Structural characterization of Ar+-ion-amorphized 6H-SiC wafers annealed at 1100°C in N2 or wet O2 ambient

In this paper, a structural characterization by Rutherford back-scattering spectrometry in a channelling geometry and transmission electron microscopy of GH-SiC samples amorphized by 170 keV Ar+ ions at room temperature and furnace treated at 1100 degrees C in N-2 or wet oxidizing ambient, is presented. The influence of the ion-damage recovery and oxidation processes on the crystalline quality of the implanted SiC layer is carefully analyzed. This study shows that these processes occur on different time scales. Moreover, the more rapid ion-damage recovery process is found to be essentially independent of the annealing ambient. This process gives rise to a polycrystalline SiC structure composed of a bilayer epitaxial structure of 6H-SiC and columnar 3C-SiC polytype close to the interface with the 6H-SiC substrate and to hexagonal and cubic SiC grains in the uppermost part of the layer. The possible role of the defects, observed at the interface with the 6H-SiC substrate, on the imperfect epitaxial regrowth of the implanted layer is also briefly discussed.