Tungsten (W) film was deposited on a bulk single crystalline 6HeSiC substrate and annealed in H2
ambient at temperatures of 700 C, 800 C and 1000 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 O2 in the deposited thin film, the GIXRD
showed the presence ofW,WO3, W5Si3 andWC. RBS results indicated the interaction betweenWand SiC
was accompanied by the removal of oxygen at 700 C. The GIXRD analysis indicated the presence of
W5Si3 and WC in the samples annealed at 700 C. At temperatures of 800 C and 1000 C, Wannealed in
a H2 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 C led to the
agglomeration of W grains into clusters making the surface rough.