Correlation between 1064 nm laser attack and thermal behavior in STT-MRAM

Abstract

In this paper, the impact of a 1064 nm laser attack on an STT-MRAM cell is experimentally studied in real-time, for the first time, during reading and writing operations, in order to understand the behavior of a sensing circuit under a temperature variation from 25 °C to 105 °C. This must be considered for the implementation of a hybrid CMOS/MRAM Light-Weight Cryptography circuit, to overcome a laser attack. We highlight a reading current variation during the laser shots, that can impact the sensing circuits. The switching probability between the two states has been measured as well as the impact of the irradiation time, laser power, and cell size. We correlate the results with electrical characterizations in a wide range of temperatures, demonstrating the 1064 nm laser attack thermally affects the STT-MRAM behavior. In conclusion, suitable countermeasures can be adopted.