Abstract:
An optoelectronic device includes a semiconductor substrate and an array of optoelectronic cells, formed on the semiconductor substrate. The cells include first epitaxial layers defining a lower distributed Bragg-reflector (DBR) stack; second epitaxial layers formed over the lower DBR stack, defining a quantum well structure; third epitaxial layers, formed over the quantum well structure, defining an upper DBR stack; and electrodes formed over the upper DBR stack, which are configurable to inject an excitation current into the quantum well structure of each optoelectronic cell. A first set of the optoelectronic cells are configured to emit laser radiation in response to the excitation current. In a second set of the optoelectronic cells, interleaved with the first set, at least one element of the optoelectronic cells, selected from among the epitaxial layers and the electrodes, is configured so that the optoelectronic cells in the second set do not emit the laser radiation.
Abstract:
One or more cross-wafer capacitors are formed in an electronic component, circuit, or device that includes stacked wafers. One example of such a device is a stacked image sensor. The image sensor can include two or more wafers, with two wafers that are bonded to each other each including a conductive segment adjacent to, proximate, or abutting a bonding surface of the respective wafer. The conductive segments are positioned relative to each other such that each conductive element forms a plate of a capacitor. A cross-wafer capacitor is formed when the two wafers are attached to each other.
Abstract:
An apparatus includes a device, a comparison circuit, and a switch. The device includes a first terminal coupled to a first power supply signal, and a second terminal coupled to a ground reference. The comparison circuit is configured to compare a first voltage level on the first power supply signal to a second voltage level of a second power supply signal, and enable the device in response to a determination that the first voltage level is greater than the second voltage level. The switch circuit is configured to couple a power supply terminal of the comparison circuit to the first power supply signal in response to determining that the first voltage level is greater than the second voltage level, and to couple the power supply terminal to the second power supply signal in response to determining that the first voltage level is less than the second voltage level.
Abstract:
A back-illuminated single-photon avalanche diode (SPAD) image sensor includes a sensor wafer stacked vertically over a circuit wafer. The sensor wafer includes one or more SPAD regions, with each SPAD region including an anode gradient layer, a cathode region positioned adjacent to a front surface of the SPAD region, and an anode avalanche layer positioned over the cathode region. Each SPAD region is connected to a voltage supply and an output circuit in the circuit wafer through inter-wafer connectors. Deep trench isolation elements are used to provide electrical and optical isolation between SPAD regions.
Abstract:
In an embodiment, an ESD protection circuit is provided in which diodes may be formed between N+ and P+ diffusions within an insulated semiconductor region and in which additional diodes may be formed between adjacent insulated regions of opposite conduction type as well. The diodes may be used in parallel to form an ESD protection circuit, which may have low on resistance and may sink high ESD current per unit area. To support the formation of the ESD protection circuit, each silicon region may have alternating N+ and P+ diffusions, and adjacent silicon regions may have N+ and P+ diffusions alternating in opposite locations. That is a perpendicular drawn between the N+ diffusions of one adjacent region may intersect P+ diffusions in the other adjacent region, and vice versa.
Abstract:
A method for performing correlated double sampling for a sensor, such as an image sensor. The method includes collecting a first charge corresponding to a first parameter, transferring the first charge to a first storage component, transferring the first charge from the first storage component to a second storage component, resetting the first storage component, transferring the first charge from the second storage component to the first storage component, and reading the first storage component to determine the first charge. The method may be implemented in electronic devices including image sensors.
Abstract:
A CMOS imager assembly may include an integrated circuit (IC) having an active-pixel image sensor that is mounted on a printed circuit board (PCB) substrate using flip chip packaging technology. The IC and the PCB may be physically and electrically connected to each other through multiple electrically conductive connectors. An underfill material (which may include an anti-reflective material) may, during assembly, be introduced around the connectors in the space between the IC and the PCB. A chemical or physical discontinuity on the integrated circuit may, during assembly, prevent the underfill material from entering an area framed by the discontinuity, which may include the pixel array of the image sensor. The discontinuity may include a dam-like structure built up on the IC, a trench-like structure created on the IC, or a low surface tension material that has been applied to the surface of the IC.
Abstract:
A pixel in an image sensor can include a photodetector and a storage region disposed in one substrate, or a photodetector disposed in one substrate and a storage region in another substrate. A buried light shield is disposed between the photodetector and the storage region. A sense region, such as a floating diffusion, can be adjacent to the storage region, with the buried light shield disposed between the photodetector and the storage and sense regions. When the photodetector and the storage region are disposed in separate substrates, a vertical gate can be formed through the buried light shield and used to initiate the transfer of charge from the photodetector and the storage region. A transfer channel formed adjacent to, or around the vertical gate provides a channel for the charge to transfer from the photodetector to the storage region.
Abstract:
In an embodiment, an ESD protection circuit may include an STI-bound SCR and a gated SCR that may be electrically in parallel with the STI-bound SCR. The gated SCR may be perpendicular to the STI-bound SCR in a plane of the semiconductor substrate. In an embodiment, the gated SCR may trigger more quickly and turn on more quickly than the STI-bound SCR. The STI-bound SCR may form the main current path for an ESD event. A low capacitive load with rapid response to ESD events may thus be formed. In an embodiment, the anode of the two SCRs may be shared.
Abstract:
A vertically stacked image sensor having a photodiode chip and a transistor array chip. The photodiode chip includes at least one photodiode and a transfer gate extends vertically from a top surface of the photodiode chip. The image sensor further includes a transistor array chip stacked on top of the photodiode chip. The transistor array chip includes the control circuitry and storage nodes. The image sensor further includes a logic chip vertically stacked on the transistor array chip. The transfer gate communicates data from the at least one photodiode to the transistor array chip and the logic chip selectively activates the vertical transfer gate, the reset gate, the source follower gate, and the row select gate.