Heteroepitaxy And Hydrogen Plasma Treatment Of ?-Ga₂O₃ Thin Films

The development of semiconductor materials has promoted technological changes in the fields of information,energy,and national defense.Compared with traditional wide-bandgap semiconductors,?-Ga2O3 has excellent properties such as wider band gap,higher breakdown field strength,and larger Baliga figure of merit.Loss of semiconductor devices and other fields show a wide range of application prospects.Epitaxial high-quality ?-Ga2O3 thin film is the premise for the preparation of high-performance devices.In this paper,LPCVD is used to carry out heteroepitaxy of ?-Ga2O3 thin film,and the influence of process parameters on film properties is systematically studied.Subsequently,the above films were subjected to hydrogen plasma exposure treatment to explore the effect of hydrogen treatment on the film properties,and to precisely control their electrical properties.The main research results obtained in this paper are roughly as follows:?.First,low-cost and high-quality heteroepitaxy of ?-Ga2O3 thin films was realized by LPCVD,and the surface morphology,crystal structure,optical properties and other properties of ?-Ga2O3 thin films were characterized.The experimental results show that the band gap of ?-Ga2O3 film is?5.0 eV,and the light transmittance in the 300?800 nm band is over 85%.The experimental results show that the epitaxial relationship between ?-Ga2O3 film and C-plane sapphire substrate is as follows:?-Ga2O3(-201)//sapphire(006)and ?-Ga2O3[102]//sapphire[1-10].?.Secondly,a systematic study of the process parameters is carried out.It was found that the temperature of the gallium source and the flow rate of O2/Ar had a significant effect on the rate of the gallium source,while the substrate temperature was related to the nucleation and desorption rates of gallium and oxygen atoms.The ?-Ga2O3 film with high crystalline quality and low surface roughness was heteroepitaxially fabricated by optimizing the process parameters:the epitaxy rate was?0.8 m/h,and the X-ray rocking curve of the(-201)plane was only 1.07°.And the introduction of surface step technology to further improve the film quality.?.First,the defects in the ?-Ga2O3 films were effectively passivated by hydrogen exposure and the electrical properties were significantly improved.The precise control of electrical properties was achieved by adjusting the process parameters,and the control mechanism was speculated.A mobility of?45 cm2/V s and a resistivity of?27 m? cm were achieved.?.Secondly,the conductive mechanism of the above films was studied by variable temperature hall.The experimental results show that the scattering mechanism related to defects,grain boundaries and roughness is the main at 100?250 K;It is dominated by acoustic wave scattering at 250?300 K.