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Apparatus for Producing Single Crystals

IP.com Disclosure Number: IPCOM000095330D
Original Publication Date: 1965-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Kampschulte, G: AUTHOR [+2]

Abstract

In the process of pulling crystals according to the Czochralski method, a crystal seed is dipped into the melt and then withdrawn slowly. The seed is fastened to a crystal holder, guided during the pulling process by magnets. However, for the operations preparing the pulling process, e.g., for degassing the apparatus by baking out, a mechanical suspension of the crystal holder is required. A transition is made to magnetic guidance without manual intervention. For this purpose, a shoulder is provided within the quartz tube in which the pulling process takes place. The crystal holder rests on this shoulder. After having been properly rotated by the magnets, the holder slides beyond it in slots.

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Apparatus for Producing Single Crystals

In the process of pulling crystals according to the Czochralski method, a crystal seed is dipped into the melt and then withdrawn slowly. The seed is fastened to a crystal holder, guided during the pulling process by magnets. However, for the operations preparing the pulling process, e.g., for degassing the apparatus by baking out, a mechanical suspension of the crystal holder is required. A transition is made to magnetic guidance without manual intervention. For this purpose, a shoulder is provided within the quartz tube in which the pulling process takes place. The crystal holder rests on this shoulder. After having been properly rotated by the magnets, the holder slides beyond it in slots.

Quartz tube 1, the top of which is sealed, is surrounded by furnace 2. The bottom part of tube 1 contains a crucible with the melt 4. This is heated by RF heating system 3. Crystal seed 5, on which single crystal 6 grows out of the melt, is fastened to a crystal holder. This consists of quartz rings 8 and 9 connected by quartz tubes 7. Tubes 7 contain iron so that the crystal holder is guided by magnets 10 and 11 mounted to be displaceable and rotatable. Placed on upper guide ring 9 is crucible 12 for receiving volatile components.

For the mechanical suspension of the crystal holder, a flat shoulder 13 is melted into tube 1, on which the rings 8 and 9 may be seated. Ring 8 effects support of the crystal holder prior to the sealing of t...