US5128007A
Expired / Lapsed
US
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Method for evaluating a lithium niobate thin film and apparatus for preparing the same
Assignee: Sharp Corp
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Filing: 1991-04-25
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Granted: 1992-07-07
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Expires: 2011-04-25
Abstract
Abstract A method for evaluating a lithium niobate thin film includes measuring an absorption edge wavelength of a lithium niobate thin film and evaluating a lithium-to-niobium composition ratio of the thin film, and an apparatus for preparing a thin film including a thin film-forming body capable of controlling the lithium-to-niobium composition ratio of a lithium niobate thin film being formed and an evaluation device for evaluating the lithium-to-niobium composition ratio, the evaluation device being provided with a monitor substrate, an optical path for spectrometry, an ultraviolet ray source and a measurement part for measuring an absorption edge wavelength of the thin film.
Inventors
- 👤 Hironori Matsunaga
- 👤 Hirotaka Ohno
- 👤 Yasunari Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:29
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/13; G01; G01N; G01N21/00; G01N21/84; G01N21/8422; G01N21/17; G01N21/21; G01N2021/218; G01N21/25; G01N21/31; G01N2021/3185; G01N2021/3192; G01N21/33
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
202 words
An apparatus for forming a lithium niobate thin film comprising: a vacuum chamber at a predetermined pressure; a high frequency coil, located in said vacuum chamber; means for introducing oxygen gas into said vacuum chamber near said high frequency coil; said high frequency coil generating an oxygen plasma atmosphere by applying Rf power of a predetermined frequency and wattage to said high frequency coil; a substrate located within said vacuum chamber; means for heating said substrate to a predetermined temperature; evaporation means, operating at a predetermined current, for producing niobium vapor; means for producing lithium vapor; means for passing the lithium vapor and niobium vapor through the oxygen plasma atmosphere; means for simultaneously depositing the lithium vapor and niobium vapor on said substrate to form a lithium niobate thin film; means for measuring an absorption edge wavelength of the lithium niobate thin film; and means for controlling the predetermined pressure of said vacuum chamber, the predetermined frequency and wattage of the Rf power, the predetermined temperature of said substrate, the predetermined current of said evaporation means, a deposition rate of the lithium vapor and a deposition rate of the niobium vapor such that the absorption edge wavelength falls within a predetermined range.
Claim 2
Independent Claim
202 words
An apparatus for forming a lithium niobate thin film comprising: a vacuum chamber at a predetermined pressure; a high frequency coil, located in said vacuum chamber; means for introducing oxygen gas into said vacuum chamber near said high frequency coil; said high frequency coil generating an oxygen plasma atmosphere by applying Rf power of a predetermined frequency and wattage to said high frequency coil; a substrate located within said vacuum chamber; means for heating said substrate to a predetermined temperature; evaporation means, operating at a predetermined current, for producing niobium vapor; means for producing lithium vapor; means for passing the lithium vapor and niobium vapor through the oxygen plasma atmosphere; means for simultaneously depositing the lithium vapor and niobium vapor on said substrate to form a lithium niobate thin film; means for measuring an absorption edge wavelength of the lithium niobate thin film; and means for controlling the predetermined pressure of said vacuum chamber, the predetermined frequency and wattage of the Rf power, the predetermined temperature of said substrate, the predetermined current of said evaporation means, a deposition rate of the lithium vapor and a deposition rate of the niobium vapor such that the absorption edge wavelength falls within a predetermined range.
Claim 3
Dependent Claim
24 words
The apparatus for forming a lithium niobate thin film of claim 1, wherein the predetermined range for the absorption edge wavelength is 310-320 nm.
Claim 4
Dependent Claim
32 words
The apparatus for forming a lithium niobate thin film of claim 2, wherein the deposition rate of lithium vapor is 10-30 Å/min and the deposition rate of niobium vapor is 10 Å/min.
Claim 5
Dependent Claim
23 words
The apparatus for forming a lithium niobate thin film of claim 3, wherein the predetermined current of said evaporation means is 100 mA.
Claim 6
Dependent Claim
22 words
The apparatus for forming a lithium niobate thin film of claim 4, wherein the predetermined temperature of said substrate is 400° C.
Claim 7
Dependent Claim
35 words
The apparatus for forming a lithium niobate thin film of claim 5, wherein the predetermined frequency and wattage of the Rf power applied by said high frequency coil is 13.56 MHz and 200 W, respectively.
Claim 8
Dependent Claim
25 words
The apparatus for forming a lithium niobate thin film of claim 6, wherein the predetermined vacuum pressure of said vacuum chamber is 1×10 -8 Torr.
Claim 9
Independent Claim
181 words
A method for forming a lithium niobate thin film, comprising the steps of: (a) pressurizing a vacuum chamber at a predetermined pressure; (b) introducing oxygen gas into the vacuum chamber near a high frequency coil; (c) applying Rf power of a predetermined frequency and wattage to the high frequency coil to generate an oxygen plasma atmosphere; (d) heating a substrate to a predetermined temperature; (e) producing niobium vapor, utilizing an evaporator operating at a predetermined current; (f) producing lithium vapor; (g) passing the lithium vapor and niobium vapor thorough the oxygen plasma atmosphere; (h) simultaneously depositing the lithium vapor and niobium vapor on the substrate to form a lithium niobate thin film; (i) measuring an absorption edge wavelength of the lithium niobate thin film; and (j) controlling the predetermined pressure of the vacuum chamber, the predetermined frequency and wattage of the Rf power, the predetermined temperature of the substrate, the predetermined current of the evaporator, a deposition rate of the lithium vapor and a deposition rate of the niobium vapor such that the absorption edge wavelength falls within a predetermined range.
Claim 10
Independent Claim
181 words
A method for forming a lithium niobate thin film, comprising the steps of: (a) pressurizing a vacuum chamber at a predetermined pressure; (b) introducing oxygen gas into the vacuum chamber near a high frequency coil; (c) applying Rf power of a predetermined frequency and wattage to the high frequency coil to generate an oxygen plasma atmosphere; (d) heating a substrate to a predetermined temperature; (e) producing niobium vapor, utilizing an evaporator operating at a predetermined current; (f) producing lithium vapor; (g) passing the lithium vapor and niobium vapor thorough the oxygen plasma atmosphere; (h) simultaneously depositing the lithium vapor and niobium vapor on the substrate to form a lithium niobate thin film; (i) measuring an absorption edge wavelength of the lithium niobate thin film; and (j) controlling the predetermined pressure of the vacuum chamber, the predetermined frequency and wattage of the Rf power, the predetermined temperature of the substrate, the predetermined current of the evaporator, a deposition rate of the lithium vapor and a deposition rate of the niobium vapor such that the absorption edge wavelength falls within a predetermined range.
Claim 11
Dependent Claim
24 words
The method for forming a lithium niobate thin film of claim 8, wherein the predetermined range for the absorption edge wavelength is 310-320 nm.
Claim 12
Dependent Claim
32 words
The method for forming a lithium niobate thin film of claim 9, wherein the deposition rate of lithium vapor is 10-30 Å/min and the deposition rate of niobium vapor is 10 Å/min.
Claim 13
Dependent Claim
22 words
The method for forming a lithium niobate thin film of claim 10, wherein the predetermined current of the evaporator is 100 mA.
Claim 14
Dependent Claim
22 words
The apparatus for forming a lithium niobate thin film of claim 11, wherein the predetermined temperature of the substrate is 400° C.
Claim 15
Dependent Claim
34 words
The apparatus for forming a lithium niobate thin film of claim 12, wherein the predetermined frequency and wattage of the Rf powers applied to the oxygen gas is 13.56 MHz and 200 W, respectively.
Claim 16
Dependent Claim
25 words
The apparatus for forming a lithium niobate thin film of claim 13, wherein the predetermined vacuum pressure of the vacuum chamber is 1×10 -8 Torr.
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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) | 1995-07-07 | 1996-01-06 | 1996-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-07 | 2000-01-06 | 2000-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-07 | 2004-01-06 | 2004-07-07 | $7700.00 | Window Closed / Lapsed |