US5227204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of ferrite films using laser deposition
Assignee: Northeastern University
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Filing: 1991-08-27
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Granted: 1993-07-13
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Expires: 2011-08-27
Abstract
Abstract A method is provided for fabricating a thin film of ferrite material upon a variety of substrates wherein pulsed high power laser light impinges upon a target of ferrite material causing localized vaporization of the ferrite material and subsequent deposition upon a proximate substrate. The rapidity with which the target material is vaporized promotes chemical stability during ferrite film growth. Both the target and the substrate are maintained inside a vacuum chamber, and are maintained substantially within a temperature range of 550°-600° C. The equipment needed to practice the method is relatively inexpensive. Furthermore, the method allows for the large-scale production of high quality ferrite films with preferential magnetic texture, wherein the magnetization of the ferrite material aligns in a preferred direction in the plane of the film.
Inventors
- 👤 Carmine Vittoria
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:31
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/06; C23C14/08; C23C14/22; C23C14/24; C23C14/28
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
125 words
A method for forming crystalline ferrite films comprising the steps of: choosing a substrate that consists essentially of a material selected from the group consisting of magnesium oxide, sapphire, SrGa 12 O 19 , and MnFe 2 O 4 ; enclosing within a vacuum chamber both a ferrite target and the substrate, upon which substrate a ferrite film is to be formed; heating said substrate to a temperature generally within the range of 500° C. to 950° C.; maintaining a flow of oxygen in the vicinity of the substrate; and directing laser light towards said ferrite target to initiate rapid vaporization of at least a portion of said ferrite target, and subsequent deposition of ferrite material upon said substrate to form a crystalline ferrite film.
Claim 2
Independent Claim
125 words
A method for forming crystalline ferrite films comprising the steps of: choosing a substrate that consists essentially of a material selected from the group consisting of magnesium oxide, sapphire, SrGa 12 O 19 , and MnFe 2 O 4 ; enclosing within a vacuum chamber both a ferrite target and the substrate, upon which substrate a ferrite film is to be formed; heating said substrate to a temperature generally within the range of 500° C. to 950° C.; maintaining a flow of oxygen in the vicinity of the substrate; and directing laser light towards said ferrite target to initiate rapid vaporization of at least a portion of said ferrite target, and subsequent deposition of ferrite material upon said substrate to form a crystalline ferrite film.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein said flow of oxygen within the vacuum chamber maintains a partial pressure of oxygen of approximately 300 mtorr in the vicinity of the substrate during formation of said ferrite film.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein said ferrite target is disposed at a distance from said substrate, the distance chosen so as to promote deposition of ferrite material upon said substrate.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said ferrite target is rotated during the step of firing said laser.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein said laser is directed obliquely at said ferrite target.
Claim 7
Dependent Claim
26 words
The method of claim 1 wherein said laser is a pulsed laser of a power sufficient to vaporize at least said portion of said ferrite target.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said laser is focused by an intervening lens.
Claim 9
Dependent Claim
11 words
The method of claim 1 wherein said target is electrically grounded.
Claim 10
Dependent Claim
30 words
The method of claim 1 wherein said substrate has been precoated with an intermediate bonding layer to promote enhanced adhesion and crystal structure of a ferrite film to be formed.
Claim 11
Dependent Claim
25 words
The method of claim 1 wherein after said ferrite film has been formed, the film is bathed in oxygen gas at room temperature and pressure.
Claim 12
Dependent Claim
11 words
The method of claim 1 wherein said substrate is radiantly heated.
Claim 13
Dependent Claim
13 words
The method of claim 1 wherein said substrate is shielded from ionizing radiation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-07-12 | 1997-01-11 | 1997-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-12 | 2001-01-11 | 2001-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-12 | 2005-01-11 | 2005-07-13 | $7700.00 | Window Closed / Lapsed |