Formation of Ohmic Contacts to n-Type 4H-SiC at Low Annealing Temperatures

Abstract

The formation of Ohmic contacts to n-type 4H-SiC layers at low annealing temperature using dopant segregation technique is reported. n-SiC epilayer was implanted with phosphorous and subsequently activated at 1700 °C. Ni metal contacts fabricated on phosphorous implanted and annealed epilayers produced Ohmic contacts with a specific contact resistivity (ρc) of ~7.2x10-5 Ω.cm2 at an annealing temperature of 550 °C. ρc decreased with further annealing temperature reaching a value of ~2.1x10-5 Ω.cm2 at 1000 °C. XRD analysis showed that nickel silicide phase was formed at both 550 °C and 1000 °C.