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The effect of ammonia flow in the AlN spacer on the electrical properties of InAlN/AlN/GaN HEMT structures
Author(s) -
Gamarra Piero,
Lacam Cedric,
Magis Michelle,
Tordjman Maurice,
Poisson MarieAntoinette di Forte
Publication year - 2012
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.201100090
Subject(s) - materials science , metalorganic vapour phase epitaxy , high electron mobility transistor , optoelectronics , epitaxy , electron mobility , surface roughness , sheet resistance , transistor , surface finish , layer (electronics) , nanotechnology , composite material , electrical engineering , engineering , voltage
During the past few years it has been reported that a thin AlN spacer of few nanometers needs to be inserted in InAlN/GaN high electron mobility transistors (HEMTs) to obtain high 2DEG carrier mobility. This work presents a systematic study of the effects of varying the ammonia flow in the AlN spacer of InAlN/AlN/GaN HEMTs grown by low pressure metalorganic vapour phase epitaxy (LP‐MOVPE). The strain state, the surface roughness and the growth rate of AlN were found to be dependent on the V/III ratio. In addition the ammonia flow in the interlayer has a strong impact on the structural properties of the subsequent InAlN barrier layer and on the electrical properties of the structure. A sheet resistance as low as 327 Ω/□ with a sheet carrier density of 1.5 × 10 13 cm −2 has been obtained at room temperature.