Optical (refractive index) and structural properties of silicon
oxynitride (SiON) and amorphous silicon (a-Si) multilayers grown by RF
sputtering with thickness in the 10–30 nm range have been
analysed by ellipsometry and TEM. Satisfactory agreement between
the two techniques is obtained as regards the thickness
determination of the SiON films. Disagreement with values obtained
by the stylus method by extrapolation for the two types of layers
is discussed. The interfaces of the SiON films are very good when
n-type P doped Si is used as a target. They are wavy with average
periodicity and amplitude on the order of 50 and 2 nm, respectively,
when a semi-insulating Si target is used, despite the presence of a
buffer layer. Hypothesis is made that P incorporation may improve
the reconstruction of the SiON surface.