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Crystal Rotation in Crystal Growth from Melt

IP.com Disclosure Number: IPCOM000075670D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Scheel, HJ: AUTHOR [+2]

Abstract

In the Czochralski method, crystal growth is subjected to periodic accelerated and decelerated rotation during pulling. Thus the concentric shearing and the thin layer of Ekman flow in the melt, immediately below the growing crystal, is caused to vary with the changes of crystal rotation.

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Crystal Rotation in Crystal Growth from Melt

In the Czochralski method, crystal growth is subjected to periodic accelerated and decelerated rotation during pulling. Thus the concentric shearing and the thin layer of Ekman flow in the melt, immediately below the growing crystal, is caused to vary with the changes of crystal rotation.

This results in a thorough mixing of the melt adjacent to the crystal interface, enhancing the material transport and homogenizing the growing crystal.

The stirring effect by accelerated crystal rotation is assisted by crucible rotation which may also be accelerated. The rotation directions and the motion programs of crystal rotation and crucible rotation differ from another. For best results, they are adjusted such that the melt level at the crystal remains constant.

In silicon, production crystals with unusually large diameters and less incidence of striations are pulled according to the method described.

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