Preparation of Barium Strontium Titanate Thin Film by Spray Deposition

Barium strontium titanate ((Ba,Sr)TiO 3 ; BST) thin films were prepared on platinum-coated silicon substrates using spray deposition. The spray condition (substrate temperature and chamber pressure) dependence on surface roughness for the fired BST thin films was investigated. We obtained BST films thinner than 100 nm on the following properties. Average roughness (Ra) and peak-to-valley value (Rmax) were 3.9 and 130 nm. Dielectric constant and dissipation factor at 1 kHz were 250 and 1.6%. These excellent properties were obtained with even thickness. This method is considered to be advantageous for use with electronic devices that have thin dielectric layers, which make for thin films.