Composite Ohmic Contacts to SiC


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Composite ohmic contacts designed for SiC devices operating in air at 350°C have been studied. Ohmic contacts to n- and p-4H-SiC were protected against inter-diffusion and oxidation by Ta-Si-N layers obtained by sputter deposition from a TaSi2 target in a mixture of Ar and N2. Platinum was sputter-deposited at 250°C to promote adhesion between the Ta-Si- N barrier layer and a thick Au cap layer. Platinum also acts as a barrier to the diffusion of Au. The electrical and mechanical characteristics of the composite contacts were stable after hundreds of hours of annealing in air at 350°C. We report the effects of thermal aging on the specific contact resistance and the semiconductor sheet resistance, and the results of wire bond pull and shear tests following aging for Ta-Si-N / Pt / Au stacks deposited on both SiO2 dielectric layers and the ohmic contact layers.



Materials Science Forum (Volumes 527-529)

Edited by:

Robert P. Devaty, David J. Larkin and Stephen E. Saddow




A.V. Adedeji et al., "Composite Ohmic Contacts to SiC", Materials Science Forum, Vols. 527-529, pp. 879-882, 2006

Online since:

October 2006




[1] E.D. Luckowski, J.M. Delucca, J.R. Williams, S.E. Mohney, M.J. Bozack, T. Isaac-Smith and J. Crofton: J. Electronic Materials 27(4) (1998), p.330.

[2] J. Crofton, P.A. Barnes, J.R. Williams and J.A. Edmond: Appl. Phys. Lett. 62(4) (1993), p.384.

[3] L. M. Porter and R. F. Davis: Mater. Sci. Eng. B, Vol. 34 (1995), p.83.

[4] J. Crofton, S.E. Mohney, J.R. Williams and T. Isaacs-Smith: Solid-State Electronics 46 (2002), p.109.

[5] S. Liu, K. Reinhardt, J. Scofield and C. Servert, Workshop on High Temperature Power Electronics for Vehicles (April, 1995).

[6] M. -A. Nicolet: Thin Solid Films 52 (1978), p.415.

[7] A. V. Adedeji, A. C. Ahyi, J. R. Williams, M. Horsey, S. E. Mohney and J. D. Scofield: Proc. High Temperature Electronics Conf., Albuquerque, NM, May, (2004).

[8] G.K. Reeves and H.B. Harrison: Electron Device Letters 30(5) (1982), p.111.

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