Inkjet-Printed BaTiO3 Nanoparticle-Embedded Capacitor Array for Physical Unclonable Function

Abstract

Nanoparticle (NP)-based physical unclonable functions (PUFs) have attracted attention as a digital fingerprint technology that alternates with microfabrication-based PUFs by utilizing natural randomness at the nanoscale. Mostly NP-based optical PUFs have been proposed due to the absence of nanomaterial fabrication method compatible with microelectronics, but the need for a bulky optical readout system makes it difficult to utilize them in microelectronics. In this work, we developed the NP-based capacitor PUF (CAP-PUF) technology that can be read electrically and integrated into microelectronics while utilizing the benefit of the natural physical randomness of NPs. We incorporated a high-k BaTiO3 NP inkjet printing micropatterning process for the fabrication of the NP-embedded CAP-PUF array. The inkjet-printing parameters have been optimized to maximize the natural randomness of the BaTiO3 NP micropatterns by increasing the intrinsic stochasticity, especially the fluid dynamics that occurring during the multilayer printing. The BaTiO3 NP-embedded CAP-PUF array shows high security performance, showing the inter-hamming distance of 0.52, uniformity of 0.44, entropy of 0.989, and intra-hamming distance up to 0.064. High-k NP inkjet-printing-based CAP-PUFs can provide highly unique digital fingerprints based on the intrinsic randomness in nanoscale for microelectronics.