An atomic force microscopy study of the microroughness of SIC thin fil
ms deposited by both plasma-enhanced chemical vapour deposition (PECVD
) and laser ablation deposition (LAD) techniques was conducted. PECVD
films present the characteristic Zone I structure type, with hill-like
domed columns separated by grooves. Both the size of the domes and th
e depth of the grooves were found to increase with the film thickness
as it is varied from 0.5 mu m to 2.0 mu m. This morphology is consiste
nt with theoretical models describing the equation of motion of the su
rface profile during the film growth. In contrast, LAD films are made
of a few protrusions embedded in an otherwise structureless surface. T
his morphology is most probably due to the large surface diffusion len
gth of Si and C atoms, arising as a consequence of their high kinetic
energy in the LAD process (0.9 and 14 eV, respectively). The mean roug
hness values are R(a) = 2.2 nm and R(a) = 0.58 nm for 2 mu m thick SiC
films deposited by PECVD and LAD techniques, respectively. The micror
oughness of both types of films did not show any significant variation
upon thermal annealing of films up to 850 degrees C, and fulfils well
the microroughness criterion of membrane materials needed for X-ray m
ask technology.