The effect of thermal annealing in a hydrogen atmosphere on tungsten deposited on 6H-SiC

Tungsten (W) film was deposited on a bulk single crystalline 6H-SiC substrate and annealed in H-2 ambient at temperatures of 700 degrees C, 800 degrees C and 1000 degrees C for 1 h. The resulting solid-state reactions, phase composition and surface morphology were investigated by Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD) and scanning electron microscopy (SEM) analysis techniques. These results are compared with the vacuum annealed results reported in our earlier work. As-deposited RBS results indicated the presence of W and O-2 in the deposited thin film, the GIXRD showed the presence of W, WO3, W5Si3 and WC. RBS results indicated the interaction between W and SiC was accompanied by the removal of oxygen at 700 degrees C. The GIXRD analysis indicated the presence of W5Si3 and WC in the samples annealed at 700 degrees C. At temperatures of 800 degrees C and 1000 degrees C, W annealed in a H-2 ambient further reacted with the SiC substrate and formed a mixed layer containing silicide phases and carbide phases, i.e.W5Si3, WSi2, WC and W2C. The SEM micrographs of the as-deposited samples indicated the W thin film had a uniform surface with small grains. Annealing at 800 degrees C led to the agglomeration of W grains into clusters making the surface rough. (C) 2016 Elsevier Ltd. All rights reserved.