Effects of ZrO2 doping on HfO2 resistive switching memory characteristics

A resistive switching (RS) random access memory device with ZrO2-doped HfO2 exhibits better RS performance than that with pure HfO2. In particular, I-res, V-res, and V-set are reduced by approximately 58%, 38%, and 39%, respectively, when HfO2 is doped with ZrO2 (9 at.%). In addition, the ZrO2 doping in HfO2 makes the distribution of most parameters steeper. Transmission electron microscopy (TEM) analysis reveals that the deposited zirconium-doped hafnium oxide (HZO) (9 at.%) is polycrystalline. Elemental mapping results by scanning TEM-energy dispersive spectroscopy also prove that ZrO2 is uniformly distributed in the HZO (9 at.%) film. The possible mechanism for the improvement in the RS characteristics is also suggested on the basis of the X-ray photoelectron spectroscopy results and filamentary RS mechanism. These results suggest that the ZrO2 doping into HfO2 likely not only will reduce power consumption but also will improve cyclic endurance by controlling the nonstoichiometric phase. (C) 2014 AIP Publishing LLC.