Imaging pixels with a fully depleted charge transfer path

A method of operating an imaging pixel, wherein the imaging pixel comprises a pinned photodiode, a first pinned transfer diode, a second pinned transfer diode, an interconnect layer that couples the first pinned transfer diode to the second pinned transfer diode, a storage diode, a floating diffusion region, a first transfer transistor coupled between the pinned photodiode and the first pinned transfer diode, a second transfer transistor coupled between the second pinned transfer diode and the storage diode, a third transfer transistor coupled between the storage diode and the floating diffusion region, a reset transistor that is coupled between the floating diffusion region and a bias voltage, and a shutter gate that is coupled between the second pinned transfer diode and the bias voltage, the method comprising:

• resetting the pinned photodiode, the first pinned transfer diode, the second pinned transfer diode, the storage diode, and the floating diffusion region by asserting the first transfer transistor, the third transfer transistor, the shutter gate, and the reset transistor;
• and
• with the photodiode, accumulating charge over a total exposure time that is split into multiple integration periods, wherein the multiple integration periods are non-continuous and are each shorter than the total exposure time, wherein the charge that is accumulated in each integration period of the multiple integration periods is transferred to the storage diode.

A method of operating an imaging pixel, wherein the imaging pixel comprises a pinned photodiode, a first pinned transfer diode, a second pinned transfer diode, an interconnect layer that couples the first pinned transfer diode to the second pinned transfer diode, a first storage diode, a second storage diode, and a third storage diode, a floating diffusion region, a first transfer transistor coupled between the pinned photodiode and the first pinned transfer diode, a second transfer transistor coupled between the second pinned transfer diode and the first storage diode, a third transfer transistor coupled between the first storage diode and the floating diffusion region, a fourth transfer transistor coupled between the second pinned transfer diode and the second storage diode, a fifth transfer transistor coupled between the second storage diode and the floating diffusion region, a sixth transfer transistor coupled between the second pinned transfer diode and the third storage diode, a seventh transfer transistor coupled between the third storage diode and the floating diffusion region, a reset transistor that is coupled between the floating diffusion region and a bias voltage, and a shutter gate that is coupled between the second pinned transfer diode and the bias voltage, the method comprising:

• resetting the pinned photodiode, the first pinned transfer diode, the second pinned transfer diode, the first storage diode, the second storage diode, the third storage diode, and the floating diffusion region by asserting the first transfer transistor, the third transfer transistor, the fifth transfer transistor, the seventh transistor, the shutter gate, and the reset transistor;
• accumulating a first amount of charge in the photodiode over a first integration time;
• transferring the first amount of charge to the first storage diode by asserting the first transfer transistor and the second transfer transistor;
• accumulating a second amount of charge in the photodiode over a second integration time;
• transferring the second amount of charge to the second storage diode by asserting the first transfer transistor and the fourth transfer transistor;
• accumulating a third amount of charge in the photodiode over a third integration time;
• and
• transferring the third amount of charge to the third storage diode by asserting the first transfer transistor and the sixth transfer transistor.