Formation and disruption of conductive filaments in a HfO₂/TiN structure

Abstract

The process of the formation and disruption of nanometric conductive filaments in a HfO2/TiN structure is investigated by conductive atomic force microscopy. The preforming state evidences nonhomogeneous conduction at high fields through conductive paths, which are associated with pre-existing defects and develop into conductive filaments with a forming procedure. The disruption of the same filaments is demonstrated as well, according to a bipolar operation. In addition, the conductive tip of the microscopy is exploited to perform electrical operations on single conductive spots, which evidences that neighboring conductive filaments are not electrically independent. We propose a picture that describes the evolution of the shape of the conductive filaments in the processes of their formation and disruption, which involves the development of conductive branches from a common root; this root resides in the pre-existing defects that lay at the HfO2/TiN interface.

Self-Compliance and High Performance Pt/HfOx/Ti RRAM Achieved through Annealing

“…For Device A, as the positive voltage applied to the titanium electrode increases, more and more oxygen ions are generated in the HfO x and move toward the titanium electrode [27], producing titanium oxide. At the same time, the oxygen vacancies accumulate toward the interface of HfO x /Pt and form conductive filaments gradually [28]. The device turns to LRS when the oxygen vacancies conducting filaments connect the TE and BE.…”

Analog Memristive Synapse in Spiking Networks Implementing Unsupervised Learning

“…Ti and TiN layers are deposited by magnetron sputtering and the HfO 2 layer is deposited by atomic layer deposition at 300 °C, as described elsewhere (Brivio et al, 2015; Frascaroli et al, 2015). The switching mechanism of the proposed memristor is filamentary (Brivio et al, 2014), i.e., it is based on the disruption and the restoration of a conductive filament formed inside the oxide.…”

Total Dose Hardness of <formula formulatype="inline"> <tex Notation="TeX">${\rm TiN}/{\rm HfO}_{\rm x}/{\rm TiN}$</tex></formula> Resistive Random Access Memory

“…It is still unknown which crystal structure is favorable in terms of resistive switching properties. Reference [22] reports on reliable switching seen in monoclinic films whereas [23] reports successful switching seen in amorphous films with degradation in switching properties observed when annealed into monoclinic structure. More research must be conducted in order to understand the effects of crystallization.…”