Physical and electrical characterizations of AlGaN/GaN MOS gate stacks with AlGaN surface oxidation treatment

作者：Yamada Takahiro^*; Watanabe Kenta; Nozaki Mikito; Shih Hong An; Nakazawa Satoshi; Anda Yoshiharu; Ueda Tetsuzo; Yoshigoe Akitaka; Hosoi Takuji; Shimura Takayoshi; Watanabe Heiji

来源：Japanese Journal of Applied Physics, 2018, 57(6): 06KA07.

DOI：10.7567/JJAP.57.06KA07

The impacts of inserting ultrathin oxides into insulator/AlGaN interfaces on their electrical properties were investigated to develop advanced AlGaN/GaN metal-oxide-semiconductor (MOS) gate stacks. For this purpose, the initial thermal oxidation of AlGaN surfaces in oxygen ambient was systematically studied by synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) and atomic force microscopy (AFM). Our physical characterizations revealed that, when compared with GaN surfaces, aluminum addition promotes the initial oxidation of AlGaN surfaces at temperatures of around 400 degrees C, followed by smaller grain growth above 850 degrees C. Electrical measurements of AlGaN/GaN MOS capacitors also showed that, although excessive oxidation treatment of AlGaN surfaces over around 700 degrees C has an adverse effect, interface passivation with the initial oxidation of the AlGaN surfaces at temperatures ranging from 400 to 500 degrees C was proven to be beneficial for fabricating high-quality AlGaN/GaN MOS gate stacks.

• 出版日期2018-6