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Growth and Characterization of Nitrogen‐Polar AlGaN/AlN Heterostructure for High‐Electron‐Mobility Transistor
Author(s) -
Ito Tadatoshi,
Sakamoto Ryota,
Isono Tatsuya,
Yao Yongzhao,
Ishikawa Yukari,
Okada Narihito,
Tadatomo Kazuyuki
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900589
Subject(s) - materials science , sapphire , high electron mobility transistor , heterojunction , polar , optoelectronics , electron mobility , layer (electronics) , transistor , metalorganic vapour phase epitaxy , transmission electron microscopy , nitride , wide bandgap semiconductor , analytical chemistry (journal) , epitaxy , nanotechnology , optics , chemistry , astronomy , chromatography , laser , physics , quantum mechanics , voltage
A nitrogen‐polar (N‐polar) AlGaN/AlN high‐electron‐mobility transistor (HEMT) is proposed, and the generation of a 2D electron gas (2DEG) is simulated. The band diagram of N‐polar (Al)GaN/AlN shows the generation of the 2DEG, whereas that of the conventional metal‐polar (Al)GaN/AlN structure shows the generation of a 2D hole gas. Furthermore, the concentration of the 2DEG is considerably high even when the (Al)GaN layer is as thin as a few nanometers. N‐polar AlGaN/AlN is grown on sapphire substrates with a misorientation angle of 2°; furthermore, atomic force microscope measurements in a range of 5 × 5 μm 2 demonstrate that the root‐mean‐square value obtained from atomic force microscopy of N‐polar AlGaN is approximately 0.7 nm. N‐polar AlGaN layers with a thickness of approximately 40–60 nm with more than 50% Al content are almost coherently grown on the N‐polar AlN layer with a thickness of approximately 400 nm.