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AlGaN/GaN/AlGaN DH‐HEMTs Grown on a Patterned Silicon Substrate
Author(s) -
Comyn Rémi,
Chenot Sébastien,
Alouani Wissam El,
Nemoz Maud,
Frayssinet Eric,
Damilano Benjamin,
Cordier Yvon
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.201700642
Subject(s) - materials science , molecular beam epitaxy , high electron mobility transistor , optoelectronics , substrate (aquarium) , planar , silicon , leakage (economics) , epitaxy , diffraction , transistor , stack (abstract data type) , layer (electronics) , nanotechnology , optics , electrical engineering , oceanography , computer graphics (images) , engineering , physics , computer science , economics , macroeconomics , programming language , voltage , geology
In the present work, a Si (111) substrate has been patterned with 120‐μm wide square mesas separated by 5‐μm deep grooves. An Al 0.29 Ga 0.71 N/GaN HEMT structure was grown by molecular beam epitaxy with a 2‐μm thick Al 0.15 Ga 0.85 N buffer on a strain‐mitigating stack previously developed for GaN and low Al‐content AlGaN buffers. Surface inspections confirm the absence of cracks and roughness modification compared to planar growth. Interestingly, contrary to planar growth, X‐ray diffraction shows that plastic strain relaxation was inhibited within the 150‐nm GaN channel grown on top of the Al 0.15 Ga 0.85 N buffer. Devices were fabricated in order to assess the electrical properties of the grown films. C–V and TLM measurements reveal the presence of a 2DEG with a density of 7 × 10 12 cm −2 and a sheet resistance around 450 Ω □ −1 . Round geometry transistors were measured up to 200–V drain bias. Compared to devices previously fabricated on planar structures with Al 0.05 Ga 0.95 N buffers, an order of magnitude lower off‐state leakage currents were obtained thanks to the larger Al content in the buffer.