Photogate sensor with improved responsivity
First Claim
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1. A depleted-gate photosensor, comprising:
- a substrate comprising continuously-doped, single-crystal silicon, the substrate defining a main surface including an exposure area exposable to light;
an oxide layer disposed on the main surface of the substrate, the oxide layer defining a gap in the main surface of the substrate, the layer including oxide immediately adjacent the gap within the exposure areas, the gap being defined in only a portion of the exposure area;
a polysilicon layer disposed on the main surface, the polysilicon layer substantially covering the gap and extending over a portion of the exposure area and over a portion of the oxide layer immediately outside the gap; and
a gate oxide layer disposed between the substrate and the polysilicon layer within the gap.
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Abstract
A depleted-gate photosensor, or photogate, structure includes a polysilicon layer disposed over a silicon substrate. The polysilicon layer occupies only a portion of each exposure area of the substrate, and is preferably in the form of a ring around the exposure area. By having a portion of the exposure area not covered by the polysilicon, the blue-light-attenuation effects of a polysilicon layer are reduced.
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Citations
6 Claims
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1. A depleted-gate photosensor, comprising:
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a substrate comprising continuously-doped, single-crystal silicon, the substrate defining a main surface including an exposure area exposable to light; an oxide layer disposed on the main surface of the substrate, the oxide layer defining a gap in the main surface of the substrate, the layer including oxide immediately adjacent the gap within the exposure areas, the gap being defined in only a portion of the exposure area; a polysilicon layer disposed on the main surface, the polysilicon layer substantially covering the gap and extending over a portion of the exposure area and over a portion of the oxide layer immediately outside the gap; and a gate oxide layer disposed between the substrate and the polysilicon layer within the gap. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification