The research of data retention of HfO2 as trapping layer: First-principles study

Abstract

Abstract The influence of the Charge Trapping Memory storage feature was researched by doping the substitutional impurity Al and introducing oxygen vacancy within HfO2. Materials studio and Vienna Ab-initio Simulation Package were used to investigate the influence of doping Al on the formation of the oxygen vacancy in HfO2 as trapping layer. At the same time, the interaction energy of two defects under different distances was calculated. The calculation results show that doping the substitutional impurity Al reduces the formation energy of oxygen vacancies in the HfO2, and the reduced formation energy of the three-fold-coordinated O vacancy is larger than that of the four-fold-coordinated O vacancy. After having studied three different defect distances between substitutional impurity Al and three-fold-coordinated O vacancy, the results indicate that the system acquires the largest charge trapping energy, the most quantum states when the distance of the defects is 2.107Å. As a conclusion, the data retention in the trapping layer of monoclinic HfO2 can be improved by doping the substitutional impurity Al. This work will provide a theoretical guidance for the performance improvement with respect to the data retention of Charge Trapping Memory.