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

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 Zr
₃
N
₂
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 Zr
₃
N
₂
films, for memory cells annealed in conventional N
₂
gas as well as H
₂
gas. Compared to the N
₂
-annealed sample, after H
₂
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 H
₂
annealed Zr
₃
N
₂
RRAM cell, we observed a lower operation voltage/current, longer endurance, and larger read margin due to the hydrogen passivation effect.