A first-principles study of interfacial fluorination at the HfO2/Al2O3 interface in charge trapping memory devices

The effect of interfacial fluorination on the structure, electronic properties, and performance of the HfO2/Al2O3 interface in charge-trapping memory (CTM) devices is investigated using the first-principles calculation. The impact of the interface states on the characteristics of traps in the HfO2 trapping layer at the HfO2/Al2O3 interface is studied first, and the results indicate that the interfacial states lead to performance degradation with respect to both reliability and the memory window of CTM devices during program/erase cycles. In the study of F passivation, F substitutions (FO) and F interstitials (Fi) tend to improve the thermal stability of the interface for higher interfacial F contents. Further, the FO-passivated interface is energetically more stable than the Fi-passivated interface. In addition, the FO-passivated interface can reduce the interface states that are partially (or completely) caused by breaking covalent interfacial bonds. Furthermore, a substantially improved HfO2/Al2O3 interface, with effective interfacial passivation in CTM devices, is obtained. Therefore, this study helps explain the intrinsic principle of interface passivation and opens new ways for performance improvement of the HfO2/Al2O3 interface in CTM devices.The effect of interfacial fluorination on the structure, electronic properties, and performance of the HfO2/Al2O3 interface in charge-trapping memory (CTM) devices is investigated using the first-principles calculation. The impact of the interface states on the characteristics of traps in the HfO2 trapping layer at the HfO2/Al2O3 interface is studied first, and the results indicate that the interfacial states lead to performance degradation with respect to both reliability and the memory window of CTM devices during program/erase cycles. In the study of F passivation, F substitutions (FO) and F interstitials (Fi) tend to improve the thermal stability of the interface for higher interfacial F contents. Further, the FO-passivated interface is energetically more stable than the Fi-passivated interface. In addition, the FO-passivated interface can reduce the interface states that are partially (or completely) caused by breaking covalent interfacial bonds. Furthermore, a substantially improved HfO2/Al2O3 inter...