Mobil Tyco Solar Energy Corporation

Herbert E Bates

Stanley W Strzepek

An improved method of growing ribbon-shaped crystalline bodies is disclosed. The method comprises the step of pulling the body from a melt pool through a very narrow gap as the body cools through a range of temperatures at which significant plastic deformation can occur so as to reduce the amount of buckling the body otherwise experienced due to transverse residual stress. The method in its preferred form utilizes an improved guidance mechanism for use with apparatus for growing ribbon-shaped bodies. The mechanism comprises a pair of heat-conductive plates rigidly positioned with respect to the melt pool. The plates are disposed in opposing relation so that their opposing surfaces define the gap therebetween and so that the plates are positioned (1) respectively on opposite sides of and close to the side surfaces of the body as the body is being pulled from the melt pool through the gap; and (2) in a region between the melt pool and the body pulling mechanism where the body cools through the range of temperatures at which significant plastic deformation occurs. The plates defining the gap are spaced apart by an amount (1) greater than the expected thickness of the ribbon-shaped bodies being grown, and (2) sufficiently small so that when flatness variations produced in the ribbon shaped body as it is pulled from the melt pool exceed a predetermined maximum as determined by the spacing provided by the gap, the ribbon will interact with the plates and the flatness variations will be reduced so as not to exceed the predetermined maximum.

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Sudbury, MA, United States of America

Herbert E Bates