Integration of Ferroelectric K0.5Na0.5NbO3 films on Si at 400 °C

In this work, polycrystalline K0.5Na0.5NbO3 (KNN) thin films were successfully integrated on Si at 400 degrees C via a RF magnetron sputtering process. These films showed a polycrystalline bulk-like orthorhombic phase with mixed (00l) and (110) orientations, as was supported by X-ray diffraction and piezoelectric force microscopy analyses. Without a post-deposition annealing process, these films already showed a clear ferroelectric polarization-electric field (P-E) hysteresis loop, characterized by a remnant polarization similar to 11 mu C/cm(2) and a coercive field of similar to 280 kV/cm. This polarization response shows a good aging resistance (similar to 2 years). A dielectric constant of similar to 230 and a low loss tangent of similar to 1.8 % (@1 kHz) were achieved in the KNN film. Lastly, large dielectric tunabilities of similar to 50 % (@ 1 MHz) was revealed for the KNN film, illustrating their good potential for applications in tunable dielectrics.