A rate-adjustable true random number generator based on the stochastic delay of a TiN/NbOx/Pt memristor

True random number generator (TRNG) is a critical component in hardware security that is increasingly important in the era of mobile computing and internet of things. A memristor is a promising candidate to construct a TRNG due to its intrinsic variability of switching behavior and high-density integration. Here, we present a 1T1R oscillation structure with a TiN/NbOx/Pt memristor for constructing a rate-adjustable TRNG. The randomness of the oscillation comes from the stochastic switch latency of the memristor. The experimental results demonstrate that the oscillation rate can be modulated by changing the gate bias of the transistor in series. Furthermore, a TRNG circuit with adjustable rates is constructed based on the 1T1R oscillation, and the simulated results revealed that the proposed TRNG output can pass eight NIST tests, indicating the true randomness of the circuit. Finally, the randomness in the memristor, the adjustable rate of the 1T1R oscillation, and the NIST test result of RNG are proved in turn. These results demonstrate the feasibility of the circuit, which can minimize the power consumption by adjusting the random number generation rate to correct the frequency drift caused by extrinsic factors, such as environment temperature and humidity.