Structural and electrical characteristics of Zr-doped HfO2 (HZO) thin films deposited by atomic layer deposition for RRAM applications

Abstract

In this study, Zr-doped HfO2 (HZO) based resistive random-access memory (RRAM) device were fabricated. The Hf:Zr (1:1) ratio in the HZO films were controlled by changing the HfO2 and ZrO2 cycle ratio during the atomic layer deposition (ALD) process. Next, we studied the structural and electrical properties of the Au/HZO/TiN RRAM device structure. The RRAM devices exhibits an excellent resistance ratio of the high resistance state (HRS) to the low resistance state (LRS) of ~103 A, and as well as good endurance (300 cycles) and retention (>103 s), respectively. Further, the device showed different conduction mechanism in LRS and HRS modes. The lower biased linear region is dominated by ohmic conductivity, whereas the higher biased nonlinear region is dominated by a space charge limited current conduction. This device is suitable for application in future high-density nonvolatile memory RRAM devices.