Effect of carrier screening on ZnO-based resistive switching memory devices
resistive switch, carrier screening effect, carrier concentration, potential gradient, annealing
ABSTRACT The carrier screening effect occurs commonly in dielectric materials. It reduces the electric potential gradient, thus negatively affecting the functionality of resistive random access memory (RRAM) devices. An Au/ZnO film/Al-doped ZnO device fabricated in this work exhibited no resistive switching (RS), which was attributed to the carrier screening effect. Therefore, annealing was used for alleviating the screening effect, significantly enhancing the RS property. In addition, different on/off ratios were obtained for various bias values, and the screening effect was accounted for by investigating electron transport mechanisms. Furthermore, different annealing temperatures were employed to modulate the free carrier concentration in ZnO films to alleviate the screening effect. The maximal on/off ratio reached 105 at an annealing temperature of 600 °C, yielding the lowest number of free carriers and the weakest screening effect in ZnO films. This work investigates the screening effect in RS devices. The screening effect not only modulates the characteristics of memory devices but also provides insight into the mechanism of RS in these devices.
Tsinghua University Press
Yihui Sun,Xiaoqin Yan,Xin Zheng,Yong Li,Yichong Liu,Yanwei Shen,Yi Ding,Yue Zhang, Effect of carrier screening on ZnO-based resistive switching memory devices. NanoRes.2017, 10(1): 77–86