Research On The Performance And Mechanism Of Tungsten-doped Hafnium Oxide Based Resistive Devices

Resistive memory devices(RRAM)are a strong contender to replace charge memory Flash in new memory devices due to their fast operating speed,scalability and compatibility with CMOS processes.To meet the higher requirements of resistive memory devices for high density storage and big data AI,performance parameters such as low power consumption and device consistency must be optimized.Among the many dielectric layer materials for RRAM,HfO_x is the system that has received the most attention from industry and research,and in recent years researchers have proposed solutions such as ion doping,stacked layer structures,optimization of excitation application methods,and electrode engineering to improve these characteristics.Of these,functional layer doping modification is considered to be the primary means,and therefore this paper employs doping to conduct an in-depth study of HfO_x-based resistive devices in order to improve the electrical properties of the devices,as follows.Firstly,the HfO_x thin film growth process conditions were optimised in terms of sputtering power and oxygen partial pressure,and it was found that the root mean square(RMS)of film roughness for HfO_x thin films was 0.594 nm at 120W sputtering power and 15%oxygen partial pressure.Based on this condition,the effect of HfO_xthickness on device performance was investigated.The basic device cell was constructed with 120W power,15%oxygen partial pressure and 10nm hafnium oxide,where the device has stable cycling characteristics and the device achieves a voltage transition at 1m A current limit and+1.8V/-0.65V.Finally,the cross-structured device is constructed with a reduced operating voltage(+0.77V/-0.6V)and Endurance to achieve 10~4 stable cycles.Next,the W doping content was optimised and the AFM characterisation revealed that the root mean square(RMS)roughness of the films could reach 0.26nm for a W magnetron sputtering time of 5s.The effect of different tungsten doping content on the electrical properties of the device,the results showed the optimal performance of the W:HfO_x film in the W:HfO_x film,and determines the optimum annealing temperature of 500℃by XRD characterization.Then,in W-sputtering time 5s,annealing temperature 500℃is explored under the conditions of annealing on the performance of the device.The device was found to be very stable at 10~4 Endurance cycles under these conditions,and a Gaussian fit to the highly resistive state of the device showed that the coefficient of variation(σ/μ)of both high and low resistance was reduced,indicating an improvement in the consistency of the device.Finally,the film components were analysed by XPS,and the high and low resistance regimes were fitted to the device and tested at variable temperature.Finally,a possible resistance transition mechanism for the device is constructed,and the results show that the doping of W influences the electric field of the dielectric layer and thus the distribution of the conducting filaments to improve the performance of the device.In summary,tungsten doped hafnium oxide films can effectively improve the uniformity of hafnium oxide based resistive transformation devices and the window value of the devices compared to intrinsic hafnium oxide.