Electrode dependence of filament formation in HfO2 resistive-switching memory

Abstract

This study investigates bipolar and nonpolar resistive-switching of HfO 2 with various metal electrodes. Supported by convincing physical and electrical evidence, it is our contention that the composition of conducting filaments in HfO 2 strongly depends upon the metal electrodes. Nonpolar resistive-switching with the Ni electrode is attributed to the migration of metal cations and the corresponding electrochemical metallization. Conversely, oxygen-deficient filaments induced by anion migration are responsible for bipolar resistive-switching. It was also found that the characteristic nature of the conducting filaments influences many aspects of switching characteristics, including the switching power, cycling variations, and retention at elevated temperatures. V

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

“…Based on the phenomena described above, the resistive switching behaviors are agreement with conductive filament model very well. Generally speaking, there are metal CF 27,35-37 and oxygen vacancy CF [38][39][40] in the binary oxide dielectric such as HfO 2 film. Many studies have been reported that active electrodes such as Ag 4,41 and Cu [35][36][37] tends to migrate and form CF connecting with counter electrodes, playing an important role in resistive switching process.…”

2D Nanovaristors at Grain Boundaries Account for Memristive Switching in Polycrystalline BiFeO3

“…1c suggests that some grain boundaries may carry some hopping current at voltages smaller than the SET voltage; this is possible if the environment of O sites happens to be more uniform than average and barriers for conduction may be smaller; see below for more detailed analysis of hopping conduction). We note that the conductive channels are not true metallic filaments as often suggested [11,12]. The hopping current is turned on by a high voltage and the grain boundaries behave as true nanovaristors.…”

Pressure-induced novel compounds in the Hf-O system from first-principles calculations

“…In electronics industry, hafnium oxide-based material is currently used as an excellent high-k gate dielectric [1] and oxygen-deficient hafnium oxide also received additional interest for resistive-switching memories [2]. As for other applications, even though the hardness of hafnia (HfO 2 ) is not that high for it to be considered as a superhard material [3], it still attracts attention as a potential candidate for hard oxide-based materials [4].…”