Premium
Characterization of AlGaN/GaN Heterostructures Grown by Metalorganic Chemical Vapor Deposition
Author(s) -
Eiting C.J.,
Lambert D.J.H.,
Kwon H.K.,
Shelton B.S.,
Wong M.M.,
Zhu T.G.,
Dupuis R.D.
Publication year - 1999
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/(sici)1521-3951(199911)216:1<193::aid-pssb193>3.0.co;2-k
Subject(s) - heterojunction , chemical vapor deposition , sapphire , materials science , metalorganic vapour phase epitaxy , wafer , substrate (aquarium) , optoelectronics , surface roughness , fermi gas , electron mobility , characterization (materials science) , surface finish , epitaxy , nanotechnology , optics , electron , layer (electronics) , composite material , laser , physics , geology , oceanography , quantum mechanics
We report the growth and characterization of high‐quality AlGaN/GaN heterojunctions by low‐pressure metalorganic chemical vapor deposition. We have measured the mobility, μ n , and sheet charge density, n s of the interfacial two‐dimensional electron gas (2DEG) as a function of Al composition, substrate orientation, and modulation doping. We have also attempted to correlate these results with (102) X‐ray diffraction linewidths and surface roughness measured by atomic force microscopy. Interestingly, we do not find any correlation between the roughness of the wafer surface and the 2DEG concentration or mobility. Inserting a short NH 3 /H 2 purge immediately before initiating the AlGaN growth improves the 2DEG mobility in these AlGaN/GaN structures. By optimizing the growth conditions, we have achieved Al 0.30 Ga 0.70 N/GaN heterostructures on (0001) sapphire with 2DEG mobilities in excess of μ n = 1300 cm 2 /Vs at 300 K and 4500 cm 2 /Vs at 100 K with n s ∼ 9.4 × 10 12 cm —2 .