Study of a reversible resistive switching mechanism in bismuth titanate deposited by electron cyclotron resonance sputtering

We studied the temperature dependence of the reversible resistance switching in the bismuth titanate (BiTiO) film deposited by electron cyclotron resonance sputtering. The reversible resistance switching was observed at 5 K in both the low resistance state (LRS) and high resistance state (HRS) in the film. The resistance in the LRS decreased with increasing temperature, and remained unchanged regardless of an electrode-pad area. On the other hand, the resistance in the HRS increased with temperature, exhibiting the electrode-pad area dependence. From the cross-sectional transmission electron microscope image, nanocrystalline Bi4Ti3O12 particles were uniformly distributed in the BiTiO film. We proposed the mechanism of reversible resistance switching in BiTiO, that is, (1) the filament of conduction path was generated along the grain boundaries of the nanocrystalline particles by electroforming, (2) the LRS was switched-on, and (3) the filament was cut off by applying reverse bias voltages, switching back to the HRS. We verified the conduction of three-dimensional variable range hopping in the HRS.