X-ray absorption spectroscopy approaches to electronic state and coordination type of lithium phosphorus oxynitride thin films

In this study, lithium phosphorus oxynitride (LiPON) thin films were deposited by radio frequency (r.f.) magnetron sputtering of a lithium phosphate (Li ₃PO ₄) target with various powers. The crystal structure, morphology, chemical environment, ionic conductivity, electronic state and coordination type were sequentially characterized by X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and X-ray absorption spectroscopy, respectively. As the results, the optimal ionic conductivity was achieved by the r.f. power of 75 W. Furthermore, the P-N valence states of hybrid orbitals were increased with increasing the nitrogen amounts.