Formation of low resistivity ohmic contacts to n-type 3C-SiC

In this study, the dependence of nickel contacts to n-type 3C-SiC on anneal temperature is characterized by the linear transmission line method. It is found that Ni contacts begin to exhibit ohmic behavior after annealing at 700 degreesC, and the specific contact resistivity decreases gradually with increasing anneal temperature. A low contact resistivity of 1.4 x 10(-5) Omegacm(2) was obtained after annealing at 1000 degreesC. Phosphorus was implanted into 3C-SiC epilayer and then activated at 1050, 1150, 1250 and 1350 degreesC, respectively. Both the sheet resistance of the 3C-SiC epilayer and the specific contact resistivity of Ni contacts decrease monotonically with increasing activation temperature. Results from Ni/Si bilayer contacts with varying layer thickness ratios (50 mn/180 nm, 50 nm/90 nm and 50 nm/50 nm) are also reported. Ni/Si bilayer contacts are found to be inferior to pure Ni contacts. (C) 2002 Published by Elsevier Science Ltd.