Abstract: A method of producing an aerogel layer on a substrate is described. A precursor mixture is provided by mixing at least one material selected from the group consisting of silicates, metal alcolates, aluminates and borates with a solvent. The precursor mixture is used to form a lyosol. The precursor mixture or the lyosol formed therefrom is then applied to the substrate wherein a layer of the lyosol is formed on the substrate. A gel is formed from the lyosol by chemical conversion at a temperature at which the solvent is present in a liquid state. At a pressure between 0.5-2.0 torr the ambient temperature is reduced by about 3-70k below the point at which the solvent is converted into a solid state. The solvent is then converted into a gaseous state in a drying chamber while reducing the pressure of the solvent below the triple point and removing solvent from the gel layer.

Abstract: A method for determining the crystal orientation of a wafer using anisotropic etching in which an etching mask having mask openings such as circle scale marks arranged one beside the other is applied in relation to a preexisting marking of the wafer. Mask openings are configured in a double-T shape and are arranged one beside the other so that their first, transversely extending segments and the second transversely extending segments are situated at a predetermined distance apart and the areas connecting the segments are situated equidistant. The crystal orientation is determined with the distance of the two particular adjacent mask openings, the intervening space of which is least undercut, from the preexisting marking.