Investigation of Au/Ti/Al ohmic contact to N-type 4H-SiC

In this study, investigation on Au/Ti/Al ohmic contact to n-type 4H-SiC and its thermal stability are reported. Specific contact resistances (SCRs) in the range of 10(-4)-10(-6) Omega cm(2), and the best SCR as low as 2.8 x 10(-6) Omega cm(2) has been generally achieved after rapid thermal annealing in Ar for 5 min at 800 degrees C and above. About 1-2 order(s) of magnitude improvement in SCR as compared to those Al/Ti series ohmic systems in n-SiC reported in literature is obtained. XRD analysis shows that the low resistance contact would be attributed to the formation of titanium silicides (TiSi2 and TiSi) and Ti3SiC2 at the inetal/n-SiC interface after thermal annealing. The Au/Ti/Al ohmic contact is thermally stable during thermal aging treatment in Ar at temperature in the 100-500 degrees C range for 20 h. (C) 2005 Elsevier Ltd. All rights reserved.