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 t he two-step method: after etching by hydrogen, carbonization is done u sing propane in hydrogen, then epitaxy can be realized using propane a nd silane in hydrogen. The carbonization layer has been studied by spe ctroscopic ellipsometry and cross-section transmission electron micros copy (XTEM). X-ray diffraction is used for epitaxial film characteriza tion grown onto buffer layer. The influence of temperature on the form ation 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 thre e-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 carboniz ation temperature on the crystalline quality of the SiC epitaxial film is also shown.