Growth of controlled profile crystals from the melt: Part II - Edge-defined, film-fed growth (EFG)

doi:10.1016/0025-5408(71)90007-9

Materials Research Bulletin

Volume 6, Issue 7, July 1971, Pages 581-589

https://doi.org/10.1016/0025-5408(71)90007-9 Get rights and content

Abstract

A crystal growth technique is described, “Edge-Defined, Film-Fed Growth” (EFG), by which continuous single crystals having virtually any cross-sectional shape can be grown from the melt. Crystals with shapes ranging from simple rods or filaments to almost arbitrarily complex cross sections may be grown with excellent dimensional control over very long lengths with minimal temperature and speed control. The EFG technique is an extension of that described in “Growth of Controlled Profile Crystals from the Melt: Part I”^∗ in that a capillary structure is used to furnish a constant liquid level at the growth interface as melt in the crucible is depleted. In the present technique, however, the shape of the growing crystal is determined by a thin melt layer sandwiched between the growing solid liquid interface and the plane top surface of the rigid capillary structure. The crystal grows only over solid regions of the die surface and not over any deep depressions in this surface. Accordingly any pattern of depressions fabricated into the top surface of the die will be propagated in the growing crystal. In this paper the application of the process to the growth of various single crystal sapphire shapes directly from the melt is described.

References (3)

H. E. LaBelle, Jr., Method and Apparatus for Growing Crystalline Materials, British Patent No....

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Citation Excerpt :
For most of these instruments, sapphire shaped crystals remain the only possible material platform, which allows achieving the desired technical characteristics and performance. An important advance in shaped crystal growth is represented by the EFG technique, proposed by H.E. LaBelle et al. [13–15]. It relies on the Stepanov concept [16] and implies the crystal growth from a melt film formed on the top of a die containing a capillary channel; see Fig. 1 (a).
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Citation Excerpt :
However, the EFG process is one of the least productive techniques for sapphire. Although a lot of experimental [1–5], theoretical [6–10] and numerical work [11–19] has been dedicated to the EFG method, growing large sapphire crystals by this technique is still a challenging task. Numerical modeling of EFG method has been mostly addressed to the growth of silicon rods, tubes and ribbons [11–15].
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^∗: “Growth of Controlled Profile Crystals from the Melt,” Parts I, II, III, and IV will be published in this Journal.

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