This letter presents energy-efficient MgO based magnetic tunnel junction (MTJ) bits for high-speed spin transfer torque magnetoresistive random access memory (STT-MRAM). We present experimental data illustrating the effect of device shape, area, and tunnel-barrier thickness of the MTJ on its switching voltage, thermal stability, and energy per write operation in the nanosecond switching regime. Finite-temperature micromagnetic simulations show that the write energy changes with operating temperature. The temperature sensitivity increases with increasing write pulsewidth and decreasing write voltage. We demonstrate STT-MRAM cells with switching energies of < 1 pJ for write times of 15 ns.
Bibliographical noteFunding Information:
Manuscript received September 5, 2010; revised September 23, 2010; accepted September 24, 2010. Date of publication November 9, 2010; date of current version December 27, 2010. This work was supported in part by the Defense Advanced Research Projects Agency STT-RAM Program and in part by the Nanoelectronics Research Initiative through the Western Institute of Nanoelectronics. The review of this letter was arranged by Editor L. Selmi.
Copyright 2011 Elsevier B.V., All rights reserved.
- Magnetic tunnel junctions (MTJs)
- magnetoresistive random access memory (MRAM)
- nonvolatile memory
- spin transfer torque (STT)