Random number generation by differential read of stochastic switching in spin-transfer torque memory

open8siThe true random number generator (TRNG) is a key enabling technology for cryptography and hardware authentication, which are becoming essential features in the era of the Internet of Things (IoT). Here, we present a novel TRNG concept based on the stochastic switching in spin-transfer torque magnetic random access memory (STT-MRAM). The new methodology relies on the STT-MRAM switching variations affecting the current response under applied rectangular or triangular pulses. Random numbers are extracted from the differential read of the integrated current across two stochastic switching cycles. The proposed concept passes all tests in the NIST SP-800-22 suite with no post-processing, thus supporting STT-MRAM as a promising technology for data/hardware security in the IoT.openCarboni, Roberto; Chen, Wei; Siddik, Manzar; Harms, Jon; Lyle, Andy; Kula, Witold; Sandhu, Gurtej; Ielmini, Daniele*Carboni, Roberto; Chen, Wei; Siddik, Manzar; Harms, Jon; Lyle, Andy; Kula, Witold; Sandhu, Gurtej; Ielmini, Daniel

Multistate spin-transfer-torque random access memory

Spin-transfer-torque random access memory (STT-RAM) is an emerging non-volatile memory technology that stores information as the relative alignment of two ferromagnets in a magnetic tunnel junction stack. Due to high scalability, speed and endurance STT-RAM is being considered as a promising candidate for future universal memory. To improve storage density various multi-state configurations have been proposed for STT-RAM. Previously, using micromagnetic simulations, it was shown that shape anisotropy of a cross-shaped ferromagnet can be used to achieve multi-state operation in a STT-RAM bit. In this work, we attempt to demonstrate the multi-state operation of such cross-shaped ferromagnet experimentally. We have explored different approach to fabricate cross-shaped magnetic tunnel junctions. Using magnetic force microscopy we demonstrate equilibrium magnetization states of a patterned cross-shaped ferromagnet. Challenges and future perspectives have been discussed.Electrical and Computer Engineerin