Defects induced by solid state reactions at the tungsten-silicon carbide interface

Abstract

Defects introduced by the solid state reactions between tungsten and silicon carbide have been studied using deep level transient spectroscopy (DLTS) and Laplace DLTS. W/4H-SiC Schottky barrier diodes were isochronally annealed in the 100–1100 C temperature range. Phase composition transitions and the associated evolution in the surface morphology were investigated using x-ray diffraction (XRD) and scanning electron microscopy (SEM). After annealing at 1100 C, the E0.08, E0.15, E0.23, E0.34, E0.35, E0.61, E0.67, and E0.82 defects were observed. Our study reveals that products of thermal reactions at the interface between tungsten and n-4H-SiC may migrate into the semiconductor, resulting in electrically active defect states in the bandgap.