US4371232A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Graded gap semiconductor optical device
Assignee: United States Department of the Navy
•
Filing: 1980-04-25
•
Granted: 1983-02-01
•
Expires: 2000-04-25
Abstract
Abstract A variable temperature method for the preparation of single and multiple epitaxial layers of single-phase (e.g., face-centered cubic), ternary lead chalcogenide alloys (e.g., lead cadmium sulfide [Pb1-wCdw]a[S]1-a wherein w varies between zero and fifteen hundredths, inclusive, and a=0.500+/-0.003), deposited upon substrates of barium fluoride, BaF2, maintained in near thermodynamic equilibrium with concurrently sublimated lead alloy and chalcogenide sources. During preparation, the temperature of the substrate is varied, thereby providing an epilayer with graded composition and predetermined electrical and optical properties along the direction of growth. This growth technique can be used to produce infrared lenses, narrowband detectors, and double heterojunction lasers.
Inventors
- 👤 James D. Jensen
- 👤 Richard B. Schoolar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:19
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/13; C; C30; C30B; C30B23/00; C30B23/007; C30B23/02; C30B23/04; C30B29/00; C30B29/10; C30B29/46; H10F77/00; H10F77/10; H10F77/12; H10F77/127; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
44 words
A lens comprising: a layer geometrically described by the orthogonal dimensions of thickness and width, the layer being prepared from a lead alloy having a cadmium-chalcogenide mole fraction, the cadmium-chalcogenide mole fraction of the layer depending upon at least one of the orthogonal dimensions.
Claim 2
Dependent Claim
44 words
A lens comprising: a layer geometrically described by the orthogonal dimensions of thickness and width, the layer being prepared from a lead alloy having a cadmium-chalcogenide mole fraction, the cadmium-chalcogenide mole fraction of the layer depending upon at least one of the orthogonal dimensions.
Claim 3
Dependent Claim
21 words
The lens set forth in claim 1 wherein the mole fraction of the layer varies along the thickness of the layer.
Claim 4
Dependent Claim
16 words
The lens set forth in claim 2 wherein the mole fraction of the layer varies uniformly.
Claim 5
Dependent Claim
16 words
The lens set forth in claim 2 wherein the mole fraction of the layer varies abruptly.
Claim 6
Dependent Claim
40 words
The lens set forth in claim 2 wherein one or more abrupt variations in the mole fraction of the layer occur along its thickness, each of the variations defining a junction between adjoining parallel planar regions of constant mole fractions.
Claim 7
Dependent Claim
32 words
The lens set forth in claim 5 wherein one of the one or more abrupt variations comprises a region having a greater mole fraction disposed between incident radiation and an adjoining region.
Claim 8
Dependent Claim
21 words
The lens set forth in claim 1 wherein the mole fraction of the layer varies along the width of the layer.
Claim 9
Dependent Claim
16 words
The lens set forth in claim 7 wherein the mole fraction of the layer varies uniformly.
Claim 10
Dependent Claim
14 words
The lens set forth in claim 8 wherein the layer comprises a diverging lens
Claim 11
Dependent Claim
15 words
The lens set forth in claim 9 wherein the lens comprises a double concave lens.
Claim 12
Dependent Claim
14 words
The lens set forth in claim 9 wherein the lens comprises a plano-concave lens.
Claim 13
Dependent Claim
14 words
The lens set forth in claim 9 wherein the lens comprises a convexo-concave lens.
Claim 14
Dependent Claim
14 words
The lens set forth in claim 8 wherein the layer comprises a converging lens.
Claim 15
Dependent Claim
15 words
The lens set forth in claim 13 wherein the lens comprises a double convex lens.
Claim 16
Dependent Claim
14 words
The lens set forth in claim 13 wherein the lens comprises a plano-convex lens.
Claim 17
Dependent Claim
14 words
The lens set forth in claim 13 wherein the lens comprises a concavo-convex lens.
Claim 18
Dependent Claim
112 words
A semiconductor device prepared from a lead-cadmium chalcogenide alloy having a first composition, an epitaxial film having a second composition within a range including the first composition deposited upon an insulating substrate in a vacuum of at least 10 -4 Torr, according to a process comprising the steps of: heating the substrate to a temperature that is a function of the second composition and greater than 400° C.; maintaining a source of the alloy at a temperature greater than its sublimation temperature; and exposing the substrate to the source until the epitaxial film is deposited on the substrate, the mole fraction of cadmium-chalcogenide in said film varying between zero and six hundredths.
Claim 19
Dependent Claim
112 words
A semiconductor device prepared from a lead-cadmium chalcogenide alloy having a first composition, an epitaxial film having a second composition within a range including the first composition deposited upon an insulating substrate in a vacuum of at least 10 -4 Torr, according to a process comprising the steps of: heating the substrate to a temperature that is a function of the second composition and greater than 400° C.; maintaining a source of the alloy at a temperature greater than its sublimation temperature; and exposing the substrate to the source until the epitaxial film is deposited on the substrate, the mole fraction of cadmium-chalcogenide in said film varying between zero and six hundredths.
Claim 20
Dependent Claim
130 words
A semiconductor device, comprising: an epitaxial layer prepared from a source of a lead-cadmium chalcogenide alloy, the source having a first cadmium-chalcogenide mole fraction, the epitaxial layer having a second cadmium-chalcogenide mole fraction; the epitaxial layer having been deposited upon a surface of an insulating substrate in a vacuum of at least 10 -4 Torr; the source having been maintained at a temperature greater than the sublimation temperature of the alloy; the surface of the substrate having been maintained while the epitaxial layer was deposited, at an elevated temperature or a sequence of elevated temperatures indirectly proportional to the second cadmium chalcogenide mole fraction and greater than 350° C.; and the substrate having been exposed to the source while maintained at the elevated temperature or a sequence of elevated temperatures.
Claim 21
Dependent Claim
130 words
A semiconductor device, comprising: an epitaxial layer prepared from a source of a lead-cadmium chalcogenide alloy, the source having a first cadmium-chalcogenide mole fraction, the epitaxial layer having a second cadmium-chalcogenide mole fraction; the epitaxial layer having been deposited upon a surface of an insulating substrate in a vacuum of at least 10 -4 Torr; the source having been maintained at a temperature greater than the sublimation temperature of the alloy; the surface of the substrate having been maintained while the epitaxial layer was deposited, at an elevated temperature or a sequence of elevated temperatures indirectly proportional to the second cadmium chalcogenide mole fraction and greater than 350° C.; and the substrate having been exposed to the source while maintained at the elevated temperature or a sequence of elevated temperatures.
Claim 22
Dependent Claim
33 words
The device set forth in claim 18 wherein the elevated temperature or sequence of elevated temperatures is greater than 400° C. and the second cadmium-chalcogenide mole fraction exceeds the first cadium-chalcogenide mole fraction.
Claim 23
Dependent Claim
17 words
The device set forth in claim 18 wherein the surface is uniformly maintained at a single temperature.
Claim 24
Dependent Claim
26 words
The device set forth in claim 18 wherein the sequence of elevated temperatures comprises a uniform variation in temperature while the epitaxial layer is being deposited.
Claim 25
Dependent Claim
26 words
The device set forth in claim 18 wherein the sequence of elevated temperatures comprises an abrupt variation in temperature while the epitaxial layer is being deposited.
Claim 26
Dependent Claim
35 words
The device set forth in claim 18 wherein the sequence of elevated temperatures comprises an abrupt variation in temperature while the epitaxial layer is being deposited and the substrate is being shielded from the source.
Claim 27
Dependent Claim
37 words
The device set forth in claim 18 wherein the epitaxial layer is described by a plurality of orthogonal dimensions and the value of the second cadimum-chalcogenide mole fraction varies along at least one of the orthogonal dimensions.
Claim 28
Dependent Claim
21 words
The device set forth in claim 24 wherein the one of the orthogonal dimensions is the thickness of the epitaxial layer.
Claim 29
Dependent Claim
21 words
The device set forth in claim 24 wherein the one of the orthogonal dimensions is the width of the epitaxial layer.
Claim 30
Dependent Claim
44 words
The device set forth in claim 18, wherein the epitaxial layer has a pair of opposed and spaced apart surfaces, and variance in value of the second cadmiumchalcogenide mole fraction along an imaginary straight line passing between the pair of surfaces defines a parabola.
Claim 31
Dependent Claim
53 words
The device set forth in claim 18, wherein the epitaxial layer has a center spaced between opposite edges, and variance in value of the second cadmiumchalcogenide mole fraction along an imaginary straight line running between the opposite edges and passing through the center in a plane parallel to the width describes a parabola.
Claim 32
Dependent Claim
115 words
A semiconductor device prepared from a lead-cadmium chalcogenide alloy having a first cadmium-chalcogenide mole fraction, an epitaxial layer having a second cadmium-chalcogenide mole fraction within a range including the first mole fraction deposited upon an insulating crystalline substrate in a vacuum of at least 10 -4 Torr, according to a process comprising the steps of: maintaining a source of the alloy at a temperature greater than its sublimation temperature, said alloy having mole fraction range limits of zero and fifteen percent; maintaining the substrate at a temperature within a range of 400° C. to 513° C.; exposing the substrate to the source; and varying the second mole fraction by changing the temperature of the substrate.
Claim 33
Dependent Claim
115 words
A semiconductor device prepared from a lead-cadmium chalcogenide alloy having a first cadmium-chalcogenide mole fraction, an epitaxial layer having a second cadmium-chalcogenide mole fraction within a range including the first mole fraction deposited upon an insulating crystalline substrate in a vacuum of at least 10 -4 Torr, according to a process comprising the steps of: maintaining a source of the alloy at a temperature greater than its sublimation temperature, said alloy having mole fraction range limits of zero and fifteen percent; maintaining the substrate at a temperature within a range of 400° C. to 513° C.; exposing the substrate to the source; and varying the second mole fraction by changing the temperature of the substrate.
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) | 1986-01-31 | 1986-08-02 | 1987-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-31 | 1990-08-02 | 1991-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-31 | 1994-08-02 | 1995-02-01 | $7700.00 | Window Closed / Lapsed |