US3703669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photocurrent cross talk isolation
Assignee: Motorola Solutions Inc
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Filing: 1971-08-12
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Granted: 1972-11-21
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Expires: 1991-08-12
Abstract
Abstract A monolithic photoresponsive array having a plurality of spacedapart photocurrent collecting regions (photocells) extending into a semiconductor substrate from one major surface. Cross talk caused by lateral flowing of photocurrents between the various photocurrent collecting regions is substantially decreased (such decrease termed photocurrent isolation) by establishing a concentration of minority carriers effectively intermediate the photocurrent collecting regions which is substantially lower than the minority carrier concentration of the semiconductor material in which such photocurrents are flowing. In one embodiment, a region having the same conductivity type as the various photocurrent collecting regions is disposed between adjacent ones thereof and is short-circuited to the substrate such that the minority carrier concentration adjacent the shorted junction is equal to the thermal equilibrium minority carrier concentration. Such photocurrent isolation may be provided within islands of an integrated circuit die or chip having a plurality of such photocurrent collecting regions. Groups of such photocurrent collecting regions may be electrically isolated as by dielectric isolation or through junction isolation.
Inventors
- 👤 Arnold London
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:55
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/80; H10F39/807; H10W; H10W10/00; H10W10/01; H10W10/031; H10W10/30; Y; Y10; Y10S; Y10S148/00; Y10S148/049; Y10S148/085
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
287 words
A radiation responsive monolithic device, including the combination: a first conductivity type monocrystalline semiconductive layer continuously electrically conductive throughout and having first and second oppositely facing major surfaces and a given minority carrier concentration; a plurality of closely packed photocurrent collecting regions extending into said layer from said first major surface and having monocrystalline semiconductive material of a conductivity type opposite to said first conductivity type, and each region having a rectifying junction with said layer; said semiconductive material in said layer being responsive to radiation penetrating therein to have minority carriers energized to a migration state, said minority carriers in said migration state being capable of lateral migration from adjacent one of said photocurrent collecting regions to another of said photocurrent collecting regions, said migration capable of causing a cross talk photocurrent in said another photocurrent collecting region; and minority carrier concentration means effectively interposed between adjacent ones of said photocurrent collecting regions, said minority carrier concentration means including auxiliary regions of semiconductive material of a type opposite said first type extending into said layer between said photocurrent collection regions so as to form rectifying junctions therebetween, and said concentration means further including means for electrically shorting said auxiliary regions to said layer such that said electrical shorting means maintains zero biases at said last mentioned rectifying junctions and a low minority carrier concentration at said auxiliary regions so as to trap and hold minority carriers migrating laterally to said auxiliary regions, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary regions and the regions immediately adjacent thereto, wherebY said circulating current flow is confined to regions immediately adjacent said auxiliary regions, thereby effectively isolating said flow from said photocurrent regions.
Claim 2
Dependent Claim
287 words
A radiation responsive monolithic device, including the combination: a first conductivity type monocrystalline semiconductive layer continuously electrically conductive throughout and having first and second oppositely facing major surfaces and a given minority carrier concentration; a plurality of closely packed photocurrent collecting regions extending into said layer from said first major surface and having monocrystalline semiconductive material of a conductivity type opposite to said first conductivity type, and each region having a rectifying junction with said layer; said semiconductive material in said layer being responsive to radiation penetrating therein to have minority carriers energized to a migration state, said minority carriers in said migration state being capable of lateral migration from adjacent one of said photocurrent collecting regions to another of said photocurrent collecting regions, said migration capable of causing a cross talk photocurrent in said another photocurrent collecting region; and minority carrier concentration means effectively interposed between adjacent ones of said photocurrent collecting regions, said minority carrier concentration means including auxiliary regions of semiconductive material of a type opposite said first type extending into said layer between said photocurrent collection regions so as to form rectifying junctions therebetween, and said concentration means further including means for electrically shorting said auxiliary regions to said layer such that said electrical shorting means maintains zero biases at said last mentioned rectifying junctions and a low minority carrier concentration at said auxiliary regions so as to trap and hold minority carriers migrating laterally to said auxiliary regions, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary regions and the regions immediately adjacent thereto, wherebY said circulating current flow is confined to regions immediately adjacent said auxiliary regions, thereby effectively isolating said flow from said photocurrent regions.
Claim 3
Dependent Claim
287 words
A radiation responsive monolithic device, including the combination: a first conductivity type monocrystalline semiconductive layer continuously electrically conductive throughout and having first and second oppositely facing major surfaces and a given minority carrier concentration; a plurality of closely packed photocurrent collecting regions extending into said layer from said first major surface and having monocrystalline semiconductive material of a conductivity type opposite to said first conductivity type, and each region having a rectifying junction with said layer; said semiconductive material in said layer being responsive to radiation penetrating therein to have minority carriers energized to a migration state, said minority carriers in said migration state being capable of lateral migration from adjacent one of said photocurrent collecting regions to another of said photocurrent collecting regions, said migration capable of causing a cross talk photocurrent in said another photocurrent collecting region; and minority carrier concentration means effectively interposed between adjacent ones of said photocurrent collecting regions, said minority carrier concentration means including auxiliary regions of semiconductive material of a type opposite said first type extending into said layer between said photocurrent collection regions so as to form rectifying junctions therebetween, and said concentration means further including means for electrically shorting said auxiliary regions to said layer such that said electrical shorting means maintains zero biases at said last mentioned rectifying junctions and a low minority carrier concentration at said auxiliary regions so as to trap and hold minority carriers migrating laterally to said auxiliary regions, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary regions and the regions immediately adjacent thereto, wherebY said circulating current flow is confined to regions immediately adjacent said auxiliary regions, thereby effectively isolating said flow from said photocurrent regions.
Claim 4
Dependent Claim
287 words
A radiation responsive monolithic device, including the combination: a first conductivity type monocrystalline semiconductive layer continuously electrically conductive throughout and having first and second oppositely facing major surfaces and a given minority carrier concentration; a plurality of closely packed photocurrent collecting regions extending into said layer from said first major surface and having monocrystalline semiconductive material of a conductivity type opposite to said first conductivity type, and each region having a rectifying junction with said layer; said semiconductive material in said layer being responsive to radiation penetrating therein to have minority carriers energized to a migration state, said minority carriers in said migration state being capable of lateral migration from adjacent one of said photocurrent collecting regions to another of said photocurrent collecting regions, said migration capable of causing a cross talk photocurrent in said another photocurrent collecting region; and minority carrier concentration means effectively interposed between adjacent ones of said photocurrent collecting regions, said minority carrier concentration means including auxiliary regions of semiconductive material of a type opposite said first type extending into said layer between said photocurrent collection regions so as to form rectifying junctions therebetween, and said concentration means further including means for electrically shorting said auxiliary regions to said layer such that said electrical shorting means maintains zero biases at said last mentioned rectifying junctions and a low minority carrier concentration at said auxiliary regions so as to trap and hold minority carriers migrating laterally to said auxiliary regions, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary regions and the regions immediately adjacent thereto, wherebY said circulating current flow is confined to regions immediately adjacent said auxiliary regions, thereby effectively isolating said flow from said photocurrent regions.
Claim 5
Dependent Claim
39 words
The subject matter of claim 1 wherein said minority carrier concentration means establishes a minority carrier concentration between said spaced-apart photocurrent collecting regions approximately equal to the thermal equilibrium minority carrier concentration of the semiconductive material in said layer.
Claim 6
Dependent Claim
90 words
The subject matter of claim 1 wherein adjacent ones of said photocurrent collecting regions have a given length along a first direction and being spaced apart a given distance transverse to said first direction; said auxiliary region disposed between said adjacent ones of said spaced-apart photocurrent collecting regions having a length along said first direction greater than said given length such that said auxiliary region extends beyond said adjacent ones of said spaced-apart photocurrent collecting regions and having a dimension transverse to said first direction less than said given distance.
Claim 7
Dependent Claim
35 words
The subject matter of claim 3 wherein said auxiliary region extends into said layer from said first major surface a depth approximately the same depth as said spaced-apart photocurrent collecting regions extend into said layer.
Claim 8
Dependent Claim
72 words
The subject matter of claim 3 wherein said layer has an outwardly opening groove in said first major surface extending in said first direction between each adjacent ones of said spaced-apart photocurrent collecting regions; said auxiliary regions extending into said layer from the bottom of said groove such that depth of penetration of said auxiliary region into said layer is greater than the depth of penetration of said spaced-apart photocurrent collecting regions.
Claim 9
Dependent Claim
138 words
The subject matter of claim 3 further including a layer of said opposite conductivity type monocrystalline material contiguous with said second major surface; said spaced-apart photocurrent collecting regions being formed in rows and columns; said rows extending along said first direction and columns of said spaced-apart photocurrent collecting regions extending transversely to said first direction; an elongated pillar of said opposite conductivity type semiconductive material extending from said second layer of said first major surface between each of said adjacent columns of said spaced-apart photocurrent collecting regions such that each column is electrically isolated from each and every other column to provide a plurality of said first layers, one said first layer in each column of said array; and said auxiliary regions being disposed between adjacent ones of said photocurrent collecting regions in each of said respective columns.
Claim 10
Dependent Claim
25 words
The subject matter of claim 3 wherein an auxiliary region extends completely around but spaced from at least one of said spaced-apart photocurrent collecting regions.
Claim 11
Dependent Claim
20 words
The subject matter of claim 3 wherein the distance between adjacent spaced-apart photocurrent collecting regions is less than 1.5 mils.
Claim 12
Dependent Claim
275 words
A photoresponsive semiconductor device, including the combination: a first region of first conductivity type monocrystalline semiconductive material having a resistivity greater than one ohm-centimeter with a given diffusion length and having minority carriers excitable to a migration state by radiation penetrating said region and having a first major surface; a photocurrent collecting region extending into said first region from said first major surface and having a second conductivity type monocrystalline semiconductive material with a rectifying junction between said first and photocurrent collecting regions, said junction adapted to collect minority carriers from said first region which are in said migration state; and an auxiliary region of said second conductivity type extending into said first region from said first major surface and spaced on said first major surface from said photocurrent colLecting region substantially less than said given diffusion length and having an electrical connection to said first region for maintaining said auxiliary region biased at approximately the same potential as said first region such that minority carriers in said migration state in said first region approaching said photocurrent collecting region but disposed closer to said auxiliary region than said photocurrent collection region tend to reach said auxiliary region rather than said photocurrent collecting region because said biasing maintains a low minority carrier concentration at said auxiliary region so as to trap and hold minority carriers migrating laterally to said auxiliary region, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary region, said circulating flow being confined to regions immediately adjacent said auxiliary region, whereby said circulating flow is effectively isolated from and has a minimal effect on said photocurrent collecting region.
Claim 13
Dependent Claim
275 words
A photoresponsive semiconductor device, including the combination: a first region of first conductivity type monocrystalline semiconductive material having a resistivity greater than one ohm-centimeter with a given diffusion length and having minority carriers excitable to a migration state by radiation penetrating said region and having a first major surface; a photocurrent collecting region extending into said first region from said first major surface and having a second conductivity type monocrystalline semiconductive material with a rectifying junction between said first and photocurrent collecting regions, said junction adapted to collect minority carriers from said first region which are in said migration state; and an auxiliary region of said second conductivity type extending into said first region from said first major surface and spaced on said first major surface from said photocurrent colLecting region substantially less than said given diffusion length and having an electrical connection to said first region for maintaining said auxiliary region biased at approximately the same potential as said first region such that minority carriers in said migration state in said first region approaching said photocurrent collecting region but disposed closer to said auxiliary region than said photocurrent collection region tend to reach said auxiliary region rather than said photocurrent collecting region because said biasing maintains a low minority carrier concentration at said auxiliary region so as to trap and hold minority carriers migrating laterally to said auxiliary region, thereby changing the lateral minority carrier flow to a circulating flow through said auxiliary region, said circulating flow being confined to regions immediately adjacent said auxiliary region, whereby said circulating flow is effectively isolated from and has a minimal effect on said photocurrent collecting region.
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) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |