Abstract
The role of oxygen deficiencies on the electrical performance of SrTiO3 films is investigated by depositing on the stack of TiN/Ti/SiO2/Si films using radio-frequency (RF) and direct current (DC) magnetron sputtering systems operating in oxygen-deficient plasma environment. Electrodes of silver (Ag) and titanium (Ti) are used to observe the effects of their sizes on the electrical properties of the SrTiO3 films. It is found that the nonlinearity in capacitance-voltage graphs (capacitance tunability) of the varactor can be controlled by varying the electrode area. In addition, the material of the electrode plays a vital role in controlling the non-linearity in the capacitance of the oxygendeficient SrTiO3 dielectric films with varying voltage. It is found that the silver top electrode instead of titanium, delivers better performance with high capacitance tunability, low leakage current and good quality factor. Post deposition annealing at 550 degrees C in nitrogen ambient, creates more oxygen deficiencies in SrTiO3 film thereby increasing the linearity of the capacitance-voltage graph and decreasing the capacitance tunability.