Ultrahigh density vertical magnetoresistive random access memory (invited)

TLDR

The paper proposes a vertical magnetoresistive random access memory (VMRAM) design derived from micromagnetic simulations. The VMRAM employs a ring‑shaped magnetic multilayer stack exploiting vertical GMR, orthogonal word lines for robust switching, and a pseudo‑spin‑valve readback scheme that requires only one transistor per bit line, enabling very high area density. The design can achieve an estimated 400 Gbits/in² area density and could potentially replace existing semiconductor memories such as FLASH, DRAM, SRAM, and even disk drives.

Abstract

In this paper, we present the vertical magnetoresistive random access memory (VMRAM) design based on micromagnetic simulation analysis. The design utilizes the vertical giant magnetoresistive effect of the magnetic multilayer. By making the memory element into a ring-shaped magnetic multilayer stack with orthogonal paired word lines, magnetic switching of the memory device becomes very robust. The design also adopts the readback scheme in pseudo spin valve MRAM so that only one transistor is needed for each bit line which can connect hundreds of memory elements, yielding a very high area density. It is estimated that the ultimate area density for the VMRAM is 400 Gbits/in.2. It is suggested that this memory design has the potential to not only replace the present semiconductor memory devices, such as FLASH, but also the potential to replace DRAM, SRAM, and even disk drives.