Single crystals and methods for fabricating same

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.

1. A sapphire single crystal, comprising:
 a single crystal sheet having a length, width and thickness, wherein length >width>thickness, the width is not less than about 15 28 cm, and the thickness is not less than about 0.5 cm. 
 
     
     
       2. The crystal of  claim 1 , wherein the width is not less than about 20 30 cm. 
     
     
       3. The crystal of  claim 1 , wherein the width is not less than about 25 cm. 
     
     
       4. The crystal of  claim 1 , wherein the thickness is not less than about 0.6 cm. 
     
     
       5. The crystal of  claim 1 , wherein the thickness is not less than about 0.7 cm. 
     
     
       6. The sapphire single crystal of  claim 1 , wherein the single crystal sheet has a variation in thickness of not greater than 0.2 cm, wherein the variation in thickness is the difference between maximum and minimum thickness values along a segment spanning the width of the sheet. 
     
     
       7. The crystal of  claim 6 , wherein the variation in thickness is not greater than 0.15 cm. 
     
     
       8. The crystal of  claim 6 , wherein the variation in thickness is not greater than 0.10 cm. 
     
     
       9. The crystal of  claim 6 , wherein the variation in thickness is not greater than 0.07 cm. 
     
     
       10. A sapphire single crystal, comprising:
 a single crystal sheet having a length, width and thickness, wherein length >width>thickness, the width is not less than about 15 cm, the thickness is not less than about 0.5 cm, and a variation in thickness of not greater than 0.2 cm. 
 
     
     
       11. A sapphire single crystal, comprising:
 an as-grown single crystal sheet having a length, width and thickness, wherein length>width>thickness, the width is not less than about 15 28 cm, the single crystal sheet further having a neck and a main body that defines first and second opposite lateral sides that are generally parallel to each other, a transition of the neck to the main body portion is defined by respective first and second transition points of the first and second opposite lateral sides, and the single crystal has a Δ T  not greater than 4.0 cm, wherein Δ T  is the distance by which the respective first and second transition points are spaced apart as projected along a length segment of the single crystal sheet. 
 
     
     
       12. The crystal of  claim 11 , wherein Δ T  is not greater than about 3.0 cm. 
     
     
       13. The crystal of  claim 11 , wherein Δ T  is not greater than about 2.0 cm. 
     
     
       14. The crystal of  claim 11 , wherein the neck increases in thickness from its distal end to the main body. 
     
     
       15. The crystal of claim 11, wherein the width is not less than 25 cm. 
     
     
       16. The crystal of claim 11, wherein the width is not less than 28 cm. 
     
     
       17. The crystal of claim 16, wherein the single crystal sheet has a variation in thickness of not greater than 0.2 cm, wherein the variation in thickness is the difference between maximum and minimum thickness values along a segment spanning the width of the sheet. 
     
     
       18. The crystal of claim 17, wherein the variation in thickness is not greater than 0.15 cm. 
     
     
       19. The crystal of claim 17, wherein the variation in thickness is not greater than 0.10 cm. 
     
     
       20. The crystal of claim 17, wherein the variation in thickness is not greater than 0.07 cm. 
     
     
       21. The crystal of claim 11, wherein the width is not less than 30 cm. 
     
     
       22. The crystal of claim 11, wherein the thickness is not less than about 0.6 cm. 
     
     
       23. The crystal of claim 11, wherein the thickness is not less than about 0.7 cm. 
     
     
       24. The crystal of claim 11, wherein the crystal is substantially transparent in the infrared and visible wavelength spectrums. 
     
     
       25. The crystal of claim 1, wherein the single crystal sheet has a surface defined by the length and the width, wherein the surface is substantially rectangular. 
     
     
       26. The crystal of claim 25, wherein the width is not less than 30 cm. 
     
     
       27. The crystal of claim 25, wherein the thickness is not less than about 0.6 cm. 
     
     
       28. The crystal of claim 25, wherein the thickness is not less than about 0.7 cm. 
     
     
       29. The crystal of claim 25, wherein the single crystal sheet has a variation in thickness of not greater than 0.2 cm, wherein the variation in thickness is the difference between maximum and minimum thickness values along a segment spanning the width of the sheet. 
     
     
       30. The crystal of claim 29, wherein the variation in thickness is not greater than 0.15 cm. 
     
     
       31. The crystal of claim 29, wherein the variation in thickness is not greater than 0.10 cm. 
     
     
       32. The crystal of claim 29, wherein the variation in thickness is not greater than 0.07 cm. 
     
     
       33. A sapphire single crystal, comprising:
 an as-grown single crystal sheet having a length, width and thickness, wherein length >width>thickness, the width is not less than 28 cm, and the thickness is not less than about 0.5 cm.   
     
     
       34. The crystal of claim 33, wherein:
 the single crystal sheet a neck and a main body adjacent to the neck;   the main body has a surface defined by the length and the width; and   the surface is substantially rectangular.   
     
     
       35. The crystal of claim 33, wherein the crystal is substantially transparent in the infrared and visible wavelength spectrums. 
     
     
       36. A sapphire single crystal, comprising:
 a single crystal sheet having a length, width and thickness, wherein:   length>width>thickness, the width is not less than 28 cm, and the thickness is not less than about 0.5 cm; and   the single crystal sheet is substantially transparent in the infrared and visible wavelength spectrums.   
     
     
       37. The crystal of claim 36, wherein the width is not less than 30 cm. 
     
     
       38. The crystal of claim 36, wherein the thickness is not less than about 0.6 cm. 
     
     
       39. The crystal of claim 36, wherein the thickness is not less than about 0.7 cm. 
     
     
       40. The crystal of claim 36, wherein the single crystal sheet has a variation in thickness of not greater than 0.2 cm, wherein the variation in thickness is the difference between maximum and minimum thickness values along a segment spanning the width of the sheet. 
     
     
       41. The crystal of claim 40, wherein the variation in thickness is not greater than 0.15 cm. 
     
     
       42. The crystal of claim 40, wherein the variation in thickness is not greater than 0.10 cm. 
     
     
       43. The crystal of claim 40, wherein the variation in thickness is not greater than 0.07 cm. 
     
     
       44. The crystal of claim 36, wherein the crystal is at least part of a window.