Ribbon Crystal String for Increasing Wafer Yield

Abstract

A ribbon crystal has a body with a width dimension, and string embedded within the body. The string has a generally elongated cross-sectional shape. This cross-section (of the string) has a generally longitudinal axis that diverges with the width dimension of the ribbon crystal body.

1 . A method of forming a ribbon crystal, the method comprising:
 providing molten material having a material coefficient of thermal expansion;   providing a string having an outer surface with a contact angle with the molten material of between about 15 and 120 degrees, the string also having a string coefficient of thermal expansion that is substantially matched to the material coefficient of thermal expansion; and   passing the string through molten material to form a sheet.   
     
     
         2 . The method as defined by  claim 1  wherein the string comprises a refractory layer supported on a substrate. 
     
     
         3 . The method as defined by  claim 2  wherein the string comprises a handling layer radially outward of the refractory layer. 
     
     
         4 . The method as defined by  claim 3  wherein the outer surface of the string comprises the handling layer. 
     
     
         5 . The method as defined by  claim 3  wherein the string comprises a reduced wetting layer radially outward of the handling layer, the reduced wetting layer comprising the outer surface of the string. 
     
     
         6 . The method as defined by  claim 1  wherein the material comprises a silicon based material.