PECVD Silicon Carbide as a Chemically-Resistant Thin Film Packaging Technology for Microfabricated Antennas

This paper describes an effort to develop microfabricated planar antennas that utilize a plasma enhanced chemical vapor deposition (PECVD) based silicon carbide (SiC) thin film packaging technology to provide chemical resistance. The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on alumina substrates that utilize a self matching impedance technique. The PEVCD SiC thin film was deposited at 300degC at a chamber pressure of 900 mTorr and a power level of 100 W. The SiC film thickness was 450 nm. The antennas exhibit a return loss better than -15 dB at 5 and 7 GHz before and after SiC deposition. The gain of the antennas is 3 dB at 5 and 7 GHz before and after SiC deposition. The SiC-coated antennas were submerged into Au etchant for over a 24 hr period with no degradation in RF performance or physical integrity