Physical Unclonable Functions Using Ferroelectric Tunnel Junctions

We propose physical unclonable function (PUF) operations using ferroelectric tunnel junctions (FTJs) and verify the effects of their dimension scaling on the PUF. First, device-to-device variation and within-device reproducibility were measured from the FTJs with various dimensions, which were to be embedded to 4×4 FTJ cross-point array. Then, to obtain inter- and intra-chip fractional hamming distances (HDs), intra-chip reproducibility and inter-chip uniqueness were extracted from the FTJ array simulations. As a result, it is revealed that the more stable PUF operations are achievable in the cross-point array with scaled FTJs since inter-device variation is deteriorated much more seriously by the variation of domain number in the ferroelectric layer than intra-device variation.