A COMPARISON OF MOCLD WITH PLD Ba_xSr_(1-x)O_3THIN FILMS ON LaAlO_3 FOR TUNABLE MICROWAVE APPLICATIONS

摘要

Historically, tunable dielectric devices using thin crystalline Ba_xSr_(1-x)O_3 (BST) films deposited on lattice-matched substrates, such as LaAlO_3, have generally been grown using pulsed laser deposition (PLD). Highly oriented BST films can be grown by PLD but large projects are hampered by constraints of deposition area, deposition time and expense. The Metal-Organic Chemical Liquid Deposition (MOCLD) process allows for larger areas, faster turnover and lower cost. Several BST films deposited on LaAlO_3 by MOCLD have been tested in 16 GHz coupled microstrip phase shifters. They can be compared with many PLD BST films tested in the same circuit design. The MOCLD phase shifter performance of 293 deg phase shift with 53 V/mu m dc bias and a figure of merit of 47 deg/dB is comparable to the most highly oriented PLD BST films. The PLD BST films used here have measured XRD full-width-at-half-maxima (FWHM) as low as 0.047 deg. The best FWHM of these MOCLD BST films has been measured to be 0.058 deg.