Abstract
Ohmic contact formation on n-GaN using a novel Ti/Al/W 2 B/Ti/Au metallization scheme was studied using contact resistance, scanning electron microscopy and Auger electron spectroscopy measurements. A minimum specific contact resistivity of 7 × 10 -6 Ω cm 2 was achieved at an annealing temperature of 800 °C. The contact resistance was essentially independent of measurement temperature, indicating that field emission plays a dominant role in the current transport .The Ti began to outdiffuse to the surface at temperatures of ∼500 °C, while at 800 °C the Al also began to intermix within the contact. By 1000 °C, the contact showed a reacted appearance and AES showed almost complete intermixing of the metallization. The contact resistance showed excellent stability for extended periods at 200 °C, which simulates the type of device operating temperature that might be expected for operation of GaN-based power electronic devices.
Original language | English |
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Pages (from-to) | 1826-1832 |
Number of pages | 7 |
Journal | Applied Surface Science |
Volume | 252 |
Issue number | 5 |
DOIs | |
State | Published - Dec 15 2005 |
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 |
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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-based power electronic devices
- Ohmic contact formation
- Ti/Al/W B/Ti/Au metallization scheme