US4803537A
Expired / Lapsed
US
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Infrared detector system based upon group III-V epitaxial material
Assignee: Texas Instruments Inc
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Filing: 1988-03-14
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Granted: 1989-02-07
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Expires: 2008-03-14
Abstract
Abstract The disclosure relates to a detector of infrared radiation which employs Group III-V compound semiconductor technology and includes a conductive substrate, of a material such as GaAs. Upon this substrate is deposited a lattice structure, including thin alternating layers of a wider and a narrower energy band gap material (AlGaAs and GaAs) periodically disposed. Upon this is deposited a layer of an alloyed semiconductor of moderate bandgap, into which photoexcited carriers are injected, and upon this is deposited a layer of wider bandgap material against which the carriers are trapped and thus collected. The lattice is designed so that the energy gap between the first two bands produced by the periodic structure is equal to the infrared photon energy. The doping is such as to nearly fill the first band with free carriers. Thus infrared radiation is efficiently absorbed, generating free carriers in the second band of the lattice. The bandgap of the next layer is chosen so that these photoexcited carriers may easily pass into this layer, while those in the lower-energy band are blocked. These carriers are propelled across this next layer by an applied electric field and are collected at the interface with a wide-gap layer.
Inventors
- 👤 Adam J. Lewis
- 👤 William R. Frensley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:52
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/222; H10F77/00; H10F77/10; H10F77/12; H10F77/124; H10F77/1248; H10F77/14; H10F77/146; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
116 words
A semiconductor detector for infrared radiation, comprising: (a) an absorption superlattice with first and second mini-bands, said mini-bands separated by an energy about equal to the energy of the photons of a frequency of infrared radiation to be detected, said superlattice with carriers in said first mini-band but not in said second mini-band; (b) a collector abutting said superlattice, said collector with energy band edge between said mini-bands at said superlattice so carriers in said first mini-band are blocked from said collector but carriers photo-excited by said infrared radiation from said first mini-band to said second mini-band can pass into said collector; and (c) a sensor coupled to said collector to detect carriers in said collector.
Claim 2
Dependent Claim
116 words
A semiconductor detector for infrared radiation, comprising: (a) an absorption superlattice with first and second mini-bands, said mini-bands separated by an energy about equal to the energy of the photons of a frequency of infrared radiation to be detected, said superlattice with carriers in said first mini-band but not in said second mini-band; (b) a collector abutting said superlattice, said collector with energy band edge between said mini-bands at said superlattice so carriers in said first mini-band are blocked from said collector but carriers photo-excited by said infrared radiation from said first mini-band to said second mini-band can pass into said collector; and (c) a sensor coupled to said collector to detect carriers in said collector.
Claim 3
Dependent Claim
50 words
The detector of claim 1, wherein: (a) said superlattice is made of alternating layers of gallium arsenide and a first aluminum gallium arsenide alloy; (b) said collector includes a second aluminum gallium arsenide alloy abutting said superlattice; and said sensor includes an insulated transparent conductive gate electrode on said collector.
Claim 4
Dependent Claim
51 words
The detector of claim 2, wherein: (a) said carriers are electrons; (b) said superlattice is doped N type; (c) said gate electrode is made of material selected from the group consisting of tin oxide and indium tin oxide; and (d) said gate electrode is insulated on said collector by silicon dioxide.
Claim 5
Dependent Claim
144 words
An infrared imaging device for detecting infrared radiation, comprising: (a) a plurality of infrared detectors arranged into rows and columns, each of said detectors including: i. an absorption superlattice with first and second mini-bands, said mini-bands separated by an energy about equal to the energy of the photons of a frequency of infrared radiation to be detected, said superlattice with carriers in said first mini-band but not in said second mini-band; ii. a collector abutting said superlattice, said collector with energy band edge between said mini-bands at said superlattice so carriers in said first mini-band are blocked from said collector but carriers photo-excited by said infrared radiation from said first mini-band to said second mini-band can pass into said collector; and iii. a sensor coupled to said collector to detect carriers in said collector; and (b) circuitry for addressing each of said detector sensors.
Claim 6
Dependent Claim
144 words
An infrared imaging device for detecting infrared radiation, comprising: (a) a plurality of infrared detectors arranged into rows and columns, each of said detectors including: i. an absorption superlattice with first and second mini-bands, said mini-bands separated by an energy about equal to the energy of the photons of a frequency of infrared radiation to be detected, said superlattice with carriers in said first mini-band but not in said second mini-band; ii. a collector abutting said superlattice, said collector with energy band edge between said mini-bands at said superlattice so carriers in said first mini-band are blocked from said collector but carriers photo-excited by said infrared radiation from said first mini-band to said second mini-band can pass into said collector; and iii. a sensor coupled to said collector to detect carriers in said collector; and (b) circuitry for addressing each of said detector sensors.
Claim 7
Dependent Claim
51 words
The device of claim 4, wherein: (a) said superlattice is made of alternating layers of gallium arsenide and a first aluminum gallium arsenide alloy; (b) said collector includes a second aluminum gallium arsenide alloy abutting said superlattice; and (c) said sensor includes an insulated transparent conductive gate electrode on said collector.
Claim 8
Dependent Claim
51 words
The detector of claim 5, wherein: (a) said carriers are electrons; (b) said superlattice is doped N type; (c) said gate electrode is made of material selected from the group consisting of tin oxide and indium tin oxide; and (d) said gate electrode is insulated on said collector by silicon dioxide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |