PUF Value Generation Using Anti-Fuse Array

The patent applies programming voltage to multiple anti-fuse memory cells simultaneously in a pair, but relies on the preliminary random variation in dielectric breakdown timing inherent in the manufacturing process. The system does not control which cell breaks down first, but rather exploits the natural random timing difference. This preliminary action approach allows simultaneous programming while maintaining randomness, as the breakdown event in each cell is predetermined by manufacturing variations rather than controlled by the system.

The patent incorporates a read-verify operation that checks the state of anti-fuse memory cells after programming. This feedback mechanism detects whether one or both cells in a pair have programmed, and if both have programmed (indicating loss of randomness), the system can identify and handle such cases. The feedback loop ensures that only pairs with exactly one programmed cell are used for PUF code generation, maintaining the required randomness.

The patent exploits the natural random timing difference in dielectric breakdown between cells in a pair, without requiring additional control circuitry to enforce the sequencing. The physical phenomenon of dielectric breakdown inherently provides the random ordering needed, and the system simply observes and utilizes this self-generated randomness. This self-service approach maintains high reliability of random bit generation while avoiding the complexity of additional control mechanisms.

The patent uses identical anti-fuse memory cell structures in pairs, with both cells having the same design and connectivity. This copying approach simplifies the overall system design, as the randomness emerges from the natural variations in identical structures rather than requiring differentiated complex circuitry. The uniform cell design reduces device complexity while maintaining reliable random bit generation through the inherent variations in breakdown timing.