[8p-A204-1~10] Gallium Oxide : Novel Wide Band-Gap Oxide Material for Future Generation

[8p-A204-8] Study on Surface Band Bending of α-Ga₂O₃

〇(M2)Yoshiki Fujiki¹, Junjiro Kikawa¹, Tsutomu Araki¹, Yasushi Nanishi¹, Tokiyoshi Matsuda², Takashi Shinohe² (1.Ritsumeikan Univ., 2.FLOSFIA Inc)

Keywords:Ga2O3, surface band bending, surface potential

Recently, α-Ga₂O₃ is being considered as a promising candidate for power device applications, because it has a larger bandgap than those of SiC, GaN and β-Ga₂O₃ which are widely studied. Furthermore, α-Ga₂O₃ can be grown on sapphire substrates at low cost by the mist-CVD method, and the carrier concentration can be controlled in the range of 10¹⁷-10¹⁹ cm^-3. However, it is difficult to form a good ohmic contact on the α-Ga₂O₃ and β-Ga₂O₃. The origin of this difficulty is suggested that the conduction band of Ga₂O₃ is bent upwards at the surface due to negatively charged crystal defects at the surface, and this might cause the degradation of an ohmic contact. Our previous work showed the existence of surface upward band bending. In this work, we study on the information of the origin of the surface upward band bending in α-Ga₂O₃ by investigating the existence of Fermi level pinning and surface potential of samples with different orientations.