High density submicron magnetoresistive random access memory (invited)

TLDR

Giant magnetoresistance structures were patterned and studied for memory applications. The preferred memory element, based on pseudo‑spin valve structures, was designed with two magnetic stacks (NiFeCo/CoFe) of different thickness separated by Cu, producing dissimilar switching fields due to shape anisotropy at deep submicron dimensions. A lower switching current is achieved when the bit’s word line wraps around the bit 1.5 times, submicron memory elements integrated with CMOS transistors retain their characteristics without degrading the CMOS, and selectivity between memory elements in high‑density arrays was demonstrated.

Abstract

Various giant magnetoresistance material structures were patterned and studied for their potential as memory elements. The preferred memory element, based on pseudo-spin valve structures, was designed with two magnetic stacks (NiFeCo/CoFe) of different thickness with Cu as an interlayer. The difference in thickness results in dissimilar switching fields due to the shape anisotropy at deep submicron dimensions. It was found that a lower switching current can be achieved when the bits have a word line that wraps around the bit 1.5 times. Submicron memory elements integrated with complementary metal–oxide–semiconductor (CMOS) transistors maintained their characteristics and no degradation to the CMOS devices was observed. Selectivity between memory elements in high-density arrays was demonstrated.