Fabrication and characterization of pulse laser deposited Ni2Si Ohmic contacts on n-SiC for high power and high temperature device applications

Ni2Si Ohmic contacts were fabricated via pulsed laser deposition on n-SiC. The contacts electrical, structural, compositional, and surface morphological properties were investigated as a function of annealing temperatures ranging from 700 to 950 degreesC. The as-deposited and 700 degreesC annealed contacts were non-Ohmic. Annealing at 950 degreesC yielded excellent Ohmic behavior, an abrupt void free interface, and a smooth surface morphology. No residual carbon was present within the contact metallization or at the contact-SiC interface and the contact showed no appreciable thickness increase as a result of the annealing process. Our results demonstrate that aside from maintaining the desirable electrical integrity associated with Ni and Ni/Si Ohmic contacts, the Ni2Si Ohmic contacts possessed improved interfacial, compositional, microstructural, and surface properties which are required for reliable high temperature and high power device operation. (C) 2001 American Institute of Physics.