Characterization of (Ba0.5Sr0.5)TiO3 thin films for Ku-band phase shifters

The microstructural properties of (Ba0.5Sr0.5)TiO3(BSTO) thin films (300, 7 00, and 1400 nm thick) deposited on LaAlO3 (LAO) substrates were characteri zed using high-resolution x-ray diffractometery. Film crystallinity was the parameter that most directly influenced tunability, and we observed that a ) the crystalline quality was highest in the thinnest film and progressivel y degraded with increasing film thickness; and b) strain at the film/substr ate interface was completely relieved via dislocation formation. Paraelectr ic films such as BSTO offer an attractive means of incorporating low-cost p hase shifter circuitry into beam-steerable reflectarray antennas.