US4593304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heterostructure interdigital high speed photoconductive detector
Assignee: The AT&T MVPD Group LLC
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Filing: 1984-02-27
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Granted: 1986-06-03
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Expires: 2004-02-27
Abstract
Abstract A high speed photoconductive detector is disclosed which comprises two interdigital electrically conducting electrodes formed on a photoconductive layer. The device speed and sensitivity are improved by using a double-heterostructure configuration comprising an active layer formed on an isolation layer in turn formed on a supporting substrate. A passivation layer is formed on the active layer. This configuration confines the generated carriers to the active layer. Consequently, current will be induced under optical illumination due to photo-carrier generation. This interdigitated geometry allows for a large device cross-section and small carrier transit distance.
Inventors
- 👤 Charles W. Slayman
- 👤 Luis Figueroa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:03
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/20; H10F30/00; H10F30/10; H10F77/30; H10F77/306
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
120 words
A high speed conductive detector responsive to incident optical radiation comprising: (a) a substrate of semiconductor material; (b) an isolation layer of semiconductor material formed on at least a portion of said substrate; (c) an active layer of semiconductor material having a bandgap less than that of said semiconductor material comprising said isolation layer and supported on said isolation layer; and (d) a pair of interdigited electrically conducting electrodes formed on a portion of the surface of said active layer so as to be in non-blocking contact therewith, at least one of said electrodes forming a Schottky-barrier contact with said active layer, the thickness of said active layer being approximately equal to or less than the spacing between said electrodes.
Claim 2
Dependent Claim
120 words
A high speed conductive detector responsive to incident optical radiation comprising: (a) a substrate of semiconductor material; (b) an isolation layer of semiconductor material formed on at least a portion of said substrate; (c) an active layer of semiconductor material having a bandgap less than that of said semiconductor material comprising said isolation layer and supported on said isolation layer; and (d) a pair of interdigited electrically conducting electrodes formed on a portion of the surface of said active layer so as to be in non-blocking contact therewith, at least one of said electrodes forming a Schottky-barrier contact with said active layer, the thickness of said active layer being approximately equal to or less than the spacing between said electrodes.
Claim 3
Dependent Claim
16 words
The detector of claim 1 further comprising means for applying a bias to said conducting electrodes.
Claim 4
Dependent Claim
12 words
The detector of claim 1 in which said substrate comprises semi-insulating material.
Claim 5
Dependent Claim
22 words
The detector of claim 1 in which said semiconductor material is selected from the group consisting of III-V and II-VI semiconductor material.
Claim 6
Dependent Claim
82 words
The detector of claim 4 comprising: (a) a substrate of III-V semi-insulating material; (b) an isolation layer of III-V material formed on at least a portion of said substrate; (c) an active layer of III-V material supported on said isolation layer; (d) a pair of interdigitated electrically conducting electrodes formed on a portion of the surface of said active layer; and (e) a passivation layer of III-V material formed on at least portions of said active layer exposed by said interdigitated electrodes.
Claim 7
Dependent Claim
105 words
The detector of claim 5 comprising: (a) a semi-insulating substrate of chromium-doped GaAs; (b) an isolation layer of undoped Al x Ga l-x As, where x ranges from about 0.37 to 0.85, ranging in thickness from about 1 to 10 μm; (c) an active layer of undoped GaAs, ranging in thickness from about 1.5 to 6 μm; (d) a pair of interdigitated electrically conducting electrodes formed on a portion of the surface of said active layer; and (e) a passivation layer of undoped Al y Ga l-y As, where y ranges from about 0.37 to 0.85, ranging in thickness from about 0.2 to 0.5 μm.
Claim 8
Dependent Claim
92 words
The detector of claim 5 comprising: (a) a semi-insulating substrate of iron-doped InP; (b) an isolation layer of undoped InP ranging in thickness from about 1 to 10 μm; (c) an active layer of undoped (In,Ga)As having a composition which is lattice-matched to the lattice of said isolation layer and ranging in thickness from about 1.5 to 6 μm; (d) a pair of interdigitated electrically conducting electrodes formed on a portion of said active layer; and (e) a passivation layer of undoped InP ranging in thickness from about 0.2 to 0.5 μm.
Claim 9
Dependent Claim
82 words
The detector of claim 4 comprising: (a) a substrate of II-VI semi-insulating material; (b) an isolation layer of II-VI material formed on at least a portion of said substrate; (c) an active layer of II-VI material supported on said isolation layer; (d) a pair of interdigitated electrically conducting electrodes formed on a portion of the surface of said active layer; and (e) a passivating layer of II-VI material formed on at least portions of said active layer exposed by said interdigitated electrodes.
Claim 10
Dependent Claim
63 words
The detector of claim 8 comprising: (a) a semi-insulating substrate of PbTe; (b) an isolation layer of undoped PbTe; (c) an active layer of undoped (Pb,Sn)Te having a composition which is lattice-matched to the lattice of said isolation layer; (d) a pair of interdigitated electrically conducting electrodes formed on a portion of said active layers; and (e) a passivation layer of undoped PbTe.
Claim 11
Dependent Claim
22 words
The detector of claim 1 in which the spacing between each finger of said interdigitated electrodes is less than about 5 μm.
Claim 12
Dependent Claim
15 words
The detector of claim 1 further comprising a microstrip transmission line connected to each electrode.
Claim 13
Dependent Claim
14 words
The detector of claim 1 in which said electrically conducting electrodes comprise a metal.
Claim 14
Dependent Claim
19 words
The detector of claim 12 in which said metal is selected from the group consisting of aluminum and gold.
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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) | 1989-06-02 | 1989-12-02 | 1990-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-02 | 1993-12-02 | 1994-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-02 | 1997-12-02 | 1998-06-03 | $7700.00 | Window Closed / Lapsed |