This article presents a Pre-Amplifier Physical Unclonable Function (PUF) fabricated in a 3-nm CMOS technology. The design achieves a “zero” Bit Error Rate (BER,$\lt 8.17\times 10^{-9}$) derived from the worst-case combination of enrollment (low voltage, low temperature) and key reconstruction (high voltage, high temperature) conditions. The design accommodates VDD voltages ranging from 650 mV to 950 mV and temperatures from$- 40~^{\circ }$C to$125~^{\circ }$C, meeting the requirements for most commercial applications in the technology sector. The BER reduction is achieved using a novel hybrid voting scheme. This scheme incorporates conservative unanimous voting during the stable bit identification (enrollment) and temporal majority voting during key reconstruction. Additionally, a gain enhancement stage using NFET cross-coupled devices is employed to maximize signal margins during reads. The design passes NIST SP800-90B and SP800-22 randomness tests while achieving 49.83% inter-chip hamming distance and 49.95% average hamming weight. The PUF can be reconfigured into a multi-stage self-destruction mode of operation in response to tamper events. The design combines electromigration (EM) and Time-Dependent Dielectric Breakdown (TDDB) to intentionally target the damage directly to the PUF data array containing stable (repeatable) bitcells. The result is an irreversible corruption of PUF encryption key to restrict all future authentication attempts.

A reconfigurable preamplifier physical unclonable function (Pre-Amp PUF) is designed to support multiple challenge–response pairs per bitcell with zero array area impact. A novel addressing scheme executed on balanced pull-up and pull-down networks of the bitcell allow for reconfigurability of the PUF key and obfuscation of the data located within the chip. The Pre-Amp PUF bitcell is uniquely situated to replace other array-based PUF designs through improved hardware security and resistance to reverse engineering using imaging. Data is sensed using tens of millivolts of differential signal and remains valid only when a bitcell is selected for a read operation.

Physical unclonable functions (PUFs) produce full security keys without needing to store the key directly in nonvolatile memory (NVM) or publicly. PUFs rely on a stable entropy source across voltage, temperature, and lifetime. A high-gain preamplifier (Pre-Amp) bit cell was built into a dense 2-D array configured as 16 cells per bitline (BL) and 64 cells per wordline (WL). A hardware (HW) sample of 40 chips (1 Kb/chip) was manufactured in GLOBAL FOUNDRIES (GF) 12-nm (12 lp) CMOS technology for a total raw bit count of 40 960 bits. HW characterization was performed to support power supply ranging from 0.7 to 1.0 V and junction temperatures ranging from −40 °C to 125 °C with a worst case bit error rate (BER) of 0.174% after stabilization. The entropy source array is complete for productization with control logic and analog power system block for process, voltage, and temperature (PVT) compensation. A stable bit identification and sensing circuit is designed to identify bit cells that are robust against varied test conditions. The NIST 800-90B test suite was run on the native array and stable entropy source bits with minimum entropy scores of 0.65/bit and 0.697/bit, respectively. This article then introduces for the first time ever the ability for a PUF key to be corrupted and physically destroyed, which can be utilized to stop a tamper event or to corrupt obsolete chips. In the self-destruct (SD) mode, the entropy source data can be irreversibly destroyed, blocking all future authentication attempts. HW data show the before and after SD bitmaps, where electromigration (EM) physically breaks the connection of the entropy source bit cells from the sensing circuits. A safety lock circuit is also included to prevent inadvertent SD.