Hardware implementation of a true random number generator integrating a hexagonal boron nitride memristor with a commercial microcontroller

Abstract

The development of the internet-of-things requires cheap, light, small and reliable true random number generator (TRNG) circuits to encrypt the data — generated by objects or humans — before transmitting it. However, all current solutions consume too much power and require a relatively large battery, hindering the integration of TRNG circuits on most objects. Here we fabricate a TRNG circuit by exploiting stable random telegraph noise (RTN) current signals produced by memristors made of two-dimensional (2D) multi-layered hexagonal boron nitride (h-BN) grown by chemical vapour deposition and coupled with inkjet-printed Ag electrodes. When biased at small constant voltages (≤70 mV), the Ag/h-BN/Ag memristors exhibit RTN signals with very low power consumption (~5.25 nW) and a relatively high current on/off ratio (~2) for long periods (>1 hour). We construct TRNG circuits connecting a h-BN memristor to a small, light and cheap commercial microcontroller, producing a highly-stochastic, high-throughput signal (up to 7.8 Mbit/s) even if the RTN at the input gets interrupted for long times up to 20s, and if the stochasticity of the RTN signal is reduced. Our study presents the first full hardware implementation of 2D-materials-based TRNG, enabled by the unique stability and figures of merit of the RTN signals in h-BN based memristors.