Impact of Heating/Cooling Rate on the Post-Annealing of LLZO thin films

This study reports the deposition of garnet structured lithium lanthanum zirconate (LLZO) thin films using radio frequency (RF) sputtering on glass substrates by varying heating/cooling rate. Deposition was carried out at a sputtering power of 70 W for 30 min. under Ar environment. As deposited films were annealed at 500°C at different heating/cooling rates (1.5, 6 and 12°C/min). It was observed that these films were amorphous in nature and no crystalline phase is reported despite the change in heating/cooling rates. Thickness and compositions of these films were estimated using Rutherford backscattering spectroscopic (RBS) measurements. Thicknesses of as deposited films was 110 nm and reduced to 90 nm on annealing at different heating/cooling rates suggesting intermixing at the interface. This intermixing phenomenon, observed at the interfaces of the LLZO thin film, suggests potential interactions or diffusion processes during the annealing process.