Controllable Threshold Voltage (Vth) 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.