Interface characterization and current conduction in HfO2-gated MOS capacitors

Metal-oxide-semiconductor (MOS) capacitors incorporating hafnium dioxide (HfO2) dielectrics were fabricated and investigated. In this work, the electrical and interfacial properties were characterized based on capacitance-voltage (C-V) and current-voltage (I-V) measurements. Thereafter the current conduction mechanism, electron effective mass (m*), mean density of interface traps per unit area and energy (D¯it), energy distribution of interface traps density and near-interface oxide traps density (NNIOT) were studied in details. The characterization reveals that the dominant conduction mechanism in the region of high temperature and high field is Schottky emission. The mean density of interface traps per unit area and energy is about 6.3 × 1012 cm−2 eV−1 by using high-low frequency capacitance method. The maximum Dit is about 7.76 × 1012 cm−2 eV−1 located at 0.27 eV above the valence band.