The growth and structure evolution of silicon nitride films prepared by rad
io frequency magnetron sputtering at low pressure were investigated for thi
ckness changes. Grazing-incidence X-ray reflectivity, atomic force microsco
py (AFM) and X-ray photoelectron spectroscopy were used to study the struct
ure, surface roughness and composition, respectively, of the films. It was
found that with an increase in thickness from 5 to 830 nm, the silicon nitr
ide films have a similar surface structure and their surface roughness only
slightly increases. The surface roughness of all the silicon nitride films
is only a little more than 0.2 nm, much less than previously reported resu
lts. AFM measurement of the fractured film surface indicated that thin sili
con nitride films with a thickness below approximately 300 nm have a dense,
smooth and uniform structure, and columnar structures gradually appear onl
y in thick films. These results are mainly attributed to the special design
of the sputtering system and the energetic particle bombardment of the gro
wing surface, by which the surface roughness and columnar growth were suppr
essed. (C) 2001 Elsevier Science B.V. All rights reserved.