Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for eye gesture recognition. In one aspect, a method includes obtaining an electrical signal that represents a measurement, by a photodetector, of an optical signal reflected from an eye and determining a depth map of the eye based on phase differences between the electrical signal generated by the photodetector and a reference signal. Further, the method includes determining gaze information that represents a gaze of the eye based on the depth map and providing output data representing the gaze information.

Abstract: A method for fabricating an image sensor array having a first group of photodiodes for detecting light at visible wavelengths a second group of photodiodes for detecting light at infrared or near-infrared wavelengths, the method including growing a germanium-silicon layer on a semiconductor donor wafer; defining pixels of the image sensor array on the germanium-silicon layer; defining a first interconnect layer on the germanium-silicon layer, wherein the interconnect layer includes a plurality of interconnects coupled to the first group of photodiodes and the second group of photodiodes; defining integrated circuitry for controlling the pixels of the image sensor array on a semiconductor carrier wafer; defining a second interconnect layer on the semiconductor carrier wafer, wherein the second interconnect layer includes a plurality of interconnects coupled to the integrated circuitry; and bonding the first interconnect layer with the second interconnect layer.

Abstract: A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

Abstract: A method for fabricating an image sensor array having a first group of photodiodes for detecting light at visible wavelengths a second group of photodiodes for detecting light at infrared or near-infrared wavelengths, the method including growing a germanium-silicon layer on a semiconductor donor wafer; defining pixels of the image sensor array on the germanium-silicon layer; defining a first interconnect layer on the germanium-silicon layer, wherein the interconnect layer includes a plurality of interconnects coupled to the first group of photodiodes and the second group of photodiodes; defining integrated circuitry for controlling the pixels of the image sensor array on a semiconductor carrier wafer; defining a second interconnect layer on the semiconductor carrier wafer, wherein the second interconnect layer includes a plurality of interconnects coupled to the integrated circuitry; and bonding the first interconnect layer with the second interconnect layer.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for eye gesture recognition. In one aspect, a method includes obtaining an electrical signal that represents a measurement, by a photodetector, of an optical signal reflected from an eye and determining a depth map of the eye based on phase differences between the electrical signal generated by the photodetector and a reference signal. Further, the method includes determining gaze information that represents a gaze of the eye based on the depth map and providing output data representing the gaze information.

Abstract: An optical apparatus includes: a substrate having a first material; an absorption region having a second material different from the first material, the absorption region configured to absorb photons and to generate photo-carriers including electrons and holes in response to the absorbed photons; a first well region surrounding the absorption region and arranged between the absorption region and the substrate, the first well region being doped with a first polarity; and one or more switches each controlled by a respective control signal, the one or more switches each configured to collect at least a portion of the photo-carriers based on the respective control signal and to provide the portion of the photo-carriers to a respective readout circuit.

Abstract: A photo-detecting apparatus is provided. The photo-detecting apparatus includes: a substrate made by a first material or a first material-composite; an absorption layer made by a second material or a second material-composite, the absorption layer being supported by the substrate and the absorption layer including: a first surface; a second surface arranged between the first surface and the substrate; and a channel region having a dopant profile with a peak dopant concentration equal to or more than 1×1015 cm?3, wherein a distance between the first surface and a location of the channel region having the peak dopant concentration is less than a distance between the second surface and the location of the channel region having the peak dopant concentration, and wherein the distance between the first surface and the location of the channel region having the peak dopant concentration is not less than 30 nm.

Abstract: A circuit, including: a photodetector including a first readout terminal and a second readout terminal different than the first readout terminal; a first readout circuit coupled with the first readout terminal and configured to output a first readout voltage; a second readout circuit coupled with the second readout terminal and configured to output a second readout voltage; and a common-mode analog-to-digital converter (ADC) including: a first input terminal coupled with a first voltage source; a second input terminal coupled with a common-mode generator, the common-mode generator configured to receive the first readout voltage and the second readout voltage, and to generate a common-mode voltage between the first and second readout voltages; and a first output terminal configured to output a first output signal corresponding to a magnitude of a current generated by the photodetector.

Abstract: A circuit, including: a photodetector including a first readout terminal and a second readout terminal different than the first readout terminal; a first readout circuit coupled with the first readout terminal and configured to output a first readout voltage; a second readout circuit coupled with the second readout terminal and configured to output a second readout voltage; and a common-mode analog-to-digital converter (ADC) including: a first input terminal coupled with a first voltage source; a second input terminal coupled with a common-mode generator, the common-mode generator configured to receive the first readout voltage and the second readout voltage, and to generate a common-mode voltage between the first and second readout voltages; and a first output terminal configured to output a first output signal corresponding to a magnitude of a current generated by the photodetector.

Abstract: A photo-detecting apparatus is provided. The photo-detecting apparatus includes: a substrate made by a first material or a first material-composite; an absorption layer made by a second material or a second material-composite, the absorption layer being supported by the substrate and the absorption layer including: a first surface; a second surface arranged between the first surface and the substrate; and a channel region having a dopant profile with a peak dopant concentration equal to or more than 1×1015 cm?3, wherein a distance between the first surface and a location of the channel region having the peak dopant concentration is less than a distance between the second surface and the location of the channel region having the peak dopant concentration, and wherein the distance between the first surface and the location of the channel region having the peak dopant concentration is not less than 30 nm.

Abstract: A photo-detecting apparatus is provided. The photo-detecting apparatus includes at least one pixel, and each pixel includes N subpixels, wherein each of the subpixels comprises a detection region, two first conductive contacts, wherein the detection region is between the two first conductive contacts, wherein N is a positive integer and is ?2.

Abstract: A photo-detecting apparatus includes an absorption layer configured to absorb photons and to generate photo-carriers from the absorbed photons, wherein the absorption layer includes germanium. A carrier guiding unit is electrically coupled to the absorption layer, wherein the carrier guiding unit includes a first switch including a first gate terminal.

Abstract: A waveguide structure includes a first surface having a first width, a second surface having a second width, the second surface being opposite to the first surface, and a sidewall surface connecting the first surface and the second surface. The first width is greater than the second width.

Abstract: A method for fabricating an optical sensor includes: forming, over a substrate, a first material layer comprising a first alloy of germanium and silicon having a first germanium composition; forming, over the first material layer, a graded material layer comprising germanium and silicon; and forming, over the graded material layer, a second material layer comprising a second alloy of germanium and silicon having a second germanium composition. The first germanium composition is lower than the second germanium composition and a germanium composition of the graded material layer is between the first germanium composition and the second germanium composition and varies along a direction perpendicular to the substrate.

Abstract: A photo-detecting apparatus includes an absorption layer configured to absorb photons and to generate photo-carriers from the absorbed photons, wherein the absorption layer includes germanium. A carrier guiding unit is electrically coupled to the absorption layer, wherein the carrier guiding unit includes a first switch including a first gate terminal.

Abstract: Structures and techniques introduced here enable the design and fabrication of photodetectors (PDs) and/or other electronic circuits using typical semiconductor device manufacturing technologies meanwhile reducing the adverse impacts on PDs' performance. Examples of the various structures and techniques introduced here include, but not limited to, a pre-PD homogeneous wafer bonding technique, a pre-PD heterogeneous wafer bonding technique, a post-PD wafer bonding technique, their combinations, and a number of mirror equipped PD structures. With the introduced structures and techniques, it is possible to implement PDs using typical direct growth material epitaxy technology while reducing the adverse impact of the defect layer at the material interface caused by lattice mismatch.

Abstract: Structures and techniques introduced here enable the design and fabrication of photodetectors (PDs) and/or other electronic circuits using typical semiconductor device manufacturing technologies meanwhile reducing the adverse impacts on PDs' performance. Examples of the various structures and techniques introduced here include, but not limited to, a pre-PD homogeneous wafer bonding technique, a pre-PD heterogeneous wafer bonding technique, a post-PD wafer bonding technique, their combinations, and a number of mirror equipped PD structures. With the introduced structures and techniques, it is possible to implement PDs using typical direct growth material epitaxy technology while reducing the adverse impact of the defect layer at the material interface caused by lattice mismatch.

Abstract: A photo-detecting apparatus is provided. The photo-detecting apparatus includes: a substrate made by a first material or a first material-composite; an absorption layer made by a second material or a second material-composite, the absorption layer being supported by the substrate and the absorption layer including: a first surface; a second surface arranged between the first surface and the substrate; and a channel region having a dopant profile with a peak dopant concentration equal to or more than 1×1015 cm?3, wherein a distance between the first surface and a location of the channel region having the peak dopant concentration is less than a distance between the second surface and the location of the channel region having the peak dopant concentration, and wherein the distance between the first surface and the location of the channel region having the peak dopant concentration is not less than 30 nm.

Abstract: A photo-detecting apparatus is provided. The photo-detecting apparatus includes: a substrate made by a first material or a first material-composite; an absorption layer made by a second material or a second material-composite, the absorption layer being supported by the substrate and the absorption layer including: a first surface; a second surface arranged between the first surface and the substrate; and a channel region having a dopant profile with a peak dopant concentration equal to or more than 1×1015 cm?3, wherein a distance between the first surface and a location of the channel region having the peak dopant concentration is less than a distance between the second surface and the location of the channel region having the peak dopant concentration, and wherein the distance between the first surface and the location of the channel region having the peak dopant concentration is not less than 30 nm.

Abstract: A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.