%0 Journal Article
%T Room-Temperature Voltage Stressing Effects on Resistive Switching of Conductive-Bridging RAM Cells with Cu-Doped SiO2 Films
%A Jian-Yang Lin
%A Bing-Xun Wang
%J Advances in Materials Science and Engineering
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/594516
%X SiO2 or Cu-doped SiO2 (Cu:SiO2) insulating films combined with Cu or W upper electrodes were constructed on the W/Si substrates to form the conductive-bridging RAM (CB-RAM) cells. The CB-RAMs were then subjected to a constant-voltage stressing (CVS) at room temperature. The experimental results show that the room-temperature CVS treatment can effectively affect the current conduction behavior and stabilize the resistive switching of the memory cells. After the CVS, the current conduction mechanisms in the high resistance state during the set process of the Cu/Cu:SiO2/W cell can be changed from OhmĄ¯s law and the space charge limited conduction to OhmĄ¯s law, the Schottky emission, and the space charge limited conduction. Presumably, it is due to the breakage of the conduction filaments during the CVS treatment that the conduction electrons cannot go back to the back electrode smoothly. 1. Introduction As the charge storage memory is approaching its scaling limit [1], the next generation nonvolatile memory (NVM) technologies have been widely investigated in recent years. New types of NVMs include the resistive random access memory (RRAM), magnetic random access memory (MRAM), and the phase-change random access memory (PRAM). The conductive-bridging RAM (CB-RAM) is one of the RRAMs within which metal cations, such as copper or silver, can form conductive bridges or break the conduction filaments between the top and the bottom electrodes via ion migration. The CB-RAMs can be switched between the high resistance state (HRS) and the low resistance state (LRS) under different bias polarities [2, 3]. The insulating materials between the active electrode (e.g., Cu or Ag) and the inert electrode (e.g., W or Pt) play important roles in the resistive switching (RS) operation and are called the solid electrolytes. Several kinds of the insulating materials, such as chalcogenide [4, 5], oxide-based [6¨C9], carbide [10], and amorphous silicon [11], have been used for the CB-RAMs. Among these materials, SiO2-based films have advantages such as simple composition, no toxicity, compatibility with the COMS technology, and low cost. In addition, most of the resistive switching improvement works of the RRAMs were done at elevated temperatures [12¨C14]. There is no room-temperature process of Cu doping in oxide found in the literature. This work has tried to develop the room-temperature process of Cu doping into oxide following the constant-voltage stressing (CVS) treatment for the RRAM application. In this work, improvement on the switching characteristics of the SiO2-based
%U http://www.hindawi.com/journals/amse/2014/594516/