Each element process for device fabrication should be carefully designed by choosing the appropriate process conditions taking account of the chemical reactivity and thermal stability of Ga₂O₃. In this report the influences of chemical cleaning processes and thermal annealing processes, as well as the selection of gate dielectric materials on Ga₂O₃ properties and MOS device characteristics were investigated to identify the technological issues that may arise in the Ga₂O₃ device process development.
　For further development of the industrial processes of Ga₂O₃ devices, it is important to accelerate the researches for understanding of the issues including the electronic structure of Ga₂O₃, the relationship between the defect formation and the electronic properties of Ga₂O₃, and the reactions at the surface of Ga₂O₃ or near its interface with dielectric materials.