College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
Abstract:
We present a new ohmic contact material NiSi2 to n-type 6H-SiC with a low specific contact resistance. NiSi2 films are prepared by annealing the Ni and Si films separately deposited on (0 0 0 1)-oriented 6H-SiC substrates with carrier concentrations (n) ranging from 5.8×1016 to 2.5×1019 cm?3. The deposited films are annealed at 900 °C for 10 min in a flow of Ar gas containing 5 vol.% H2 gas. The specific contact resistance of NiSi2 contact exponentially decreases with increasing carrier concentrations of substrates. NiSi2 contacts formed on the substrates with n=2.5×1019 cm?3 show a relatively low specific contact resistance with 3.6×10?6 Ω cm2. Schottky barrier height of NiSi2 to n-type 6H-SiC is estimated to be 0.40±0.02 eV using a theoretical relationship for the carrier concentration dependence of the specific contact resistance.