Abstract: The C-V characteristics of the MOS capacitor with ultra thin HfO₂ as gate dielectrics pretreated in NH₄F and annealed in high temperature are investigated by simulation and experiment. Distribution of interface states is consistent with the experimental results. Shift of the flat-band voltage, density of oxide traps and interface states are calculated. The electrical properties of samples under different processes are compared using high frequency C-V methods. The investigation shows that the novel combination of NH₄F pretreatment and high annealing temperature can reduce interface states and oxide traps dramatically, thus decreasing the gate leakage current.

Key words: HfO₂, C-V characteristics, interface states, oxide traps