Schottky barrier height of a new ohmic contact NiSi 2 to n-type 6H-SiC

Abstract

We present a new ohmic contact material NiSi 2 to n-type 6H-SiC with a low specific contact resistance. NiSi 2 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 5.8×10 16 to 2.5×10 19 cm −3. The deposited films are annealed at 900 °C for 10 min in a flow of Ar gas containing 5 vol.% H 2 gas. The specific contact resistance of NiSi 2 contact exponentially decreases with increasing carrier concentrations of substrates. NiSi 2 contacts formed on the substrates with n=2.5×10 19 cm −3 show a relatively low specific contact resistance with 3.6×10 −6 Ω cm 2. Schottky barrier height of NiSi 2 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.