Characterization of Reactively Sputter Deposited Lithium Phosphorus Oxynitride Thin Films

Lithium phosphorous oxynitride (LiPON) is an important thin film solid state electrolyte material in lithium battery technology due to its ionic conductivity and stability against metallic lithium. Substrate biasing during RF sputter deposition of LiPON thin films has played a significant role in increasing ionic conductivity. However the fundamental mechanism of the high ionic conductivity is not yet well understood. The present study reports the XPS analysis of the LiPON films (to obtain atomic bonding information), Stress measurements (to understand delamination issues) and chemical composition measurements using inductivtely coupled plasma optical emission spectroscopy. Previous research [1] has shown that nitrogen incorporation in reactively sputter-deposited lithium orthophosphate shows an increase in the extent of phosphorusnitrogen bonds, which replace phosphorus-oxygen bonds. This study will bring upon the correlation between ionic conductivity against biasing with bonding information, stress measurements and chemical analysis. Infra-red spectroscopy will also be used to characterize the films.