Patterned carbon nanotube films formed by surface decomposition of SiC wafers

Well-aligned carbon nanotubes (CNTs) have been formed selectively on SiC wafers by a surface decomposition method. A SiC(000-l)C-face wafer was patterned with amorphous SiN deposited by a photoresist method used in the silicon semiconductor process, after which the wafer was heated at 1500°C for half an hour in a vacuum. Transmission electron microscopy revealed that 50-nm-long aligned CNTs were formed only at the open areas of the mask. The mask was removed entirely before reaching 1500°C, and a thin graphite layer 6.8 nm thick was formed at the naked SiC surface. This demonstration of the selective growth of CNTs suggests that this surface decomposition method has the potential to be used for the development of nanotube devices integrated into silicon technology.