Observation of Both Potential Barrier-Type and Conductive-Bridge-Type Resistance Switching with LiNbO3 Thin Films

Electric transport in sputtered LiNbO₃ (LN) films sandwiched between TiN and Si electrodes revealed Schottky emission at low electric field and Poole-Frenkel conduction at higher electric field without any hysteresis. The Poole-Frenkel conduction region was brought into the reproducible potential barrier-controlled conduction region by inserting a thin SiO₂ layer between LN and TiN, where current hysteresis appeared. Trapping of electrons at SiO₂/LN interface states when TiN is negatively biased produces the highest potential barrier, resulting in a high resistance state, whereas releasing the trapped electrons at positive bias leads to a low resistant state. When electric contact to the TiN electrode was taken using Ag paste, another current hysteresis resulting from the connection and disconnection of Ag filaments was observed after time-dependent soft dielectric breakdown.