Schottky barrier height of a new ohmic contact NiSi2 to n-type 6H-SiC

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 x 10(16) to 2.5 x 10(19) cm(-3). The deposited films are annealed at 900 degreesC for 10 min in a flow of Ar gas containing 5 vol.% H-2 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 x 10(19) cm(-3) show a relatively low specific contact resistance with 3.6 x 10(-6) Omega cm(2). 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. (C) 2002 Elsevier Science Ltd. All rights reserved.