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Impact of AlN/Si Nucleation Layers Grown Either by NH 3 ‐MBE or MOCVD on the Properties of AlGaN/GaN HFETs
Author(s) -
Yacoub Hady,
Zweipfennig Thorsten,
Kalisch Holger,
Vescan Andrei,
Dadgar Armin,
Wieneke Matthias,
Bläsing Jürgen,
Strittmatter A.,
Rennesson Stephanie,
Semond Fabrice
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.201700638
Subject(s) - nucleation , metalorganic vapour phase epitaxy , materials science , silicon , epitaxy , optoelectronics , chemical vapor deposition , layer (electronics) , nitride , molecular beam epitaxy , nanotechnology , chemistry , organic chemistry
Epitaxial growth of group III nitrides on silicon substrates is challenging as large lattice and thermal expansion coefficient mismatches have to be accounted for. It is generally accepted that AlN is the best nucleation layer for GaN‐on‐Si growth. However, some open questions remain about this AlN nucleation layer. In this study, it is investigated how the choice of deposition method of the AlN nucleation layer affects the material and electrical properties of a full HFET structure. First, electrical characterization is performed on thin AlN layers deposited on two inch p‐type silicon substrates grown by NH 3 ‐MBE. CV characteristics indicate that electron injection from an inversion‐like layer at the AlN/Si‐interface is suppressed. Based on previous studies, this leads to the expectation that choosing MBE‐AlN may actually result in superior properties at the device level. Finally, the full HFET stack is grown by MOCVD on both types of AlN nucleation layers. Hall measurements on active devices yield comparable mobilities for both nucleation methods. Preliminary data suggest that MBE‐AlN does not have any detrimental impact the dynamic properties of the buffer. The vertical breakdown voltage measured at 1 μA mm −2 is increased by 30% and the leakage current measured at 600 V is reduced by two orders of magnitude.