Apparatus and a method of forming a single crystal sheet
AssigneeSaint-Gobain Ceramics & Plastics, Inc.
InventorsJohn Walter Locher, Steven Anthony Zanella, Ralph Lampson MacLean, JR., Herbert Ellsworth Bates
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Abstract
Various single crystals are disclosed including sapphire. The single crystals have desirable geometric properties, including a width not less than about 15 cm and the thickness is not less than about 0.5 cm. The single crystal may also have other features, such as a maximum thickness variation, and as-formed crystals may have a generally symmetrical neck portion, particularly related to the transition from the neck to the main body of the crystal. Methods and for forming such crystals and an apparatus for carrying out the methods are disclosed as well.
Claims20
1-13. (canceled)
A method of forming a sapphire single crystal sheet, the method comprising providing a melt in a crucible having a die;
- and drawing the sapphire single crystal sheet from the die, wherein the sapphire single crystal sheet has a length, a width, and a thickness, wherein the length>width>thickness, the width is not less than 15 cm, and the thickness is not less than 0.5 cm, and a thermal gradient along a length of the die is not greater than 0.6° C./cm.
An apparatus for forming a sapphire single crystal sheet, the apparatus comprising a crucible having a die, wherein the die has an opening having a length and a width, the length is greater than the width and not less than 15 cm, the width is not less than 0.5 cm, and the apparatus has a thermal gradient along the length of the die that is not greater than 0.6° C./cm.
Dependencies are inferred from the claim text.