Patent DE-102006017621-A1 (DE)
Title: Crystallization device for production of single- or multi crystalline silicon by vertical-gradient-freeze-method, comprises stable crucible, and heating device for melting the silicon and exhibiting jacket heater for rejection of heat flow
Inventor: MUELLER MATTHIAS
IPC: C30B29/06
Filed: 2006-04-12
Abstract: The crystallization device for production of single- or multi crystalline silicon by vertical-gradient-freeze-method, comprises a stable crucible (2) with upper- and lower end, and a heating device for melting the silicon and exhibiting a jacket heater (7) for rejection of heat flow perpendicular to longitudinal direction. The device is designed to form a temperature gradient in the longitudinal direction in the crucible. The crucible exhibits a rectangular- or square shaped cross-section. The heater comprises heating elements arranged at side surfaces of the crucible. The crystallization device for production of single- or multi crystalline silicon by vertical-gradient-freeze-method, comprises a stable crucible (2) with upper- and lower end, and a heating device for melting the silicon and exhibiting a jacket heater (7) for rejection of heat flow perpendicular to longitudinal direction. The device is designed to form a temperature gradient in the longitudinal direction in the crucible. The crucible exhibits a rectangular- or square shaped cross-section. The heater comprises heating elements arranged at side surfaces of the crucible. The jacket heater forms a heating zone, which is displayed so that a delivered heat output decreases from the upper end to the lower end, in order to maintain the temperature gradient. The heat output of the jacket heater in the longitudinal direction decreases in correspondence to the temperature gradient in the center of the crucible. The jacket heater is designed to maintain a number of even isotherms vertical to the longitudinal direction. The outer contour of the jacket heater is formed corresponding to the outer contour of the crucible, so that a distance is maintained constant between the heater and the crucible. The heating elements exhibit a meander shaped course in the longitudinal or perpendicular direction to it. The rectangular shaped bars run equidistant and parallel to each other. A conductor cross-section of the bars is constricted at the reverse regions of the meander shaped course in diagonal direction, so that the section is likely assigned to bars before or after the respective reverse regions. The constrictions of the conductor cross-section are formed at the reverse regions through a number of perforations or recesses in and/or from the bar materials that are arranged diagonally to the distributed conductor cross-section. The heating elements extending vertically to the longitudinal direction are formed as rectangular shaped bars, whose conductor cross-section increases from the upper end to the lower end in continuous or discrete steps. The conductor cross-section of the bars exhibits a number of segments, which are solvable connected together by connecting element in material fit. Non-thermal insulation is provided between the crucible wall and the jacket heater. An independent claim is included for a method for the production of single- or multi crystalline silicon based on vertical-gradient-freeze-method.