In this Letter, the self-rectifying resistive switching (RS) behavior is demonstrated in Ti/ZrN/Pt/p-Si resistive random access memory (RRAM) devices. Compared to an RS characteristic of the conventional Ti/ZrN/Pt structures, the memory cell with a p-Si bottom layer shows a larger current ratio. However, a current-limited region is also more clearly obtained in a low voltage region, which can result in one diode-type RRAM with self-selecting properties. Consequently, these results infer that the proposed ZrN-based RRAM cells with a Pt/p-Si selector warrant the realization of the self-selecting RRAM cell without any additional peripheral elements to suppress a disturbance in the reading operation.

Oxygen (O 2 ) sensing in trace amounts and mixed gas is essential in many types of industries. Semiconductor sensors have proven to be invaluable tools for the O 2 measurements in a wide concentration range, but the sensors are only able to quantify O 2 in a concentration range of subppm, thus far, especially in mixed gas. We present in this paper a new concept for O 2 sensing with incomparable sensitivity using IGZO-films with oxygen vacancy-based conducting filaments (CFs). O 2 sensing relies on rupturing of the CFs, and the proposed device quickly recovers to the initial state using a pulse of 0.6 V/90 μs after the sensing. The proposed device has a high sensitivity of 14 even at an O 2 concentration of 500 ppb, a detection limit of 150 ppb for O 2 at RT, and excellent selectivity for O 2 in mixed gas, which is remarkable compared to other gas sensors. The proposed device can be widely used in gas sensors especially for detecting O 2 at a low ppb level, which is due to excellent sensing characteristics.

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In this work, we report the feasibility of resistive switching (RS) properties of oxygen-doped zirconium nitride (O-doped ZrN) films with platinum (Pt) and platinum silicide (PtSi) bottom electrode (BE), produced by a sputtering method. Compared to O-doped ZrN using Pt BE, when Pt/p-Si was used as BE, the foaming voltage slightly increased, but the operation current was reduced by about two orders. In particular, the average reset current of the O-doped ZrN memory cells was reduced to 50 µA, which can delay deterioration of the element, and reduces power consumption. Therefore, the use of PtSi as the BE of the O-doped ZrN films is considered highly effective in improving reliability through reduction of operating current of the memory cells.

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 (N it ) at the Zr 3 N 2 /p-Si layer and nitride trap density (N 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, N 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.INDEX TERMS Hydrogen passivation, rapid thermal annealing, resistive switching, self-rectifying, Zr 3 N 2 , nitride trap density, interface trap density.