Thick polysilicon films (>0.5 μm) become increasingly attractive for MEMS applications. However, thicker films can experience greater variability in morphology and in surface roughness due to the longer deposition time. In this study, 3.0 μm thick polysilicon films were deposited on silicon wafers by the LPCVD process. Asperities were observed on the surface of the polysilicon films by SEM and AFM. TEM studies showed the co-existence of equiaxed fine grains and some discrete long columnar crystallites containing microtwins (fine laths) in the materials microstructure. The asperities on the surface are found to be the caps of the columnar grains that grow continuously out of the flat surface of the equiaxed grains. The effect of the film thickness on these asperities and the surface quality was discussed.