Preparation of silicon-on-insulator substrate on large free-standing carbon nanotube film formation by surface decomposition of SiC film

Epitaxial 3C-SiC films were grown on silicon-on-insulator (SOI) substrates with [111] and [100] orientations by a chemical vapor deposition (CVD) method using an alternating gas supply. The SiC films were removed from the SOI substrates by chemical etching treatments. The sizes of the free-standing SiC (111) films, which were restricted by crack formation during the etching process, depended on the thickness and crystal quality of the silicon overlayer (SOL) on SOI substrates, while that of the free-standing SiC (100) film was maintained even after the etching. Carbon nanotubes (CNTs) were formed on both C and Si faces of the SiC (111) films by surface decomposition at 1973 K at 1.33 x 10(-2) Pa. The growth rate of CNTs on the C face was three times faster than that of CNTs on the Si face. A free-standing CNT film was formed after complete surface decomposition of the SiC film. The area of the free-standing CNT film was about 80 mm(2). On the other hand, graphite was formed on the SiC (100) film surface which was removed from the SOI (100) substrate.