Lid for improved dendritic web growth

• US 5,098,287 A
• Filed: 03/16/1990
• Issued: 03/24/1992
• Est. Priority Date: 12/18/1986
• Status: Expired due to Fees

• Current Assignee: United States Department of Energy (Government of the United States of America)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Duncan, Charles S., Piotrowski, Paul A., Kochka, Edgar L., Seidensticker, Raymond G.
• Primary Examiner(s): Yuen, Henry C.
• Application Number:
  US07/525,205
• Time in Patent Office: 739 Days
• Field of Search: 432/262, 432/263, 432/253, 432/254
• US Class Current: 432/262
• CPC Class Codes: C30B 15/14 Heating of the melt or the crystallised materials
• CPC Class Codes: C30B 15/34 Edge-defined film-fed crystal-growth using dies or slits

Abstract

A lid for a susceptor in which a crystalline material is melted by induction heating to form a pool or melt of molten material from which a dendritic web of essentially a single crystal of the material is pulled through an elongated slot in the lid and the lid has a pair of generally round openings adjacent the ends of the slot and a groove extends between each opening and the end of the slot. The grooves extend from the outboard surface of the lid to adjacent the inboard surface providing a strip contiguous with the inboard surface of the lid to produce generally uniform radiational heat loss across the width of the dendritic web adjacent the inboard surface of the lid to reduce thermal stresses in the web and facilitate the growth of wider webs at a greater withdrawal rate.

Claims

1. A lid for a susceptor in which a crystalline material is melted, said lid being in the form of a plate having an inboard side and an outboard side and a centrally disposed counter bored dog-bone shaped slot through which a dendritic web of essentially a single crystal of said material having a dendrite extending along each margin is pulled, a pair of counter bored openings aligned with and disposed outboard and spaced from opposite ends of said counter bored dog-bone shaped slot and a groove extending between said countered dog-bone shaped slot and each counter bored opening;

said groove extending partially inwardly from the outboard side to adjacent the inboard side of said lid deeper than said counter bores forming a thin strip adjacent the inboard side of the lid, whereby said counter bored dog-bone shaped slot, said counter bored openings and said grooves cooperate to control the radiation of heat from said dendritic web by preventing heat from radiating from the margin dendrites and allowing heat energy to radiate from the central portion of the web to produce a generally flat distribution of isotherms across the width of the web adjacent the location where the material crystallizes adjacent the inboard side of said lid to produce a wider web, which can be pulled at a higher rate with substantially less defects in the web.