22nm STT-MRAM for Reflow and Automotive Uses with High Yield, Reliability, and Magnetic Immunity and with Performance and Shielding Options

We demonstrate high yield results from a solder-reflow-capable spin-transfer-torque MRAM embedded in 22nm ultra-low leakage (ULL) CMOS technology. The technology supports −40 to 150°C operation and data retention though six solder reflow cycles and far exceeding 10 years at 150°C. Ten year native magnetic field immunity is >1100 Oe at 25°C at the 1ppm bit upset level. A shield-in-package solution demonstrates <1ppm bit upset rates from a disc magnet providing 3.5 kOe disturb field exposure for ~80 hours at 25°C. Trading off reflow capability, using smaller CD magnetic tunnel junctions, higher performance is achieved, for example read signal development times of 6ns at 125°C and average write pulse times slightly over 30ns at −40°C in a 20Mb design.