Buried channel charge coupled devices

Claim 2

A charge coupled device comprising: a planar charge storage medium; a multiplicity of discrete electrode field plates arranged adjacent to the charge storage medium, each capable when electrically biased of forming an associated charge storage site within the charge storage medium, the field plates being spaced sequentially in a direction parallel to the plane of the charge storage medium with each adjacent to at least two other field plates so that, with appropriate electrical bias applied to at least two of said field plates, electrical charge can be made to pass controllably between selected charge storage sites and ultimately to a detection site; input means for introducing mobile electrical charge into the charge storage medium; detection means for detecting the presence or absence of charge in the storage medium at a detection site; charge transfer means including said field plates for transferring within the storage medium, the electrical charge between storage sites, and to the detection site; the invention characterized in that the storage medium is bounded on all sides with electrical barriers except for a limited area, ohmic contact means to the storage medium at said limited area for electrically biasing the storage medium with respect to said barriers to deplete the storage medium and, with the electrical bias applied to the field plates, to create potential minima for the stored electrical charge, the potential minima existing physically within the storage medium, interior of the boundary electrical barriers whereby said charge storage sites exist physically within said interior.

Claim 3

The device of claim 1 in which the storage medium is silicon.

Claim 4

The device of claim 1 further including an insulating layer overlying the field plates, a conductive layer on the insulating layer, and electrode means independent of the field plates adapted for biasing the conductive layer.

Claim 5

A charge coupled device comprising: a planar semiconductor charge storage medium of a single conductivity type; a multiplicity of discrete electrode field plates arranged adjacent to the charge storage medium, each capable when electrically biased of forming an associated charge storage site within the charge storage medium, the field plates being spaced sequentially in a direction parallel to the plane of the charge storage medium with each adjacent to at least two other field plates so that, with appropriate electrical bias applied to at least two of said field plates, electrical charge can be made to pass controllably between selected charge storage sites and ultimately to a detection site; input means for introducing mobile electrical charge into the charge storage medium; detection means for detecting the presence or absence of charge in the storage medium at a detection site; charge transfer means including said field plates for transferring within the storage medium, the electrical charge between storage sites, and to the detection site; the invention characterized in that the storage medium is bounded on one major surface by a semiconducting isolating layer of the opposite conductivity type and on the other major surface by an insulating isolating layer with the multiplicity of electrode field plates situated on the iNsulating layer, and ohmic contact means to the storage medium for biasing the storage medium with respect to the isolating layers to deplete the storage medium and, with the electrical bias applied to the field plates, to create potential minima for the stored electrical charge, the potential minima existing physically within the storage medium interior of the boundary electrical barriers whereby said charge storage sites exist physically within said interior.

Claim 6

A charge coupled device comprising: a planar semiconductor charge storage medium of a single conductivity type; a multiplicity of discrete electrode field plates arranged adjacent to the charge storage medium, each capable when electrically biased of forming an associated charge storage site within the charge storage medium, the field plates being spaced sequentially in a direction parallel to the plane of the charge storage medium with each adjacent to at least two other field plates so that, with appropriate electrical bias applied to at least two of said field plates, electrical charge can be made to pass controllably between selected charge storage sites and ultimately to a detection site; input means for introducing mobile electrical charge into the charge storage medium; detection means for detecting the presence or absence of charge in the storage medium at a detection site; charge transfer means including said field plates for transferring within the storage medium, the electrical charge between storage sites, and to the detection site; the invention characterized in that the storage medium is bounded on one major surface by a semiconducting isolating layer of the opposite conductivity type and on the other major surface by an insulating isolating layer with the multiplicity of electrode field plates situated on the iNsulating layer, and ohmic contact means to the storage medium for biasing the storage medium with respect to the isolating layers to deplete the storage medium and, with the electrical bias applied to the field plates, to create potential minima for the stored electrical charge, the potential minima existing physically within the storage medium interior of the boundary electrical barriers whereby said charge storage sites exist physically within said interior.

Claim 7

The charge coupled device of claim 4 in which the planar storage medium is a p-type semiconductor and the input means is adapted for introducing mobile positive charge into the charge storage medium.

Claim 8

The charge coupled device of claim 4 in which the planar storage medium is an n-type semiconductor and the input means is adapted for introducing mobile negative charge into the charge storage medium.

Claim 9

The device of claim 4 in which the bias applied to the storage medium creates an abundance of free energy states within said medium, having average energies different from those of the states at the boundaries by an amount greater than kT, where k is Boltzmann''s constant and T is the temperature, said free energy states being located at a distance W within the semiconductor storage medium as measured from the surface of the insulating layer satisfying the following relationship: 1/100 < W/xp < 10 where Xp is the average width of the field plates.

Claim 10

The device of claim 7 in which the semiconductor storage medium has a doping density satisfying the following relationship:

Claim 11

A charge coupled storage device comprising: a first semiconductor storage layer of a first conductivity type bounded on both major surfaces by a semiconductor isolating layer of a second conductivity type, an insulating layer covering one of said isolating layers, a plurality of charge coupled drive electrodes situated on said insulating layer, electrode means adapted for biasing said storage layer with respect to said isolating layers, means adapted for facilitating the introduction of free charge carriers into said storage layer in accordance with input information, and means for detecting the presence or absence in the storage layer of said free charge carriers.

Claim 12

A charge coupled storage device comprising: a first semiconductor storage layer of a first conductivity type bounded on both major surfaces by a semiconductor isolating layer of a second conductivity type, an insulating layer covering one of said isolating layers, a plurality of charge coupled drive electrodes situated on said insulating layer, electrode means adapted for biasing said storage layer with respect to said isolating layers, means adapted for facilitating the introduction of free charge carriers into said storage layer in accordance with input information, and means for detecting the presence or absence in the storage layer of said free charge carriers.

Claim 13

The charge coupled device of claim 9 further including a second semiconductor storage layer bounded on each major surface by a semiconductor isolating layer, means for biasing said second storage layer with respect to its boundary isolating layers and means for controllably introducing free charge carriers into said second storage layer.

Claim 14

The charge coupled device of claim 10 further including means for interconnecting said first and second storage layers.