Quick search Find article
Quick search
Find article

Structural and electrical characterization of ohmic contacts to graphitized silicon carbide

Mohammad H Maneshian1, Ming-Te Lin1, David Diercks2 and Nigel D Shepherd1,2,3

Show affiliations


Titanium was deposited onto silicon carbide (6H-SiC) using the 248 nm line of an excimer laser in a vacuum of 10−6 Torr, and ohmic contacts were formed by annealing the structure at ~1000 °C. Further anneals between 1350 and 1430 °C did not degrade the formed contacts, and Raman analysis confirmed that sublimation of silicon from the near surface layers of the silicon carbide between the contact pads resulted in graphene formation after 5 min, 1428 °C anneals. The graphene formation was accompanied by a significant enhancement of ohmic behavior, and, it was found to be sensitive to the temperature ramp-up rate and annealing time. High-resolution transmission electron microscopy showed that the interface between the metal and silicon carbide remained sharp and free of macroscopic defects even after 30 min, 1430 °C anneals. The interface was determined to be carbon rich by elemental analysis, which indicates metal carbide formation. The potential of this approach for achieving ohmic contacts and graphene formation on silicon carbide substrates is discussed. A mechanism for the sequential formation of ohmic contacts then graphene is proposed.


PACS

73.40.Ns Metal-nonmetal contacts

78.30.-j Infrared and Raman spectra

61.48.-c Structure of fullerenes and related hollow molecular clusters

81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

68.37.Lp Transmission electron microscopy (TEM)

73.63.-b Electronic transport in nanoscale materials and structures

Subjects

Condensed matter: electrical, magnetic and optical

Surfaces, interfaces and thin films

Nanoscale science and low-D systems

Condensed matter: structural, mechanical & thermal

Dates

Issue 49 (9 December 2009)

Received 10 August 2009, in final form 2 October 2009

Published 6 November 2009



View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.