NOVELTY - The method comprises charging a crucible (1) of a crystallization system containing a material to be processed, melting the material, setting a stereometric temperature field with planar isothermal surfaces in a melt (2), and initiating crystallization of the melt by lowering the temperature in the isothermal surfaces below a melting point of the material. The crystallization system comprises a horizontal and flat bottom, a wall perpendicular to the bottom, and a crucible heater such as a heater magnetic module (3) surrounding the wall of the crystallization system.    USE - The method is useful for directional crystallization of ingots of silicon (claimed), alloys, eutectics, semiconductors and dielectrics for manufacturing solar cells.    ADVANTAGE - The method ensures economic directional crystallization of ingots with high yield thus increasing energy conversion efficiency and quality of the solar cell.    DETAILED DESCRIPTION - The method comprises charging a crucible (1) of a crystallization system containing a material to be processed, melting the material, setting a stereometric temperature field with planar isothermal surfaces in a melt (2), and initiating crystallization of the melt by lowering the temperature in the isothermal surfaces below a melting point of the material. The crystallization system comprises a horizontal and flat bottom, a wall perpendicular to the bottom, and a crucible heater such as a heater magnetic module (3) surrounding the wall of the crystallization system to predetermine a vertically extending temperature gradient. Regions of the heater magnetic module facing the walls of the crucible are divided into two opposite portions in which the temperature gradient is predetermined, where each of the portions extend over the entire height of the crucible wall. The planar isothermal surfaces are tilted at an angle (1-10 degrees ) with respect to the bottom of the crucible, where the temperature of the isothermal surfaces increases from top to bottom by a variation of the temperature gradient in the portions of the heater magnetic module. The crucible has a rectangular or square basic shape with four side walls, and the heater magnetic module has side segments controllable opposite to the side walls of the crucible. The temperature gradients are predetermined in the region of the side walls such that a nucleation takes place at an inner edge between one of the side walls and the bottom of the crucible or a nucleation takes place in corners of the crucible. The crystallization initiation step comprises adjusting amplitude, frequency and/or phase displacement in a moving magnetic field to generate a back-and progressive isothermal crystallization for a predetermined period. A melt flow is generated due to the adjustment of amplitude, frequency and/or phase displacement of the moving magnetic field thus leading to a convex shaped isothermal crystallization on the walls of the crucible.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a temperature field in a region of a crucible surrounded by a heater magnetic module.    Melting crucible (1)    Melt (2)    Heater magnetic module. (3)