Dual Entropy Source Physical Unclonable Functions of Reconfigurable Feedback Field‐Effect Transistors with Polycrystalline Silicon Channels

Physically unclonable functions (PUFs) have emerged as candidates for compact hardware security. In this study, PUFs of reconfigurable feedback field‐effect transistors (R‐FBFETs) with polycrystalline silicon channels are designed for dual entropy sources; the channels have inherent random grain boundary‐induced variabilities. Dual entropy source schemes offer a strategic advantage for resource‐constrained platforms by improving the entropy density, area efficiency, and robustness against cyberattacks within a minimized device footprint. An R‐FBFET operates with two‐channel types in a single device through p‐ and n ‐channel modes controlled by the gate bias; hence, two random bits are extracted from a single device. The uniqueness and high reliability of the dual entropy source PUF are confirmed by an inter‐Hamming distance of 49.13% and an intra‐Hamming distance of 3.47%. The PUF passed the U.S. National Institute of Standards and Technology statistical tests. Moreover, the PUF is used to implement XOR (exclusive‐OR)‐based text encryption and decryption, demonstrating its feasibility for Internet‐of‐things and edge applications.