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Ohmic contacts to Al-rich AlGaN heterostructures

Journal Article · · Physica Status Solidi. A, Applications and Materials Science

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.

Research Organization:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
Grant/Contract Number:
AC04-94AL85000
OSTI ID:
1398780
Alternate ID(s):
OSTI ID: 1374948
Report Number(s):
SAND--2017-9872J; 656978
Journal Information:
Physica Status Solidi. A, Applications and Materials Science, Journal Name: Physica Status Solidi. A, Applications and Materials Science Journal Issue: 8 Vol. 214; ISSN 1862-6300
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (3)

Design of compositionally graded contact layers for MOCVD grown high Al-content AlGaN transistors journal July 2019
Multidimensional thermal analysis of an ultrawide bandgap AlGaN channel high electron mobility transistor journal October 2019
Planar Ohmic Contacts to Al 0.45 Ga 0.55 N/Al 0.3 Ga 0.7 N High Electron Mobility Transistors journal January 2017

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