下电极对ZnO薄膜电阻开关特性的影响

Effects of bottom electrode on resistive switching characteristics of ZnO films

本文采用直流磁控溅射法在三种不同的下电极(BEs)上制备了ZnO薄膜,获得了W/ZnO/BEs存储器结构.研究了不同的下电极材料对器件电阻开关特性的影响.研究结果表明,以不同下电极所制备的器件都具有单极性电阻开关特性.在低阻态时,ZnO薄膜的导电机理为欧姆传导,而高阻态时薄膜的导电机理为空间电荷限制电流.不同下电极与ZnO薄膜之间的肖特基势垒高度对电阻开关过程中的操作电压有较大的影响,并基于导电细丝模型对不同下电极上ZnO薄膜的低阻态阻值及reset电流的变化进行了解释.

In this paper, thin films of ZnO were deposited on different bottom electrodes （BEs） by DC magnetron sputtering to fabricate resistive random access memory （ReRAM） with a W/ZnO/BEs structure. The effects of different BEs on the resistive switching characteristics of the fabricated device have been investigated. The results reveal that the devices fabricated on different BEs exhibit reversible and steady unipolar resistive switching behaviors. The conduction behavior in the low resistance state has an Ohmic behavior. However, the conduction mechanism in the high resistance state fits well with the classical space charge limited conduction. Schottky barrier heights between ZnO and different BEs have great effect on the operation voltages during the resistive switching processes. The resistances in low resistance state and the reset currents of the ZnO films fabricated on different BEs were discussed based on the filamentary model.