Open AccessComparative study on thermal robustness of GaN and AlGaN/GaN MOS devices with thin oxide interlayers
Author(s) -
Mitsuhiro Nozaki,
Daiki Terashima,
Takahiro Yamada,
Akitaka Yoshigoe,
Takuji Hosoi,
Takayoshi Shimura,
Heiji Watanabe
Publication year - 2019
Publication title -
japanese journal of applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 129
eISSN - 1347-4065
pISSN - 0021-4922
DOI - 10.7567/1347-4065/ab0ad2
Subject(s) - materials science , optoelectronics , oxide , thermal stability , dielectric , thin film , layer (electronics) , semiconductor , wide bandgap semiconductor , thermal , chemical engineering , nanotechnology , metallurgy , engineering , physics , meteorology
Similarities and differences in the design of the interfaces between gate dielectrics and GaN-based semiconductors were systematically investigated with a focus on the thermal stability of the interlayers. Although the excellent electrical properties of a SiO 2 /GaN interface with a thin Ga-oxide interlayer (SiO 2 /GaO x /GaN) were deteriorated by high-temperature treatment at around 1000 °C, the thin oxide on the AlGaN surface (SiO 2 /GaO x /AlGaN) exhibited superior thermal stability and interface quality even after treatment at 1000 °C. Physical characterizations showed that thermal decomposition of the thin GaO x layer on the GaN surface is promoted by oxygen transfer, which produces volatile products, leading to remarkable roughening of the GaN surface. In contrast, decomposition of the thin GaO x layer was suppressed on the AlGaN surface under the high temperatures, preserving a smooth oxide surface. The mechanisms behind both the improved and degraded electrical properties in these GaN-based MOS structures are discussed on the basis of these findings.