Effect of Aluminum Doping on Performance of HfOₓ-Based Flexible Resistive Memory Devices

Abstract

The Al-doped HfO x -based resistive memory devices have been fabricated on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) flexible substrate at room temperature. X-ray photoelectron spectroscopy is used to extract the different doping percentage of Al which allows optimizing the switching performance. It improves the cycle-to-cycle and cell-to-cell uniformity of switching parameters by tuning the oxygen vacancies in HfO x layers. The 7.5% Al-doped HfO x -based flexible resistive memory device shows excellent switching characteristics such as resistance ratio ( $> 10^{3}$ ) and retention ( $\sim 10^{4}$ s). There is no degradation of memory window under the mechanical strain with bending radius ranging from 25 to 5 mm. The temperature-dependent resistive switching characteristics have also been studied. There is sufficient memory window ( $> 10^{2}$ ) till $\sim 10^{4}$ s at elevated temperature. The ${I}$ – ${V}$ curve fitting shows the ohmic (hopping) conduction in low resistance state (LRS) and the trap-controlled space charge limited conduction (SCLC) in high resistance state (HRS), supported by Arrhenius plot.