Studies on read-stability and write-ability of fast access STT-MRAMs

It is shown that the 4T2MTJ and the 6T2MTJ-1 STT-MRAMs are more stable than SRAM at read operation in 90 nm, partly because the imbalanced resistances R_AP and R_P in a pair of MTJs increase the read-stability. However, the 6T2MTJ-2 STT-MRAM is not practical because of its destructive readout feature. For the worst cell (-5σ) in the tail distribution, the read-stability margin of the 4T2MTJ STT-MRAM is larger than the 6T2MTJ-1 one.