Atomic scale characterization of titanium Ohmic contacts to SiC using three dimensional atom probe tomography and high resolution transmission electron microscopy

Three dimensional atom probe tomography coupled with high resolution transmission electron microscopy were used to analyze the structural and compositional transitions across interfaces of Ti Ohmic contacts on SiC. The results conclusively show that during the interfacial reaction carbon diffuses into the Ti layer, with the reaction zone extending beyond the immediate interface. The resultant TiC/TiCx interfacial layer provides a graded work function profile between the Ti and SiC, and facilitates low contact resistance which was measured by the transmission line, current-voltage method. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3464322]