In this article the processes of formation of single crystals during its growing by Stepanov’s method are studied. This growing method consists of drawing crystals through the crystal former (shaper). The presence of a form-building agent (i.e. non-free growth of crystals) leads to increase in concentration of defects in the crystal structure, which decreases the quality of solar cells. In this regard, the article explores the question: what forms of growth arise during the growing of silicon single crystals by Stepanov’s method. Typical defects that arise when growing single crystals of silicon in the form of ribbons and pipes are considered. Experimental investigations of defects in profiled crystals have shown that the defects are characterized by the formation of twining structures, i.e. two neighboring single crystals separated by an atomic plane. The influence of the seed orientation on twining formation process is studied. In particular, the peculiar angles between the growth directions and the twins formation are found. The formation of mosaic structure which competes with the twin structure and is displaced by the latter is observed. The appearance of spiral structures during the growth of single crystals of tubular forms is also observed. To explain the features of formation we calculated (per one atom) the interaction energies of neighboring parallel atomic layers. The Lennard-Jones potential was chosen as the interaction potential. The results of the calculation showed that among the planes with small values of Miller’s indices the plane (112) possesses the smallest interaction energy. The family of planes equivalent to the (112) plane has a close orientation, and the angles between its directions are in good agreement with the angles in which direction the twins are formed. The presence of three close directions of twinning also explains the formation of spiraling structures when growing silicon single crystals with tubular cross section.

Рассмотрены особенности процесса формообразования при выращивании профилированных монокристаллов кремния методом Степанова. Перечислены характерные кристаллические формы, возникающие в процессе роста. Поведено теоретическое исследование особенностей роста монокристалла при различных направлениях роста. Исследованы особенности процесса образования двойников при выращивании профилированных кристаллов. Предложено объяснение спиралевидных структур при выращивании профилированных монокристаллов кремния.