Disordered Mixture of Self-Assembled Molecular Functional Groups on Heterointerfaces with p-Si Leads to Multiple Key Generation in Physical Unclonable Functions

Physical unclonable function (PUF) security devices based on hardware are becoming an effective strategy to overcome the dependency of the internet cloud and software-based hacking vulnerabilities. On the other hand, existing Si-based artificial security devices have several issues, including the absence of a method for multiple key generation, complex and expensive fabrication processes, and easy prediction compared to devices retaining natural randomness. Herein, to generate unique and unpredictable multiple security keys, this paper proposes novel PUF devices consisting of a disordered random mixture of two self-assembled monolayers (SAMs) formed onto p-type Si. The proposed PUF devices exhibited multikeys at different voltage biasing, including 0 V, through the arbitrary dipole effect. As a result, multiple unpredictable hardware security keys were generated from one device using a simple solution-coating process. The PUF security device based on the mixture of materials with different dipoles developed in this study can provide valuable insights for implementing various PUF devices in the future.