International Business Machines Corporation
MTJ CAPPING LAYER STRUCTURE FOR IMPROVED WRITE ERROR RATE SLOPES AND THERMAL STABILITY

Abstract:

A magnetic tunnel junction (MTJ) stack structure having an enhanced write performance and thermal stability (i.e., retention) is provided which can be used as an element/component of a spin-transfer torque (STT) MRAM device. The improved write performance, particularly the write error rate slope as a function of write voltage (Vfrc) which is essential in defining the overdrive voltage needed to successfully write a bit at low write error floors, is provided by a MTJ stack structure in which a zirconium (Zr) cap layer is inserted between a MTJ capping layer and an etch stop layer.