Hardware implementation of physically unclonable function (puf) in perpendicular STT MRAM
Ding-Yeong Wang, Yu-Chen Hsin, K. Y. Lee, G. L. Chen, S. Y. Yang, H. H. Lee, Y. J. Chang, I. J. Wang, Yi-Ching Kuo, Y. S. Chen, P. H. Wang, Chih‐I Wu, D.D. Tang · 2017
The pSTT MRAM array with stepped structure MTJ is fully integrated with standard 0.18 μm CMOS process. Using a low power etch process greatly improves the uniformity of MR and RP. The bit pattern is randomized with a voltage method and a cost-effective field method; the latter can be incorporated into wafer processing. We showed the bit pattern is unpredictable under the same sub-critical stimulation, thus, practically unclonable. The Hamming Weight and inter-chip Hamming Distance are both ~50%, an evidence of sufficient uniqueness. A single embedded STT-MRAM PUF can cover many needs of security electronics.