Fully microcrystalline silicon, mu c-Si, thin films have been deposited on corning glass by plasma enhanced chemical vapor deposition (PECVD) using SiH4-H-2. The effects of the surface treatment and of the deposition temperature on microstructure of mu c-Si films are investigated by "in situ" laser reflectance interferometry (LRI), "ex situ" spectroscopic ellipsometry (SE) and Raman spectroscopy. LRI indicated the existence of a "crystalline seeding time", which is indicative of the crystallite nucleation, and depends on substrate treatments. Longer "crystalline seeding time" results in a lower density of crystalline nuclei, which grow laterally, yielding to complete suppression of the amorphous incubation layer and to growth of very dense, fully crystalline layer at a growth temperature as low as 120 degrees C. (c) 2006 Published by Elsevier B.V.