Patent US3607139A successfully refreshed from Google Patents.
US3607139A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single crystal growth and diameter control by magnetic melt agitation
Assignee: Airco Inc
•
Filing: 1968-05-02
•
Granted: 1971-09-21
•
Expires: 1988-05-02
Abstract
Abstract A method and apparatus are described for growing a single crystal from a molten pool formed of crystalline material, such as silicon and super alloy metals. Growth of the single crystal is controlled by controlling the thermal pattern, in the molten pool from which the product is grown, through variation in the relative rotation between the molten pool and a magnetic field.
Inventors
- 👤 Charles W Hanks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:24
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/20; C30B15/22; C30B15/24; C30B15/30; C30B15/305; Y; Y10; Y10S; Y10S117/00; Y10S117/905; Y10S117/917; Y10T; Y10T117/00; Y10T117/10; Y10T117/1024; Y10T117/1032; Y10T117/1068
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
21 words
A method according to claim 1 wherein the heated region of the pool is heated by means of electron beam bombardment.
Claim 2
Dependent Claim
43 words
A method according to claim 1 wherein the relative rotation between the single crystal and the molten pool is controlled to cause a necking down of the single crystal at a surface angle greater than 30* from the axis of the single crystal.
Claim 3
Dependent Claim
26 words
A method according to claim 3 wherein, after necking down, the relative rotational speed is reduced to produce an enlargement of the single crystal cross section
Claim 4
Dependent Claim
185 words
Apparatus for growing a single crystal from a molten pool of material capable of epitaxial growth, comprising, means for supporting the molten pool, means for supporting a single crystal seed and for contacting the surface of the molten pool with the seed to establish an interface between the seed and the molten pool and for withdrawing the seed from the molten pool at a rate such that a single crystal of material is grown, means for heating the material in the molten pool at a region of the pool between the interface and the periphery of the pool, means for establishing a magnetic field having lines of force extending through the molten pool generally parallel with the axis of the single crystal, means for rotating said pool-supporting means to effect a relative rotation between the molten pool and the magnetic field to produce a flow of molten material from the heated region toward the interface, and means for controlling the rate of rotation of said pool-supporting means to control the rate of such a flow, thereby controlling the diameter of the single crystal being grown.
Claim 5
Dependent Claim
20 words
Apparatus according to claim 5 wherein said pool supporting means comprise a solid pedestal composed of the epitaxial growth material.
Claim 6
Dependent Claim
29 words
Apparatus according to claim 5 wherein said heating means comprise an electron beam gun having an annular emitter so that the impact pattern is annular, surrounding the single crystal.
Claim 7
Dependent Claim
46 words
Apparatus according to claim 5 wherein the lines of force of the magnetic field are directed to produce an initial inward excursion of electrons, and wherein the emitter is positioned above the molten pool a distance substantially equal to the pitch of the helical electron paths.
Claim 8
Dependent Claim
26 words
Apparatus according to claim 5 wherein said field producing means comprises an annular electromagnetic coil positioned surrounding said pool at the level of the surface thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |