Controllable Threshold Voltage (V_th) Drift in Ovonic Threshold Switch Devices Under a High-Frequency Continuous Operation

In this work, we studied the threshold voltage ${V} _{\text {th}}$ for an ovonic threshold switch (OTS) device in a high-frequency continuous operation. By applying a pulse sequence with small pulse intervals, the dependence of ${V} _{\text {th}}$ on the falling edge of the prior pulse has been investigated in the Te-based OTS device. The results indicate that the ${V} _{\text {th}}$ presents a Weibull distribution in the pulse sequence, and the ${V} _{\text {th}}$ distribution drifts nonmonotonically with the pulse falling edge. Meanwhile, the drift tendency of the ${V} _{\text {th}}$ distribution was found depending on the device area. Furthermore, the recovery process and the time-resolved current profiles in the device operation have been investigated to further study the ${V} _{\text {th}}$ drift. The results indicate that the ${V} _{\text {th}}$ drift in continuous device operation is controllable and results from a combination of the effects of heat accumulation and the recovery process. The ${V} _{\text {th}}$ drift at high-frequency operating can be reduced by optimizing the device lateral dimension according to the mapping results of the ${V} _{\text {th}}$ . Our results can guide the design and operation of the OTS device with a low ${V} _{\text {th}}$ drift requirement.