Optimisation of Ti Ohmic Contacts Formed by Laser Annealing on 4H-SiC

Abstract

This work is focused on the fabrication of Titanium-based ohmic contacts by Laser Thermal Annealing (LTA) on n-type silicon carbide (4H-SiC). Their morphologies and electrical properties were studied by using two sets of parameters impacting the laser pulse overlap. With both sets, the ohmic contact transition was reached. The high overlap conditions produced a massive degradation of the contact morphology by leaving uncovered SiC. An optimisation of the annealing parameters was successfully performed by reducing the overlap. With the low overlap configuration, a specific contact resistance of 1.2×10-4 Ω.cm2 was measured for a fluence of 4.25 J.cm-2 with a satisfying contact surface morphology.