Nonvolatile Write Driver for Spin Transfer Torque Memory and Logic Design

This paper proposes a compact model of STT-MTJ being operated in the sub-volume (MTJ lateral diameter less than 40 nm) region. The model is found to have lower switching currents as well as higher thermal stability factor as compared to the conventional MTJ models being used. This paper mainly deals with the description of the static behavior of the model. This includes the critical current calculations, thermal stability calculations, TMR and MTJ resistance dependence on bias voltage. This paper also proposes a new READ and WRITE circuitry to facilitate an easier read and write operation. The paper illustrates a transmission gate based 2T1M MRAM bit cell which uses MTJ as a memory element.