Optical Investigation of Cubic SiC Layers Grown on Hexagonal SiC Substrates by CVD and VLS
We report an optical investigation of cubic Silicon Carbide (3C-SiC) layers grown on 6H-SiC substrates by Chemical Vapour Deposition and Vapour-Liquid-Solid mechanism. Micro- Infrared reflectance ('-IR), micro-Raman ('-Raman) and low temperature photoluminescence spectroscopies were used for the characterisation of such layers. '-IR measurements showed unusual optical behaviour of 3C-SiC layers. The difference of refraction index between the 3C-SiC film and the 6H-SiC substrate cannot explain this result. The experimental '-IR reflectance spectrum was modelled by introducing a thin (thickness ≤ 0.5 'm) metallic-like (doping ≥ 1020 at.cm-3) interfacial film between the layer and the substrate. The photoluminescence spectra revealed the presence of a peak which may be attributed to recombination at the 3C/6H interface. All these results suggest the presence of a two dimensional electron gas at the interface.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
N. Habka et al., "Optical Investigation of Cubic SiC Layers Grown on Hexagonal SiC Substrates by CVD and VLS", Materials Science Forum, Vols. 556-557, pp. 403-406, 2007