Validating Supply Chain against Recycled COTS ICs using I/O Pad Transistors: A Zero-Area Intrinsic Odometer Approach

Commercial-off-the-shelf (COTS) components are integral to the application-specific IC industry, offering cost-effective and reliable solutions. However, with the increasing demand for mission-critical zero-trust applications, there is a growing concern about the security and reliability of recycled/ counterfeit COTS ICs in the supply chain. The conventional methods of identifying recycled ICs often involve integrating additional components (e.g., on-chip sensors), an impractical approach for highly (2.5D/ 3D) integrated electronics with strict constraint on the chip-area footprint. Here, we focus on the degradation (due to aging) in the intrinsic I/O pad transistors to provide a novel zero-area overhead odometer for detecting recycled ICs. In this study, we: (i) program several Arm Cortex-M0+ (32 and 72 MHz) based microcontrollers/MCUs to directly access the individual I/O buffer transistors (NMOS/ PMOS), (ii) analyze the parametric NBTI and PBTI degradation in these PMOS and NMOS transistors, respectively, under both AC and DC stress (ii) develop an algorithm to distinguish between recycled (with estimated age) and fresh ICs, by observing their nonlinear rate of degradation. This novel technique offers a rapid, practical, and cost-effective way to identify recycled ICs without requiring additional on-chip circuitry.