Active microwave device applications of ferroelectric thin films

Abstract

We describe the deposition of Sr x Ba 1-x TiO 3 (0.5 x Ba 1-x TiO 3 thin films (approximately equals 5000 angstrom) deposited at 775-850 degree(s)C in 350 mTorr of oxygen onto (100) MgO and LaAlO 3 were smooth, single phase, and epitaxial with the underlying substrate. Highly oriented Sr 0.5 Ba 0.5 TiO 3 films on LaAlO 3 with x- ray rocking curves of 72 arc seconds were observed. The dielectric constant of Sr 0.5 Ba 0.5 TiO 3 thin films, determined from the signal in patterned transmission lines between 100 kHz and 0.1 GHz, was approximately equals 20% of that observed for the bulk and the zero field temperature dependence was broad in comparison to the sharply peaked behavior seen in bulk. The dielectric loss tangent was measured as a function of stoichiometry for Sr x Ba 1-x TiO 3 (0.2 0.8 Ba 0.2 TiO 3 . The results for Sr x Ba 1-x TiO 3 thin films presented in this paper are encouraging for future applications in active microwave devices.