Aluminium doped tin oxide coatings

A method is disclosed for the growth of aluminium doped tin oxide on a substrate 4, particularly glass, by chemical vapour deposition (CVD) using aluminium 2-ethylethanoate as a chemical precursor serving as a source of aluminium. The method comprises the steps of preparing a precursor gas mixture containing a source of tin, a source of oxygen, water, and the aluminium 2-ethylethanoate, acting as the source of aluminium, and delivering 1 the precursor gas mixture to a coating chamber opening onto the substrate 4. Preferably, the precursor gas mixture comprises dimethyltin dichloride, oxygen, water and aluminium 2-ethylethanoate, and the mixture is maintained at a temperature between 180 and 200ºC prior to introduction to the substrate. The coating chamber may be a static chamber (as shown) or may be a dynamic coating apparatus for CVD coating of a moving substrate, e.g. during a float gas production method (figure 2).