Method and apparatus for dark current and blooming supression in 4t cmos imager pixel

A method of operating a pixel cell comprising:

• applying a first polarity voltage to a transfer transistor adjacent a photosensor in a substrate to lower a depletion region associated with the photosensor during a charge integration period;
• and
• applying a plurality of pulses of a second polarity voltage to the transfer transistor to facilitate the movement of electrons to a floating diffusion region during the charge integration period.

A method of operating a pixel cell comprising:

• applying a first polarity voltage to a gate electrode adjacent a photo sensitive region in a substrate to lower a depletion region associated with the photo sensitive region during a charge integration period;
• and
• applying a plurality of pulses of a second polarity voltage to the gate electrode to facilitate the transfer of accumulated charge to a floating diffusion region subsequent to the charge integration period.

A method of operating a pixel cell comprising:

• applying a first polarity voltage to a transfer transistor adjacent a photosensor in a substrate to lower a depletion region associated with the photosensor during a first portion of a charge integration period;
• and
• applying a plurality of pulses of a second polarity voltage to the transfer transistor to facilitate the movement of electrons to a floating diffusion region during a second portion of the charge integration period.