ODESY: a novel 3T-3MTJ cell design with optimized area DEnsity, scalability and latencY

The STT-RAM (Spin-Transfer Torque Magnetic RAM) technology is a promising candidate for cache memory because of its high density, low standy-power, and non-volatility. As technology scales, especially under 40nm technology node, the read disturbance becomes severe since the read current approaches closely to the switching current. In addition, the read latency and access performance degrade significantly as well. The conventional 1T-1MTJ and 2T-2MTJ cell designs cannot address these challenges efficiently. In this paper, we propose a novel 3T-3MTJ cell structure using the advanced perpendicular MTJ technology. This memory cell has higher storage density and better performance, and is particularly suitable for the deeply scaled technology node. A two-stage sensing scheme is also proposed to facilitate the read operation of the 3T-3MTJ cell design. Circuit-level and architecture-level simulations show that the proposed 3T-3MTJ cell structure can achieve a better tradeoff between storage density, access performance, energy consumption, and reliability compared to the prior 1T-1MTJ and 2T-2MTJ cell structures.