Al/Ti Ohmic Contacts to P-type Ion Implanted 6H-SiC: Mono- and Two-dimensional Analysis of the TLM Data

This paper deals with the electrical characterization of low resistance Al-Ti 70/30 wt.% ohmic contacts to a p-type ion implanted 6H-SiC layer. Transmission Line Model (TLM) structures were realized on the top of mesa islands defined in the ion implanted layer. A metal scheme composed of Al-1%Si(350nm)/Ti(80nm) was deposited by sputtering, photolitography defined and annealed at 1000degreesC in Ar for 2 min. Contact resistance was measured from in-line TLM structures as a function of the temperature in the range 25-290degreesC. The TLM data were analyzed by both the usual one-dimensional model and a more realistic 2-dimensional finite difference simulation tool that takes into account the current crowding effect at the contact periphery. Extracted contact resistivity values fall in the low range of data from the literature.