P-STT-MRAM Thermal stability and modeling of its temperature dependence

International audienceDue to their high speed[1], high endurance[2] and non-volatility, perpendicular STT-MRAM (P-STT-MRAM) are seen as one of thebest candidate for non volatile memory embedded applications. However, their data retention time at elevated temperature such as thesoldering reflow criterion and the automotive application temperature range is still a critical point. In this paper, P-STT-MRAM deviceswith diameters ranging from 20nm to 150nm have been tested in temperature. The thermal stability factor has been extractedelectrically for temperatures up to 190°C. Then the loss in the Curie temperature of the storage layer compared to bulk values has beenmeasured and directly linked to the thermal stability values. At last, a model is proposed to predict the temperature dependance of thethermal stability factor