Low-voltage and high-tunability interdigital capacitors employing lead zinc niobate thin films

Employing high-tunability PbO-ZnO-Nb2O5 thin film dielectrics, low-voltage and high-tunability interdigital capacitors (IDCs) were implemented on a silicon substrate. In order to reduce the bias voltage of the IDC and increase its tunability, its electrodes were fully embedded into the thin film dielectrics to confine fringing electric fields within them. At 4 V, the tunability of the IDCs was analyzed in terms of the electrode width and spacing by measuring reflection coefficients at 1 GHz. The fabricated IDC with width and spacing of 1.5 and 1.8 mu m, respectively, achieved tunability of 26% and a Q factor of 10 at 5.5 V. (c) 2007 American Institute of Physics.