[18p-PA6-1~30] 13.7 Compound and power electron devices and process technology

[18p-PA6-20] Comprehensive Study of Native Oxides on GaN(0001)

〇Yoshihiro Irokawa¹, Taku T. Suzuki¹, Kazuya Yuge¹, Akihiko Ohi¹, Toshihide Nabatame¹, Koji Kimoto¹, Tsuyoshi Ohnishi¹, Kazutaka Mitsuishi¹, Yasuo Koide¹ (1.NIMS)

Keywords:GaN, native oxides

In this study, native oxides on free-standing GaN(0001) wafers were investigated by low-energy ion scattering spectroscopy (LEIS) and reflection high-energy electron diffraction (RHEED) analysis in order to obtain structural information on native oxides. In addition, native oxides on GaN(0001) were also characterized using high-resolution scanning transmission electron microscopy (STEM) and ultraviolet photoemission spectroscopy (UPS) in order to obtain the micro-structural information on native oxides and to reveal the electronic properties of them. As a result, azimuthal angle-resolved LEIS revealed that the surface structure of the native oxide with a thickness of ~1.1 nm showed a low sixfold symmetry. Moreover, the RHEED patterns of native oxides on GaN showed (1x1) surface spots, reflecting the same lattice constant of GaN regardless of the glancing angle of the incident beam. The obtained results suggest that native oxides on GaN(0001) could be either epsilon-Ga₂O₃, gamma-Ga₂O₃(111), or their mixture, with lattice-matched structures. The same conclusion was drawn using STEM.