  Reactive dual ion beam sputter deposition of AlN thin films was carried out
for the analysis of surface growth characteristics by Atomic Force Microscopy.
The variation of roughness as a function of deposition time was analysed by
Dynamic Scaling Theory (DST). Two distinct exponents, static and dynamic were
used to unravel the film growth characteristics. As the deposition time
increased, static scaling exponent decreased gradually and substrate surface
coverage was increased which is indicated by a decrease in critical length Lc.
The rms roughness of the film was increased from 1.99 to 3.42 nm as the
deposition time was increased from 3 minutes to 15 minutes. Dynamic scaling
exponent was found to be 0.36. During the growth, surface diffusion (n = 4)
becomes the major roughening phenomenon while Bulk diffusion (n = 3) turns into
the dominating smoothening phenomenon.
