Processing and characterization of lithium niobate thin films for ferroelectric nonvolatile memory applications.

摘要

Both highly c-axis and randomly-oriented LiNbO₃ thin films are grown on p-type Si (111) substrates by RF magnetron sputtering and metallo-organic decomposition (MOD), respectively. Ellipsometry, X-ray diffraction, AFM and SEM are used to analyze the structural quality of the deposited ferroelectric thin films, including thickness, crystallinity, stoichiometry and surface roughness. Metal-ferroelectric-semiconductor structures are fabricated and electrically characterized with polarization vs. electric field (P-E) and capacitance vs. voltage (C-V) measurements. Hysteresis curves based on polarization switching are observed, verifying the ferroelectricity of deposited LiNbO₃ thin films. Comparison of different film growth mechanisms between these two deposition methods is made, and their effects on physical and electrical characteristics of the derived LiNbO₃ thin films are discussed. RF magnetron sputtering is proved to be a more promising thin-film growth technique than MOD for ferroelectric nonvolatile memory applications.