Direct Deposition of Low Resistance Thermally Stable Ohmic Contacts to n-SiC.

摘要

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 deg C. The as-deposited and 700 deg C annealed contacts were non-Ohmic. Annealing at 950 deg 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. The 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.