Electron phenomena in LiNbO3-based heterostructures

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In this chapter, we examine the electrical properties of Si-LiNbO₃ heterostructures fabricated by RFMS and IBS methods without the ion assist effect. Through an analysis of current-voltage and capacitance-voltage characteristics, we propose an energy band diagram for the fabricated Si-LiNbO₃ heterostructures, detailing all main parameters. Regardless of the conductivity type of Si wafers, a positive oxide charge is formed, which limits the functionality of LiNbO₃-based heterostructures. The concentration of localized charge centers varies with the deposition method. The remnant polarization in the synthesized films is significantly lower than that in bulk lithium niobate, negatively impacting the application of the fabricated heterostructures in memory units. This reduction in polarization is likely due to the arbitrary orientation of grains. We investigate the charge transport mechanisms affecting DC conductivity of the studied heterostructures in detail, considering both temperature and applied voltage. Using impedance spectroscopy, we demonstrate that dielectric relaxation in LiNbO₃ films is influenced by the Maxwell-Wagner relaxation phenomenon.