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

Abstract

Ni 2 Si 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 °C. The as-deposited and 700 °C annealed contacts were non-Ohmic. Annealing at 950 °C 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.