Project 2.1. The introduction of technological research and the development of an optimized cathode-ray heater for the production of high-purity materials.

1. A model of the design of an electron-beam heater integrated with a gas-dynamic window (GDW) for the subsequent connection of the magnetic separation unit (MSU) has been created – the model is ready – the production of working drawings has begun.
2. Tenders were held to control the purity of silicon by FTIR spectroscopy (CFI LU); ICP MS (Faculty of Chemistry of LU); NAA (Technical University, Munich).
3. The control of FTIR samples for oxygen content showed satisfactory operation of GDW – at the level of the results previously obtained in VU 1.
It was found that during the growth of electron-beam-heated crystals from a melt when using a standard quartz crucible as a container, the oxygen content in such crystals is in the range 2-7 * 2-7 *1017 см-3.
In crystals grown from their own skull, the oxygen content drops to 2-8 *1016 см-3. The oxygen source is a hydrogen-oxygen mixture entering the process chamber from electron-beam heaters. Obviously, the contribution of this oxygen source is an order of magnitude smaller than that of the crucible.
The processes carried out using GDW allowed to reduce the oxygen concentration in the melt residues to 1-2 *1015 cm-3, and in the crystal to 4-5 *1015 cm-3. The data are not enough to discuss the oxygen distribution coefficient in this process, but in all process modifications, the oxygen content in silicon is higher than in the melt residues