Sub-nanosecond threshold switching dynamics in GeTe₄ ovonic threshold switching selector devices

Abstract The threshold switching (TS) dynamics of Ovonic Threshold Switching (OTS) selector devices play a pivotal role in the programming speeds of Phase Change Random Access Memory (PCRAM) and Selector Only Memory (SOM). The TS phenomenon in amorphous selector devices rapidly reduces the initial high-resistance state to a low-resistance state within nanoseconds. In this work, we present a detailed experimental study of the time-resolved transient threshold switching characteristics of GeTe 4 OTS devices, including measurements of delay time and holding voltage. The voltage-dependent delay time analysis reveals an exponential decrease in the delay time for the increase in the applied voltage above the threshold voltage. Moreover, the delay time rapidly decreased by an order for 10% increase over the steady-state threshold voltage. Furthermore, the lowest delay time of approximately 300 picoseconds was observed for the input voltage of 1.8 V, i.e. 50% higher than the steady state threshold voltage. These experimental findings on sub-nanosecond threshold switching dynamics in GeTe 4 OTS devices pave the way for the development of high-speed PCRAM and SOM devices.