Strontium-barium-titanate thin films by sol-gel processing

摘要

Barium and strontium titanate are known to form solid-solutions with each other at all compositions because of their identical crystal structures. The solid-solutions have potential applications in the electronic ceramic industry and specifically for high performance microwave phase shifters. Phase shifters are an essential component of phase-array antennas. Recently ceramic phase shifters have shown better performance than ferrite and PIN diode phase shifters because of their high power handling capacity, low drive power, wide operating temperature and low cost. Such ferroelectric materials for phase shifters should exhibit a large change of dielectric constant with applied DC bias voltages and very low loss tangents at microwave frequencies [1,2], These materials are also required to be insensitive against environmental changes. In the past, SBT bulk ceramics have shown some promise in meeting the above criteria [1, 2]. This work is an attempt to produce SBT thin films to realize small, low-loss, inexpensive, and tunable microwave capacitors.