Wy. Lin et al., Thin films of CCVD Ba0.5Sr0.5TiO3 and SrTiO3 for electrically tunable coupled microstripline phase shifters, INTEGR FERR, 29(1-2), 2000, pp. A1-A12
Epitaxial barium strontium titanate and strontium titanate thin films were
deposited on (100) MgO single-crystal substrates, utilizing Combustion Chem
ical Vapor Deposition. The as-deposited films were patterned with gold elec
trodes to form interdigitated structure to function as electrically tunable
devices, namely, coupled microstripline phase shifters (CMPS). Microwave d
ielectric properties were characterized at 11-20 GHz with an applied electr
ic field up to +/-35 V/mu m. A maximum figure of merit of 53 degrees/dB at
20 GHz and 23 degrees C was measured. The demonstrated high degree of tunab
ility and relatively low loss showed great potential of these films for the
targeted frequency agile device applications. Characterization, using SEM,
EDS, and XRD, is presented in addition to microwave performance as a funct
ion of do bias and frequency.