Preparation of (Ba, Sr)TiO₃ Thin Films with High Pyroelectric Coefficients at Ambient Temperatures

Ferroelectric barium strontium titanate (BST) thin films were grown on Pt/Ta 2 O 5 /SiO 2 /Si by sputtering Ba 0.66 Sr 0.34 TiO 3 targets containing different amounts of excess SrO. It was found that the excess SrO in the target strongly influenced the microstructures and pyroelectric properties of the BST films. Compared with the BST film grown using a target without excess SrO, BST films grown using targets containing excess SrO of 0.02–0.04 by molar fraction showed larger grains and higher tendency to grow along (200) orientation, resulting in better pyroelectric characteristics at ambient temperatures. We obtained BST films with a considerably high pyroelectric coefficient of 240 nC·cm -2 ·K -1 .