Apparatus for sensing radiation and providing electrical read out

Claim 2

A radiation sensing device comprising a substrate of semiconductor material of one conductivity type having a major surface, a first conducting member overlying a first portion of a region of said substrate adjacent said major surface and in insulating relationship therewith, a second conducting member overlying a second portion of said surface adjacent region of said substrate and in insulating relationship therewith, means for coupling said first and second portions of said surface adjacent region, a first voltage means for providing a first voltage between said first conducting member and said substrate to deplete said portion of majority charge carriers, a second voltage means for providing a second voltage between said second conducting member and said substrate to deplete said second portion of majority charge carriers, means for exposing said substrate to radiation whereby minority carriers generated in said portions are stored therein, means for collapsing said first voltage to cause charge stored in said first portion to flow into said second portion, means for collapsing said second voltage whereby charge stored in said second portion is injected therefrom, capacitive means in series circuit with the capacitor formed by said second conducting member and said substrate for integrating a first displacement current flow in said series circuit in response to the collapsing of said second voltage thereon, means forming a rectifying contact with said substrate for substantially collecting said injected minority carrier charge and removing it from said substrate without substantially altering the charge on said capacitive means, means for reestablishing said second voltage on said second conducting member whereby a second displacement current flows in said series circuit in response to the reestablishment of said second voltage, the time integrated first and second displacement current flows in said capacitive means constituting a measure of said stored charge.

Claim 3

The device of claim 1 in which said means for collecting includes a region of opposite conductivity type in said surface adjacent region of said substrate spaced from both of said portions of said surface adjacent region of one conductivity type and adjacent to said second portion of said surface adjacent region.

Claim 4

The combination of claim 2 in which said region of opposite conductivity type is adjacent to both of said portions of said surface adjacent region of one conductivity type.

Claim 5

The device of claim 2 including means for conductively connecting said region of opposite conductivity type to said substrate to deplete mobile carriers from the vicinity of the PN junction formed between said region of opposite conductivity and said substrate.

Claim 6

The device of claim 4 in which said connecting means is non-rectifying connection between said region of opposite conductivity type and said substrate.

Claim 7

The device of claim 4 in which said connecting means is a source of voltage for reversely biasing said PN juntion.

Claim 8

The device of claim 1 in which said substrate of one conductivity type has high resistivity and said region of opposite conductivity type has low resistivity.

Claim 9

The device of claim 1 in which said substrate is of N-type conductivity and region of opposite conductivity type is P-type.

Claim 10

The device of claim 1 in which said conducting members are transparent and said major surface is adapted to receive radiation.

Claim 11

The device of claim 1 in which said substrate has a surface opposed to said major surface and adapted to receive radiation, said opposed surface being closely spaced to said major surface.

Claim 12

The device of claim 2 in which said region of opposite conductivity type is spaced a predetermined from said second portion substantially less than a diffusion length of minority carriers in said substrate of one conductivity type.

Claim 13

The device of claim 11 in which said predetermined distance is substantially less than the thickness of said substrate.

Claim 14

Apparatus for storing electrical charge in a surface adjacent portion of a substrate of semiconductor material in response to radiation and for providing a read out of the stored charge comprising means including a conducting member in insulating relationship to said substrate for establishing a potential well in said surface adjacent portion of said substrate, means for exposing said surface adjacent portion of said substrate to radiation to generate minority carriers therein, said minority carriers being stored in said potential well, means for reducing the magnitude of said potential well to inject said stored minority carrier charge therefrom into said substrate, capacitive means in series circuit with the capacitor formed by said conducting member and said substrate for integrating a first displacement current flow in said series circuit in response to the reduction of the magnitude of said potential well, means forming a rectifying contact with said substrate for substantially collecting said injected minority carrier charge and removing it from said substrate without substantially altering the charge on said capacitive means, means for reestablishing the original magnitude of said potential well whereby a second displacement current flows in said series circuit in response to the reestablishment of the original magnitude of said potential well, the time integrated first and second displacement current flows in said capacitance means constituting a measure of said stored minority carrier charge.

Claim 15

Apparatus for storing electrical charge in a surface adjacent portion of a substrate of semiconductor material in response to radiation and for providing a read out of the stored charge comprising means including a conducting member in insulating relationship to said substrate for establishing a potential well in said surface adjacent portion of said substrate, means for exposing said surface adjacent portion of said substrate to radiation to generate minority carriers therein, said minority carriers being stored in said potential well, means for reducing the magnitude of said potential well to inject said stored minority carrier charge therefrom into said substrate, capacitive means in series circuit with the capacitor formed by said conducting member and said substrate for integrating a first displacement current flow in said series circuit in response to the reduction of the magnitude of said potential well, means forming a rectifying contact with said substrate for substantially collecting said injected minority carrier charge and removing it from said substrate without substantially altering the charge on said capacitive means, means for reestablishing the original magnitude of said potential well whereby a second displacement current flows in said series circuit in response to the reestablishment of the original magnitude of said potential well, the time integrated first and second displacement current flows in said capacitance means constituting a measure of said stored minority carrier charge.

Claim 16

In combination, a substrate of semiconductor material of one conductivity type having a major surface, a plurality of first conductive plates, each overlying and in insulating relationship to said major surface and forming a first conductor-insulator-semiconductor capacitor with said substrate, a plurality of second conductive plates, each adjacent a respective first conductive plate to form a plurality of pairs of plates, said pairs of plates being arranged in a matrix of rows and columns, each of said second conductive plates overlying and in insulating relationship to said major surface and forming a second conductor-insulator-semiconductor capacitor with said substrate, each coupled to a respective first conductor-insulator-semiconductor capacitor, a plurality of column conductor lines, the first conductive plates in each of said columns connected to a respective column conductor line, a plurality of row conductor lines, the second conductive plates in each of said rows connected to a respective row conductor line, a first voltage means for providing a first voltage between said first conducting plates and said substrate to deplete respective first portions of said substrate lying thereunder of majority charge carriers, a second voltage means for providing a second voltage between said second conducting plates and said substrate to deplete respective second portions of said substrate lying thereunder of majority charge carriers, means for exposing said substrate to radiation whereby charge is stored in said first and second portions of said substrate, first means for collapsing and reestablishing said first voltage on each of said row conductor lines in sequence during a respective period of time, second means for collapsing and reestablishing said second voltage on each of said column conductor lines in sequence during a respective other period of time shorter than said one period of time and included in said one period whereby charges in said second portion are injected in sequence into said substrate, a capacitor and said second voltage means in series circuit between said column conductor lines and said substrate, means for short circuiting said capacitor at times other than said other periods of time whereby each pair of first and second displacement current flows through said capacitor corresponding to collapsing and reestablishing said second voltage on a respective column conductor line produces a respective net voltage on said capacitor, each net voltage corresponding to a respective quantity of charge injected into said substrate, adjacent said second portions for collecting the injected charge carriers without substantially altering the charge on said capacitor whereby upon reestablishment of said second voltage in sequence on said column conductor lines said injected minority carriers are not substantially recollected in said second portions of said substrate.

Claim 17

In combination, a substrate of semiconductor material of one conductivity type having a major surface, a plurality of first conductive plates, each overlying and in insulating relationship to said major surface and forming a first conductor-insulator-semiconductor capacitor with said substrate, a plurality of second conductive plates, each adjacent a respective first conductive plate to form a plurality of pairs of plates, said pairs of plates being arranged in a matrix of rows and columns, each of said second conductive plates overlying and in insulating relationship to said major surface and forming a second conductor-insulator-semiconductor capacitor with said substrate, each coupled to a respective first conductor-insulator-semiconductor capacitor, a plurality of column conductor lines, the first conductive plates in each of said columns connected to a respective column conductor line, a plurality of row conductor lines, the second conductive plates in each of said rows connected to a respective row conductor line, a first voltage means for providing a first voltage between said first conducting plates and said substrate to deplete respective first portions of said substrate lying thereunder of majority charge carriers, a second voltage means for providing a second voltage between said second conducting plates and said substrate to deplete respective second portions of said substrate lying thereunder of majority charge carriers, means for exposing said substrate to radiation whereby charge is stored in said first and second portions of said substrate, first means for collapsing and reestablishing said first voltage on each of said row conductor lines in sequence during a respective period of time, second means for collapsing and reestablishing said second voltage on each of said column conductor lines in sequence during a respective other period of time shorter than said one period of time and included in said one period whereby charges in said second portion are injected in sequence into said substrate, a capacitor and said second voltage means in series circuit between said column conductor lines and said substrate, means for short circuiting said capacitor at times other than said other periods of time whereby each pair of first and second displacement current flows through said capacitor corresponding to collapsing and reestablishing said second voltage on a respective column conductor line produces a respective net voltage on said capacitor, each net voltage corresponding to a respective quantity of charge injected into said substrate, adjacent said second portions for collecting the injected charge carriers without substantially altering the charge on said capacitor whereby upon reestablishment of said second voltage in sequence on said column conductor lines said injected minority carriers are not substantially recollected in said second portions of said substrate.