Direct observation of microscopic change induced by oxygen vacancy drift in amorphous TiO2 thin films

Abstract

To clarify the resistive switching and failure mechanisms in Al/amorphous TiO2/Al devices we investigate the microscopic change in amorphous titanium oxide films and interface layers after the set process according to film deposition temperatures. For low temperature (<150 °C) samples, the thickness of top interface layer decreased after the set process due to the dissociation of a top interface layer by uniform migration of oxygen vacancies. Meanwhile, for high temperature samples, crystalline TiO phases emerged in the failed state, meaning the formation of conducting paths from the local clustering of oxygen vacancies in nonhomogeneous titanium oxide film.

Dynamical behaviour of the resistive switching in ceramic YBCO/metal interfaces

“…Most of the studies performed until now have particularly focused on trying to reveal the key parameters that determine the existence of the RS effect [7,10] (such as the different metal-oxide interfaces or the pulsing protocols) and which are the characteristics of the non-volatile resistance memory state (such as the repeatability and retentivity of the remanent resistance after the pulsing treatment) [11]. It was also established that, for some binary oxide devices [12,13] and for perovskite oxide devices [14], RS is directly associated with the electromigration of oxygen ions (or vacancies).…”

Correlation between evolution of resistive switching and oxygen vacancy configuration in La0.5Ca0.5MnO3based memristive devices

“…The resistive switching phenomenon discovered in metaloxide-metal structures has attracted intense research interest as it encompasses intriguing physics and the promise of applications in nonvolatile memristive devices [1,2]. Among the concerted efforts for understanding its physical mechanism, the phenomenological model in terms of oxygen vacancy (ion) electromigration has received much attention [3][4][5][6][7][8][9][10][11][12][13][14]. On the one hand, this is because the oxygen vacancy is one of the fundamental defects in oxides and its migration driven by current or voltage pulses can occur at ambient and even cryogenic conditions [15,16].…”

Bipolar resistive switching in an amorphous zinc tin oxide memristive device

“…5 For TiO 2 based memristors, a significant change in the Al/TiO 2 interfacial layer thickness was observed using transmission electron microscopy whether a device was in the high (thickness $ 2.8 nm) or low (thickness $ 1.0 nm) resistive state. 29 The authors proposed that the uniform migration of oxygen ions into the TiO 2 films during the SET process reduces the thickness of the interfacial layer and results in the lower resistivity. It has been proposed by several groups that the redox based processes can lead to switching of memristive devices, where a negative voltage on a reactive electrode can lead to enhanced oxygen diffusion from the interfacial region leading to a reduction in the thickness of the interfacial oxide layer.…”