Poly-Si-Based Physical Unclonable Functions

Abstract

Physically unclonable functions (PUFs) were introduced over a decade ago for a variety of security applications. Silicon PUFs exploit uncontrollable random variations from manufacturing to generate unique and random signatures/responses. However, such sources of randomness may become limited during standard CMOS manufacturing as processes continue to mature especially with the advances in design for manufacturability. Recently, poly-Si is proposed to improve PUF quality by offering considerable random variations at the materials level, which is from randomly distributed grain boundaries and trapped charges in poly-Si. In this paper, we develop a poly-Si field-effect transistor (FET) model to study the properties of poly-Si-based PUFs under different supply voltages ( $V_{\mathrm{ DD}}$ ) and temperatures ( $T$ ). Simulation results obtained from ring oscillator and arbiter PUFs show that compared with conventional CMOS-based PUFs, the reliability of poly-Si-based PUFs can be improved from around 90% to 98% and the PUF devices are robust against varying $V_{\mathrm{ DD}}$ and $T$ .