Improved Resistive Switching Observed in Ti/Zr₃N₂/<italic>p</italic>-Si Capacitor via Hydrogen Passivation

Abstract

Charge-trap based resistive switching (RS) has attracted attention in the resistive random-access memory (RRAM) industry due to its gradual RS behavior for multi-level and synaptic applications. In this work, in order to lower the operating current level closely related to device’s degradation, we applied a hydrogen passivation to Zr3N2 based RRAM devices and investigated the correlation between current level and trap density, such as an interface trap density ( $\text{N}_{\mathrm {it}}$ ) at the Zr $_{3}\text{N}_{2}/p$ -Si layer and nitride trap density ( $\text{N}_{\mathrm {nt}}$ ) within Zr3N2 films, for memory cells annealed in conventional N2 gas as well as H2 gas. Compared to the N2-annealed sample, after H2 annealing, $\text{N}_{\mathrm {it}}$ is lowered by the hydrogen passivation effect, which results in a reduction of both current level at high resistive state (HRS) and variation of HRS and low resistive state (LRS). As a result, in the H2 annealed Zr3N2 RRAM cell, we observed a lower operation voltage/current, longer endurance, and larger read margin due to the hydrogen passivation effect.

Keywords

• Hydrogen passivation
• rapid thermal annealing
• resistive switching
• self-rectifying
• Zr₃N₂
• nitride trap density