Area and Energy Efficient Diode Based Spin Orbit Torque Non-Volatile Latch Design

This paper proposes a compact diode based spin orbit torque non-volatile latch (D-SOT-NVL) design. The proposed NVL can accommodate two different operation schemes. Firstly, a nominal scheme at which the data is stored on the SOT-MTJs when an external enable signal is exerted. Secondly, a special scheme that is only initiated if supply instability is indicated, at which data is stored every clock cycle. In addition, our proposed NVL only needs one overhead (OH) transistor. This is due to the replacement of the read transistor by an oxide based diode. Hence, our NVL achieves only 20% area OH over conventional volatile latch, which is at least 60% smaller than other designs. It also offers at least 21% lower backup energy compared to others. Further study shows that our NVL is robust and stable even with process and device variations.