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Elimination of Crystal Orbiting in Czochralski Cable Puller With a Coaxial Magnet and Magnetic Weight

IP.com Disclosure Number: IPCOM000042047D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Kim, KM: AUTHOR [+2]

Abstract

A coaxial magnet traveling synchronously with a magnetic weight attached to a crystal pull cable in a Czochralski (CZ) puller centers the growing crystal and prevents orbiting of the crystal. This allows an increase in the crystal rotation rate in the CZ puller as high as in the rigid shaft CZ puller. A CZ crystal puller with a cable pull mechanism has the advantage of a smaller overall height of the equipment compared to a CZ puller with a rigid pull shaft. However, a serious drawback of the cable CZ puller is that the rotation of crystal causes crystal orbiting during rotation which adversely affects the yield of single crystal production. Crystal orbiting is further aggravated with the increase of the rotation rate, typically above 20 rpm, which is not a problem with a rigid shaft CZ puller.

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Elimination of Crystal Orbiting in Czochralski Cable Puller With a Coaxial Magnet and Magnetic Weight

A coaxial magnet traveling synchronously with a magnetic weight attached to a crystal pull cable in a Czochralski (CZ) puller centers the growing crystal and prevents orbiting of the crystal. This allows an increase in the crystal rotation rate in the CZ puller as high as in the rigid shaft CZ puller. A CZ crystal puller with a cable pull mechanism has the advantage of a smaller overall height of the equipment compared to a CZ puller with a rigid pull shaft. However, a serious drawback of the cable CZ puller is that the rotation of crystal causes crystal orbiting during rotation which adversely affects the yield of single crystal production. Crystal orbiting is further aggravated with the increase of the rotation rate, typically above 20 rpm, which is not a problem with a rigid shaft CZ puller. On the other hand, a high crystal rotation rate above 20 rpm is required for the development of some special crystal growth processes to achieve a uniform dopant/impurity incorporation in the CZ semiconductor crystal. By using a coaxial magnet traveling synchronously with a magnetic weight of a cylindrical shape which is attached to the crystal pull cable in a CZ cable puller, the growing crystal is continually centered. Thus, orbiting of the crystal during rotation is eliminated which permits an increase in the crystal rotation rate in the CZ cable puller as high as is fe...