US4681440A — High-sensitivity CID photometer/radiometer

Claim 1

Independent Claim 360 words

Apparatus for sensing at least the amplitude of incident optical radiation, comprising: a charge-injection device (CID) sensor having a single pixel, including (1) a drain potential well delimiting a photon-responsive area from which charge carriers, formed responsive to impingent photons of said optical radiation, can be collected, (2) a column potential well in which said carriers are collected, (3) a row potential well, and (4) a gate electrode positioned between said drain well and said column and row wells for respectively connecting and disconnecting said drain well and said column potential well responsive to respective first and second states of a gate signal to respectively allow and prevent removal of said charge carriers to said drain well from at least said column well; means for reducing the operating temperature of said CID sensor; sequencer means for first permanently removing charge carriers from said column and row potential wells at least via said drain well, in a charge removal time interval at the commencement of each of at least one optical radiation sensing time interval, and for then causing, for a predetermined number, on the order of 10,000, of cycles in each sensing time interval, charge carriers present in said column and row wells during each of said cycles to repeatedly and non-destructively move between said column and row wells in a predetermined manner; and means for converting a charge current, resulting from each of said charge carrier movement cycles, to a human-viewable display of the amplitude of said optical radiation incident upon said sensor, with a sensitivity of at least 10E-14 Watts/cm 2 , and comprising: (a) charge amplifier means for converting the charge current to the amplitude of a signal representative of the total charge then in said sensor pixel; (b) correlated double sampling means for providing an output signal in which is cancelled from the amplitude thereof contributions by portions of the total charge in said pixel not responsive to photons of said incident optical radiation; and (c) means for accumulating the amplitude of the correlated double sampling means output signal to provide, responsive to the completion of said predetermined number of charge movement cycles, said amplitude display.

Claim 2

Dependent Claim 360 words

Apparatus for sensing at least the amplitude of incident optical radiation, comprising: a charge-injection device (CID) sensor having a single pixel, including (1) a drain potential well delimiting a photon-responsive area from which charge carriers, formed responsive to impingent photons of said optical radiation, can be collected, (2) a column potential well in which said carriers are collected, (3) a row potential well, and (4) a gate electrode positioned between said drain well and said column and row wells for respectively connecting and disconnecting said drain well and said column potential well responsive to respective first and second states of a gate signal to respectively allow and prevent removal of said charge carriers to said drain well from at least said column well; means for reducing the operating temperature of said CID sensor; sequencer means for first permanently removing charge carriers from said column and row potential wells at least via said drain well, in a charge removal time interval at the commencement of each of at least one optical radiation sensing time interval, and for then causing, for a predetermined number, on the order of 10,000, of cycles in each sensing time interval, charge carriers present in said column and row wells during each of said cycles to repeatedly and non-destructively move between said column and row wells in a predetermined manner; and means for converting a charge current, resulting from each of said charge carrier movement cycles, to a human-viewable display of the amplitude of said optical radiation incident upon said sensor, with a sensitivity of at least 10E-14 Watts/cm 2 , and comprising: (a) charge amplifier means for converting the charge current to the amplitude of a signal representative of the total charge then in said sensor pixel; (b) correlated double sampling means for providing an output signal in which is cancelled from the amplitude thereof contributions by portions of the total charge in said pixel not responsive to photons of said incident optical radiation; and (c) means for accumulating the amplitude of the correlated double sampling means output signal to provide, responsive to the completion of said predetermined number of charge movement cycles, said amplitude display.

Claim 3

Dependent Claim 37 words

The apparatus of claim 1, wherein said sequencer means further provides all necessary sequences of signals to said sensor and all portions of said converting means, responsive to an externally-provided command to display the incident radiation value.

Claim 4

Dependent Claim 43 words

The apparatus of claim 1, wherein a sufficient number of charge carriers are left within at least one of said row and column potential wells, during each charge removal time interval, to substantially compensate for deleterious charge interface states existant within said sensor.

Claim 5

Dependent Claim 37 words

The apparatus of claim 3, wherein said sequencer means further provides all necessary sequences of signals to said sensor and all portions of said converting means, responsive to an externally-provided command to display the incident radiation value.

Claim 6

Dependent Claim 166 words

The apparatus of claim 1, wherein said sensor comprises: a substrate of a first conductivity-type semiconductor material, said substrate having a first surface; an epitaxial layer of a second conductivity-type, opposite in polarity to said first conductivity-type, of said semiconductor material, and having a surface opposite said substrate surface; a drain region formed adjacent to said epitaxial layer surface; first means for insulatively enclosing at least a portion of said layer surface and said drain region; means, juxtaposed with said epitaxial layer, with respect to said first enclosing means, for defining row and column electrodes so positioned as to be insulated from one another and to form connectable potential wells beneath said column and row electrodes, and for defining a gate electrode so positioned as to be insulated from the other electrodes and to cause a gate potential well to be temporarily establishable between at least a portion of the total column and row potential wells and a potential well formed adjacent to said drain region.

Claim 7

Dependent Claim 19 words

The apparatus of claim 5, further comprising second means for insulatively enclosing said column electrodes and said row electrodes.

Claim 8

Dependent Claim 32 words

The apparatus of claim 6, wherein said row and gate electrodes are fabricated substantailly co-planar with one another, in a plane spaced from another plane in which said column electrode is fabricated.

Claim 9

Dependent Claim 26 words

The apparatus of claim 7, further comprising third insulative means, acting in conjunction with said first and second insulating means, for completely enclosing said column electrode.

Claim 10

Dependent Claim 18 words

The apparatus of claim 5, wherein said gate electrode has at least one narrow and elongated finger portion.

Claim 11

Dependent Claim 61 words

The apparatus of claim 9, wherein said row electrode has a plurality of narrow elongated finger portions, with each different pair of row electrode finger portions being substantially parallel to, and insulated from, a different one of said at least one gate electrode finger portion, and with all of said row electrode finger portions being in electrical connection with one another.

Claim 12

Dependent Claim 30 words

The apparatus of claim 10, wherein the spacing distance between each adjacent pair of row electrode finger portions does not exceed the charge carrier diffusion length in said semiconductor material.

Claim 13

Dependent Claim 81 words

The apparatus of claim 10, wherein said collector electrode comprises a plurality of narrow finger portions elongated in a direction substantially transverse to the direction of elongation of the plurality of row electrode finger portions, each of said column electrode finger portions having a first end aligned with all other first ends and a second end aligned with all other second ends, and first and second common portions respectively connecting all of said first ends and all of said second ends.

Claim 14

Dependent Claim 30 words

The apparatus of claim 12, wherein the spacing distance between each adjacent pair of column electrode finger portions does not exceed the charge carrier diffusion length in said semiconductor material.

Claim 15

Dependent Claim 66 words

The apparatus of claim 5, wherein said epitaxial layer is maintained at a substantially zero potential; said row electrode is switched between a first magnitude of potential, with respect to a second potential magnitude substantially permanently provided to said column electrode, and a third potential of magnitude greater than the column electrode potential, to respectively move charge carriers into, and out of, said column potential well.

Claim 16

Dependent Claim 71 words

The apparatus of claim 14, wherein said sequencer means operates to switch the potential at said gate electrode between a value substantially equal to the potential at the epitaxial layer and a fourth potential value, greater than said third value, and only present at said gate electrode when substantial flow of charges is required from said column and row potential wells and into said drain region for removal from the sensor.

Claim 17

Dependent Claim 140 words

The apparatus of claim 1, wherein said sensor comprises: a substrate of a first conductivity-type bulk semiconductor material, said substrate having a first surface; a drain region formed adjacent to said first surface; first means for insulatively enclosing at least a portion of said first surface and said drain region; means, juxtaposed with said first surface, with respect to said first enclosing means, for defining row and column electrodes so positioned as to be insulated from one another and to form connectable potential wells beneath said column and row electrodes, and for defining a gate electrode so positioned as to be insulated from the other electrodes and to cause a gate potential well to be temporarily establishable between at least a portion of the total column and row potential wells and a potential well formed adjacent to said drain region.

Claim 18

Dependent Claim 19 words

The apparatus of claim 16, further comprising second means for insulatively enclosing said column electrodes and said row electrodes.

Claim 19

Dependent Claim 32 words

The apparatus of claim 17, wherein said row and gate electrodes are fabricated substantially co-planar with one another, in a plane spaced from another plane in which said column electrode is fabricated.

Claim 20

Dependent Claim 26 words

The apparatus of claim 18, further comprising third insulative means, acting in conjunction with said first and second insulating means, for completely enclosing said column electrode.

Claim 21

Dependent Claim 18 words

The apparatus of claim 16, wherein said gate electrode has at least one narrow and elongated finger portion.

Claim 22

Dependent Claim 61 words

The apparatus of claim 20, wherein said row electrode has a plurality of narrow elongated finger portions, with each different pair of row electrode finger portions being substantially parallel to, and insulated from, a different one of said at least one gate electrode finger portion, and with all of said row electrode finger portions being in electrical connection with one another.

Claim 23

Dependent Claim 30 words

The apparatus of claim 21, wherein the spacing distance between each adjacent pair of row electrode finger portions does not exceed the charge carrier diffusion length in said semiconductor material.

Claim 24

Dependent Claim 81 words

The apparatus of claim 21, wherein said collector electrode comprises a plurality of narrow finger portions elongated in a direction substantially transverse to the direction of elongation of the plurality of row electrode finger portions, each of said column electrode finger portions having a first end aligned with all other first ends and a second end aligned with all other second ends, and first and second common portions respectively connecting all of said first ends and all of said second ends.

Claim 25

Dependent Claim 31 words

The apparatus of claim 23, wherein the spacing distance between each adjacent pair of column electrode finger portions does not exceed the charge carrier diffusion length in said bulk semiconductor material.

Claim 26

Dependent Claim 56 words

The apparatus of claim 16, wherein said row electrode is switched between a first magnitude of potential, with respect to a second potential magnitude substantially permanently provided to said columm electrode, and a third potential of magnitude greater than the column electrode potential, to respectively move charge carriers into, and out of, said column potential well.

Claim 27

Dependent Claim 71 words

The apparatus of claim 25, wherein said sequencer means operates to switch the potential at said gate electrode between a value substantially equal to the potential of the bulk material and a fourth potential value, greater than said third value, and only present at said gate electrode when substantial flow of charges is required from said column and row potential wells and into said drain region for removal from the sensor.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-07-20	1991-01-19	1991-07-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-07-20	1995-01-19	1995-07-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-07-20	1999-01-19	1999-07-21	$7700.00	Window Closed / Lapsed

High-sensitivity CID photometer/radiometer

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