A 4kb memory array for MRAM development

Abstract

The circuits for a A 4kb array of Magnetic Tunnel Junctions (MTJs) have been designed and fabricated in a 0:18¹m CMOS process with three levels of metal. Support circuitry for addressing, reading, writing, and test mode probing enables the characterization of the switching of a thin-film ferromagnetic layer in the MTJs. Specifically, novel mechanisms involving spin-transfer or thermal assistance can be studied and compared to current MRAM designs that switch the MTJ with current-induced magnetic fields. Using this array design, both high speed digital and quasi-static dI/dV experiments can be conducted to investigate the nature of the MTJ resistance hysteresis and process variation in addition to the switching behavior under both polarities of current.