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Nanocrystalline diamond capped AlGaN/GaN high electron mobility transistors via a sacrificial gate process
Author(s) -
Tadjer Marko J.,
Anderson Travis J.,
Feygelson Tatyana I.,
Hobart Karl D.,
Hite Jennifer K.,
Koehler Andrew D.,
Wheeler Virginia D.,
Pate Bradford B.,
Eddy Charles R.,
Kub Fritz J.
Publication year - 2016
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.201532570
Subject(s) - materials science , passivation , optoelectronics , diamond , etching (microfabrication) , transistor , electron mobility , sheet resistance , layer (electronics) , nanocrystalline material , fabrication , plasma enhanced chemical vapor deposition , nanotechnology , chemical vapor deposition , composite material , voltage , electrical engineering , engineering , medicine , alternative medicine , pathology
Top‐side integration of nanocrystalline diamond films in the fabrication sequence of AlGaN/GaN high electron mobility transistors is demonstrated. Reliable oxygen plasma etching of the diamond capping layer, required for a diamond‐before‐gate process, was implemented by using a sacrificial SiN “dummy” gate. Hall characterization showed minimal (∼6%) reduction in sheet carrier density and commensurate increase in sheet resistance, while maintaining mobility and on‐state drain current density. Off‐state drain current and threshold voltage were increased, likely by fluorination of the AlGaN surface after removal of the sacrificial gate, even though a 20 nm thick Al 2 O 3 layer was used as a SF 6 ‐plasma etch stop. Pulsed I DS and on‐resistance were improved, indicating that a 10 nm SiN/500 nm NCD could offer improved AlGaN surface passivation compared to a more conventional 100 nm thick PECVD SiN film.