Memristive behaviour of Si-Al oxynitride thin films: the role of oxygen and nitrogen vacancies in the electroforming process

Abstract

The resistive switching properties of silicon-aluminium oxynitride (SiAlON) based devices have been studied. Electrical transport mechanisms in both resistance states were determined, exhibiting an ohmic behaviour at low resistance and a defect-related Poole-Frenkel mechanism at high resistance. Nevertheless, some features of the Al top-electrode are generated during the initial electroforming, suggesting some material modifications. An in-depth microscopic study at the nanoscale has been performed after the electroforming process, by acquiring scanning electron microscopy and transmission electron microscopy images. The direct observation of the devices confirmed features on the top electrode with bubble-like appearance, as well as some precipitates within the SiAlON. Chemical analysis by electron energy loss spectroscopy has demonstrated that there is an out-diffusion of oxygen and nitrogen ions from the SiAlON layer towards the electrode, thus forming silicon-rich paths within the dielectric layer and indicating vacancy change to be the main mechanism in the resistive switching.

Resistive switching and charge transport mechanisms in ITO/ZnO/p-Si devices

“…Further study on a stressed device and comparison with a pristine one (not shown) has provided prove of the modification of the ZnO structure, by comparing the resonant Raman E 1 (LO) overtones between both devices. As it has previously been suggested, 40,41 this fact is compatible with our hypothesis of oxygen out-diffusion in RS. Thus, the use of electrodes non-transparent to oxygen, ITO in our case, becomes an important factor in improving the endurance of these ZnO-based devices.…”

White Cathodoluminescence Emission from Eu‐Doped SiAlON Thin Films

“…The as‐grown and thermally treated SiAlON films were found to be amorphous as determined by X‐ray diffraction analysis (see Material S2, Supporting Information). The amorphous nature of the films was further confirmed by Raman measurements that showed no crystalline modes in the spectrum, and by transmission electron microscopy cross‐section analysis in a recent publication . Note that the amorphous structure is the usual structure of oxide films deposited by PLD as we have demonstrated in our previous works .…”

“…The amorphous nature of the films was further confirmed by Raman measurements that showed no crystalline modes in the spectrum, and by transmission electron microscopy cross‐section analysis in a recent publication . Note that the amorphous structure is the usual structure of oxide films deposited by PLD as we have demonstrated in our previous works . Furthermore, the procedure to produce the nanostructure doping of the films and the actual doping structure has been evidenced by different techniques, including transmission electron microscopy analysis (TEM) in our previous works in which we have investigated the doping with other rare‐earths ions and nanoparticles …”

“…This result is promising for the application of SiAlON thin films for the development of white light solid‐state emitters in field emission flat lamps and displays. Finally, together with the recent finding that undoped amorphous SiAlON films show a memresistive behavior, these results open up new promising application fields in optoelectronics for these interesting oxy‐nitride materials.…”

Observation of H-Ion Migration in a Low-Temperature-Processed Boehmite Layer for Nonvolatile Memory

“…To well describe the resistive switching behaviors, various models have been proposed based on different devices and materials. − Further, filament theory can be seen as a widely accepted explanation to describe the switching process. − In the previous work, hydrogen ions with low activation energies are also expected to facilitate the variety of local conductivity due to the formation of a carrier transport path . In other words, the movement of H ions can induce resistive switching behaviors under an applied bias.…”