A product produced in a PVD method is described, which consists of thin plane-parallel structures having a thickness in the range from 20 to 2000 nm and small dimensions in the range below one mm. Production is carried out by condensation of silicon suboxide onto a carrier passing by way of the vaporisers. The carrier is pre-coated, before condensation of the silicon suboxide, with a soluble, inorganic or organic separating agent in a PVD method. All steps, including that of detaching the product by dissolution, can be carried out continuously and simultaneously at different locations. As final step, the SiO.sub.y may be oxidised to SiO.sub.2 in an oxygen-containing gas at atmospheric pressure and temperatures of more than 200.degree. C. or SiO.sub.y may be converted to SiC at the surface of the plane-parallel structures in a carbon-containing gas at from 500.degree. C. to 1500.degree. C. The products produced in that manner are distinguished by high uniformity of thickness.