DC field dependent properties of Na0.5K0.5NbO3/SiO2/Si structures at millimeter-wave frequencies

Abstract

Dielectric properties of laser-ablated 0.5-μm-thick c-axis epitaxial Na0.5K0.5NbO3 films on high-resistivity (7.7 Ω cm) silicon SiO2/Si substrate are studied experimentally at frequencies up to 40 GHz. For measurements, planar 0.5-μm-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of Na0.5K0.5NbO3 films. The slot width between the electrodes is 2 or 4 μm. 13% capacitance change at 40 V dc bias and Q factor more than 15 are observed at 40 GHz, which makes the structure useful for applications in electrically tunable millimeter-wave devices.