Measurement of mismatch factor and noise of SRAM PUF using small bias voltage

Mismatch factor of SRAM bit cell and noise factor that affects its power up state are measured using 256 bit SRAM PUF test structure with bias voltage inputs. Probability of power up state is used to extract a mismatch factor normalized by σ
n
(sigma noise voltage). By combining shifted bias voltages and repeat evaluation, whole 256 bit mismatch factors from real SRAM with small modification are obtained. According to the measurement data, it is confirmed that both noise factor and mismatch factor follow Gaussian distribution within a range of ±3.5σ and ± 2.9σ, respectively.