Fast flush structure for solid-state image sensors
View Patent ↗An image sensor includes a substrate; a plurality of pixels on the substrate, one or more of the pixels comprises (i) first and second charge-storage regions having at least one photosensitive area; (ii) a lateral overflow drain; (iii) a first lateral overflow gate adjacent the first charge-storage regions that passes substantially all charges from the first charge-storage region to the lateral overflow drain; and (iv) a second lateral gate adjacent the second charge-storage region that passes excess photo-generated charge into the lateral overflow drain for blooming control.
1. An image sensor comprising:
(a) a substrate;
(b) a plurality of pixels on the substrate, one or more of the pixels comprising:
(i) a first charge-storage region covered by a first electrode of a first electrode layer;
(ii) a second charge-storage region having at least one photosensitive area and covered by a second electrode of a second electrode layer;
(iii) a lateral overflow drain;
(iv) a fast flush gate formed of a third electrode and a third electrode layer and adjacent the second charge-storage region that passes substantially all charges from the second charge-storage region to the lateral overflow drain; and
(v) a lateral gate formed by a contiguous portion of the first electrode layer and adjacent the first charge-storage region that passes excess photo-generated charge into the lateral overflow drain for blooming control.
2. The image sensor as in claim 1 , wherein the first charge-storage region passes substantially all its charges to the second charge-storage region before the fast flush gate passes all charges to the lateral overflow drain.
3. A camera comprising:
an image sensor comprising:
(a) a substrate;
(b) a plurality of pixels on the substrate, one or more of the pixels comprising:
(i) a first charge-storage region covered by a first electrode of a first electrode layer;
(ii) a second charge-storage region having at least one photosensitive area and covered by a second electrode of a second electrode layer;
(iii) a lateral overflow drain;
(iv) a fast flush gate formed of a third electrode and a third electrode layer and adjacent the second charge-storage region that passes substantially all charges from the second charge-storage region to the lateral overflow drain; and
(v) a lateral gate formed by a contiguous portion of the first electrode layer and adjacent the first charge-storage region that passes excess photo-generated charge into the lateral overflow drain for blooming control.
4. The camera as in claim 3 , wherein the first charge-storage region passes all its charges to the second charge-storage region before the fast flush gate passes all charges to the lateral overflow drain.