Abstract: A time-of-flight detector includes a semiconductor layer and a light modulation structure. The semiconductor layer is configured to translate light radiation into electrical charge. The light modulation structure is configured to increase a path of interaction of light radiation through the semiconductor layer. In some example implementations, the light modulation structure is configured to deflect at least some light radiation at an increased angle through the semiconductor layer. In some example implementations, the light modulation structure is configured to reflect light radiation more than once through the semiconductor layer.

Abstract: A time-of-flight detector includes a semiconductor layer and a light modulation structure. The semiconductor layer is configured to translate light radiation into electrical charge. The light modulation structure is configured to increase a path of interaction of light radiation through the semiconductor layer. In some example implementations, the light modulation structure is configured to deflect at least some light radiation at an increased angle through the semiconductor layer. In some example implementations, the light modulation structure is configured to reflect light radiation more than once through the semiconductor layer.

Abstract: Image sensors may include a plurality of photodiodes. The photodiodes may be isolated from each other using isolations regions formed from p-well or n-well implants. Deep and narrow isolation regions may be formed using a multi-step process that selectively places implants at desired depths in a substrate. If desired, the multi-step process may include only one photolithographic patterning step, which in turn can help reduce costs, fabrication time, and alignment errors. The process may include passing ions through a stack of alternating layers of material such as alternating layers of oxide and nitride. After each implant, a layer in the stack may be removed and ions may be passed through the layers remaining in the stack to form an implant at a different depth in the substrate.

Abstract: This is generally directed to a switchable impedance to ground. In particular, a pixel array can be coupled to and surrounded by a ground ring. The ground ring can be coupled to a switchable impedance to ground. During a correlated double sampling (“CDS”) phase of the pixel array, the switchable impedance can be set to a high resistance value. For example, the switchable impedance can be set to 500 ohms. During an analog-to-digital conversion (“ADC”) readout phase of the pixel array, however, the switchable impedance can be set to a low resistance value. For example, the switchable impedance can be set to 1-10 ohms. Setting the switchable impedance to the high impedance value during the CDS phase can prevent imaging errors such as black hole artifacts. Setting the switchable impedance to the low impedance value during the ADC readout phase can, for example, prevent errors due to ground drift.

Abstract: An imaging system may include an image sensor having an array of image pixels formed in a substrate. Each image pixel may include a photodiode directly coupled to an anti-blooming diode. The anti-blooming diode may be connected to a positive voltage supply line and may be configured to drain excess charge from the photodiode when the photodiode is saturated. The anti-blooming drain may be formed from an n-type diffusion region partially surrounded by a p-type doped layer. The p-type doped layer may be interposed between and in contact with the n-type diffusion region of the anti-blooming diode and an n-type doped region of the photodiode. The anti-blooming diode may begin to drain excess charge from the photodiode in response to the photodiode reaching a threshold potential during integration. If desired, multiple pixels may share a common anti-blooming diode.

Abstract: Image sensors may include a plurality of photodiodes. The photodiodes may be isolated from each other using isolations regions formed from p-well or n-well implants. Deep and narrow isolation regions may be formed using a multi-step process that selectively places implants at desired depths in a substrate. If desired, the multi-step process may include only one photolithographic patterning step, which in turn can help reduce costs, fabrication time, and alignment errors. The process may include passing ions through a stack of alternating layers of material such as alternating layers of oxide and nitride. After each implant, a layer in the stack may be removed and ions may be passed through the layers remaining in the stack to form an implant at a different depth in the substrate.

Abstract: An imaging system may include an image sensor having an array of image pixels formed in a substrate. Each image pixel may include a photodiode directly coupled to an anti-blooming diode. The anti-blooming diode may be connected to a positive voltage supply line and may be configured to drain excess charge from the photodiode when the photodiode is saturated. The anti-blooming drain may be formed from an n-type diffusion region partially surrounded by a p-type doped layer. The p-type doped layer may be interposed between and in contact with the n-type diffusion region of the anti-blooming diode and an n-type doped region of the photodiode. The anti-blooming diode may begin to drain excess charge from the photodiode in response to the photodiode reaching a threshold potential during integration. If desired, multiple pixels may share a common anti-blooming diode.

Abstract: Image sensors have photodiodes separated by isolations regions formed from p-well or n-well implants. Isolation regions may be formed that are narrow and deep. Isolation regions may be formed in a multi-step process that selectively places implants at desired depths in a substrate. Complementary photoresist patterns may be used. To form an implant near the surface of a substrate, a photoresist pattern with openings over the desired implant area may be used. Subsequent implantation may use a complementary pattern such that ions pass through photoresist before implanting in desired regions of a substrate.

Abstract: An image sensor pixel includes a photo-sensor region, a microlens, a first color filter layer, and a second color filter layer. The photo-sensor region is disposed within a semiconductor die. The microlens is disposed on the semiconductor die in optical alignment with the photo-sensor region. The first color filter layer is disposed between the photo-sensor region and the microlens. The second color filter layer is disposed on an opposite side of the microlens as the first color filter layer.

Abstract: This is generally directed to a switchable impedance to ground. In particular, a pixel array can be coupled to and surrounded by a ground ring. The ground ring can be coupled to a switchable impedance to ground. During a correlated double sampling (“CDS”) phase of the pixel array, the switchable impedance can be set to a high resistance value. For example, the switchable impedance can be set to 500 ohms. During an analog-to-digital conversion (“ADC”) readout phase of the pixel array, however, the switchable impedance can be set to a low resistance value. For example, the switchable impedance can be set to 1-10 ohms. Setting the switchable impedance to the high impedance value during the CDS phase can prevent imaging errors such as black hole artifacts. Setting the switchable impedance to the low impedance value during the ADC readout phase can, for example, prevent errors due to ground drift.

Abstract: Image sensors have photodiodes separated by isolations regions formed from p-well or n-well implants. Isolation regions may be formed that are narrow and deep. Isolation regions may be formed in a multi-step process that selectively places implants at desired depths in a substrate. Complementary photoresist patterns may be used. To form an implant near the surface of a substrate, a photoresist pattern with openings over the desired implant area may be used. Subsequent implantation may use a complementary pattern such that ions pass through photoresist before implanting in desired regions of a substrate.

Abstract: An image sensor pixel includes a photo-sensor region, a microlens, a first color filter layer, and a second color filter layer. The photo-sensor region is disposed within a semiconductor die. The microlens is disposed on the semiconductor die in optical alignment with the photo-sensor region. The first color filter layer is disposed between the photo-sensor region and the microlens. The second color filter layer is disposed on an opposite side of the microlens as the first color filter layer.

Abstract: An image sensor pixel includes a photo-sensor region, a microlens, a first color filter layer, and a second color filter layer. The photo-sensor region is disposed within a semiconductor die. The microlens is disposed on the semiconductor die in optical alignment with the photo-sensor region. The first color filter layer is disposed between the photo-sensor region and the microlens. The second color filter layer is disposed on an opposite side of the microlens as the first color filter layer.

Abstract: A light sensor cell includes a photosensitive element, a floating diffusion region, and a gate oxide disposed between the photosensitive element and the floating diffusion region. The gate oxide has a non-uniform thickness, with a greater thickness near the photosensitive element and a lesser thickness near the floating diffusion region. A transfer gate is disposed on the gate oxide. The transfer gate has a non-uniform threshold voltage, with a greater threshold voltage near the photosensitive element and a lesser threshold voltage near the floating diffusion region.

Abstract: A light sensor cell includes a photosensitive element, a floating diffusion region, and a gate oxide disposed between the photosensitive element and the floating diffusion region. The gate oxide has a non-uniform thickness, with a greater thickness near the photosensitive element and a lesser thickness near the floating diffusion region. A transfer gate is disposed on the gate oxide. The transfer gate has a non-uniform threshold voltage, with a greater threshold voltage near the photosensitive element and a lesser threshold voltage near the floating diffusion region.

Abstract: An image sensor pixel includes a photo-sensor region, a microlens, a first color filter layer, and a second color filter layer. The photo-sensor region is disposed within a semiconductor die. The microlens is disposed on the semiconductor die in optical alignment with the photo-sensor region. The first color filter layer is disposed between the photo-sensor region and the microlens. The second color filter layer is disposed on an opposite side of the microlens as the first color filter layer.

Abstract: A pixel includes a photodiode and a transfer transistor. The transfer transistor is formed between the photodiode and a floating node and selectively operative to transfer a signal from the photodiode to the floating node. The transfer transistor has a bird's beak structure formed at the interface of its transfer gate and said floating node. Also included is a reset transistor for resetting the floating node to a voltage reference and an amplification transistor controlled by the floating node.

Abstract: An image sensor in which the metal interconnects are coated with an anti-reflective coating is disclosed. The top, bottom and sides of the metal interconnects may be coated to reduce reflection from all directions. The thickness of the coating is chosen to suppress reflection of light of certain wavelengths incident at certain expected angles. In particular, the thickness of the coating may be chosen to reduce reflections from neighboring pixels. The metal may be coated in multiple layers of anti-reflective coating to suppress multiple wavelengths of light or multiple angles of incidence.

Abstract: An image sensor that has a pixel array using an isolation structure between pixels that reduce electrical cross-talk is disclosed. The pixel array is formed on a substrate that has a thin (less than 5 microns) epitaxial layer. The isolation structure uses a deep p-well to surround a shallow trench isolation. The deep p-well is formed using an implant energy of typically over 700 keV.

Abstract: A pixel includes a photodiode and a transfer transistor. The transfer transistor is formed between the photodiode and a floating node and selectively operative to transfer a signal from the photodiode to the floating node. The transfer transistor has a bird's beak structure formed at the interface of its transfer gate and said floating node. Also included is a reset transistor for resetting the floating node to a voltage reference and an amplification transistor controlled by the floating node.