Comprehensive trap-level study in SiOx-based resistive switching memory

The charge-trapping characteristics and trap levels of SiO_x-based (TaN/SiO₂/n⁺⁺ Si-substrate) resistive switching memory (RS) have been investigated. Multilevel operation under compliance current control is demonstrated and current transport behavior is analyzed using the normalized conductance of low resistive state (LRS) and high resistive state (HRS). Temperature dependence of I-V characteristics indicates that corresponding trap-level depths and hopping distance are consistent with Frenkel-Poole emission and hopping conductance with voltage-dependent activation energy. In the high-voltage region in LRS, Fowler-Nordheim fitting indicates a weak dependence of tunneling distance on temperature, whereas the effective filament area shows a strong dependence with a calculated filament radius of about 10nm. SEM images of small gaps formed in a planar structure and EDX analysis indicate oxygen-deficient regions within the gap. Our experimental results not only provide additional insights into the trap-level system of SiO_x-based RS memory but also help to construct a physical picture for the switching mechanism.