Method of fabricating sidewall charge-coupled device with trench isolation
First Claim
1. A method of fabricating a sidewall charge-coupled device with trench isolation comprising the steps of:
- providing a substrate of semiconductor material;
defining a plurality of isolation trenches in a surface of said substrate to form columns of charge coupled cells between the isolation trenches, said plurality of isolation trenches being formed to increase the surface areas of the charge coupled cells therebetween and facilitate transport of charges along the cell sidewalls;
disposing a plurality of alternating first and second sets of substantially parallel surface electrodes arranged in an overlapping electrode configuration over substantially the entire upper surface of the substrate extending substantially perpendicular to the isolation trenches, said plurality of alternating first and second sets of surface electrodes producing, by an applied electric field, an induced potential well in the substrate beneath each of the plurality of alternating first and second sets of surface electrodes, such that substantially the entire upper surface of the substrate and the sidewalls in common with the upper portions of the sidewalls of the isolation trenches produce photon to electron conversion in response to incident light; and
disposing a plurality of shallow trenches, shallow relative to the deeper isolation trenches, under the surface electrodes in each column of cells defined between adjacent isolation trenches to increase the charge carrying surface area and provide better gate control.
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Accused Products
Abstract
A charge-coupled imaging device comprising a plurality of trenches in the surface of the silicon substrate which separate adjacent columns in the CCD device. A plurality of surface electrodes are provided on the surface of the charge-coupled device extending perpendicular to the isolation trenches, which electrodes provide for clocked transfer of charges between adjacent cells within each column of the charge-coupled device. The CCD cells are formed on the silicon ridges delineated between the isolation trenches, and this structure maximizes the three dimensional surface area of the CCD cells and facilitates transport of charges along the CCD cell sidewalls. The sidewall CCD with trench isolation provides a CCD cell layout size the same as that of a conventional two dimensional CCD cell, but with an increased charge capacity per CCD cell because of the larger three dimensional areas of the CCD cells. The increase in charge capacity means a larger signal-to-noise ratio and consequently a larger dynamic range. In one embodiment, a plurality of shallow electrodes are defined under the surface electrodes to increase the charge carrying surface area and provide better gate control.
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Citations
4 Claims
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1. A method of fabricating a sidewall charge-coupled device with trench isolation comprising the steps of:
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providing a substrate of semiconductor material; defining a plurality of isolation trenches in a surface of said substrate to form columns of charge coupled cells between the isolation trenches, said plurality of isolation trenches being formed to increase the surface areas of the charge coupled cells therebetween and facilitate transport of charges along the cell sidewalls; disposing a plurality of alternating first and second sets of substantially parallel surface electrodes arranged in an overlapping electrode configuration over substantially the entire upper surface of the substrate extending substantially perpendicular to the isolation trenches, said plurality of alternating first and second sets of surface electrodes producing, by an applied electric field, an induced potential well in the substrate beneath each of the plurality of alternating first and second sets of surface electrodes, such that substantially the entire upper surface of the substrate and the sidewalls in common with the upper portions of the sidewalls of the isolation trenches produce photon to electron conversion in response to incident light; and disposing a plurality of shallow trenches, shallow relative to the deeper isolation trenches, under the surface electrodes in each column of cells defined between adjacent isolation trenches to increase the charge carrying surface area and provide better gate control. - View Dependent Claims (2, 3, 4)
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Specification