Reconfigurable Electronic Physically Unclonable Functions Based on Organic Thin‐Film Transistors with Multiscale Polycrystalline Entropy for Highly Secure Cryptography Primitives

Abstract In this study, organic thin‐film transistors (OTFTs) are investigated as a promising platform for cost‐effective, reconfigurable, and strong electronic physically unclonable functions (PUFs) for highly secure cryptography primitives. Simple spin‐casting of solution‐processable small‐molecule organic semiconductors forms unique and unclonable fingerprint thin films with randomly distributed polycrystalline structures ranging from nanoscale molecular orientations to microcrystalline orientations, which provides a stochastic entropy source of device‐to‐device variations for OTFT arrays. Blending organic semiconductors with polymer materials is a promising strategy to improve the reliability of OTFT‐based PUFs. Studies on the relationship between the phase‐separated polycrystalline microstructure of organic semiconductor/polymer blend films and PUF characteristics reveal that the 2D mosaic microcrystalline structure of organic semiconductors in the vertically phase‐separated trilayered structure enables the implementation of OTFT‐based PUFs that simultaneously satisfy the requirements of being unclonable and unpredictable, with reliable cryptographic properties. The inherent multiscale randomness of the crystalline structure allows random distribution in OTFT‐based PUFs even with various channel dimensions. The secret bit stream generated from the OTFT‐based PUF developed in this study is reconfigurable by simply changing the gate bias, demonstrating the potential to counter evolving security attack threats.