Piskun N. Effect of the conditions of electron-beam zone melting in the properties of single crystal silicon.

The thesis deals with investigation of properties of silicon single-crystals for the needs of microelectronics, produced by the method of electron beam crucibleless zone melting with application of various technological measures. Calculation method and experiments were used to show that refining of silicon single-crystals during electron beam crucibleless zone melting is achieved due to processes of recrystallization and evaporation, as well as degassing in vacuum. It is established that in order to improve vacuum purity in the vacuum chamber and vacuum system, its pumping down should be performed simultaneously with helium purging. It is shown that electron beam melting of silicon single-crystals with melt mixing in the zone and with application of a thermal shield allows lowering the dislocation density and level of stressed state in the grown crystals that improves electrophysical characteristics. It is established that combining electron beam cruciblelesss zone melting with electric transfer process promotes further cleaning of silicon single-crystals from impurities. It is shown that at electric current flowing through a sample during melting, an ordered crystalline lattice forms that promotes lowering of the level of inner stresses and provides an increase of specific electrical resistance. Single-crystal strengthening with nitrogen by their alloying during melting, promotes an increase of mechanical characteristics and improvement of their electrophysical properties. Key words: perfect single crystals of silicon, electron-beam crucibleless melting, removal from impurities, electrical resistivity, crystallization front is close to flat, monocrystallinity, stress refining, doping from the gas phase process, technologic parameters.