Elimination of Crystal Orbiting in Czochralski Cable Puller With a Coaxial Magnet and Magnetic Weight
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
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.