Bipolar resistive switching in Ag/VO₂(B)/SiO_x/n⁺⁺Si RRAM

Abstract

Non-volatile resistive random-access memory (RRAM) is being promoted as a possible alternative to flash memory, however the optimal material system and sophisticated fabrication techniques hinder its utilization in practical routes. Here, we demonstrate the direct fabrication of metal/oxides/semiconductor (MOS) structured Ag/VO2(B)/SiOx/n++Si RRAM via drop-coating process, in which bipolar resistive switching behavior was obtained and investigated systematically. The RRAM devices exhibit good cycle-to-cycle endurance (>30 cycles) and high on/off ratio (>60). The switching mechanism is proposed to form Ag conducting filaments via VO2(B) nanorods’ guide by comparing the resistive switching behavior of Ag/SiOx/n++Si, Ag/VO2(B)/n++Si, Ag/VO2(B)/SiOx/n++Si devices and the corresponding SEM images before and after the application of electric field, which is confirmed by introducing NaCl barrier layer in Ag/VO2(B)-NaCl/SiOx/n++Si devices. The present study may pave a convenient route for fabricating the ultrahigh density resistive memory devices without the aid of complex fabrication techniques, as well as provide a new potential material system for RRAM.

Forming-Free, Low-Voltage, and High-Speed Resistive Switching in Ag/Oxygen-Deficient Vanadium Oxide(VOx)/Pt Device through Two-Step Resistance Change by Ag Filament Formation

“…The properties of the CBRAM device with the VO x layer are summarized and compared with previously reported devices in Table . ,, Compared with other reports on vanadium oxide–based CBRAM devices, our device shows advanced or comparable performance with a low operation voltage, a low programming time, a high on/off ratio, good cycling endurance, and good retention properties.…”

“…24 The resistive switching in Ag/VO 2 /SiO x /n ++ -Si devices using brookite-phase vanadium dioxide nanorods occurs at voltages of +3 V and −3 V for SET and RESET, respectively. 26 In addition, Yalagala et al reported that the switching in vanadium oxide nanosheet-based flexible memristors with an Ag/V 2 O 5 /Cu structure occurs at V SET and V RESET of approximately ±1 V, respectively. 27 As aforementioned, the facilitated switching in CBRAM devices requires a high migration rate of metal cations in oxides.…”

“…It also possesses the Mott transition characteristic, due to which its electronic conductance changes via the metal–insulator transition (MIT) at ∼340 K; therefore, it can be used in low-voltage electronic devices, radio frequency (RF) switches, sensors, catalysts, supercapacitors, smart windows, and so on. − Additionally, it has been explored for use as a selector device to suppress unwanted current leakage through the sneak path in crossbar array memory architectures using abrupt resistance change. − The properties of VO x -based RRAM devices have also been investigated, especially in CBRAM devices with silver , or copper ion filaments. , For example, Kuo et al reported the properties of Cu/VO x /Al CBRAM devices, where resistive switching was achieved at a switching voltage of +1 V for switching from the HRS to LRS, called SET, and −0.5 V for reverse switching (from the LRS to HRS), called RESET . The resistive switching in Ag/VO 2 /SiO x /n ++ -Si devices using brookite-phase vanadium dioxide nanorods occurs at voltages of +3 V and −3 V for SET and RESET, respectively . In addition, Yalagala et al reported that the switching in vanadium oxide nanosheet-based flexible memristors with an Ag/V 2 O 5 /Cu structure occurs at V SET and V RESET of approximately ±1 V, respectively …”