US3660062A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for crucible-free floating zone melting a crystalline rod, especially of semi-crystalline material
Assignee: Siemens AG
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Filing: 1969-02-26
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Granted: 1972-05-02
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Expires: 1989-02-26
Abstract
Abstract In method of floating zone melting a crystalline rod, especially of semiconductor material, disposed in a sealed receptacle wherein an induction heating coil surrounds the rod and forms a molten zone therein, the rod and heating coil being relatively movable so as to pass the molten zone through the rod, the improvement is provided which comprises passing hydrogen gas of at least 99.9 percent purity into the receptacle so as to form a protective atmosphere therein, and adjusting the pressure of the atmosphere in the receptacle to a value below atmospheric pressure; and device for carrying out the foregoing method.
Inventors
- 👤 Wolfgang Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:05
CPC Classifications
C; C30; C30B; C30B13/00; H; H10; H10P; H10P95/00; Y; Y10; Y10S; Y10S117/00; Y10S117/906; Y10S148/00; Y10S148/041; Y10S148/107; Y10S65/00; Y10S65/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
15 words
Method according to claim 1 wherein the hydrogen gas has a purity of 99.995 percent.
Claim 2
Dependent Claim
18 words
Method according to claim 1 wherein the pressure of the atmosphere in the receptacle is about 100 Torr.
Claim 3
Dependent Claim
25 words
Method according to claim 1 wherein a gaseous dopant selected from the group consisting of phosphine and boron hydride is mixed with the hydrogen gas.
Claim 4
Dependent Claim
31 words
Method according to claim 1 which comprises passing a molten zone through the crystalline rod at least once in vacuo prior to zone melting the same in the hydrogen gas atmosphere.
Claim 5
Dependent Claim
16 words
Method according to claim 1 which comprises adding a further protective gas to the hydrogen gas.
Claim 6
Dependent Claim
14 words
Method according to claim 6 wherein the further protective gas is a noble gas.
Claim 7
Dependent Claim
23 words
Method according to claim 6 wherein the further protective gas is a gas selected from the group consisting of argon, helium and nitrogen.
Claim 8
Dependent Claim
21 words
Method according to claim 6 wherein the further protective gas is nitrogen having a partial pressure of at most 100 Torr.
Claim 9
Dependent Claim
37 words
Method according to claim 1 which comprises adding at least one further protective gas to the hydrogen gas in a quantity so that the total pressure of gas in the receptacle is between 30 and 600 Torr.
References Cited (Backward Citations)
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Cited
US3265470A
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US3223493A
Cited
US2992311A
Cited
US3157537A
Cited
US3351433A
Cited
US3342970A
Cited
US3442622A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |