Journal article

Publication year: 2004

Pages: 494-504

Journal: Journal of Crystal Growth

Volume number: 265

Issue number: 3-4

ISSN: 0022-0248

DOI Link: https://doi.org/10.1016/j.jcrysgro.2004.02.087

Publisher: Elsevier

Abstract: 
High melting point oxides show an interface inversion from a convex interface shape to a flat or concave interface when grown after the Czochralski method with constant crystal rotation rate and increasing crystal radius (as in the shoulder region). Under the described conditions one observes during YAG-growth a sudden and uncontrollable interface change, called interface flip, at a certain critical crystal rotation rate. We describe model experiments and numerical simulations of this inversion process. We show that it is connected with a flow transition at a certain critical rotational Reynolds number Re-c. This Re-c increases with the convex interface deflection and with the strength of the buoyant-thermocapillary flow near the free melt surface towards the crystal. A self-amplifying process, involving the back-melting of the crystal cone, starts when Re-c is reached. The dynamics of the back-melting is explained. A more vigerous interface inversion process is expected for systems with large interface deflections and for systems with smaller dynamic Bond number, e.g. smaller crucibles. (C) 2004 Elsevier B.V. All rights reserved.

Harvard Citation style: Schwabe, D., Sumathi, R. and Wilke, H. (2004) The interface inversion process during the Czochralski growth of high melting point oxides, Journal of Crystal Growth, 265(3-4), pp. 494-504. https://doi.org/10.1016/j.jcrysgro.2004.02.087

APA Citation style: Schwabe, D., Sumathi, R., & Wilke, H. (2004). The interface inversion process during the Czochralski growth of high melting point oxides. Journal of Crystal Growth. 265(3-4), 494-504. https://doi.org/10.1016/j.jcrysgro.2004.02.087