Creating room temperature Ohmic contacts to 4H–SiC: studied by specific contact resistance measurements and X-ray photoelectron spectroscopy

The use of a silicon interface pre-treatment to produce low resistance Ohmic nickel contacts to 4H–SiC, circumventing the need for contact post annealing, is reported. The effects of two different SiC pre-metal deposition surface preparation techniques: RCA cleaning (control sample) and a silicon in...

Full description

Saved in:
Bibliographic Details
Published in:Surface science 2004-12, Vol.573 (2), p.253-263
Main Authors: Guy, O.J., Pope, G., Blackwood, I., Teng, K.S., Chen, L., Lee, W.Y., Wilks, S.P., Mawby, P.A.
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Contact
Cross-disciplinary physics: materials science
rheology
Electrical transport measurements
Exact sciences and technology
Metal–semiconductor interfaces
Nickel
Physics
Schottky Barrier
Silicides
Silicon carbide
X-ray photoelectron spectroscopy
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The use of a silicon interface pre-treatment to produce low resistance Ohmic nickel contacts to 4H–SiC, circumventing the need for contact post annealing, is reported. The effects of two different SiC pre-metal deposition surface preparation techniques: RCA cleaning (control sample) and a silicon interlayer pre-treatment (SIP), are discussed. Electrical characterization of contacts on treated surfaces, using circular transfer length measurements (CTLM), revealed that contacts to RCA cleaned samples were Schottky in nature, unless annealed at temperatures greater than 700 °C. In contrast, contacts formed on SIP SiC surfaces exhibited Ohmic behaviour directly after fabrication, without the need for post metallisation annealing. Average contact resistances as low as 1.3E−05 Ω cm 2 have been recorded for SIP samples. This fabrication process has distinct technological advantages compared to standard techniques for forming Ohmic contacts to SiC. To consolidate our findings the chemical and electrical nature of the SIP nickel–SiC interface, as it was sequentially formed and annealed, was examined using X-ray photoelectron spectroscopy (XPS). Based on these results, a model is proposed to explain the as-deposited Ohmic contact nature of the SIP sample.
ISSN:0039-6028
1879-2758
DOI:10.1016/j.susc.2004.09.035