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