Microwave Characterization of Hydrothermally Crystallized Barium Strontium Titanate Sol-Gel Composite Thin Films using a Coplanar Waveguide Technique

摘要

Barium strontium titanate (BST) and BST doped with 5 at percent Mn films have been fabricated on gold-patterned alumina substrates by hydrothermal sol-gel composite recrys-tallization at <200 deg C. A spun-on sol-gel BST composite film is hydrothermally treated in an alkaline aqueous solution at elevated pressure. The dielectric constant and loss tangent between 5 and 40 GHz has been determined using the response of a series of coplanar waveguide spur-line band stop filters. The film shows a maximum dielectric constant between 15-40 GHz of 94 +- 5 for a film 2.6 mu m in thickness. The loss tangent at 15 GHz is 0.07.