Li depth profiles of metal/Li-electrolyte/metal capacitors under biasing studied by means of MeV ion beam analysis techniques

摘要

Li Depth profiles at the interfaces of capacitors of Cu/LiPON/Cu and Al/LiPON/Al prepared on buffer Ti layer /SiO2 glass and Au/LATP/Au (LiPON = Li3.3PO3.8N0.2, LATP = Li3.1Al0.84Ti1.16Ge1.27P1.73O12) under biasing bottom metal against top metal at earth potential have been in-situ measured by means of elastic recoil detection analysis (ERD) and Rutherford backscattering spectrometry (RBS) techniques. Li has been found to be enriched near the interface with electrode biased negatively, while it is depleted near that biased positively. The Li depth profile in electrolyte has been theoretically calculated, taking into account the transport faction of Li ions, based on hopping diffusion model of Li ions under potential gradient. It is shown that the Li depth profile calculated as a solution of diffusion equation at steady state agrees qualitatively well with the experimental ones and the transport fraction of Li ions in electrolyte is less than unity.