Ion beam synthesis by tungsten-implantation into 6H-silicon carbide

Abstract

Synthesis of a highly conductive surface layer on 6H-silicon carbide was achieved by high-dose, room temperature implantation of tungsten at 200 keV. Subsequently, the samples were annealed in two steps, namely at 500°C and 950°C. The influence of both dose and annealing on the reaction of W with SiC was investigated. Rutherford Backscattering Spectrometry (RBS), X-Ray Diffraction (XRD) and Auger Electron Spectroscopy (AES) contributed to study the structure and composition of the layer as well as the chemical states of the elements. During implantation sputtering becomes significant for doses exceeding 1.0 × 10 17 cm −2. Formation of tungsten carbide and silicide is already observed in the as-implanted state. An annealing temperature of 950°C is necessary to crystallize tungsten carbide. However, tungsten silicide remains amorphous at this temperature. Therefore, a mixture of polycrystalline tungsten carbide and amorphous tungsten silicide develops under these conditions. The resistivity of such a layer implanted with 1.0 × 10 17 W +cm −2 and annealed at 950°C is 565 μΩ cm.