Premium
Ohmic contacts to Al‐rich AlGaN heterostructures
Author(s) -
Douglas E. A.,
Reza S.,
Sanchez C.,
Koleske D.,
Allerman A.,
Klein B.,
Armstrong A. M.,
Kaplar R. J.,
Baca A. G.
Publication year - 2017
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.201600842
Subject(s) - ohmic contact , materials science , fabrication , annealing (glass) , heterojunction , optoelectronics , contact resistance , electrical resistivity and conductivity , schottky barrier , schottky diode , wide bandgap semiconductor , planar , nanotechnology , composite material , electrical engineering , diode , layer (electronics) , computer science , medicine , alternative medicine , engineering , pathology , computer graphics (images)
Due to the ultra‐wide bandgap of Al‐rich AlGaN, up to 5.8 eV for the structures in this study, obtaining low resistance ohmic contacts is inherently difficult to achieve. A comparative study of three different fabrication schemes is presented for obtaining ohmic contacts to an Al‐rich AlGaN channel. Schottky‐like behavior was observed for several different planar metallization stacks (and anneal temperatures), in addition to a dry‐etch recess metallization contact scheme on Al 0.85 Ga 0.15 N/Al 0.66 Ga 0.34 N. However, a dry etch recess followed by n + ‐GaN regrowth fabrication process is reported as a means to obtain lower contact resistivity ohmic contacts on a Al 0.85 Ga 0.15 N/Al 0.66 Ga 0.34 N heterostructure. Specific contact resistivity of 5 × 10 −3 Ω cm 2 was achieved after annealing Ti/Al/Ni/Au metallization.