The major achievements in recent years

Theoretical fundamentals and methods of substance ultrapurification are being developed. The notions on the form of impurity presence in high-purity substances and on the mechanism of their effect upon the properties of high-purity substances and materials have been substantially expanded which contributed to the further advancement of the technological processes, to the higher purification and structural perfection of efficient materials for micro- and nano-electronics, fiber and power optics, opto-electronics.

• Scientific fundamentals are being developed for production of high-purity monoisotopic silicon. A method is suggested and it is for the first time in the world practice that structurally perfect single crystals of monoisotopic silicon 28Si , 29Si and 30Si have been produced (in collaboration with domestic and foreign scientific organizations). Their properties are being investigated.

• The methods of production are being developed and quartz optical fibers, doped with rare-earth ions and highly doped with the oxides of germanium and phosphorus, are produced in pilot batches (jointly with OFSC of RAS). From these optical fibers the fiber lasers and optical amplifiers are produced with record-breaking characteristics.

• Physical and chemical fundamentals are being developed for chemical vapor deposition of high-purity polycrystalline chalcogenides and single-crystal films of AIIBVI compounds. A technology has been developed and a set of equipment has been made for the production of high-purity polycrystalline zinc selenide used for power optics in the middle infrared range.

• Production methods have been developed to fabricate high-purity chalcogenide glasses and optical fibers on their basis with low optical losses in the middle IR-range (jointly with OFSC of RAS). There are no analogs to the fibers with respect to some technical parameters.

• A technique and equipment have been developed for the production of single-crystal epitaxial layers of cadmium-hydrogen-tellurium by chemical vapor deposition from the vapors of hydrogen and organo-metallic compounds of cadmium and tellurium. The testing of pilot samples of the produced layers indicated that their degrees of purity and structural perfection are suitable for the manufacture of infrared radiation photodetectors.

• A technique and equipment for micro- and opto-electronics have been developed to produce specially-pure hydrides of silicon, germanium, sulfur and selenium with the content of metals 10-7-10-6 %.

• A technique and equipment have been developed for the production of high-purity halogenides of silicon, phosphorus, germanium and carbon with the content of the limiting impurities 10-5 – 10-7 %.

• New high-sensitive techniques have been developed to determine micro-impurities in high-purity substances and materials, including isotopically enriched, as well as the techniques to determine the isotopic composition of isotopically pure substances. Now in use are the methods of laser mass spectrometry, mass spectrometry with inductively coupled plasma, atomic-emission spectrometry, including concentration of impurities, atomic-emission spectrometry with inductively coupled plasma, electron microscopy and X-ray microanalysis, IR spectroscopy, gas and liquid chromatography, chromato-mass spectrometry, laser ultramicroscopy. The joint use of these methods makes it possible to determine the elemental composition of high-purity substances in the range of components content 10-9 - 100 % and the molecular composition of impurities in volatile substances with the limit of detection 10-5- 10-8 %.