Controllability of Electrical Conductivity by Oxygen Vacancies and Charge Carrier Trapping at Interface between CoO and Electrodes

Abstract

Recently, the role of resistance random access memory (RRAM) is becoming extremely important in the development of nonvolatile memories. RRAM works by changing the resistance of the transition metal oxide contained in RRAM after the application of a sufficiently high voltage, however, this switching mechanism has not been fully clarified. In this study, by performing first principles calculations based on the density functional theory, we first investigate the change in the property of bulk CoO resulting from oxygen vacancies and charge carrier trapping in the vicinity of the oxygen vacancies. Next, we perform calculations for slab models of CoO in contact with Ta, W, and Pt electrodes and hence investigate the effects of oxygen vacancies at the interface between the CoO layer and the electrode layer. On the basis of the obtained results, we conclude that W is the most suitable electrode material compared with Ta and Pt.

Recent Advances and Future Prospects in Functional-Oxide Nanoelectronics: The Emerging Materials and Novel Functionalities that are Accelerating Semiconductor Device Research and Development

“…Since ReRAMs were first reported, clarification of their operating principles has been a hot topic. [31][32][33][34][35][36][37][38][39] The operating principles are roughly divided into two models: (1) a filament model, in which conductive paths connecting electrodes are locally formed on the device plane, and (2) an interface model, in which the resistance of devices with a MOM structure changes owing to a change in the Schottky barrier height and other factors at the entire metal/oxide interface. A typical example of (1) includes the Ni nanofilament deposited on NiO grain boundaries reported in 2009.…”

Detailed analyses of electric field-induced resistance switching behavior of SrFeO3− x film

“…[6][7][8][9] Most of the papers explain these switching behaviors using a metallic filament model or oxygen migration mechanism. [10][11][12][13][14][15][16] We also reported that negative differential resistance (NDR) behaviors in the current-voltage (I-V) curve are responsible for the EIR properties of PCMO. 17) We speculated that the oxidation/reduction process between the electrode and base material could play an important part in the EIR phenomenon.…”

Improvement of Uniformity of Resistive Switching Parameters by Selecting the Electroformation Polarity in IrOx/TaOx/WOx/W Structure

“…Being a strong contender for resistive switching memories, transition metal oxides (TMO), 8) especially binary oxides, have been investigated recently. Among other various oxides such as HfO x , [9][10][11][12] WO x , [13][14][15] ZrO 2 , [16][17][18] CoO, 19,20) TiO 2 , [21][22][23][24] CuO, 25,26) Ta 2 O 5 , [27][28][29][30][31] NiO, 32) Nb 2 O 5 , 33) and AlO x , [34][35][36] tantalum oxide (TaO x )-based devices are becoming attractive owing to their ease of deposition using existing conventional systems, high thermal stability, compatibility with CMOS processes and high dielectric constant (" r $ 25). Commonly, the use of platinum (Pt) as an electrode material in a Pt/Ta 2 O 5 /Pt structure 28) is reported for RRAM applications owing to its high work function and inertness.…”