Design of SRAM PUF with improved uniformity and reliability utilizing device aging effect

SRAM Physical Unclonable Function (PUF) makes use of efficient silicon fabrication process where duplication of exact replica devices is difficult. One of the major issues with SRAM-PUF is the reliability and uniformity of the start-up pattern with environmental fluctuations. This paper presents a technique for improving uniformity (distribution of 1's & 0's) and reliability (variations in power-up patterns) of SRAM-PUF utilizing aging effects (mainly NBTI). The proposed technique maintains the uniformity of SRAM-PUF by controlling the polarity of the aging in SRAM arrays. The reliability is controlled by further injecting aging to the SRAM arrays after achieving target uniformity.