  Ultra-thin crystal targets in shape of self-supporting membranes were
produced for our experiments with parametric x-rays emitted by low-energy
electrons. Concise description of the technology developed for production of
silicon crystal membranes and the technique for the membrane thickness
measurements are considered in the paper. Membrane thickness of ~0.5 micron at
1.0 mm diameter supporting by 2x2 mm silicon substrate of ~200 microns
thickness is achieved. Developed technology for thin crystal membrane
production can also be applied for manufacturing of various membrane-containing
sensors
