Nanofilamentary resistive switching in binary oxide system; a review on the present status and outlook

Abstract

This review article summarized the recent understanding of resistance switching (RS) behavior in several binary oxide thin film systems. Among the various RS materials and mechanisms, TiO(2) and NiO thin films in unipolar thermo-chemical switching mode are primarily dealt with. To facilitate the discussions, the RS was divided into three parts; electroforming, set and reset steps. After short discussions on the electrochemistry of 'electrolytic' oxide materials, the general and peculiar aspects of these RS systems and mechanism are elaborated. Although the RS behaviors and characteristics of these materials are primarily dependent on the repeated formation and rupture of the conducting filaments (CFs) at the nanoscale at a localized position, this mechanism appears to offer a basis for the understanding of other RS mechanisms which were originally considered to be irrelevant to the localized events. The electroforming and set switching phenomena were understood as the process of CF formation and rejuvenation, respectively, which are mainly driven by the thermally assisted electromigration and percolation (or even local phase transition) of defects, while the reset process was understood as the process of CF rupture where the thermal energy plays a more crucial role. This review also contains several remarks on the outlook of these resistance change devices as a semiconductor memory.

Mechanism for resistive switching in chalcogenide-based electrochemical metallization memory cells

“…2, 3, and 4, it can be reasonably concluded that the rupture and rejuvenation of Cu filament occur at the ZnS/Pt (or ITO) interface. Given that the filament is apt to be ruptured at the weakest position along its length, [1][2][3]51 it very likely has a conical shape, with the base and the tip located at the anodic (AE, Cu) and the cathodic (CE, Pt or ITO) interfaces, respectively. It follows that the filament is most likely to grow from the anode towards the cathode.…”

Anomalous C-V response correlated to relaxation processes in TiO2 thin film based-metal-insulator-metal capacitor: Effect of titanium and oxygen defects

“…At 1000 K, in an x range of 0 0.008 TiO 2 x maintains its rutile, anatase, or brookite phase structure. 22 Outside this x range, the major defects that arise are titanium interstitials (Ti i ) and oxygen vacancies (V O ). [23][24][25][26] Both defect types can explain oxygen-deficient non-stoichiometric TiO 2 x .…”

Unipolar resistive switching with forming-free and self-rectifying effects in Cu/HfO2/n-Si devices

“…[1][2][3][4] Unfortunately, sneak current issue, which refers to the undesired current through unselected cells and thus leads to misreading when reading the selected cell, is still a tough obstacle in real application of crossbar RRAMs. 1,5 This issue will be further exacerbate when the selected cell is in the high resistance state (HRS), whereas all unselected cells are in the low resistance state (LRS).…”