Imaging with gate controlled charge storage

1. A method of forming a pixel cell, the method comprising:

forming a photo-conversion device that generates charge;

forming a gate controlled charge storage region that stores the charge;

forming a control gate that controls the charge storage region;

forming a first transistor having its gate between the photo-conversion device and the charge storage region for transferring charge from the photo-conversion device to the charge storage region;

forming a sensing node; and

forming a second transistor gate of a second transistor between the charge storage region and the sensing node.

2. The method of claim 1 , wherein the act of forming the sensing node comprises forming a floating diffusion region.

3. The method of claim 1 , wherein the act of forming the control gate comprises forming the control gate at least partially overlapping the first and second transistor gates.

4. A method of forming a pixel cell, the method comprising:

forming a photo-conversion device for generating charge;

forming a doped region of a second conductivity type spaced apart from the photo-conversion device;

forming a doped surface layer of a first conductivity type over the doped region of a second conductivity type;

forming a gate of a first transistor between the photo-conversion device and the doped region of a second conductivity type;

forming a gate electrode over the doped surface layer;

forming a sensing node; and

forming a gate of a second transistor between the doped region of a second conductivity type and the sensing node.

5. The method of claim 4 , wherein the act of forming the gate electrode over the doped surface layer comprises forming the gate electrode overlapping the first and second transistor gates.

6. A method of operating an image sensor, the method comprising:

generating charge in response to incident light concurrently within a plurality of pixel cells during an integration time;

transferring the photo-generated charge to gate controlled charge storage regions within respective pixel cells simultaneously by operating gates of shutter transistors and operating control gates that control the charge storage regions;

storing the photo-generated charge in the charge storage regions until a time for readout by operating the control gates;

at a time for readout of a first pixel cell, transferring photo-generated charge from a first charge storage region to a first sensing node by operating a gate of an associated first transistor;

sampling a value of the first sensing node;

at a time for readout for a second pixel cell, transferring photo-generated charge from a second charge storage region to a second sensing node by operating a gate of an associated second transistor;

sampling a value of the second sensing node; and

processing the values to obtain an image.

7. The method of claim 6 , wherein the act of generating charge comprises generating charge within all pixel cells of an array concurrently.

8. The method of claim 7 , wherein the act of transferring the photo-generated charge to a plurality of storage regions comprises transferring the photo-generated charge to charge storage regions within all pixel cells of an array concurrently.