Aerosol-gel process is a thin film deposition process based on the sol-gel polymerization of a liquid film deposited from an ultrasonically sprayed aerosol. This process offers an attractive alternative for the deposition of sol-gel thin films. The effects of the aerosol deposition route on the film characteristics were investigated with regard to sol-gel chemistry. TEOS solutions were studied by viscosimetry and FTIR spectroscopy using an ATR device. Silica xerogel coatings were studied by transmission FTIR and optical microscopy. We observed that film morphology and uniformity depend closely on the aerosol deposition conditions. The film growth mechanism was studied and some general rules for the deposition of good quality thin films were set up.