Preparation Of Ga₂O₃ Thin Films By Magnetron Sputtering And Its Ultraviolet Photoproperties

Gallium oxide is widely used as a representative of third-generation semiconductor materials.It can be used as the main material of transparent conductive film,gas-sensitive detector and power semiconductor device,because it has the characteristics of wide band gap,high breakdown voltage and stable chemical and physical properties in harsh environment such as high temperature.Compared with second-generation semiconductor materials,gallium oxide has a large bandgap and has no response to light other than the ultraviolet,so ultraviolet light can be accurately detected.Ultraviolet detectors can be used in missile early warning,ozone hole detection and fire detection.At present,most scholars and research institutions focus on the research of gallium oxide on improving the performance of solar blind ultraviolet?200?280nm?detectors with different preparation processes and structures.In this paper,the preparation technology of Ga₂O₃thin film is studied,and its structure and optical characteristics are analyzed.The effects of annealing temperature,film thickness,electrode material and bias voltage on the photoelectric performance of the detector were investigated.The future development of Ga₂O₃ thin film detector is prospected based on the actual experimental results.Ga₂O₃ films were prepared by magnetron sputtering on 20×10mm rectangular single cast?100?silicon wafers and 2-inch quartz wafers respectively.The selected target was a ceramic target with gallium oxide powder high temperature sintering purity of 99.99%.The effects of sputtering power,argon-oxygen ratio,sputtering pressure and annealing on the properties of thin films were studied by means of controlling a single variable.The Ga₂O₃ film was annealed,the transmittance,refractive index and thickness of the film were measured,and the optical properties of the film were analyzed.By means of X-ray diffraction?XRD?,Raman scattering?Raman?and scanning electron microscope?SEM?,the crystallinity,microstructure and structure characteristics of Ga₂O₃ film were analyzed.Through the analysis and comparison of the optical and structural test data of Ga₂O₃ film,the process parameters of the film were obtained.On the basis of the preparation of Ga₂O₃ film,the film was covered by a metal mask and the forked finger electrode was prepared by magnetron sputtering.The electrode material was30nm Ti+100nm Au.The electrode parameters are:the length of the finger is 5.8mm,the width of the finger is 0.2mm,the spacing between the fingers is 0.2mm,and the effective photosensitive area is 8.72mm².The test platform consists of an ultraviolet lamp with a wavelength of 254nm and a power density of 7.58 x 10^-3 mw/mm²,a semiconductor parameter analyzer,and a probe platform with a black box.The preliminary test of the photoelectric characteristics of Ga₂O₃ film shows that the light-dark current ratio of detector sample can reach 10³,and the detector has a good ultraviolet detection ability.