Optimization of post deposition annealing temperature of direct current magnetron reactive sputtered zirconium titanate thin films for refractory oxide applications

Nano crystalline Zirconium titanate thin films with Zr/Ti/O compositions of 51.22/45.32/3.46 have been deposited on to the glass substrates at a substrate temperature of 250 °C under ultra high vacuum conditions by employing direct current magnetron reactive sputtering. Later on the sputtered films were treated with post deposition rapid thermal annealing with temperatures ranging from 100 to 600 °C for 1 h in a flowing Oxygen (1 standard cubic centimeter) atmosphere. The micro structural, optical, electrical and morphological film properties have been analyzed as a function of annealing temperature by employing x ray diffraction in glancing incident angle mode, ultra violet visible spectroscopy, four point probe technique, atomic force microscopy, scanning electron microscopy and energy dispersive x ray analysis studies. The evolution of structural properties began at an annealing temperature of 300 °C and improved up to 500 °C. Annealing resulted in the re crystallization in the films. Once the re crystallization of amorphous films has occurred, the annealing temperature did not affect the film thickness. However higher temperatures promote inter diffusion of the substrate and film elements, which is undesirable. Here the films exhibited smooth, crack free, homogeneous micro structure and a consistent thickness of ∼400 nm. From the results obtained it is found that the optimal annealing temperature range is 400-500 °C.