Forming-free RRAM device based on HfO2 thin film for non-volatile memory application using E-beam evaporation method

This paper studies the deposition of Hafnium Oxide (HfO2) thin films (TF) based on forming-free resistive random access memory (RRAM) devices using the method of electron beam evaporation. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the deposited TF. The cross-sectional Field Emission Gun Scanning Electron Microscope (FEG-SEM) image of HfO2 TF shows a growth of ~ 134 nm thickness. Moreover, Energy-Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) determine the purity and chemical states of the sample, respectively. XPS also demonstrated the presence of oxygen vacancies in HfO2 TF responsible for enhanced resistive switching. HfO2 TF device exhibited forming-free resistive switching characteristics with stable retention of > 103 s and good endurance up to 1500 cycles at the reading voltage of + 1.4 V. The current–voltage (I–V) linear fitting reveals that in the charge transmission mechanism, Space Charge-Limited Current (SCLC) behaviour and Ohmic conduction dominate in the High Resistance State (HRS) and Low Resistance State (LRS), respectively. In addition, the device also recorded an excellent OFF/ON ratio (resistance window) in the order of ~ 102, which makes it a promising candidate for resistive switching non-volatile memory application.