Heteronanostructured Field-Effect Transistors for Enhancing Entropy and Parameter Space in Electrical Unclonable Primitives.

Hardware security is not a new problem but is ever-growing in consumer and medical domains owing to hyperconnectivity. A physical unclonable function (PUF) offers a promising hardware security solution for cryptographic key generation, identification, and authentication. However, electrical PUFs using nanomaterials or two-dimensional (2D) transition metal dichalcogenides (TMDCs) often have limited entropy and parameter space sources, both of which increase the vulnerability to attacks and act as bottlenecks for practical applications. We report an electrical PUF with enhanced entropy as well as parameter space by incorporating 2D TMDC heteronanostructures into field-effect transistors (FETs). Lateral heteronanostructures of 2D molybdenum disulfide and tungsten disulfide serve as a potent entropy source. The variable feature of FETs is further leveraged to enhance the parameter space that provides multiple challenge-response pairs, which are essential for PUFs. This combination results in stably repeatable yet highly variable FET characteristics as alternative electrical PUFs. Comprehensive PUF performance analyses validate the bit uniformity, reproducibility, uniqueness, randomness, false rates, and encoding capacity. The 2D material heteronanostructure-driven electrical PUFs with strong FET-to-FET variability can potentially be augmented as an immediately deployable and scalable security solution for various hardware devices.