INFLUENCE OF TEMPERATURE ON THE FORMATION BY REACTIVE CVD OF A SILICON-CARBIDE BUFFER LAYER ON SILICON

Silicon carbide has been grown by VPE on (100) silicon substrates by the two-step method: after etching by hydrogen, carbonization is done using propane in hydrogen, then epitaxy can be realized using propane and silane in hydrogen. The carbonization layer has been studied by spectroscopic ellipsometry and cross-section transmission electron microscopy (XTEM). X-ray diffraction is used for epitaxial film characterization grown onto buffer layer. The influence of temperature on the formation of the carbonization layer has been studied: at low temperature (1200-degrees-C) the growth proceeds via a two-dimensional mechanism, while at higher temperature (1340-degrees-C) it is dominated by a three-dimensional mechanism. Detailed XTEM shows that the lattice mismatch between silicon and silicon carbide is accommodated by the formation of dislocations in the carbonization layer. The impact of the carbonization temperature on the crystalline quality of the SiC epitaxial film is also shown.