Shared amplifier pixel with matched coupling capacitances
View Patent ↗A method of making an image sensor, the method includes the steps of providing a plurality of pixels each with a photodetector; providing an amplifier that is shared between the plurality of photodetectors; providing a transfer gate associated with each photodetector; providing a charge-to-voltage conversion region that is shared between the plurality of photodetectors; determining a capacitance between each transfer gate and the charge-to-voltage conversion region; and modifying the capacitance to be substantially the same by altering a physical structure within one or more pixels.
1. A method of making an image sensor, the method comprising the steps of:
(a) providing a plurality of pixels each with a photodetector;
(b) providing an amplifier that is shared between the plurality of photodetectors;
(c) providing a transfer gate associated with each photodetector;
(d) providing a charge-to-voltage conversion region that is shared between the plurality of photodetectors;
(e) determining a capacitance between each transfer gate and the charge-to-voltage conversion region; and
(f) modifying the capacitance to be substantially the same by altering a physical structure within one or more pixels.
2. The method as in claim 1 wherein step (f) includes altering interconnects within one or more pixels.
3. The method as in claim 1 wherein step (f) includes altering a physical design of the one or more charge-to-voltage conversion regions.
4. The method as in claim 1 wherein step (f) includes altering a physical design of one or more transfer gates.
5. The method as in claim 1 further comprising the step of making a CMOS image sensor.
6. An image sensor comprising:
(a) a plurality of pixels each with a photodetector;
(b) an amplifier that is shared between the plurality of photodetectors;
(c) a transfer gate associated with each photodetector;
(d) a charge-to-voltage conversion region that is shared between the plurality of photodetectors; wherein a capacitance between each transfer gate and the charge-to-voltage conversion region is substantially the same.
7. The image sensor as in claim 6 further comprising interconnects that provide substantially matched capacitance.
8. The image sensor as in claim 6 , wherein the image sensor is a CMOS image sensor.
9. A digital camera comprising:
an image sensor comprising:
(a) a plurality of pixels each with a photodetector;
(b) an amplifier that is shared between the plurality of photodetectors;
(c) a transfer gate associated with each photodetector;
(d) a charge-to-voltage conversion region that is shared between the plurality of photodetectors; wherein a capacitance between each transfer gate and the charge-to-voltage conversion region is substantially the same.
10. The digital camera as in claim 9 further comprising interconnects that provide substantially matched capacitance.
11. The digital camera as in claim 9 , wherein the image sensor is a CMOS image sensor.