Patent US5598014A successfully refreshed from Google Patents.
US5598014A
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US
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High gain ultraviolet photoconductor based on wide bandgap nitrides
Assignee: Honeywell Inc
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Filing: 1995-02-28
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Granted: 1997-01-28
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Expires: 2015-02-28
Abstract
Abstract A photoconductor has an active layer of gallium nitride having approximately 10 15 to 5×10 15 net donor sites per cubic centimeter and is sensitive to UV radiation. This photoconductor has at least one of a sheet resistance in the approximate range of 10 4 to 5×10 6 ohms/unit area and a relatively low level of photoluminescence in the range from about 430-450 nm when excited with light of energy higher than the bandgap energy of 3.4 eV. These criteria tend to define similar semiconductor materials which can form the active layer of an ultraviolet (UV) photodetector having the improved characteristics of a relatively low dark resistance, high sensitivity over at least a range of UV radiation intensity, and decreasing gain with increasing UV radiation.
Inventors
- 👤 Barbara G. Barany
- 👤 Scott T. Reimer
- 👤 Robert P. Ulmer
- 👤 J. David Zook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:45
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; H10F77/124; H10F77/1243; H10F30/00; H10F30/10; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
103 words
A UV photoconductor having an active layer comprising gallium nitride, and having a number of electron donor sites and a smaller number of electron acceptor sites, wherein the difference between the number of donor sites and the number of acceptor sites is approximately 10 15 to 5×10 16 per cubic centimeter, said active layer having a surface for exposure to UV illumination and adjacent to the surface, a depletion region having a first thickness when incident UV illumination on the surface is relatively low, and a second thickness smaller than the first thickness while incident UV illumination on the surface is relatively large.
Claim 2
Dependent Claim
103 words
A UV photoconductor having an active layer comprising gallium nitride, and having a number of electron donor sites and a smaller number of electron acceptor sites, wherein the difference between the number of donor sites and the number of acceptor sites is approximately 10 15 to 5×10 16 per cubic centimeter, said active layer having a surface for exposure to UV illumination and adjacent to the surface, a depletion region having a first thickness when incident UV illumination on the surface is relatively low, and a second thickness smaller than the first thickness while incident UV illumination on the surface is relatively large.
Claim 3
Dependent Claim
33 words
The UV photoconductor of claim 1 wherein the active layer has an effective sheet resistance in the approximate range of 10 4 to 5×10 6 ohms/square after a short period without UV illumination.
Claim 4
Dependent Claim
53 words
The UV photoconductor of claim 2 wherein the effective sheet resistance of the active layer has a first value without UV illumination and a second value smaller than the first value by a factor of at least approximately 4 during a period of relatively intense UV illumination after a period without UV illumination.
Claim 5
Dependent Claim
23 words
The UV photoconductor of claim 1, wherein at least a substantial fraction of the donor sites in the active layer comprise silicon atoms.
Claim 6
Dependent Claim
21 words
The UV photoconductor of claim 4, wherein at least 90% of the donor sites in the active layer comprise silicon atoms.
Claim 7
Dependent Claim
35 words
The UV photoconductor of claim 4, wherein the gallium nitride layer has a predetermined thickness and a higher concentration of silicon atoms in the vicinity of the center of the thickness of the active layer.
Claim 8
Dependent Claim
86 words
A UV photoconductor having an active layer mainly comprising gallium nitride, said active layer having an effective sheet resistance in the approximate range of 10 4 to 5×10 6 ohms/square after a short period without UV illumination, and said active layer having a surface for exposure to UV illumination and adjacent to the surface, a depletion region having a first thickness in the absence of detectable UV illumination of the surface, and a second thickness smaller than the first thickness while the surface receives UV illumination.
Claim 9
Dependent Claim
86 words
A UV photoconductor having an active layer mainly comprising gallium nitride, said active layer having an effective sheet resistance in the approximate range of 10 4 to 5×10 6 ohms/square after a short period without UV illumination, and said active layer having a surface for exposure to UV illumination and adjacent to the surface, a depletion region having a first thickness in the absence of detectable UV illumination of the surface, and a second thickness smaller than the first thickness while the surface receives UV illumination.
Claim 10
Dependent Claim
53 words
The UV photoconductor of claim 7 wherein the effective sheet resistance of the active layer has a first value without UV illumination and a second value smaller than the first value by a factor of at least approximately 4 during a period of relatively intense UV illumination after a period without UV illumination.
Claim 11
Dependent Claim
25 words
The UV photoconductor of claim 7, wherein the active layer includes a plurality of electron donor sites of which a substantial fraction comprise silicon atoms.
Claim 12
Dependent Claim
21 words
The UV photoconductor of claim 9, wherein at least 90% of the donor sites in the active layer comprise silicon atoms.
Claim 13
Dependent Claim
34 words
The UV photoconductor of claim 9, wherein the active layer has a predetermined thickness and a higher concentration of silicon atoms in the vicinity of the center of the thickness of the active layer.
Claim 14
Dependent Claim
152 words
A UV photoconductor having an active layer mainly comprising gallium nitride deposited on a surface of a substrate and having a first surface in contact with the deposition surface and a second surface facing away from the deposition surface, at least one of said first and second surfaces for accepting incident UV radiation, said active layer having within itself and adjacent to the second surface, a depletion region in which is present a lesser concentration of charge carriers than in the active layer adjacent to the depletion region, and spaced from each surface, a conduction channel in which is present a greater concentration of charge carriers than in the active layer adjacent to the conduction channel, said depletion region having a first thickness responsive to UV illumination on an active layer surface, and a second thickness greater than the first thickness in the absence of UV illumination of an active layer surface.
Claim 15
Dependent Claim
152 words
A UV photoconductor having an active layer mainly comprising gallium nitride deposited on a surface of a substrate and having a first surface in contact with the deposition surface and a second surface facing away from the deposition surface, at least one of said first and second surfaces for accepting incident UV radiation, said active layer having within itself and adjacent to the second surface, a depletion region in which is present a lesser concentration of charge carriers than in the active layer adjacent to the depletion region, and spaced from each surface, a conduction channel in which is present a greater concentration of charge carriers than in the active layer adjacent to the conduction channel, said depletion region having a first thickness responsive to UV illumination on an active layer surface, and a second thickness greater than the first thickness in the absence of UV illumination of an active layer surface.
Claim 16
Dependent Claim
62 words
The UV photoconductor of claim 12, wherein the depletion region and the conduction channel each have a thickness dimension normal to the second surface, wherein the ratio of the depletion region thickness to the conduction channel thickness decreases by a factor of at least approximately 4 during a period of relatively intense UV illumination after a period of relatively low UV illumination.
Claim 17
Dependent Claim
26 words
The UV photoconductor of claim 12, wherein the active layer includes at least one of indium gallium nitride, aluminum gallium nitride, and aluminum indium gallium nitride.
Claim 18
Dependent Claim
48 words
The UV photoconductor of claim 14 wherein the active layer has a doped region approximately midway between the first and second surfaces thereof in which is a concentration of atoms of at least one element selected from a doping group of silicon, sulphur, tin, tellurium, selenium, and germanium.
Claim 19
Dependent Claim
17 words
The UV photoconductor of claim 15, wherein the doped region is approximately 1 to 100 nm thick.
Claim 20
Dependent Claim
28 words
The UV photoconductor of claim 15, wherein the concentration of atoms from the doping group is approximately 10 17 to 5×10 18 per cc. in the doped region.
Claim 21
Dependent Claim
33 words
The UV photoconductor of claim 12 wherein the active layer has a concentration of atoms of at least one element selected from a doping group of silicon, sulphur, tin, tellurium, selenium, and germanium.
Claim 22
Dependent Claim
24 words
The UV photoconductor of claim 18, wherein the concentration of atoms from the doping group is 10 15 to 8×10 16 per cubic centimeter.
References Cited (Backward Citations)
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| 7.5 Years (Year 8) | 2004-01-28 | 2004-07-29 | 2005-01-28 | $3760.00 | Window Closed / Lapsed |
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