Suboxide interface induced digital-to-analog switching transformation in all Ti-based memristor devices

Abstract

Oxidation of TiN is a diffusion-limited process due to the high stability of the TiN metallic state at the TiN/TiO2 junction. Hence, the TiN/TiO2/TiN device being the inability to form a suitable interfacial layer results in the exhibition of abrupt current (conductance) rise and fall during the set (potentiation) and reset (depression) processes, respectively. Interfacial engineering by depositing Ti film served as the oxygen gettering material on top of the TiO2 layer induces a spontaneous reaction to form a TiOx interfacial layer (due to the low Gibbs free energy of suboxide formation). Such an interface layer acts as an oxygen reservoir that promotes gradual oxidation and reduction during the set and reset processes. Consequently, an excellent analog behavior having a 2-bit per cell and robust epoch training can be achieved. However, a thick interfacial layer may degrade the switching behavior of the device due to the high internal resistance. This work suggests that interfacial engineering could be considered in designing high-performance analog memristor devices.

HfO2‐Based Memristor as an Artificial Synapse for Neuromorphic Computing with Tri‐Layer HfO2/BiFeO3/HfO2 Design

“…It is also can be regarded that the BFO layer can act as an oxygen reservoir to promote gradual oxidation and reduction of the Hf CFs during the set and reset processes. [ 50 ] Therefore, it is reasonable to believe that the BFO inserting layer can lead to the linearity improvement of the LTP and LTD.…”

Oxygen Vacancy Transition in HfOx‐Based Flexible, Robust, and Synaptic Bi‐Layer Memristor for Neuromorphic and Wearable Applications

“…interfacial engineering techniques such as doping of impurity, [23][24][25] multiple temperature annealing and insertion of barrier layer or modulation layer were applied to confine the filament area in order to achieve stable MLC capability. [26][27][28] Moreover, mostly memristors tend to degrade their storage capabilities under humid and varying temperature environment. Considerable amount of research is inclined toward this to mitigate these issues and make devices favorable for wearable electronics.…”

Transformation of digital to analog switching in TaOx-based memristor device for neuromorphic applications

“…12,13 Henceforth, careful engineering in the formation and rupture of conductive filament/bridge to achieve gradual switching is required. 14 Several techniques are recently reported that digital switching can be transformed into analog switching in memristor devices either by using annealing processes, different doping concentrations, or different top electrodes. [15][16][17] In this work, we demonstrate that such transformation could also be achieved by the employment of a barrier layer(BL) in TaOxbased CBRAM devices.…”