A simple PECVD SiO2 OTP memory based PUF for 180nm node for IoT

Internet of Things (IoT) requires chip level unique identification like a random binary barcode. For secure random binary barcode, a physically un-clonable function (PUF) is preferred over software which produces a random binary barcode based on fundamentally stochastic (hence un-clonable) processes e.g. Ring Oscillator Frequency due to scaled transistor variability[1], RRAM off-state current due to stochastic nature of filaments [2], stochastic switching in MTJ [3]. As IoT applications maybe partially enabled by previous generation technology nodes e.g. 90nm or 180nm [4], such strategies are challenging e.g. RO variability is low at 180nm technology [1] while MTJ and RRAM require advanced materials integration at 180nm, which has cost-implications. Alternatively, fundamentally stochastic gate oxide breakdown based OTP / RNG has been commercialized [5-6]. However, it requires higher breakdown voltage (V
bd
) than supply voltage (i.e. V
bd
e.g. 3.3V at 180nm technology). This requires high voltage transistors and charge pumps. In this work, we propose the stochastic breakdown in PECVD oxide for OTP PUF to demonstrate broader V
bd
distribution, lower Vg
bd
than 3.3 V. We compare the failure rates, voltage tolerance window for random numbers generation (RNG) using NIST tests [7] and PUF uniqueness tests [2].