Experimental and Simulation Studies of the Effects of Heavy-Ion Irradiation on HfO2-Based RRAM Cells

HfO2-based resistive RAMs have been irradiated with high-linear energy transfer heavy ions and subjected to an extensive characterization, showing that the cells are immune from upsets. No relevant changes were observed in the irradiated cells on resistance distribution and programming voltages. The irradiation experiment has been performed without any applied bias (retention mode). Reasons for the observed hardness are discussed using physics-based simulations. Moreover, simulations put in evidence that the cell might be sensitive if it is struck during a read operation, since the applied read voltage prevents the instantaneous recombination of the generated defects due to the Coulomb interaction between oxygen ions and vacancies.