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Title: Ohmic contacts to Al-rich AlGaN heterostructures

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 0.85Ga 0.15N/Al 0.66Ga 0.34N. 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 0.85Ga 0.15N/Al 0.66Ga 0.34N heterostructure. In conclusion, specific contact resistivity of 5×10 -3 Ω cm 2 was achieved after annealing Ti/Al/Ni/Au metallization.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND-2017-9872J
Journal ID: ISSN 1862-6300; 656978
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Physica Status Solidi. A, Applications and Materials Science
Additional Journal Information:
Journal Volume: 214; Journal Issue: 8; Journal ID: ISSN 1862-6300
Publisher:
Wiley
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AlGaN; AlN; band gap; heterostructures; ohmic contacts
OSTI Identifier:
1398780
Alternate Identifier(s):
OSTI ID: 1374948

Douglas, E. A., Reza, S., Sanchez, C., Koleske, D., Allerman, A., Klein, B., Armstrong, A. M., Kaplar, R. J., and Baca, A. G.. Ohmic contacts to Al-rich AlGaN heterostructures. United States: N. p., Web. doi:10.1002/pssa.201600842.
Douglas, E. A., Reza, S., Sanchez, C., Koleske, D., Allerman, A., Klein, B., Armstrong, A. M., Kaplar, R. J., & Baca, A. G.. Ohmic contacts to Al-rich AlGaN heterostructures. United States. doi:10.1002/pssa.201600842.
Douglas, E. A., Reza, S., Sanchez, C., Koleske, D., Allerman, A., Klein, B., Armstrong, A. M., Kaplar, R. J., and Baca, A. G.. 2017. "Ohmic contacts to Al-rich AlGaN heterostructures". United States. doi:10.1002/pssa.201600842. https://www.osti.gov/servlets/purl/1398780.
@article{osti_1398780,
title = {Ohmic contacts to Al-rich AlGaN heterostructures},
author = {Douglas, E. A. and Reza, S. and Sanchez, C. and Koleske, D. and Allerman, A. and Klein, B. and Armstrong, A. M. and Kaplar, R. J. and Baca, A. G.},
abstractNote = {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 Al0.85Ga0.15N/Al0.66Ga0.34N. 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 Al0.85Ga0.15N/Al0.66Ga0.34N heterostructure. In conclusion, specific contact resistivity of 5×10-3 Ω cm2 was achieved after annealing Ti/Al/Ni/Au metallization.},
doi = {10.1002/pssa.201600842},
journal = {Physica Status Solidi. A, Applications and Materials Science},
number = 8,
volume = 214,
place = {United States},
year = {2017},
month = {6}
}