Investigation Of Resistive Switching Characteristics And Solar Blind Detectors Of Gallium Oxide Thin Films

With the advent of the information age,information storage not only involves the computer field,but also has penetrated into every corner of our lives.Resistive random access memory（RRAM）devices have the characteristics of high storage density,fast operation speed and easy integration,and are considered as the strong competitors of the next generation nonvolatile memory.Solar blind detection technology has important application prospects in missile early warning,forest fire monitoring and other fields.This thesis is aiming at the resistive switching characteristics of gallium oxide thin films and solar blind detectors.The main contents of the research work are as follows:（1）Gallium oxide thin films were prepared via sol-gel method and characterized by X-ray diffraction,scanning electron microscope and atomic force microscope.The experimental results of X-ray diffraction show that gallium oxide films with better crystallization can be obtained when annealing temperature is 800℃.Scanning electron microscopy（SEM）and atomic force microscopy（AFM）were used to observe the film surface.The results showed that the film surface was smooth,with average surface roughness（Ra）of 0.87 nm and root mean square surface roughness（Rq）of 1.13 nm.（2）Gallium oxide RRAM devices with three different electrode combinations of Ag-Pt,Ag-TiN and Ag-ITO were fabricated by sol-gel method combined with microelectronic processing technology.The resistive switching characteristics of these three kinds of RRAM devices are tested by semiconductor parameter analyzer.The experimental results show that different electrode combinations have great influence on the resistive switching characteristics of the devices,and not all gallium oxide RRAM devices with active electrode and inert electrode combination have the characteristics of large resistance window and small limiting current.Among the three gallium oxide resistive random access devices,Ag-Pt,Ag-TiN and Ag-ITO,the performance of Ag-Pt resistive random access device is the best,its resistance window is larger than 3600,and its limiting current is only 0.01 m A.The Ag-Pt resistive random access devices exhibit multi-order characteristics,while the Ag-TiN and Ag-ITO resistive random access devices do not have multi-order characteristics due to their small resistance window.（3）According to the simulation results of forming polarity experiment,experimental data fitting and Stephan Menzel theoretical model,the resistive switching mechanism of Ag-Pt,Ag-TiN and Ag-ITO RRAM devices is attributed to the active metal electrode participating in the formation and fusing of conductive filaments.The theoretical simulation results show that the resistance state change of RRAM devices is caused by the change of tunneling gap.For Ag-ITO resistive random access devices,when the tunneling gap is 0.81 nm,the devices are in low resistance state,and when the tunneling gap is 12 nm,the devices are in high impedance state.The results of fitting the experimental data of high and low resistance states show that the low resistance states of the three RRAM devices conform to the ohmic conduction mechanism.The high resistance state of Ag-Pt resistive devices conform to Schottky emission mechanism,while the high resistance state of Ag-TiN and Ag-ITO resistive devices accords with space charge limiting current mechanism.（4）Pure gallium oxide solar blind photodetectors,indium doped gallium oxide solar blind photodetectors and gallium oxide heterojunction solar blind photodetectors were fabricated by sol-gel method combined with microelectronic processing technology,and their performances were tested.The experimental results show that indium doping and heterojunction structure are beneficial to improve the responsivity of the device.The time constantτ_r1 of the gallium oxide heterojunction solar blind detector is 1.59 s,and the responsivity is 681.39 m A/W,which has the same order of magnitude as that of the gallium oxide solar blind detector prepared by magnetron sputtering.