Impact of Relaxation on the Performance of GeSe True Random Number Generator Based on Ovonic Threshold Switching

Volatile Ovonic threshold switching (OTS) are promising not only as the selector in crossbar resistive switching memory arrays, but also as true random number generators (TRNG) by utilizing its probabilistic switching characteristics. However, investigation on the reliability of OTS-based TRNG is still lacking, which hinders its practical application. Previously, we found that switching probability is dependent on the pulse amplitude and width. In this work, we report that relaxation which happens during the time interval between pulses can also cause switching probability drift. Optimizing the bit-generation waveform and modulating the pulse conditions could provide a practical solution, in addition to the impact of external bias and temperature. This work provides useful guidance for the practical design and operation of OTS-based TRNGs.