The scaling behaviour of surface roughness evolution of high rate deposited μc-Si:H by very high frequency plasma-enhanced chemical vapor deposition （VHF-PECVD） is investigated using spectroscopic ellipsometry （SE）. Films deposited at Pg=300 Pa with deposition rate of 5 ?/s, show abnormal scaling behavior with the exponent β of about 0.81, which is much larger than 0.5 of zero diffusion limit in the scaling theory. This implies that there are some roughening increasing mechanisms, and this roughening increasing mechanism is correlated with the shadowing effect.