Phase formation at rapid thermal annealing of Al/Ti/Ni ohmic contacts on 4H-SiC

Ohmic contacts to the top p-type layers of 4H-SiC p(+)-n-n(+) epitaxial structures having an acceptor concentration lower than 1 x 10(19) cm(-3) were fabricated by the rapid thermal anneal of multilayer Al/Ti/Pt/Ni metal composition. The rapid thermal anneal of multilayer Al/Ti/Pt/Ni metal composition led to the formation of duplex cermet composition containing Ni2Si and TiC phases. The decomposition of the SIC under the contact was found to be down to a depth of about 100 nm. The contacts exhibited a contact resistivity R-c of 9 x 10(-5) Omega cm(-2) at 21 degreesC, decreasing to 3.1 x 10(-5) Omega cm(-2) at 186 degreesC. It was found that thermionic emission through the barrier having a height of 0.097 eV is the predominant curl ent transport mechanism in the fabricated contacts. (C) 2001 Elsevier Science B.V. AII rights reserved.