Microwave properties of AgTa0.5Nb0.5O3 thin film varactors on various substrates

400nm thick AgTa0.5Nb0.5O3 (ATN) films have been sintered by pulsed laser deposition technique on LaAlO3 (001), sapphire (Al2O3-01 (1) under bar2, r-cut) single crystal substrates and Coming 7059 Glass. Photolithography and metal lift-off technique were used to fabricate tunable Coplanar Waveguide Interdigital Capacitors (CPWIDCs). On-wafer test of varactors was performed with microwave network analyzer and G-S-G microwave probe. ATN/LaAlO3 capacitors demonstrated the highest tunability (similar to 5.8%@20GHz), ATN/Glass showed the best flat dispersion (similar to 3.9%) and ATN/ Al2O3 showed the lowest loss tangent (similar to 0.06@20GHz) in the microwave range from 1 to 40 GHz.
QC 20100906