The effect of annealing atmosphere on the (HfO2)0.9(Al2O3)0.1 based charge trapping nonvolatile memory

Charge trapping flash memory devices using (HfO2)0.9(Al2O3)0.1 as the charge trapping layer were fabricated, and the effect of post-annealing atmospheres (NH3 and N2) on its charge storage characteristics was investigated. It was found that NH3 annealed memory device showed a larger memory window of 7.3 V and improved data retention even at 85 °C compared to N2 annealed memory devices. The enhanced memory characteristics should be attributed to deep level bulk charge traps induced in the charge trapping layer by NH3 annealing. In addition, the large conduction band offset value between tunneling layer and charge trapping layer also resulted in good retention performance.