Stability of Ti/Al/ZrB                         2                         /Ti/Au ohmic contacts on n-GaN

R. Khanna; S. J. Pearton; F. Ren; I. I. Kravchenko

doi:10.1016/j.apsusc.2006.04.042

Stability of Ti/Al/ZrB ₂ /Ti/Au ohmic contacts on n-GaN

R. Khanna, S. J. Pearton, F. Ren, I. I. Kravchenko

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

Ohmic contacts on n-GaN using a novel Ti/Al/ZrB ₂ /Ti/Au metallization scheme were studied using contact resistance, scanning electron microscopy and Auger electron spectroscopy (AES) measurements. A minimum specific contact resistivity of 3 × 10 ^-6 Ω cm ² was achieved at an annealing temperature of 700 °C. The lowest contact resistance was obtained for 60 s anneals. The contact resistance was essentially independent of measurement temperature, indicating that field emission plays a dominant role in the current transport. The Ti and Al in the contact stack began to outdiffuse to the surface at temperatures of ∼500 °C, while at 1000 °C the B also began to migrate to the surface. By this latter temperature, AES showed almost complete intermixing of the metallization even though the contact morphology was still smooth. The boride appears susceptible to getting of residual water vapor during sputter deposition.

Original language	English
Pages (from-to)	2340-2344
Number of pages	5
Journal	Applied Surface Science
Volume	253
Issue number	4
DOIs	https://doi.org/10.1016/j.apsusc.2006.04.042
State	Published - Dec 15 2006
Externally published	Yes

Funding

The work at UF is partially supported by AFOSR (F49620-02-1-0366, G. Witt), ONR (N00014-98-1-02-04, H. B. Dietrich) and NSF DMR 0101438.

Funders	Funder number
National Science Foundation	DMR 0101438
Office of Naval Research	N00014-98-1-02-04
Air Force Office of Scientific Research	F49620-02-1-0366
University of Florida

Keywords

GaN
Ohmic contacts

Access to Document

10.1016/j.apsusc.2006.04.042

Cite this

@article{28eb6f096aae40ef83c26d11e086306f,

title = " Stability of Ti/Al/ZrB 2 /Ti/Au ohmic contacts on n-GaN ",

abstract = " Ohmic contacts on n-GaN using a novel Ti/Al/ZrB 2 /Ti/Au metallization scheme were studied using contact resistance, scanning electron microscopy and Auger electron spectroscopy (AES) measurements. A minimum specific contact resistivity of 3 × 10 -6 Ω cm 2 was achieved at an annealing temperature of 700 °C. The lowest contact resistance was obtained for 60 s anneals. The contact resistance was essentially independent of measurement temperature, indicating that field emission plays a dominant role in the current transport. The Ti and Al in the contact stack began to outdiffuse to the surface at temperatures of ∼500 °C, while at 1000 °C the B also began to migrate to the surface. By this latter temperature, AES showed almost complete intermixing of the metallization even though the contact morphology was still smooth. The boride appears susceptible to getting of residual water vapor during sputter deposition.",

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AU - Khanna, R.

AU - Pearton, S. J.

AU - Ren, F.

AU - Kravchenko, I. I.

PY - 2006/12/15

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N2 - Ohmic contacts on n-GaN using a novel Ti/Al/ZrB 2 /Ti/Au metallization scheme were studied using contact resistance, scanning electron microscopy and Auger electron spectroscopy (AES) measurements. A minimum specific contact resistivity of 3 × 10 -6 Ω cm 2 was achieved at an annealing temperature of 700 °C. The lowest contact resistance was obtained for 60 s anneals. The contact resistance was essentially independent of measurement temperature, indicating that field emission plays a dominant role in the current transport. The Ti and Al in the contact stack began to outdiffuse to the surface at temperatures of ∼500 °C, while at 1000 °C the B also began to migrate to the surface. By this latter temperature, AES showed almost complete intermixing of the metallization even though the contact morphology was still smooth. The boride appears susceptible to getting of residual water vapor during sputter deposition.

AB - Ohmic contacts on n-GaN using a novel Ti/Al/ZrB 2 /Ti/Au metallization scheme were studied using contact resistance, scanning electron microscopy and Auger electron spectroscopy (AES) measurements. A minimum specific contact resistivity of 3 × 10 -6 Ω cm 2 was achieved at an annealing temperature of 700 °C. The lowest contact resistance was obtained for 60 s anneals. The contact resistance was essentially independent of measurement temperature, indicating that field emission plays a dominant role in the current transport. The Ti and Al in the contact stack began to outdiffuse to the surface at temperatures of ∼500 °C, while at 1000 °C the B also began to migrate to the surface. By this latter temperature, AES showed almost complete intermixing of the metallization even though the contact morphology was still smooth. The boride appears susceptible to getting of residual water vapor during sputter deposition.

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