Tin oxide CCD imager
AssigneeTexas Instruments Incorporated
InventorsChang-Feng Wan, Yingsheng Tung, Steven N. Frank
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Abstract
A novel process for fabricating a CCD imager arrray (10) having a tin oxide electrode monolayer (18) is disclosed. The process includes a low pressure chemical vapor deposition step using tetramethyltin and oxygen, and an ion implantation step that increased conductivity of the tin oxide electrodes to as high as 700 ohm.sup.-1 cm.sup.-1.
Claims44
A charge coupled device array, comprising
- a semiconductor layer;
- a gate insulator layer formed on said semiconductor layer;
- a normally insulative layer formed on said gate insulator layer;
- a plurality of conductive electrodes defining at least one row of charge-coupled devices, all of said electrodes formed in said normally insulative layer and horizontally spaced by predetermined electrode gaps having a width between electrodes of no greater than about one micron, said electrodes and said gaps formed by selectively doping said normally insulative layer after said normally insulative layer is formed on said gate insulator layer.
An imager array having a plurality of charge coupled devices formed in a plurality of rows and in a plurality of columns disposed at an angle to said rows, comprising:
- a semiconductor substrate;
- a plurality of parallel elongate channel stop regions formed in said semiconductor substrate to define said rows of charge coupled devices therebetween;
- a transparent gate insulator layer formed on said substrate;
- a tin oxide layer formed on said gate insulator layer;
- a plurality of electrodes formed by selectively doping said tin oxide layer, an electrode provided for each one of said columns;
- said electrodes uniformly horizontally spaced from each other by electrode gaps having a predetermined width.
A method for manufacturing a charge-coupled device imager array, comprising the steps of:
- forming a transparent gate insulator layer on a semiconductor substrate;
- depositing a tin oxide layer on the gate insulator layer;
- selectively implanting the tin oxide with a dopant to form a plurality of spaced-apart conductive electrodes therein;
- and
- annealing the tin oxide layer.
A low-pressure chemical vapor deposition process for depositing a tin oxide film on a surface, comprising the steps of:
- placing at least one surface in a reactor chamber;
- mixing a minor proportion of tetramethyltin with a major proportion of oxygen to create a reactant gas mixture;
- introducing the reactant mixture into the chamber at a pressure ranging from 0.3 to 1.1 torr, a temperature ranging from about 450.degree. C. to about 550.degree. C. and a flux per unit reactor cross-sectional area from about 0.15 scm.sup.3 /cm.sup.2 -min to about 1.1 scm.sup.3 /cm.sup.2 -min;
- and
- depositing a film of tin oxide on the surface as a reaction product of the reactant mixture.
A process for reducing the sheet resistance of selected regions of a tin oxide layer, comprising the steps of:
- selecting an implantation dopant from the group consisting of phosphorus, arsenic, fluorine, boron difluoride, and boron;
- implanting the dopant into the regions at a dose selected from the range of about 1.times.10.sup.15 cm.sup.-2 to about 1.times.10.sup.16 cm.sup.-2, and an energy ranging from about 60 to about 195 keV;
- and
- annealing the regions under an annealing atmosphere at a temperature ranging from 600.degree. C. to 950.degree. C.
Dependencies are inferred from the claim text.