Browse Prior Art Database

Magnetically Supported Seed Holder for Crystal Growing within a Sealed System

IP.com Disclosure Number: IPCOM000094532D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Blum, SE: AUTHOR [+2]

Abstract

This seed holder is coupled to a rotating and lifting ensemble of permanent magnets. The seed holder has a spool consisting of a heavy walled quartz tube axle 1 to which are joined two quartz bearings 2 and 3. These are precision ground to close tolerances and are precisely in line. The lower portion of axle 1 is precision ground and drilled so that a precision bore seed holder tube 4, flared at the top, can be mounted and firmly fixed to axle 1. The upper portion of 1 is extended to facilitate handling during loading and unloading or the seed holder in the puller tube. Each bearing 2 and 3 contains two sets of two closely spaced precision holes 5... 12. The holes of the upper and lower bearings are in line.

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Magnetically Supported Seed Holder for Crystal Growing within a Sealed System

This seed holder is coupled to a rotating and lifting ensemble of permanent magnets. The seed holder has a spool consisting of a heavy walled quartz tube axle 1 to which are joined two quartz bearings 2 and 3. These are precision ground to close tolerances and are precisely in line. The lower portion of axle 1 is precision ground and drilled so that a precision bore seed holder tube 4, flared at the top, can be mounted and firmly fixed to axle 1.

The upper portion of 1 is extended to facilitate handling during loading and unloading or the seed holder in the puller tube. Each bearing 2 and 3 contains two sets of two closely spaced precision holes 5... 12. The holes of the upper and lower bearings are in line. In each of four magnetic susceptors 13, a high permeability, high Curie point magnetic material such as PERMENDUR* or HIPERCO**** 12, is encapsulated as in the left-hand drawing. A susceptor 13 is inserted into each of the four pairs of holes from the bottom. These are fixed in position by tube 4. This is held precisely and keeps the four susceptors 13 in position when the whole ensemble is in the vertical position. When the seed holder is supported within a magnetic field, the stop of each susceptor 13 supports the entire ensemble.

The seed crystal is fixed precisely and held firmly in tube 4 by quartz pin 14. The seed holder ensemble is positioned into the crystal puller tube by lowering by hand until susceptors 13 are in the magnetic field. The seed holder is th...