Realization of spin-torque transfer magnetoresistive RAM

Spin-torque transfer (STT) programming is a promising, maturing, non-volatile memory technology for future memory applications. When a sufficient current density passes through the MTJ, the spin polarized current will exert a spin transfer torque to switch the magnetization of the free layer. This is the fundamental of the write mechanism in STT-RAM, current induced magnetization switching. It allows STT-RAM to have a smaller cell size and write current than MRAM.The new MRAM cell structure design can realize high speed and reliable sensing operations in the presence of relatively poor magnetoresistive ratio, while maintain the low sensing current through the magnetic tunnellingjunctions (MTJs). The effectiveness of the proposed RAM structure was demonstrated by circuit simulation at 0.18µm CMOS technology using Mentor Graphics tool.