[14a-P6-1~20] 13.8 Compound and power electron devices and process technology

[14a-P6-13] Diffusion of Ga into SiO₂ Films Deposited on GaN or AlGaN after Annealing Treatment

〇Keita Kataoka¹, Masakazu Kanechika¹, Yuko Aoki¹, Hiroyuki Ueda¹, Tetsuo Narita¹, Yasuji Kimoto¹, Akira Uedono² (1.Toyota Central R&D Labs., Inc., 2.Tsukuba Univ.)

Keywords:SiO2/GaN, SiO2/AlGaN, Ga diffusion

Diffusion of Ga into SiO₂ films deposited on GaN or AlGaN after annealing treatment was investigated by SIMS and positron annihilation technique. We found that Ga diffuses into SiO₂ at more than 10¹⁸ cm^-3 in density by annealing at 800°C. In the positron annihilation measurements, the concentration of Ga vacancy at the near interface region of GaN did not change after the annealing, which indicates that the nature of Ga diffusion into SiO₂ positions at the SiO₂/GaN interface. We prepared another GaN sample by forceful oxidation (annealing at 650°C in O₂), and SiO₂ film was subsequently deposited. In this sample, the Ga concentration in SiO₂ after annealing at 800°C increases compared to the case of the as-epitaxial GaN sample. From the result, we suggest that the nature of Ga diffusion into SiO₂ correlates with the oxidation states at the SiO₂/GaN interface. The SiO₂/AlGaN samples showed the similar results as the SiO₂/GaN case.