EP0149178A2
Expired / Lapsed
EP
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Infrared detector system based on III-V epitaxial material
Assignee: Texas Instruments Inc
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Filing: 1984-12-19
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Granted: —
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Expires: 2004-12-19
Abstract
Abstract The disclosure relates to a detector of infrared radiation which employs Group III-V compound semiconductor technology and includes a conductive substrate 11, of a material such as GaAs. Upon this substrate is deposited a lattice structure 13, including thin alternating layers of a wider and a narrower energy band gap material (AIGaAs and GaAs) periodically disposed. Upon this is deposited a layer 15 of an alloyed semiconductor of moderate bandgap. into which photoexcited carriers are injected, and upon this is deposited a layer 19 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
EP
Data Source
google_patents
Last Synchronized
2026-10-31 03:45
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
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
140 words
An infrared detector comprising: a. superlattice material, said superlattice comprising first and second materials spaced in a regular periodic order, said superlattice having at least first and second mini-bands in the conduction-band characteristic thereof; a collection layer adjacent to said superlattice, said collection layer being lattice-matched to said superlative and comprising a semiconductor having a conduction-band energy level which is intermediate between the respective energies of said first and second mini bands of said superlattice; said superlattice material being positioned to be exposed to infrared light; said superlattice material being doped to provide a background carrier concentration of at least 10 17 ; whereby infrared light absorbed in said superlattice layer causes carriers in said superlattice layer to make a transition from said first to said second mini band, whereby some of said carriers are injected into said collection layer.
Claim 2
Dependent Claim
140 words
An infrared detector comprising: a. superlattice material, said superlattice comprising first and second materials spaced in a regular periodic order, said superlattice having at least first and second mini-bands in the conduction-band characteristic thereof; a collection layer adjacent to said superlattice, said collection layer being lattice-matched to said superlative and comprising a semiconductor having a conduction-band energy level which is intermediate between the respective energies of said first and second mini bands of said superlattice; said superlattice material being positioned to be exposed to infrared light; said superlattice material being doped to provide a background carrier concentration of at least 10 17 ; whereby infrared light absorbed in said superlattice layer causes carriers in said superlattice layer to make a transition from said first to said second mini band, whereby some of said carriers are injected into said collection layer.
Claim 3
Dependent Claim
18 words
The device in Claim 1, further comprising an insulator on said collection layer; a conductor on said insulator.
Claim 4
Dependent Claim
28 words
The device in Claim 2, further comprising: means, connected to said conductor for periodically sensing the amount of charge injected into said collection layer at local points thereof.
Claim 5
Dependent Claim
31 words
The device in Claim 1, further comprising: a barrier layer of top said collection layer, said barrier layer having a large band gap than the band gap of said collection layer.
Claim 6
Dependent Claim
33 words
The device in Claim 4, wherein said barrier layer is a semiconductor having a larger band gap than the band gap of said collection layer and is lattice matched to said collection layer.
Claim 7
Dependent Claim
67 words
An infrared detector which comprises: (a) a Group III-V substrate, (b) a first layer of doped Group III-V material on one surface of said substrate, (c) a second layer of a moderate band gap Group III-V material over said first layer, and (d) a third layer of a Group III-V material over said second layer, said third layer being of wider band gap then said second layer.
Claim 8
Dependent Claim
67 words
An infrared detector which comprises: (a) a Group III-V substrate, (b) a first layer of doped Group III-V material on one surface of said substrate, (c) a second layer of a moderate band gap Group III-V material over said first layer, and (d) a third layer of a Group III-V material over said second layer, said third layer being of wider band gap then said second layer.
Claim 9
Dependent Claim
29 words
7 . An infrared detector as set forth in Claim 6 further including an insulating layer over said third layer and a transparent contact element over said insulating layer.
Claim 10
Dependent Claim
41 words
8 - An infrared detector as set forth in Claim 6 wherein said substrate is gallium arsenide, said first layer is of N-type and comprises aluminum gallium arsenide and gallium arsenide, and said second and third layers comprise aluminum gallium arsenide.
Claim 11
Dependent Claim
38 words
An infrared detector as set forth in Claim 7 wherein said substrate is gallium arsenide, said first layer is of N-type and comprises aluminum gallium arsenide and gallium arsenide, said second and third layers comprise aluminum gallium arsenide.
Claim 12
Dependent Claim
30 words
An infrared detector as set forth in Claim 6 wherein said first layer is a lattice structure comprising spaced layers of aluminum gallium arsenide separated by layers of gallium arsenide.
Claim 13
Dependent Claim
30 words
An infrared detector as set forth in Claim 7 wherein said first layer is a lattice structure comprising spaced layers of aluminum gallium arsenide separated by layers of gallium arsenide.
Claim 14
Dependent Claim
30 words
An infrared detector as set forth in Claim 8 wherein said first layer is a lattice structure comprising spaced layers of aluminum gallium arsenide separated by layers of gallium arsenide.
Claim 15
Dependent Claim
30 words
An infrared detector as set forth in Claim 9 wherein said first layer is a lattice structure comprising spaced layers of aluminum gallium arsenide separated by layers of gallium arsenide.
Claim 16
Dependent Claim
24 words
An infrared detector as set forth in Claim 10 wherein said layers of aluminum gallium arsenide in said lattice structure are substantially equally spaced.
Claim 17
Dependent Claim
24 words
An infrared detector as set forth in Claim 11 wherein said layers of aluminum gallium arsenide in said lattice structure are substantially equally spaced.
Claim 18
Dependent Claim
24 words
An infrared detector as set forth in Claim 12 wherein said layers of aluminum gallium arsenide in said lattice structure are substantially equally spaced.
Claim 19
Dependent Claim
24 words
An infrared detector as set forth in Claim 13 wherein said layers of aluminum gallium arsenide in said lattice structure are substantially equally spaced.
References Cited (Backward Citations)
No citation records indexed.
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