Low-frequency and microwave performances of laser-ablated epitaxial Na_(0.5)K_(0.5)NbO_(3) films on high-resistivity SiO_(2)/Si substrates

摘要

The dielectric properties of laser-ablated 0.5-μm-thick c-axis epitaxial Na_(0.5)K_(0.5)NbO_(3) (NKN) films on high-resistivity (>7.7 kΩcm) silicon SiO_(2)/Si substrates are studied experimentally in the temperature interval of 30-320 K and at frequencies of 1.0 MHz-40 GHz. The films are grown by laser ablation from a stoichiometric target. For the measurements, planar 0.5-μm-thick gold electrodes (interdigital and straight slot) are photolithography defined on the top surface of NKN films. The slot width between the electrodes is 2.0 or 4.0 μm. At low frequencies (f1. At microwave frequencies (f>10 GHz), the voltage dependence of the capacitance is given by the NKN film. More than a 13 capacitance change at 40 V dc bias and a Q factor of more than 15 are observed at 40 GHz, which make the structure useful for applications in electrically tunable millimeter-wave devices.