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Improvement of Channel Mobility of GaN‐MOSFETs With Thermal Treatment for Recess Surface
Author(s) -
Uesugi Kenjiro,
Shindome Aya,
Kajiwara Yosuke,
Yonehara Toshiya,
Kato Daimotsu,
Hikosaka Toshiki,
Kuraguchi Masahiko,
Nunoue Shinya
Publication year - 2018
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201700511
Subject(s) - fabrication , materials science , thermal , thermal treatment , impurity , optoelectronics , surface roughness , epitaxy , mosfet , surface finish , nanotechnology , composite material , layer (electronics) , chemistry , transistor , electrical engineering , voltage , medicine , physics , alternative medicine , organic chemistry , engineering , pathology , meteorology
In this work, a thermal treatment technique under NH 3 ambient for the recess surface of GaN‐MOSFETs is developed. Immediately following the fabrication process of the recess, the bottoms of these structures have rough surfaces and step‐terrace structures cannot be observed because of the plasma‐induced damage. However, clear step‐terrace structures are formed by the thermal treatment, and the RMS values of the surface roughness decrease from 0.26 to 0.14 nm, which is comparable to those of the as‐grown epitaxial film. In addition, it is confirmed that concentrations of impurity atoms introduced during the recess fabrication process are decreased by the thermal treatment. The channel mobility of the GaN‐MOSFETs without the thermal treatment is 118 cm 2 Vs −1 , whereas that of the device whose fabrication process includes the thermal treatment increased to 149 cm 2 Vs −1 . These results indicate that the thermal treatment under NH 3 ambient is effective for reducing on‐state resistance of GaN‐MOSFETs.