Amorphous or polycrystalline silicon layers are sometimes used in the metallization steps of IC processes, for example as antireflex coatings or as etching stopper layers for etching back of tungsten. A problem is that such a layer cannot be provided by CVD or LPCVD on account of the high deposition temperature which is not compatible with standard Al metallizations. Other deposition techniques, such as sputtering or plasma CVD, often lead to a lesser material quality, a longer processing time per wafer, or a worse step covering. According to the invention, the layer is provided by CVD or LPCVD at a temperature below 500° C. under the addition of Ge. The GexSi1−x layer (8) thus obtained is found to have good properties as regards step covering, optical aspects, electrical aspects, and etching aspects, and is compatible with any Al metallization (6) already present.