Reduction of oxide and interface charge density of reactive sputtered HfO_2 thin films by rapid thermal annealing

摘要

Hafnium oxide ceramic thin films were deposited on silicon substrates by RF magnetron reactive sputtering at room temperature. Post-deposition rapid thermal annealing of the sputtered HfO_2 films was carried out with the variation in process duration in oxygen ambient. The structural properties were studied by X-ray diffraction technique, where an enhancement in the crystallinity of HfO_2 (111) orientation was observed with annealing durations. The capacitance-voltage (C-V) and current density-voltage (J-V) characteristics of the annealed ceramic films were investigated using Al/HfO_2/Si metal oxide semiconductor capacitor structure. The flatband voltage (Vfb) and oxide charge density (Qox) were extracted from the high frequency (1 MHz) C-V curve. The interface charge density (Dit) and leakage current density were found to be minimum for RTA treatment at 600 °C for 135 sec, which is due to the decrease in dangling bonds at the HfO_2/Si interface.