Abstract: A pixel cell for an image sensor includes a first photodiode, a second photodiode, and a floating diffusion, each disposed within a semiconductor material. The pixel cell further includes a multi-gate transfer transistor configured to selectively couple the first photodiode and the second photodiode to the floating diffusion to transfer image charge from the first photodiode or the second photodiode to the floating diffusion. The multi-gate transfer transistor includes a plurality of separated gate electrodes including a first gate electrode disposed proximate to the first photodiode, a second gate electrode disposed proximate to the second photodiode, and a shared gate electrode disposed proximate to the floating diffusion. The multi-gate transfer transistor further includes an isolation structure disposed within the semiconductor substrate between the first photodiode and the second photodiode.

Abstract: Image sensors with improved memory effect are disclosed herein. In one embodiment, a method for reducing image lag associated with a pixel included in a plurality of pixels is described. The pixel includes a photodiode, a first floating diffusion coupled to the photodiode through a transfer transistor, a second floating diffusion coupled to the first floating diffusion through a dual floating diffusion transistor, and a lateral overflow integration capacitor coupled between the second floating diffusion and a bias voltage source. The lateral overflow integration capacitor is further coupled to a pixel reference voltage source through a reset transistor. Operation of the pixel comprises an idle period and an integration period after the idle period. The method also includes configuring the lateral overflow integration capacitor to be either zero-biased or forward-biased during the idle period.

Abstract: Image sensors, isolation structures, and techniques of fabrication are provided. An image sensor includes a source of electromagnetic radiation disposed on a substrate, a pixel array disposed on the substrate and thermally coupled with source of electromagnetic radiation, and an isolation structure disposed on the substrate between the source of electromagnetic radiation and the pixel array. The isolation structure can define a first reflective surface oriented on a first bias relative to a lateral axis of the pixel array and a second reflective surface oriented on a second bias relative to the lateral axis. The isolation structure can be configured to attenuate residual electromagnetic radiation reaching a proximal region of the pixel array by pairing a first reflection and a second reflection of the electromagnetic radiation by the first reflective surface and the second reflective surface.

Abstract: Image sensors with improved memory effect are disclosed herein. In one embodiment, a method for reducing image lag associated with a pixel included in a plurality of pixels is described. The pixel includes a photodiode, a first floating diffusion coupled to the photodiode through a transfer transistor, a second floating diffusion coupled to the first floating diffusion through a dual floating diffusion transistor, and a lateral overflow integration capacitor coupled between the second floating diffusion and a bias voltage source. The lateral overflow integration capacitor is further coupled to a pixel reference voltage source through a reset transistor. Operation of the pixel comprises an idle period and an integration period after the idle period. The method also includes configuring the lateral overflow integration capacitor to be either zero-biased or forward-biased during the idle period.

Abstract: An image sensor is described. The image sensor comprises a plurality of pixels arranged to form an active pixel array, a plurality of contact pads disposed within a peripheral region of the image sensor that surrounds the active pixel array, and an optical structure disposed within the peripheral region between the plurality of contact pads and the active pixel array. The optical structure is adapted to mitigate stray light from reaching the active pixel array.

Abstract: A pixel circuit includes a photodiode configured to photogenerate image charge in response to incident light. A floating diffusion is coupled to receive the image charge from the photodiode. A transfer transistor is coupled between the photodiode and the floating diffusion. The transfer transistor is configured to transfer the image charge from the photodiode to the floating diffusion. A reset transistor is coupled between a reset voltage and the floating diffusion. A plurality of capacitor-switch pairs is coupled between the reset transistor and a bias voltage source. Each of the plurality of capacitor-switch pairs includes a lateral overflow integration capacitor (LOFIC) and a switch transistor coupled to the LOFIC.

Abstract: A pixel circuit includes a photodiode configured to photogenerate image charge in response to incident light. A transfer transistor is coupled between the photodiode and a floating diffusion to transfer the image charge from the photodiode to the floating diffusion. A reset transistor is coupled between a pixel voltage source and the floating diffusion. A lateral overflow integration capacitor (LOFIC) network includes a first LOFIC coupled between the floating diffusion and the first bias voltage source, and a second LOFIC coupled between the floating diffusion and the second bias voltage source. The first LOFIC is configured to be forward biased and the second LOFIC is configured to be reverse biased at an end of an integration period, and image charge discharged from the first LOFIC and image charge discharged from the second LOFIC compensate each other during a readout period.

Abstract: A pixel circuit includes a photodiode configured to photogenerate image charge in response to incident light. A transfer transistor is coupled between the photodiode and a floating diffusion to transfer the image charge from the photodiode to the floating diffusion. A reset transistor is coupled between a pixel voltage source and the floating diffusion. A lateral overflow integration capacitor (LOFIC) network includes a first LOFIC coupled between the floating diffusion and the first bias voltage source, and a second LOFIC coupled between the floating diffusion and the second bias voltage source. The first LOFIC is configured to be forward biased and the second LOFIC is configured to be reverse biased at an end of an integration period, and image charge discharged from the first LOFIC and image charge discharged from the second LOFIC compensate each other during a readout period.

Abstract: A reduced cross-talk pixel-array substrate includes a semiconductor substrate, a buffer layer, a metal annulus, and an attenuation layer. The semiconductor substrate includes a first photodiode region. A back surface of the semiconductor substrate forms a trench surrounding the first photodiode region in a cross-sectional plane parallel to a first back-surface region of the back surface above the first photodiode region. The buffer layer is on the back surface and has a feature located above the first photodiode region with the feature being one of a recess and an aperture. The metal annulus is on the buffer layer and covers the trench. The attenuation layer is above the first photodiode region.

Abstract: An image sensor comprises a first photodiode region and circuitry. The first photodiode region is disposed within a semiconductor substrate proximate to a first side of the semiconductor substrate to form a first pixel. The first photodiode region includes a first segment coupled to a second segment. The circuitry includes at least a first electrode associated with a first transistor. The first electrode is disposed, at least in part, between the first segment and the second segment of the first photodiode region such that the circuity is at least partially surrounded by the first photodiode region when viewed from the first side of the semiconductor substrate.

Abstract: A pixel circuit includes a photodiode configured to photogenerate image charge in response to incident light. A floating diffusion is coupled to receive the image charge from the photodiode. A transfer transistor is coupled between the photodiode and the floating diffusion. The transfer transistor is configured to transfer the image charge from the photodiode to the floating diffusion. A reset transistor is coupled between a reset voltage and the floating diffusion. A plurality of capacitor-switch pairs is coupled between the reset transistor and a bias voltage source. Each of the plurality of capacitor-switch pairs includes a lateral overflow integration capacitor (LOFIC) and a switch transistor coupled to the LOFIC.

Abstract: CMOS image sensor with LED flickering reduction and low color cross-talk are disclosed. In one embodiment, an image sensor includes a plurality of pixels arranged in rows and columns of a pixel array that is disposed in a semiconductor substrate. Each pixel includes a plurality of large subpixels (LPDs) and at least one small subpixel (SPD). A plurality of color filters are disposed over individual subpixels. Each individual SPD is laterally adjacent to at least one other SPD.

Abstract: Image sensors, isolation structures, and techniques of fabrication are provided. An image sensor includes a source of electromagnetic radiation disposed on a substrate, a pixel array disposed on the substrate and thermally coupled with source of electromagnetic radiation, and an isolation structure disposed on the substrate between the source of electromagnetic radiation and the pixel array. The isolation structure can define a first reflective surface oriented on a first bias relative to a lateral axis of the pixel array and a second reflective surface oriented on a second bias relative to the lateral axis. The isolation structure can be configured to attenuate residual electromagnetic radiation reaching a proximal region of the pixel array by pairing a first reflection and a second reflection of the electromagnetic radiation by the first reflective surface and the second reflective surface.

Abstract: An image sensor includes a substrate. An array of photodiodes is disposed in the substrate. A plurality of spacers is arranged in a spacer pattern. At least one spacer of the plurality of spacers has an aspect ratio of 18:1 or greater. A buffer layer is disposed between the substrate and the spacer pattern. An array of color filters is disposed in the spacer pattern.

Abstract: A flicker-mitigating pixel-array substrate includes a semiconductor substrate and a metal annulus. The semiconductor substrate includes a small-photodiode region. A back surface of the semiconductor substrate forms a trench surrounding the small-photodiode region in a cross-sectional plane parallel to a back-surface region of the back surface above the small-photodiode region. The metal annulus (i) at least partially fills the trench, (ii) surrounds the small-photodiode region in the cross-sectional plane, and (iii) extends above the back surface. A method for fabricating a flicker-mitigating pixel-array substrate includes forming a metal layer (i) in a trench that surrounds the small-photodiode region in a cross-sectional plane parallel to a back-surface region of the back surface above the small-photodiode region and (ii) on the back-surface region. The method also includes decreasing a thickness of an above-diode section of the metal layer located above the back-surface region.

Abstract: A reduced cross-talk pixel-array substrate includes a semiconductor substrate, a buffer layer, a metal annulus, and an attenuation layer. The semiconductor substrate includes a first photodiode region. A back surface of the semiconductor substrate forms a trench surrounding the first photodiode region in a cross-sectional plane parallel to a first back-surface region of the back surface above the first photodiode region. The buffer layer is on the back surface and has a feature located above the first photodiode region with the feature being one of a recess and an aperture. The metal annulus is on the buffer layer and covers the trench. The attenuation layer is above the first photodiode region.

Abstract: A backside-illuminated image sensor includes arrayed photodiodes separated by isolation structures, and interlayer dielectric between first layer of metal interconnect and substrate. The image sensor has barrier metal walls in the interlayer dielectric between isolation structures and first layer interconnect, the barrier metal walls aligned with the isolation structures and disposed between the isolation structures and first layer interconnect. The barrier metal wall deflects light passing through photodiodes of the sensor that would otherwise be reflected by interconnect into different photodiodes.

Abstract: A pixel cell includes a plurality of subpixels to generate image charge in response to incident light. The subpixels include an inner subpixel laterally surrounded by outer subpixels. A first plurality of transfer gates disposed proximate to the inner subpixel and a first grouping of outer subpixels. A first floating diffusion is coupled to receive the image charge from the first grouping of outer subpixels through a first plurality of transfer gates. A second plurality of transfer gates disposed proximate to the inner subpixel and the second grouping of outer subpixels. A second floating diffusion disposed in the semiconductor material and coupled to receive the image charge from each one of the second grouping of outer subpixels through the second plurality of transfer gates. The image charge in the inner subpixel is received by the first, second, or both floating diffusions through respective transfer gates.

Abstract: CMOS image sensor with LED flickering reduction and low color cross-talk are disclosed. In one embodiment, an image sensor includes a plurality of pixels arranged in rows and columns of a pixel array that is disposed in a semiconductor substrate. Each pixel includes a plurality of large subpixels (LPDs) and at least one small subpixel (SPD). A plurality of color filters are disposed over individual subpixels. Each individual SPD is laterally adjacent to at least one other SPD.

Abstract: An image sensor comprises a first photodiode region and circuitry. The first photodiode region is disposed within a semiconductor substrate proximate to a first side of the semiconductor substrate to form a first pixel. The first photodiode region includes a first segment coupled to a second segment. The circuitry includes at least a first electrode associated with a first transistor. The first electrode is disposed, at least in part, between the first segment and the second segment of the first photodiode region such that the circuity is at least partially surrounded by the first photodiode region when viewed from the first side of the semiconductor substrate.