Methods and systems for infrared sensing

An infrared (IR) photodetecting system operable to detect IR radiation, comprising:

• at least one photosite comprising a Ge photosensitive area, operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive area comprising an absorber doped area having a first polarity and a silicon (Si) layer comprising a first doped area, a storage well, a floating diffusion, and a transfer gate;
• at least one controllable power source, operable to modulate voltage to at least one of the first doped area, the Ge photosensitive area and the floating diffusion;
• and
• a controller operable to control the at least one controllable power source and the transfer gate, to provide at one time voltages to the Ge photosensitive area, to the first doped area, and to the floating diffusion, thereby forcing charge carriers of the second polarity (CCSP) to move from the Ge photosensitive area toward the storage well, to provide at another time other voltages to the Ge photosensitive area, to the first doped area and to the floating diffusion, thereby diminishing the forcing of the CCSP toward the storage well, thereby ceasing the collection of signals by the storage well, and to intermittently transfer charge carriers of the second polarity from the storage well via the transfer gate to the floating diffusion, where the charge carriers are read via a readout electrode electrically coupled to the floating diffusion.

A method for detecting infrared (IR) radiation, comprising:

• providing a first area voltage to a first doped area of a photosite (PS) and providing a second area voltage to a second doped area of the PS that comprises a germanium (Ge) photosensitive area, operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive area comprising an absorber doped area having a first polarity, the PS further comprising a silicon layer comprising a diode, the diode comprising the first doped area of the first polarity and the second doped area of a second polarity opposite to the first polarity, wherein the first doped area is located between the second doped area and the absorber doped area;
• while providing the first area voltage and the second area voltage, providing to the Ge photosensitive area for a sampling duration of the photosite an activation voltage that forces charge carriers of the second polarity (CCSP) to move from the Ge photosensitive area toward the photodiode where the CCSP are collected via a readout electrode electrically coupled to the second doped area;
• and
• upon ending of the sampling duration, providing to the Ge photosensitive area a rest voltage that diminishes the forcing of the CCSP toward the photodiode, thereby ceasing the collection of signals by the photosite.

A method for detecting infrared (IR) radiation, comprising:

• modulating a voltage to at least one area of a photosite (PS), the area selected from the group consisting of a first doped area of the PS, a germanium (Ge) photosensitive area of the PS and a floating diffusion of the PS, wherein the PS comprises at least (a) the Ge photosensitive area that is operable to generate electron-hole pairs in response to impinging IR photons and which comprises an absorber doped area having a first polarity and (b) a silicon layer comprising the first doped area, a storage well, the floating diffusion, and a transfer gate, wherein the modulating comprises:
• at one time, providing some voltages to the Ge photosensitive area, to the first doped area, and to the floating diffusion, thereby forcing charge carriers of the second polarity (CCSP) to move from the Ge photosensitive area toward the storage well,
• at another time, providing other voltages to the Ge photosensitive area, to the first doped area, and to the floating diffusion, thereby diminishing the forcing of the CCSP toward the storage well, thereby ceasing the collection of signals by the storage well, and
• intermittently transferring charge carriers of the second polarity from the storage well via the transfer gate to the floating diffusion, where the CCSP are read via a readout electrode electrically coupled to the floating diffusion.