Photodiode having transparent insulating film around gate islands above P-N junction
AssigneeIntel Corporation
InventorsJung S Kang, James E Breisch
Life of this patent
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Abstract
An embodiment of the invention is directed to a semiconductor photodiode made of a number of gate islands being spaced from each other and electrically insulated from each other by spacers. The spacers are formed above a p-n junction of the photodiode. The incident light is detected after it passes through the spacers and into a photosensitive region of the photodiode. The photodiode can be built using conventional metal oxide semiconductor (MOS) processes of the polysilicon-silicided gate or self-aligned types that use a lower doped drain (LDD) structure, without requiring an additional mask step that prevents the formation of the opaque silicide above the photosensitive semiconductor regions.
Claims9
A method for building a sensor array, comprising:
- placing a first semiconductor layer above a first region of semiconductor material, the first region having a first conductivity type;
- patterning the first semiconductor layer as part of a gate formation step in a metal-oxide-semiconductor (MOS) fabrication process used to form a plurality of field effect transistor gates, to yield a plurality of gate islands that are spaced sufficiently close to each other as to prevent the formation of a transistor at each gate island;
- forming a second region of semiconductor material in the first region as part of a source/drain formation step in the MOS process, the second region having a second conductivity type, a p-n junction of a photodiode being formed between the first and second regions;
- placing an insulating layer over the first semiconductor layer and the second region;
- removing a portion of the insulating layer to expose the first semiconductor layer;
- placing a conducting layer over the first semiconductor layer and the insulating layer;
- and
- removing a portion of the conducting layer to expose the insulating layer and allow incident light to pass through the insulating region and reach a photosensitive region of the photodiode in the first region.
Dependencies are inferred from the claim text.