TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The silicon dioxide-dispersion containing phosphoric acid is diluted with at least a soluble, volatile organic solvent in the liquid phase of the dispersion. The silicon dioxide-dispersion containing phosphoric acid contains 3-7.5 wt.% of pyrogenic silicon dioxide particle; 1.5-5 wt.% of hydrolysis- and condensation-product of tetraethoxysilane, which is obtained from the dispersion in the presence of the pyrogenic silicon dioxide particle; 5-9 wt.% of phosphoric acid, added as orthophosphoric acid; 25-30 wt.% of water; and 50-65 wt.% of ethanol, where the amount of these materials is at least 98 wt.%, based on the total quantity of the dispersion. The coating process further comprises introducing the coated and dried silicon-wafer at room temperature in an environment exhibiting a temperature of 850-930 degrees C; holding the silicon-wafer at the same temperature for 5-15 minutes and subsequently transferring into an environment exhibiting the room temperature; and cooling the obtained product. Preferred Components: The silicon dioxide in the starting dispersion (I) and (II) is a pyrogen produced silicon dioxide. The BET surface of the silicon dioxide is 150-250 m2/g. The average aggregate diameter of the silicon dioxide particle is less than 100 nm. The amount of silicon dioxide in the starting dispersion (I) is 10-15 wt.%. The ratio of silicon dioxide from hydrolysis (calculated)/silicon dioxide from the starting dispersion (II) is 0.4-0.8. The silicon compound is tetramethoxysilane and/or tetraethoxysilane. The organic solvent is an alcohol of methanol, ethanol, n-propanol, iso-propanol, n-butanol and/or 1,2-ethanediol. The weight ratio of organic solvent and water is 0.2-4. EXAMPLE - Orthophosphoric acid (54 g) (85 wt.% in water) was added to starting dispersion (I) (containing 12 wt.% pyrogenic silicon dioxide dispersion (300 g) with a BET-surface of 200 m2/g, an average particle diameter of less than 100 nm and a pH-value of 5.5), and stirred to obtain the starting dispersion (II). Tetraethoxysilane (100 g) was added to the starting dispersion (II) and homogenized for 30 minutes by stirring with a magnetic stirrer to obtain the silicon dioxide-dispersion containing phosphoric acid.