Graphene and carbon nanotubes (CNT) can be produced by vacuum decomposition of SiC, but discrepancies and conflicting data in the literature limit the use of this method for CNT synthesis. A systematic study of the effects of SiC surface morphology and carbon transport through the gas phase leads to reproducible and controlled growth of arrays of small-diameter (1-4 walls) nanotubes, which show pronounced radial breathing modes in Raman spectra, on either carbon (0 0 0 over(1, -)) or silicon (0 0 0 1) face of 6H SiC wafers at 1400-1900 °C. These nanotube arrays have a very high density and are catalyst-free with no internal closures. They show a higher oxidation resistance compared to CNTs produced by catalytic chemical vapor deposition (CVD). Their integration with graphite/graphene or silica layers on SiC wafers is possible in a simple 2-step process and opens new horizons in nanoscale device fabrication.