STT-RAM read stability in DRAM operating region

Spin-transfer-torque RAM (STT-RAM) is the most promising candidate for replacing DRAM while gaining an additional function of non-volatility. The relationship between rapid increase of spin-inversion current and stability of read operation (read disturbance) in the DRAM-array operating time region of less than 10 ns (i.e., "fast" region) was examined by using a Landau-Lifshitz-Gilbert equation based simulator. The results revealed a difference in the magnetization-reversal paths in the fast region compared to that in the "slow" time region in terms of spin behavior during the inversion operation and the dependence of switching current on the direction of applied magnetic field. As a result, the stability of read operation in this fast region is sufficiently increased. Accordingly, configurations of STT-RAM based on these results are discussed.