will certainly deepen our understanding on the crystallization mechanism toward a longstanding goal of low-power and high-speed PCM. On the applied side, we successfully fabricate PCM devices with a semi-confined cell geometry and demonstrate their reliable operations from room temperature to 4 K, supported by temperature-dependent resistance change. It will, therefore, be a promising option as the interface processing memory component for quantum computing often operated in the mK range.