Formation of epitaxial Ti-Si-C Ohmic contact on 4H-SiC C face using pulsed-laser annealing

Abstract

Epitaxial Ti-Si-C Ohmic contacts on the 4H-SiC C-face for SiC power devices by pulsed-laser annealing were demonstrated. Titanium (Ti) is one of the carbon-interstitial type metals. In a conventional nickel silicide (NiSi) electrode on SiC, carbon agglomeration at the silicide/SiC interface occurs, and the contact resistance between NiSi and SiC substrates becomes larger. For the carbon agglomeration suppression, a nanosecond non-equilibrium laser annealing was performed, and also Ti was deposited for the formation of both silicide and carbide. As a result, the lowest specific contact resistance of 4.0 × 10−4 Ω cm2 was obtained for an Al/Ti-Si-C/SiC structure at a laser power of 2.5 J/cm2. The Ti-Si-C Ohmic electrode showed TiC and Ti5Si3 crystal phases, and these crystals were epitaxially grown on 4H-SiC at the interface.