Using a conventional electric furnace without any vacuum system, the top Si layer surface of an SOI (Silicon-on-Insulator) substrate was metamorphosed into the SiC layer under atmospheric pressure at about 1250degreesC. Two methods were attempted for the metamorphosis, i.e., (i) carbonization in hydrogen and propane after temperature elevation to about 1250degreesC under a pure hydrogen ambient, and (ii) carbonization by temperature elevation to about 1250degreesC under a hydrogen and propane ambient. For both specimens, SiC peaks (2 theta = 35.6degrees, Cu-k alpha) were clearly observed from X-ray diffraction measurements, indicating good crystallinity of the formed SiC layers. However, the surface roughness differed between the two specimens. The surface of specimen (ii) was much smoother (rms: <20nm) than that of (i). The cross-sectional TEM image for specimen (ii) indicated the formation of a uniform and flat mono-crystal line SiC layer with a thickness of about 3nm.