[14p-502-1~15] 21.1 Joint Session K

△ [14p-502-1] Study on Surface Band Bending of α-Ga₂O₃

〇(M1)Yoshiki Fujiki¹, Junjiro Kikawa¹, Tsutomu Araki¹, Yasushi Nanishi¹, Masaya Oda² (1.Ritsumeikan Univ., 2.FLOSFIA Inc.)

Keywords:alpha Gallium Oxide, surface band bending, Kelvin probe force microscopy

Ga₂O₃ is being considered as a promising candidate for power device applications, because it has a larger bandgap than that of SiC or GaN. Ga₂O₃ takes five different polymorphs (α, β, γ, ε, and δ) and the β-Ga₂O₃ is the most stable crystal structure among them. On the other hand α-Ga₂O₃ has the largest bandgap in this crystals, and can be grown on sapphire substrates at a low cost by using mist chemical vapor deposition despite of its metastable polymorph. We investigated about the influence of crystal defects for α-Ga₂O₃ based devices. In the case of β-Ga₂O₃, there is a problem of forming Ohmic contact and some researchers explain its origin as the energy band of un-doped β-Ga₂O₃ is bent upwards at the surface due to negatively charged crystal defects at the surface. This problem can be solved by forming Ohmic contact by high concentration of donor doping. Therefore, we think that similar phenomenon occurs in α-Ga₂O₃. In this work, we investigated about the possibility of the existence of surface upward band bending in α-Ga₂O₃.