2-Mb SPRAM design: bi-directional current write and parallelizing-direction current read based on spin-transfer torque switching

A 1.8 V 2-Mb SPRAM (SPin-transfer torque RAM) chip using 0.2-μm logic process with MgO tunneling barrier cell is reviewed, which demonstrates the circuit technologies for potential low power non-volatile RAM, or universal memory. This chip features: an array scheme with bit-by-bit bi-directional current write to achieve proper spin-transfer torque writing of 100-ns, and parallelizing-direction current reading with low voltage bit-line that leads to 40-ns access time. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)