A True Random Number Generator Based on High-Speed Ag/a-Si/Pt Memristor

The inherent variability in memristor switching behavior has been a challenge to its adoption as a next-generation general-purpose memory. However, the randomness of its switching behavior may be helpful for hardware security applications. Herein, a true random number generator (TRNG) based on a high-speed Ag/amorphous-Si/Pt threshold switching (TS) device was constructed. The device possesses a large on-off ratio of about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> and a fast switching speed of about 30 ns. The results show that the delay time of the device decreases as the pulse amplitude or the pulse frequency increases. Using the random delay time as a random source, we built a TRNG circuit and achieved the flipping of “0” and “1” with a fast bit generation rate of 48 kb/s. The random bits generated by our TRNG pass 14 randomness tests of the National Institute of Standards and Technology (NIST) without any processing. This work paves the way for diffusive memristors in hardware security applications in the era of the Internet of Things.