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




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