Abstract
The chemical, electrical, and microstructural properties of Au/Pd contacts on p-type GaN(0001) surfaces previously cleaned either ex situ or ex situ and in situ have been investigated. The in situ process involved a high temperature, NH 3-based chemical vapor clean (CVC); it produced ordered, stoichiometric, p-type GaN surfaces with no detectable C and an O constituent which was subsequently reduced from 15 at% on the ex situ treated surface to 2 ± 1 at% following the CVC process. The Pd contacting layer grew epitaxially in a layer-by-layer mode on the CVC surface and formed an abrupt, unreacted metal-semiconductor interface. The Au capping layer also grew epitaxially on the Pd. Au/Pd contacts on both HCl and CVC treated surfaces exhibited identical surface roughness values (RMS) in the as-deposited state and following a 500°C anneal. Contact structures on CVC treated surfaces demonstrated excellent high-temperature microstructural stability as evidenced by the absence of significant change in the surface roughness (RMS) with successive annealing at 600 and 700°C. Identical contact structures on ex situ cleaned surfaces exhibited poor high temperature microstructural stability, as indicated by a significant increase in the surface roughness (RMS) following successive anneals at 600 and 700°C. There was a significant degradation in the morphology of both surfaces following the 800°C anneal as evidenced by the formation of large voids in the contact metallization and the exposure of the underlying p-type GaN substrate. The lowest resistance contact structures with uniform metal coverage were obtained for Au/Pd contacts on a CVC treated surface annealed at 700°C.
| Original language | English (US) |
|---|---|
| Title of host publication | Materials Research Society Symposium - Proceedings |
| Editors | J.E. Northrup, J. Neugebauer, D.C. Look, S.F. Chichibu, H. Riechert |
| Pages | 737-742 |
| Number of pages | 6 |
| Volume | 693 |
| State | Published - 2002 |
| Externally published | Yes |
| Event | GaN and Related Alloys-2001 - Boston, MA, United States Duration: Nov 26 2001 → Nov 30 2001 |
Other
| Other | GaN and Related Alloys-2001 |
|---|---|
| Country | United States |
| City | Boston, MA |
| Period | 11/26/01 → 11/30/01 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
Cite this
Chemical, electrical, and structural properties of Au/Pd contacts on chemical vapor cleaned p-type GaN surfaces. / Hartlieb, P. J.; Roskowski, A.; Rodriguez, B. J.; Nemanich, Robert; Davis, R. F.
Materials Research Society Symposium - Proceedings. ed. / J.E. Northrup; J. Neugebauer; D.C. Look; S.F. Chichibu; H. Riechert. Vol. 693 2002. p. 737-742.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Chemical, electrical, and structural properties of Au/Pd contacts on chemical vapor cleaned p-type GaN surfaces
AU - Hartlieb, P. J.
AU - Roskowski, A.
AU - Rodriguez, B. J.
AU - Nemanich, Robert
AU - Davis, R. F.
PY - 2002
Y1 - 2002
N2 - The chemical, electrical, and microstructural properties of Au/Pd contacts on p-type GaN(0001) surfaces previously cleaned either ex situ or ex situ and in situ have been investigated. The in situ process involved a high temperature, NH 3-based chemical vapor clean (CVC); it produced ordered, stoichiometric, p-type GaN surfaces with no detectable C and an O constituent which was subsequently reduced from 15 at% on the ex situ treated surface to 2 ± 1 at% following the CVC process. The Pd contacting layer grew epitaxially in a layer-by-layer mode on the CVC surface and formed an abrupt, unreacted metal-semiconductor interface. The Au capping layer also grew epitaxially on the Pd. Au/Pd contacts on both HCl and CVC treated surfaces exhibited identical surface roughness values (RMS) in the as-deposited state and following a 500°C anneal. Contact structures on CVC treated surfaces demonstrated excellent high-temperature microstructural stability as evidenced by the absence of significant change in the surface roughness (RMS) with successive annealing at 600 and 700°C. Identical contact structures on ex situ cleaned surfaces exhibited poor high temperature microstructural stability, as indicated by a significant increase in the surface roughness (RMS) following successive anneals at 600 and 700°C. There was a significant degradation in the morphology of both surfaces following the 800°C anneal as evidenced by the formation of large voids in the contact metallization and the exposure of the underlying p-type GaN substrate. The lowest resistance contact structures with uniform metal coverage were obtained for Au/Pd contacts on a CVC treated surface annealed at 700°C.
AB - The chemical, electrical, and microstructural properties of Au/Pd contacts on p-type GaN(0001) surfaces previously cleaned either ex situ or ex situ and in situ have been investigated. The in situ process involved a high temperature, NH 3-based chemical vapor clean (CVC); it produced ordered, stoichiometric, p-type GaN surfaces with no detectable C and an O constituent which was subsequently reduced from 15 at% on the ex situ treated surface to 2 ± 1 at% following the CVC process. The Pd contacting layer grew epitaxially in a layer-by-layer mode on the CVC surface and formed an abrupt, unreacted metal-semiconductor interface. The Au capping layer also grew epitaxially on the Pd. Au/Pd contacts on both HCl and CVC treated surfaces exhibited identical surface roughness values (RMS) in the as-deposited state and following a 500°C anneal. Contact structures on CVC treated surfaces demonstrated excellent high-temperature microstructural stability as evidenced by the absence of significant change in the surface roughness (RMS) with successive annealing at 600 and 700°C. Identical contact structures on ex situ cleaned surfaces exhibited poor high temperature microstructural stability, as indicated by a significant increase in the surface roughness (RMS) following successive anneals at 600 and 700°C. There was a significant degradation in the morphology of both surfaces following the 800°C anneal as evidenced by the formation of large voids in the contact metallization and the exposure of the underlying p-type GaN substrate. The lowest resistance contact structures with uniform metal coverage were obtained for Au/Pd contacts on a CVC treated surface annealed at 700°C.
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UR - http://www.scopus.com/inward/citedby.url?scp=0036377362&partnerID=8YFLogxK
M3 - Conference contribution
VL - 693
SP - 737
EP - 742
BT - Materials Research Society Symposium - Proceedings
A2 - Northrup, J.E.
A2 - Neugebauer, J.
A2 - Look, D.C.
A2 - Chichibu, S.F.
A2 - Riechert, H.
ER -