SPUTTERING ON HE COOLED SUBSTRATE - A NEW METHOD FOR PRODUCING NANOMETER-SIZE MATERIALS

A multi-opposed targets sputtering system with a substrate cooled by l iquid helium is proposed as a novel method for preparing small particl es and nanocrystalline composites. Three pairs of targets are supplied with both de and rf power supplies. All of the materials including ce ramics and polymers, can be sputtered simultaneously. Sputtering of th e various target materials is accompanied by a properly controlled pro cess in which the media gas (Ar, for example) is solidified. The sputt ered particles are embedded into the solid inert gas matrix on the sub strate. After the sputtering is terminated, the substrate temperature and the pressure are increased; the solid argon is liquified and, toge ther with the particles. collected in the container. However, such par ticles are not stable. They aggregate rapidly in liquid spontaneously after the argon is evaporated. The application of this inert-gas matri x isolation technique allows us to produce free-standing particles of lour contamination metal-metal, metal-ceramic, and metal-polymer compo sites at low temperatures (below 84 K). Addition of other gases makes it possible to react or stabilize the particles. In this way a new rou te for the synthesis of novel phases of nano-sized materials is achiev ed.