Simulation Of Gallium Oxide Schottky Devices And Study On Aluminum-gallium Oxide With High Aluminum Composition

Ga₂O₃ has the advantages of large band gap(about 4.8 eV)and high breakdown field strength(about 8 m V/cm).At the same time,Ga₂O₃ has higher Baliga value compared with Si C and Ga N,which can achieve higher breakdown voltage and maintain lower forward on-resistance.It is promising to be a candidate material for power electronic devices.In this paper,Ga₂O₃ Schottky diode was simulated by Silvaco software,and?-(Al_xGa_1-x)₂O₃ thin film with high Al component was grown by CVD method.The specific work is as follows:First,this paper introduces the properties and advantages of Ga₂O₃ material,introduces the theoretical knowledge of Schottky diode,designed the simulation of the basic structure of Schottky diode,to explore the influence of doping concentration on the characteristics of Schottky diode.The simulation results show that the breakdown voltage is 2 600 V when the doping concentration in the drift region is 2.5×10¹⁶ cm^-3,the on-resistance is 2.89 m?·cm²,and the Baliga value is 9.35×10⁷ W/cm².With the increase of doping concentration,the breakdown voltage of the device increases,but the on-resistance also increases.With the increase of gallium oxide mobility,the breakdown voltage and on-resistance of the device decrease.Second,the Ga₂O₃ Schottky diode field plate structure is designed in this paper.Through simulation,it is found that the field plate structure can effectively reduce the impact of electric field concentration effect on the breakdown voltage of the device.In this simulation,the length of the field plate and the thickness of the insulation layer are optimized,and the breakdown voltage of the device is increased from 2600 V to 3291 V.The optimal length of the field plate is 15?m and the thickness of the insulation layer is 0.5?m.Thirdly,in this paper,?-(Al_xGa_1-x)₂O₃ thin films with high aluminum composition were grown by CVD method.The results showed that?-(Al_xGa_1-x)₂O₃ thin films did not contain other elements by XRD characterization.According to the peak position offset of((?)02),the Al was calculated to be 60%by Vegard's law.The band gap reference of?-(Al_xGa_1-x)₂O₃ films precipitated from XPS O 1s peak position is 6.1 eV.The breakdown field strength of?-(Al_0.6Ga_0.4)₂O₃ was evaluated to be 14 m V/cm.SEM and AFM characterization proved that the growth quality of the films was good.