Microwave Dielectric And Optical Properties Of Amorphous And Crystalline Ba0.5Sr0.5TiO3 Thin Films

The thin films of composition Ba0.5Sr0.5TiO3 (BST5) were deposited by Pulsed Laser Deposition technique on amorphous fused silica substrates at room temperature (RT) and at 700 degrees C. The film deposited at RT is amorphous while the other crystallized in cubic structure. The refractive index (n) and optical band gap (Eg) extracted from transmission spectra in the 190-2500 nm range. Microwave dielectric properties were investigated using the Split Post Dielectric Resonators (SPDR) technique at spot frequencies of 10GH(z) and 20GHz. The experimental results show that thin films deposited at high temperature (700 degrees C) shows very high dielectric constant for both 10GHz and 20 GHz. These high dielectric constant films can be used in a wide range of applications such as capacitors, non-volatile high speed random access memories, and electro-optic devices.