THERMALLY STABLE LOW OHMIC CONTACTS TO P-TYPE 6H-SIC USING COBALT SILICIDES

Cobalt silicide (CoSi2) ohmic contacts possessing low specific contact resistivity (rho(c) < 4.0 +/- 0.7 x 10(-6) Omega cm(2)) to p-type 6H- SiC are reported. The contacts were fabricated through sequential elec tron-beam evaporation of Co and Si layers forming a Si/Co/SiC structur e, followed by a two-step vacuum annealing process at 500 and 900 degr ees C, respectively. Specific contact resistivities were extracted fro m transmission line model (TLM) structures at temperatures ranging fro m 22 to 200 degrees C. rho(c) is investigated as a function of current density, temperature and ageing in a vacuum furnace at 1100 degrees C . Furthermore, comparison with a Co/SiC contact structure subjected to an identical annealing process revealed higher rho(c) and a modified sheet resistance requiring a different method of contact parameter ext raction. Copyright (C) 1996 Published by Elsevier Science Ltd