The Effect of Nanoscale Nonuniformity of Oxygen Vacancy on Electrical and Reliability Characteristics of $\hbox{HfO}_{2}$ MOSFET Devices

To understand the influence of oxygen vacancies in $\hbox{HfO}_{2}$ on the electrical and reliability characteristics, we have investigated area-dependent leakage-current characteristics of $\hbox{HfO}_{2}$ with large-area device and conducting atomic force microscopy (C-AFM). Unlike with the large-area analysis with typical capacitor and transistor, a clear evidence of oxygen vacancy was observed in nanoscale-area measurement using the C-AFM. Similar observations were made in various postdeposition annealing ambients to investigate the generation and reduction of oxygen vacancy in $\hbox{HfO}_{2}$. With optimized postdeposition annealing for oxygen vacancy, significantly reduced charge trapping was observed in $\hbox{HfO}_{2}$ nMOSFET.