Design and control of interface reaction between Al-based dielectrics and AlGaN layer in AlGaN/GaN metal-oxide-semiconductor structures

• Published in: Applied physics letters Vol. 111; no. 4
• Main Authors: Watanabe, Kenta, Nozaki, Mikito, Yamada, Takahiro, Nakazawa, Satoshi, Anda, Yoshiharu, Ishida, Masahiro, Ueda, Tetsuzo, Yoshigoe, Akitaka, Hosoi, Takuji, Shimura, Takayoshi, Watanabe, Heiji
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 24.07.2017
• Subjects: Aluminum gallium nitrides; Aluminum oxide; Applied physics; Charge injection; Dielectrics; Gallium nitrides; Immunity; Insulators; Interface reactions; Interface stability; Metal oxide semiconductors; MOS devices; Thermal stability
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4986419

Important clues for achieving well-behaved AlGaN/GaN metal-oxide-semiconductor (MOS) devices with Al-based gate dielectrics were systematically investigated on the basis of electrical and physical characterizations. We found that low-temperature deposition of alumina insulators on AlGaN surfaces is crucial to improve the interface quality, thermal stability, and variability of MOS devices by suppressing Ga diffusion into the gate oxides. Moreover, aluminum oxynitride grown in a reactive nitric atmosphere was proven to expand the optimal process window that would improve the interface quality and to enhance immunity against charge injection into the gate dielectrics. The results constitute common guidelines for achieving high-performance and reliable AlGaN/GaN MOS devices.