Method and system for generating a depth image of a scene based on detection of a short-wave infrared electro-optical imaging system, and sensor operable to detect depth information of an object

Abstract

To provide a method and system for generating a depth image of a scene based on detection of a short-wave infrared electro-optic imaging system, and a sensor operable to detect depth information of an object.SOLUTION: A method for generating a depth image of a scene based on detection of a short-wave infrared (SWIR) electro-optical imaging system (SEI system) includes obtaining a plurality of detection signals of the SEI system and processing the plurality of detection signals such that a three dimensional detection map is determined that includes a plurality of three dimensional locations within a field of view where a plurality of objects are detected. The processing includes compensating for a dark current level accumulated during collection of the detection signals from the germanium elements. A sensor operable to detect depth information of an object includes a focal plane array including a plurality of photosites, a readout set of a plurality of readout circuits, a controller, and a processor.SELECTED DRAWING: Figure 24

Description

Detailed Description of the Invention

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 118,745, filed November 27, 2020, U.S. Provisional Patent Application No. 63 / 136,429, filed January 12, 2021, and U.S. Provisional Patent Application No. 63 / 194,977, filed May 29, 2021.

[0002] [Field] This disclosure relates to infrared (IR) focal plane arrays (FPAs) and methods of operation thereof, and more particularly to short wave IR (SWIR) FPAs that include germanium on silicon.

[0003] 〔background〕 A light-detecting device, such as a photodetector array or "PDA" (also referred to as a "photosensor array"), includes a large number of photosites. Each photosite includes one or more photodiodes for detecting impinging light and a capacitance for storing the charge provided by the photodiode. Hereinafter, "photosite" will often be replaced with the acronym "PS." The capacitance may be implemented as a dedicated capacitor and / or using the parasitic capacitance of the photodiodes, transistors, and / or other components of the PS. Hereinafter, for ease of explanation, the term "photodetecting device" will often be replaced with the acronym "PDD," the term "photodetector array" will often be replaced with the acronym "PDA," and the term "photodiode" will often be replaced with the acronym "PD."

[0004] The term "photosite" refers to a single sensor element in an array of sensors (also referred to as a "sensel" as a portmanteau of the words "sensor" and "cell" or as a portmanteau of the words "sensor" and "element"), and is also referred to as a "sensor element," "photosensor element," "photodetector element," etc. Each PS may include one or more PDs (e.g., if a color filter array is implemented, PDs that detect light in various portions of the spectrum may, optionally, be referred to collectively as a single PS). A PS may also include some circuitry or additional components in addition to the PDs.

[0005] Dark current is a well-known phenomenon. In the context of PDs, dark current refers to the current that flows through the PD even when no photons are entering the device. Dark current in PDs can be the result of random generation of electrons and holes within the depletion region of the PD.

[0006] In some cases, it is necessary to provide a PS with a photodiode that has a relatively high dark current characteristic while implementing a capacitor of limited size. In some cases, it is necessary to provide a PS with a PD that has a relatively high dark current characteristic while reducing the effect of the dark current on the output detection signal. A PS with high dark current accumulation characteristic needs and would be advantageous in overcoming the deleterious effects of dark current on electro-optical systems. Hereinafter, for simplicity, the term "electro-optical" may be replaced with the acronym "EO."

[0007] Short-wave infrared (SWIR) imaging enables a variety of applications that are difficult to implement using visible light imaging, including electronic board inspection, solar cell inspection, agricultural product inspection, gated imaging, identification and sorting, surveillance, anti-counterfeiting, process quality control, etc. Many existing InGaAs-based SWIR imaging systems are expensive to manufacture and currently suffer from limited manufacturing capabilities.

[0008] It would therefore be advantageous to provide a SWIR imaging system using a more cost-effective photoreceiver based on PDs that can be more easily integrated into surrounding electronics.

[0009] Photodetector arrays including multiple PDAs, each sensitive to a portion of the electromagnetic spectrum, are known in the art. However, these PDAs are either expensive, insensitive to ranges of interest in the electromagnetic spectrum, and / or inefficient at distance analysis. Therefore, there is a need in the art for improved PSs and PDAs. Further limitations and drawbacks of conventional, conventional, and proposed approaches will become apparent to those skilled in the art through a comparison of such approaches with the subject matter of the present application described in the remainder of this application, with reference to the drawings.

[0010] 〔overview〕 In some embodiments, an IR light detection system operable to detect IR radiation, comprising: (a) at least one PS, (i) a germanium (Ge) photosensitive region operable to generate electron-hole (eh) pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (ii) a silicon (Si) layer including a diode, the diode including a first doped region of the first polarity and a second doped region of a second polarity opposite to the first polarity; wherein the first doped region is located between the second doped region and the absorber doped region; and (b) at least one power supply operable to provide a first region voltage to the first doped region and a second region voltage to the second doped region; (c) a controllable power source, (i) providing an activation voltage to the Ge photosensitive region for a sampling duration of the PS, the activation voltage forcing charge carriers of the second polarity (CCSP) to migrate from the Ge photosensitive region toward the photodiode, the CCSP being collected in the photodiode via a readout electrode electrically connected to the second doped region; (ii) stopping signal collection by the PS after the end of the sampling duration by providing a rest voltage to the Ge photosensitive region that reduces the forcing of the CCSP toward the photodiode; a controllable power source operable to: An IR light detection system is disclosed, including:

[0011] In some embodiments, an electro-optical (EO) detection system, comprising: (a) an IR light detection system or an IR light detection sensor including a plurality of PSs; (b) at least one optical interface for directing light from a field of view (FOV) of the electro-optical detection system to the IR light detection sensor; (c) a readout circuit operable to read at least one electrical signal from each of the plurality of PSs corresponding to the number of photons captured by the Ge photosensitive region during the sampling duration of the respective PS; (d) a processor operable to process detection data provided by the readout circuitry indicative of a plurality of the electrical signals such that an IR image of the FOV is provided; and An electro-optical detection system is disclosed, including:

[0012] In some embodiments, an IR light detection system operable to detect IR radiation, comprising: (a) at least one PS, (i) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (ii) a silicon (Si) layer, the Si layer including a first doped region, a storage well, a floating diffusion, and a transfer gate; At least one PS including (b) at least one controllable power supply operable to modulate a voltage to at least one of the first doped region, the Ge photosensitive region, and the floating diffusion; (c) a control device, (i) forcing charge carriers of the second polarity to migrate from the Ge photosensitive region toward the storage well by providing voltages across the Ge photosensitive region, the first doped region, and the floating diffusion at one time; (ii) at another time, providing another voltage to the Ge photosensitive region, the first doped region, and the floating diffusion to attenuate the forced migration of charge carriers of the second polarity toward the storage well, thereby stopping signal collection by the storage well; and (iii) intermittently transferring charge carriers of the second polarity from the storage well through the transfer gate to the floating diffusion, where the charge carriers of the second polarity are read out at the floating diffusion through a readout electrode electrically connected to the floating diffusion. a controller operable to control the controllable power supply and the transmission gate such that An IR light detection system is disclosed, including:

[0013] In some embodiments, an IR light detection system operable to detect IR radiation, comprising: (a) at least one PS, (i) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region doped to have a first polarity; (ii) a silicon layer having implemented thereon a plurality of readout structures, each readout structure comprising: (1) a remote doped region doped to have a second polarity; (2) an intermediate doped region disposed between the remote doped region and the Ge photosensitive region, the intermediate doped region being doped to have a second polarity opposite to the first polarity; a silicon layer comprising: At least one PS including (b) a controllable power supply operable to provide a controlled voltage to the Ge photosensitive region and the remotely doped region and the intermediately doped region of each readout structure of the plurality of readout structures; (i) maintaining relative voltages on the Ge photosensitive region, on a first remotely doped region of the first readout structure, and on a first intermediately doped region of the first readout structure for a first sampling duration such that the CCSP is forced to move by a first pulling force from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein the CCSP is collected in the first readout structure via a first readout electrode electrically connected to the first remotely doped region; (ii) maintaining a voltage on the plurality of doped regions of the first group of readout structures for the first sampling duration such that a tensile force applied to the CCSP toward each of the plurality of remote doped regions of a first group of readout structures, including the remainder of the plurality of readout structures other than the first readout structure, is less than half of the first tensile force; (iii) maintaining relative voltages on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure for a second sampling duration that is later than the first sampling duration, such that the CCSP is forced to move by a second tensile force from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein the CCSP is collected in the second readout structure via a second readout electrode electrically connected to the second remotely doped region; (iv) maintaining a voltage on the doped regions of the second group of readout structures for the second sampling duration such that a tensile force applied to the CCSP toward each of the remote doped regions of a second group of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half of the second tensile force; (v) maintaining relative voltages on the Ge photosensitive region, the first remotely doped region, and the first intermediately doped region for a third sampling duration that is later than the second sampling duration, such that CCSPs are forced by a third tensile force to move from the Ge photosensitive region toward the first readout structure, wherein the CCSPs are collected at the first readout structure via the first readout electrode; and (vi) maintaining a voltage on the doped regions of the first group of readout structures during the third sampling duration such that a tensile force applied to a CCSP toward each of the remote doped regions of the first group of readout structures is less than half of the third tensile force. a controllable power source operable to: An IR light detection system is disclosed, including:

[0014] In some embodiments, a method for detecting IR radiation, comprising: (a) providing a first region voltage to a first doped region of a PS and a second region voltage to a second region of the PS, wherein the PS: (i) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (ii) a Si layer including a diode, the diode including the first doped region of the first polarity and the second doped region of a second polarity opposite to the first polarity; wherein the first doped region is located between the second doped region and the absorber doped region; (b) providing an activation voltage to the Ge photosensitive region during a sampling duration of the PS while providing the first region voltage and the second region voltage, the activation voltage forcing charge carriers of the second polarity to migrate from the Ge photosensitive region toward the photodiode, the CCSP being collected at the photodiode via a readout electrode electrically connected to the second doped region; and (c) stopping signal collection by the PS after the end of the sampling duration by providing a rest voltage to the Ge photosensitive region that attenuates forced migration of the CCSP toward the photodiode. A method is disclosed, including:

[0015] In some embodiments, a method for detecting IR radiation, comprising: modulating the voltage to at least one region of the PS (PS); Including, at least one of the regions is selected from the group consisting of a first doped region of the PS, a Ge photosensitive region of the PS, and a floating diffusion of the PS; The PS comprises at least (a) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (b) a silicon layer including the first doped region, a storage well, the floating diffusion, and a transfer gate; The modulating step comprises: (i) forcing charge carriers of the second polarity to migrate from the Ge photosensitive region toward the storage well by providing a voltage across the Ge photosensitive region, the first doped region, and the floating diffusion; (ii) at another time, providing another voltage to the Ge photosensitive region, the first doped region, and the floating diffusion to attenuate the forced migration of the CCSP toward the storage well, thereby stopping signal collection by the storage well; and (iii) intermittently transferring charge carriers of the second polarity from the storage well through the transfer gate to the floating diffusion, wherein the charge carriers of the second polarity are read out at the floating diffusion through a readout electrode electrically connected to the floating diffusion. Includes:

[0016] In some embodiments, a method for detecting IR radiation, comprising: providing a controlled voltage to multiple regions of the PS; Including, The PS is (i) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region doped to have a first polarity; (ii) a plurality of doped regions of a plurality of readout structures implemented on the Si layer of the PS, wherein for each of the plurality of readout structures: (a) a remote doped region doped to have a second polarity; (b) an intermediate doped region disposed between the remote doped region and the Ge photosensitive region, the intermediate doped region being doped to have a second polarity opposite to the first polarity; a plurality of doped regions of a plurality of readout structures, including: The providing step includes: (i) maintaining relative voltages on the Ge photosensitive region, on a first remotely doped region of the first readout structure, and on a first intermediately doped region of the first readout structure for a first sampling duration such that charge carriers of the second polarity are forced by a first tensile force to move from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein the CCSP is collected in the first readout structure via a first readout electrode electrically connected to the first remotely doped region; (ii) maintaining a voltage on the doped regions of the first group of readout structures for the first sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the remotely doped regions of the first group of readout structures, including the remainder of the plurality of readout structures other than the first readout structure, is less than half of the first pulling force; (iii) maintaining a relative voltage on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure for a second sampling duration that is later than the first sampling duration, such that charge carriers of the second polarity are forced by a second tensile force to migrate from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein the CCSP is collected in the second readout structure via a second readout electrode electrically connected to the second remotely doped region; (iv) maintaining a voltage on the doped regions of the second group of readout structures for the second sampling duration such that a tensile force exerted on charge carriers of the second polarity toward each of the remotely doped regions of a second group of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half of the second tensile force; (v) maintaining a relative voltage on the Ge photosensitive region, the first remotely doped region, and the first intermediately doped region for a third sampling duration that is later than the second sampling duration, such that charge carriers of the second polarity are forced by a third tensile force to migrate from the Ge photosensitive region toward the first readout structure, wherein the CCSP is collected at the first readout structure via the first readout electrode; and (vi) maintaining a voltage on the doped regions of the first group of readout structures for the third sampling duration such that a tensile force applied to charge carriers of the second polarity toward each of the remotely doped regions of the first group of readout structures is less than half of the third tensile force. Includes:

[0017] In some embodiments, a method for generating a depth image of a scene based on detections of a SWIR electrooptical imaging system (SEI system) comprising: obtaining a plurality of detection signals of the SEI system, each detection signal indicative of an amount of light from a particular direction within a FOV of the SEI system captured by at least one focal plane array detector (FPA) of the SEI system over a respective detection time frame, the at least one FPA including a plurality of individual PSs, each PS including a Ge element where impinging photons are converted into detected charges therein, and for each of a plurality of directions within the FOV, different detection signals indicative of reflected SWIR illumination levels from different distance ranges along that direction; and processing the detection signals such that a 3D detection map is determined that includes a plurality of 3D locations within the FOV at which a plurality of objects are detected; Including, the processing step includes compensating for a dark current (DC) level accumulated during collection of the plurality of detection signals from the plurality of Ge elements; A method is disclosed wherein the compensating step includes applying different degrees of DC compensation to a plurality of detected signals detected by different PSs of at least one of the FPAs.

[0018] In some aspects, a sensor operable to detect depth information of an object, comprising: an FPA including a plurality of PSs, each operable to detect light coming from an instantaneous field of view (IFOV) of that PS, with different PSs oriented in different directions within the field of view of the sensor; a readout set of a plurality of readout circuits, each of which is connected by a plurality of switches to a readout group of a plurality of PSs of the FPA, the readout set of a plurality of readout circuits operable to output an electrical signal indicative of an amount of light impinging on a plurality of the PSs of the readout group when the readout group is connected to a respective readout circuit via at least one of the plurality of switches; a control device operable to change a plurality of switching states of a plurality of said switches such that different readout circuits of said readout set are connected to said readout group at different times to expose different readout circuits to reflections of illumination light from a plurality of objects located at different distances from said sensor; a processor configured to obtain a plurality of the electrical signals from the readout set indicative of detected levels of reflected light collected from a plurality of the IFOVs of the readout group of a plurality of photosites to determine depth information about the object indicative of a distance of the object from the sensor; A sensor is disclosed that includes:

[0019] BRIEF DESCRIPTION OF THE DRAWINGS In order that the present disclosure may be understood and how it may be carried out in practice, several embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which the following examples corresponding to various aspects of the subject matter of the present disclosure are provided: 1A and 2A are cross-sectional views showing examples of photosites of an IR light detection system; 1B and 2B illustrate the attenuation of charge carrier movement during rest duration in the systems of FIGS. 1A and 2A, respectively; 1C and 2C are diagrams illustrating the movement of charge carriers during the sampling duration in the systems of FIGS. 1A and 2A, respectively; 3A and 3B are top views showing two examples of photosites; Figure 4 shows the voltages applied to the photosite electrodes during successive sampling cycles; Figure 5 shows the IR light detection system; FIG. 6 is a block diagram illustrating an electro-optical system including an IR light detection system; FIG. 7 is a flow chart illustrating an example of a method for sensing light from a field of view; Figure 8 is a cross-sectional view showing a photosite of an IR light detection system; FIG. 9 shows the conditions applied to the voltage modulation on one or more electrodes of a photosite and the conditions applied to the transmission gate during successive sampling cycles; Figure 10 shows a photosite; Figure 11 shows a photosite; Figure 12A is a top view of a photosite; Figure 12B is a top view of an example photosite; Figures 13A, 13B, and 13C show cross-sectional and top views of a photosite; Figure 13D shows an example of a photosite with four separate readout structures; 14A and 14B show the relative voltages that may be applied to various regions of a photosite during its operation; 14C and 14D show exemplary relationships between voltages applied to various electrodes in various operating states; Figures 15, 16, 17, and 18 show photodetector arrays with N-tap photosites; FIG. 19 shows a method for detecting light coming from the field of view of a photodetector array containing a plurality of photosites; 20A and 20B are cross-sectional views showing an example of a photosite of an IR light detection system; Figure 21 shows a photosite; Figures 22 and 23 show methods for detecting IR radiation; FIG. 24 illustrates a method for generating a depth image of a scene based on the detection of a SWIR electro-optical imaging system; Figure 25 shows the timing of three different detected signals coming from the same direction within the FOV; 26A-26C show the sensor in various operating states; Figure 27 includes various timing diagrams; 28A-28C show the sensor in various operating states; Figure 29 shows the sensor; Figure 30 shows the field of view of the electro-optical system, and multiple instantaneous FOVs; 31A and 31B show various examples of sensors according to embodiments of the presently disclosed subject matter.

[0020] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Furthermore, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or similar elements.

[0021] Detailed Description In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present disclosure.

[0022] In the disclosed drawings and descriptions, identical reference numbers designate components that are common to different embodiments or configurations.

[0023] Unless otherwise indicated, and as will be apparent from the discussion that follows, throughout the specification, discussions using terms such as "processing," "calculating," "computing," "determining," "generating," "setting," "configuring," "selecting," "defining," and the like, are understood to include computer acts and / or processes that manipulate data and / or transform such data into other data, where such data may be represented as physical quantities, e.g., electronic quantities, and / or where such data represent physical objects.

[0024] The terms "computer," "processor," and "controller" should be interpreted broadly to encompass any type of electronic device having data processing capabilities, including, by way of non-limiting example, a personal computer, a server, a computing system, a communication device, a processor (e.g., a digital signal processor (DSP), a microcontroller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.), any other electronic computing device, and / or any combination thereof.

[0025] Operations according to the teachings herein may be performed by a computer specially created for the desired purpose, or may be performed by a general-purpose computer specially configured for the desired purpose by a computer program stored on a computer-readable storage medium.

[0026] As used herein, the phrases "for example," "such," "for instance," and variations thereof describe non-limiting embodiments of the subject matter disclosed herein. As used herein, reference to "one case," "some cases," "other case," or variations thereof means that a particular configuration, structure, or characteristic described in connection with one or more embodiments is included in at least one embodiment of the subject matter disclosed herein. Thus, appearances of the phrases "one case," "some cases," "other case," or variations thereof do not necessarily refer to the same embodiment(s).

[0027] It will be understood that certain features of the subject matter disclosed herein, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the subject matter disclosed herein, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0028] In embodiments of the presently disclosed subject matter, one or more of the stages shown may be performed in a different order and / or one or more groups of the stages may be performed simultaneously, or vice versa. Each figure shows a general schematic of a system architecture according to embodiments of the presently disclosed subject matter. Each module in the figure may be configured by any combination of software, hardware, and / or firmware that performs the functions as defined and described herein. Each module in the figure may be centrally located in one location or may be distributed across two or more locations.

[0029] Any reference herein to a method shall apply mutatis mutandis (i) to a system capable of carrying out that method, and (ii) to a non-transitory computer-readable medium storing instructions that, once executed by a computer, produce the result of carrying out that method.

[0030] Any reference herein to a system shall also apply mutatis mutandis to (i) a method that may be performed by the system, and (ii) a non-transitory computer-readable medium storing instructions that may be executed by the system.

[0031] Any reference herein to a non-transitory computer-readable medium shall apply mutatis mutandis to (i) a system capable of executing instructions stored on the non-transitory computer-readable medium, and (ii) a method that may be executed by a computer reading instructions stored on the non-transitory computer-readable medium.

[0032] In order that the present disclosure may be understood and how it may be carried out in practice, several embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings. It will be understood that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Furthermore, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or similar elements.

[0033] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present disclosure.

[0034] In the disclosed drawings and descriptions, identical reference numbers designate components that are common to different embodiments or configurations.

[0035] Unless otherwise indicated, and as will be apparent from the discussion that follows, throughout the specification, discussions using terms such as "processing," "calculating," "computing," "determining," "generating," "setting," "configuring," "selecting," "defining," and the like, are understood to include computer acts and / or processes that manipulate data and / or transform such data into other data, where such data may be represented as physical quantities, e.g., electronic quantities, and / or where such data represent physical objects.

[0036] The terms "computer," "processor," and "controller" should be interpreted broadly to encompass any type of electronic device having data processing capabilities, including, by way of non-limiting example, a personal computer, a server, a computing system, a communication device, a processor (e.g., a digital signal processor (DSP), a microcontroller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.), any other electronic computing device, and / or any combination thereof.

[0037] Operations according to the teachings herein may be performed by a computer specially created for the desired purpose, or may be performed by a general-purpose computer specially configured for the desired purpose by a computer program stored on a computer-readable storage medium.

[0038] As used herein, the phrases "for example," "such," "for instance," and variations thereof describe non-limiting embodiments of the subject matter disclosed herein. As used herein, reference to "one case," "some cases," "other case," or variations thereof means that a particular configuration, structure, or characteristic described in connection with one or more embodiments is included in at least one embodiment of the subject matter disclosed herein. Thus, appearances of the phrases "one case," "some cases," "other case," or variations thereof do not necessarily refer to the same embodiment(s).

[0039] It will be understood that certain features of the subject matter disclosed herein, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the subject matter disclosed herein, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0040] In embodiments of the presently disclosed subject matter, one or more of the stages shown may be performed in a different order and / or one or more groups of the stages may be performed simultaneously, or vice versa. Each figure shows a general schematic of a system architecture according to embodiments of the presently disclosed subject matter. Each module in the figure may be configured by any combination of software, hardware, and / or firmware that performs the functions as defined and described herein. Each module in the figure may be centrally located in one location or may be distributed across two or more locations.

[0041] Any reference herein to a method shall apply mutatis mutandis (i) to a system capable of carrying out that method, and (ii) to a non-transitory computer-readable medium storing instructions that, once executed by a computer, produce the result of carrying out that method.

[0042] Any reference herein to a system shall also apply mutatis mutandis to (i) a method that may be performed by the system, and (ii) a non-transitory computer-readable medium storing instructions that may be executed by the system.

[0043] Any reference herein to a non-transitory computer-readable medium shall apply mutatis mutandis to (i) a system capable of executing instructions stored on the non-transitory computer-readable medium, and (ii) a method that may be executed by a computer reading instructions stored on the non-transitory computer-readable medium.

[0044] 1A is a cross-sectional view illustrating an example photosite 6202 of an IR light detection system 6200, according to an embodiment of the presently disclosed subject matter. The IR light detection system 6200 (hereinafter also referred to as "IR system 6200" or simply "system 6200") is sensitive to photons in the IR range. Although not necessarily so, the IR light detection system 6200 may be or include an IR light detection sensor. Although not necessarily so, the IR light detection system 6200 may be or include a SWIR light detection sensor. With respect to the light detection sensors discussed and claimed below, it should be noted that the term “short-wave infrared sensor” and similar terms (e.g., “short-wave infrared FPA sensor,” “short-wave infrared FPA”) refer to a photosensitive sensor capable of absorbing and detecting impinging short-wave infrared radiation (i.e., radiation with wavelengths between 1,000 and 1,700 nm). It should also be noted that such sensors, in addition to being sensitive to portions of the SWIR spectrum, may also be sensitive to other portions of the spectrum (e.g., portions shorter than 1,000 nm). In particular, such light detection sensors may optionally be sensitive to portions of the visible spectrum (400 to 700 nm), although this need not be the case. In at least portions of the SWIR spectrum, the quantum efficiency of these SWIR sensors is higher than that achievable by Si-based light sensors (which are more suited to sensing in the visible spectrum). Optionally, the disclosed and claimed SWIR systems may be sensitive to impinging radiation within a subsection of the shortwave IR spectrum (for purposes of this disclosure, 1,000 nm to 1,700 nm), and even more specifically, to impinging radiation between 1,200 nm and 1,550 nm. For a given wavelength within the context of this disclosure, a sensor is defined as sensitive if the quantum efficiency of the sensor for that wavelength is greater than 5%.

[0045] The IR system 6200 may include one or more photosites (PS) 6202. For example, the IR system 6200 may include hundreds, thousands, tens of thousands, hundreds of thousands, millions, or more PSs 6202. The detected signals may be processed to generate an image, video, or 3D model of an object within the FOV of the IR system 6200 (or an electro-optical system in which the IR system 6200 is incorporated). For example, the IR system 6200 may include a 1280x720 PS 6202 to generate an HD resolution image. In other embodiments, the IR system 6200 may include a 640x480 PS 6202, a 1440x900 PS 6202, or a 1920x1080 PS 6202, or any other arrangement of PSs (standard or non-standard, rectangular tiled, hexagonal tiled (also referred to as "honeycomb tiled"), or any other geometric arrangement of PSs). Any of the PS arrays discussed throughout this disclosure can be used as an image receptor.

[0046] The PS 6202 includes a Si layer 6210 on which a diode 6230 is implemented. The diode 6230 includes two doped regions: a first doped region 6232 and a second doped region 6234. The first doped region 6232 has a first polarity (positive in the example of FIG. 1A and negative in the example of FIG. 2A), and the second doped region has a second polarity opposite to the first polarity (negative in the example of FIG. 1A and positive in the example of FIG. 2A). Optionally, the Si layer 6210 is a silicon-on-insulator (SOI) layer.

[0047] In addition to the Si layer, the PS 6202 further includes a Ge photosensitive area (or simply "Ge area") 6220. The Ge photosensitive area 6220 is operable to generate eh pairs in response to impinging IR photons (and possibly also in response to photons in other portions of the electromagnetic spectrum, such as the near IR (NIR) and visible (VIS) portions of the electromagnetic spectrum). The term "Ge area" refers to a bulk of material in which light-induced excitation of electrons occurs within Ge, within a Ge alloy (e.g., SiGe), or at the interface between Ge (or a Ge alloy) and another material (e.g., Si, SiGe). Specifically, the term "Ge area" refers to both pure Ge bulk and Ge-Si bulk. When using a Ge bulk containing both Ge and Si, various concentrations of Ge may be used. For example, the relative portion of Ge in a Ge region (whether alloyed with Si or adjacent to Si) may be between 5% and 99%. For example, the relative portion of Ge in a Ge region may be between 15% and 40%. Note that materials other than Si (such as aluminum, nickel, silicide, or any other suitable material) may also be part of the Ge region. In some embodiments, the Ge region may be a pure Ge region (comprising greater than 99.0% Ge). The Ge region 6220 may be deposited on the Si layer 6210 by any suitable method (such as, but not limited to, uniform layer epi growth, selective layer epitaxy, etc.).

[0048] Within Ge region 6220 is at least one doped region 6222 (also referred to as an "absorber doped area") having a first polarity (i.e., the same polarity as first region 6232; positive in the example of FIG. 1A and negative in the example of FIG. 2A). With reference to the doping levels of various portions of PS 6202, it should be noted that the relative doping ratios shown are exemplary, and the various relative doping levels (e.g., "-", "+", "++") are provided merely as examples, and any suitable combination of relative doping levels and polarities may be used.

[0049] Geometrically, the first doped region 6232 is located between the second doped region and the absorber-doped region. In the context of the present disclosure, this means that most (or all) of the straight lines between a point on the Ge region 6220 and a point on the second doped region 6234 (of opposite electrical polarity) pass through at least one point in the first doped region 6232, pass below at least one point in the first doped region 6232, or pass above at least one point in the first doped region 6232. Thus, controlling the relative voltages in the Ge region 6220, the first doped region 6232, and the second doped region 6234 affects the movement of charge carriers generated in the Ge region 6220 to the readout portion of the respective PS 6202, as described below. Figures 3A and 3B are top views showing two example PSs 6202 (only some of the components are shown for clarity). The voltages applied to the various doped regions are transmitted via three electrodes (or multiple combinations of electrodes). One or more electrodes 6221 provide a voltage to the Ge region 6220 (optionally, specifically to the doped region 6222 with the Ge region 6220). This voltage is shown in the figure as a "modulation voltage" and a "V MOne or more electrodes 6233 provide a voltage to the first doped region 6232, and one or more electrodes 6235 provide a voltage to the second doped region 6234. The voltages provided to the positively doped regions (of region 6232 and region 6234) are shown in the figures as "Anode voltage" and "V A ", while the voltages provided to the negatively doped regions (of region 6232 and region 6234) are shown in the figures as "Cathode voltage" and "V C The voltages are provided by one or more power sources. Such power sources may be constant power sources (routinely providing a single constant voltage when on), modulated power sources (e.g., providing a voltage modulated between discrete voltages or gradually varying the provided voltage), or any other type of power source. In the illustrated example, only the voltage provided to the Ge region 6220 is modulated, but as will be described below, other types of voltages may be modulated (V A and V C Other voltage modulations (denoted by ) may also be implemented.

[0050] The IR system 6200 includes at least one power supply (e.g., power supply 6250 and / or a power supply connected to electrode 6235) operable to provide a first region voltage to the first doped region 6232 and a second region voltage to the second region 6234. These voltages are used to bias the diode 6230. Optionally, this biasing may be constant in time; however, this need not be the case. In the illustrated embodiment, the biasing is always active (V A and V C and are set to a high level during both the active read phase and the idle rest time of each PS6202), although in some embodiments the biasing voltages are not necessarily active all the time.

[0051] The IR system 6200 further includes at least one controllable power source 6240 operable as follows: a. Provide an activation voltage to Ge region 6222 (during the sampling duration of PS 6202) that forces charge carriers of a second polarity to migrate from Ge region 6222 (where charge carriers are generated as a result of impinging light) toward diode 6230, where the CCSPs are collected via readout electrode 6235 electrically coupled to second doped region 6234. In the example of FIGS. 1A-1C, the CCSPs are electrons, and in the example of FIGS. 2A-2C, the CCSPs are holes. The movement of charge carriers during the sampling duration is illustrated in FIGS. 1C and 2C. In the figures, the connection to readout circuitry is indicated at 6260.

[0052] b. Signal collection by each PS 6202 is stopped after the end of the sampling duration by providing a quiescent voltage to the Ge region 6222 that reduces (and in some cases completely stops) the forced migration of CCSPs towards the diode 6230. The reduction in charge carrier migration during the quiescent duration is illustrated in Figures 1B and 2B.

[0053] During the activation period, charge carriers of the second polarity are repelled by the voltage applied to Ge region 6220 and attracted by the voltage applied to first doped region 6232. These charge carriers move through first doped region 6232 and toward second doped region 6234 using a drift velocity resulting from the applied voltage between first doped region 6232 and second doped region 6234 (e.g., in depletion region 6280 (identified only in FIGS. 1A and 2A so as not to reduce the visual load of the other diagrams)).

[0054] The IR system 6200 may optionally include a controller 6270 (which may be implemented on the same chip as the PS 6202 or may be part of a larger electro-optical system in which the chip is part). The optional controller may control the provision of the modulated voltage(s) to the associated PS electrode, as well as other aspects of the operation of the IR system 6200.

[0055] The sampling cycle of PS6202 includes two phases: (i) a sampling duration during which a signal is collected (and then sampled and, optionally, provided to an external module), and (ii) a rest duration during which no signal is collected. Stopping application of the activation voltage damps out the movement of charge carriers of the second polarity to readout electrode 6235. Optionally, the sampling cycle of PS6202 includes only these two phases and no other phases. During the rest duration, movement is damped and not intentionally directed toward another useful (valid) location on the PS. Notably, in some or all embodiments, PS6202 does not include another readout electrode used for collecting signals during the rest period. Optionally, the charge damping is due to the expected short lifetime of charge carriers in Ge region 6220.

[0056] If the first polarity is positive, the voltage combination (V A , V C , V M ) is condition V C ≧V A >V M and when the sampling duration ends (e.g., during an idle duration), the voltage combination satisfies at least the condition V M ≧V A and optionally further satisfying condition V C ≧V A Meet the following.

[0057] Directing charge carriers of the second polarity toward the readout electrode only at certain times may be used to selectively collect electrical signals during relatively short time spans (e.g., corresponding to illumination by a light source). This may be useful, for example, to prevent dark current charges generated in the Ge region 6220 (which may be relatively high compared to dark current in Si photodetectors) from saturating the detector capacitance. In the IR system 6200, switching between sampling and idle times is implemented at the semiconductor level, compared to readout circuit electronic switching implemented using transistors or other electrical components. Implementation of switching at the semiconductor level is characterized by significantly lower noise compared to noise introduced by switching at the readout circuit level (e.g., thermal noise, also referred to as Johnson-Nyquist noise or kTC noise). Nevertheless, it should be noted that the above-described switching at the semiconductor level may be combined with other forms of switching, even those implemented in the readout circuit.

[0058] It should be noted that any of the activation voltage and / or rest voltage may be a single voltage or a range of voltages. Any of the voltages applied to the first doped region 6232 and the second doped region 6234 may be a single voltage or a range of voltages. For example, the activation voltage may be 1 V, 2 V, or a range of voltages in the range of 1 to 2 V. Similarly, the rest voltage may be 0.0 V, −0.2 V, 0.3 V, or a range of voltages in the range of −0.2 to 0.3 V. Optionally, the amplitude of the rest voltage is at least 0.2 V lower than the amplitude of the activation voltage. Optionally, the rest voltage may be zero or close to zero, but this is not necessarily the case.

[0059] Referring to the power supplies that provide voltages to electrode 6221, electrode 6233, and electrode 6235, each of these power supplies (modulated or constant) may provide voltages to one or more PSs 6202. The power supplies (e.g., 6240, 6250) may be contained within an individual PS 6202 (as illustrated in FIG. 1A) or may be contained external to an individual PS 6202 (as illustrated in FIG. 2A). Note that the location of the power supplies relative to an individual PS 6202 is not related to the polarity of the various doped regions illustrated in a particular figure.

[0060] In the illustrated embodiment, modulation is performed only on electrode 6221, which provides a voltage to Ge region 6220. However, equivalent embodiments will be apparent to those skilled in the art that use modulation on the anode voltage and / or modulation on the cathode voltage to create a migration of charge carriers of a second polarity from Ge region 6220 to second doped region 6234 during the activation duration of PS 6202 and attenuate that migration during the rest duration of PS 6202. A Modulation of and / or V C The modulation of V M , optionally the voltage on the Ge region 6220 may be modulated with V A and / or V C may be kept constant when modulated. An example of such an embodiment is provided below for one side of the PS with respect to PS 6502 in Figure 13A. This may be implemented mutatis mutandis in PS 6202 (or any other PS described below).

[0061] FIG. 4 includes a voltage diagram 40 illustrating voltages applied to electrodes 6221, 6233, and 6235 during successive sampling cycles according to an embodiment of the presently disclosed subject matter. The top graph relates to an embodiment in which the first polarity is positive (e.g., as shown in FIGS. 1A-1C), and the bottom graph relates to an embodiment in which the first polarity is negative (e.g., as shown in FIGS. 2A-2C). Multiple sampling cycles may be of the same duration, for example, as illustrated in FIG. 4, but this need not be the case. The sampling durations of various sampling cycles may be constant, for example, as illustrated in FIG. 4, but this need not be the case. The pause durations of various sampling cycles may be constant, for example, as illustrated in FIG. 4, but this need not be the case.

[0062] The duration of the sampling cycle may optionally be determined with respect to the frame rate of the IR system 6200. For example, for a frame rate of 60 fps, the duration of multiple sampling cycles may each be 1 / 60 seconds. If each frame of the 60 fps example requires multiple exposures, the sampling cycles may be much shorter than this and may not necessarily be of equal length. The sampling cycles may optionally be synchronized with illumination by the associated illumination source (if any). For example, the IR system 6200 may be combined with at least one illumination source (e.g., laser, light emitting diode (LED)) in a single electro-optical system (e.g., camera, LIDAR, spectrograph), and the sampling duration may begin upon emission of light by the at least one light source. Each sampling duration may be associated with a single illumination span, multiple illumination spans (e.g., in some pulsed illumination embodiments), or asynchronous with illumination (e.g., when no illumination or constant illumination is implemented). The sampling durations and / or sampling cycles of the various PSs 6202 may be synchronized (e.g., starting at the same time), cascaded (e.g., various columns of multiple PSs in a photodetector array may be triggered one after the other), or otherwise modulated.

[0063] The sampling duration may be varied in various embodiments of the present disclosure. Optionally, one or more of the at least one sampling duration of PS 6202 is shorter than 10 nanoseconds. Optionally, one or more of the at least one sampling duration of PS 6202 is between 10 and 100 nanoseconds. Optionally, one or more of the at least one sampling duration of PS 6202 is between 100 and 500 nanoseconds. Optionally, one or more of the at least one sampling duration of PS 6202 is between 0.5 and 5 microseconds. Optionally, one or more of the at least one sampling duration of PS 6202 is longer than 5 microseconds.

[0064] Although not required, Si layer 6210 and Ge region 6220 may optionally be doped to have a first polarity, which may be used to create a positive channel (or a negative channel).

[0065] Optionally, the IR light detection system 6200 may include a spectral filter to block photons in the visible spectrum from reaching the photodiode. Spectral filters that block other portions of the electromagnetic spectrum (e.g., the far-infrared portion of the spectrum, the ultraviolet portion of the spectrum) may also be implemented. Blocking photons in selected portions of the spectrum from reaching the diode may be done to prevent accumulation of a signal caused by these photons (in the Ge region 6220 and / or the Si layer 6210). Optionally, in an electro-optical system incorporating the IR system 6200, one or more spectral filters may be implemented at the system level. For example, a window, lens, mirror, prism, or another optical component that deflects light to be sensed by the system may be coated with a spectral filtering coating, or a dedicated spectral filter may be placed on the incident optics. If implemented, the spectral filter may be implemented on the same chip as the IR system 6200 or in any other portion of the electro-optical system (not shown).

[0066] Optionally, the IR light detection system 6200 (or an electrical system incorporating the IR sensing chip) may include a cooling module (e.g., a heat transfer fluid, a heat sink, a cold plate, a Peltier cooling plate) to reduce heat caused by charge carriers of the first polarity collected via electrodes electrically coupled to the Ge region 6220. Note that the current resulting from these charge carriers of the first polarity may be larger than the detection signal collected by the readout circuitry. The intrinsic doping of the Si layer 6210 and / or the Ge region 6220 may be such that it reduces the mobility of charge carriers of the first polarity, thereby reducing the modulation current of the charge carriers of the first polarity. This reduction of the modulation current of charge carriers of the first polarity (by selecting an appropriate doping level (e.g., a low level of doping)) helps reduce the thermal effect of the modulation current, thereby reducing power consumption and alleviating (or reducing) the need for expensive cooling mechanisms.

[0067] Optionally, IR photons from the FOV of IR light detection system 6200 pass through Si layer 6210 before being absorbed in Ge region 6220 (where, depending on the quantum efficiency of the detector, the IR photons may cause the generation of eh pairs).

[0068] Optionally, the IR light detection system 6200 may include a passivation layer 6290 between (a) the Ge region 6220 and the diode 6230 on one side and (b) the at least one power source (e.g., 6240, 6250) on the other side. Such a passivation layer may be made of SiO2, Si3N4, or any other suitable material. Optionally, the IR light detection system 6200 may include a planarization layer (e.g., between (a) the Ge region 6220 and the diode 6230 on one side and (b) the at least one power source on the other side). Such a planarization layer may be made of SiO2, Si3N4, or any other suitable material. Note that the optional passivation layer 6290 is shown only in FIGS. 2A-2C but is not related to any particular polarity of the portions of the IR system 6200.

[0069] Optionally, the Ge region 6220 may overlay (directly or indirectly overlay) the Si layer. In other embodiments (not shown), at least a portion of the Ge region is buried within the Si layer (e.g., within an etched hole) and / or within the passivation layer (if present).

[0070] Optionally, the IR light detection system 6200 may include at least one photo-effective layer bonded to a polished side of the Si layer located opposite the side of the Si layer on which the Ge region is deployed. A photo-effective layer in the context of the present disclosure is a layer that manipulates radiation passing through it. For example, the photo-effective layer may function as a chromatic filter, a polarizing filter, any other type of optical filter, a retarder, a diffraction grating, or any other type of layer that affects optical radiation traversing the layer.

[0071] FIG. 5 shows an IR light detection system 6200 according to an embodiment of the previously disclosed subject matter. In the illustrated example, multiple PSs 6202 are arranged in a rectangular matrix, and a power supply provides voltage to all PSs 6202 simultaneously. To keep the drawing simple and readable, all electrodes to various portions of each PS 6202 are represented by single lines. Optionally, the IR light detection system 6200 may include one or more readout circuits 6810 implemented on the same wafer as one or more of the multiple PSs 6202, operable to read at least one electrical signal from each of the multiple PSs corresponding to the number of photons captured by the Ge region during the sampling duration of the respective PS. Optionally, the IR light detection system 6200 may include one or more power supplies 6820 that provide voltage for operation of the multiple PSs 6202 (and possibly provide voltage for additional components of the IR light detection system 6200). The power supply 6820 may provide power under the direction of a controller 6830, which may (but need not) be implemented on the same wafer. Additionally, the optional controller 6830 may control the operation of other portions of the IR light detection system 6200, such as a switching module.

[0072] Figure 6 is a block diagram illustrating an electro-optical system 6299 including an IR light detection system 6200, according to an embodiment of the presently disclosed subject matter. While Figure 6 illustrates some of the components that may be included in such an electro-optical system, it will be apparent to one skilled in the art that many other components may be implemented in an operational electro-optical system 6299. Examples of electro-optical systems 6299 that may include system 6200 are IR cameras, lidars, spectrographs, etc.

[0073] Optionally, electro-optical detection system 6299 may include various additional components, many of which are known in the art, such as (but not limited to) any combination of one or more of the following components: a. Any variation of IR light detection system 6200 (including multiple PSs); b. At least one optical interface 6792 for directing light from the FOV of the electro-optical detection system 6299 onto the IR light detection sensor 6200. While the optical interface 6792 is illustrated as a single lens, those skilled in the art will appreciate that any suitable combination of optical components may be used, such as, but not limited to, lenses, mirrors, prisms, optical fibers, filters, beam splitters, retarders, etc. Such optical components may be fixed or movable (particularly in a controllable manner); c. At least one readout circuit 6710 operable to read at least one electrical signal from each of the plurality of PSs corresponding to the number of photons captured by the Ge region during the sampling duration of the respective PS. The readout circuit 6710 may be used, for example, to read the detection signal from the PSs 6202 and provide the signal for further processing (e.g., to reduce noise, for image processing), storage, or any other use. For example, the readout circuit 6710 may sequentially organize the readings of the various PSs 6202 in time (possibly after some processing) before providing them for further processing, storage, or any other action. Optionally, the readout circuit 6710 may be implemented as one or more units fabricated on the same wafer as other components of the IR light detection system 6200 (e.g., PSs 6202, amplifiers). Optionally, the readout circuit 6710 may be implemented as one or more units on a printed circuit board (PCB) connected to such wafer. Also, any other suitable type of readout circuit may be implemented as the readout circuit 6710. Examples of analog signal processing that may be performed in the electro-optical detection system 6299 (e.g., by readout circuit 6710 or by one or more processors 6720 of each electro-optical detection system 6299) prior to optional digitization of the signal include changing gain (amplification), offset, and binning (combining output signals from two or more PSs). Digitization of readout data may be performed by the electro-optical detection system 6299 or external to it. Optionally, readout circuit 6710 may include (or consist of) the readout circuit 6810 described above, although this need not be the case.

[0074] d. At least one processor 6720 operable to process the detection data provided by the readout circuitry 6710, indicative of a plurality of electrical signals, such that an IR image of the FOV is provided. Note that the readout circuitry 6710 is optional, and therefore any suitable method of providing information indicative of the signal levels of the various PSs to the processor 6720 may be utilized. The processing by the processor 6720 may include, for example, signal processing, image processing, spectroscopic analysis, etc. Optionally, the results of the processing by the processor 6720 may be used to modify the operation of the controller 6270 (or another controller). Optionally, the controller 6270 and the processor 6720 may be implemented as a single processing unit. Optionally, the results of processing by processor 6720 may be provided to any one or more of the following components: a tangible memory module 6740 (e.g., for storage or later retrieval, see below), to an external system (e.g., a remote server or a vehicle computer of a vehicle in which system 6299 is installed), for example via communication module 6730, a display 6750 for displaying images or another type of result (e.g., graphs, spectrograph textural results), another type of output interface (e.g., speaker, not shown), etc. Note that optionally, signals from multiple PSs may be processed by processor 6720, for example, to assess the status (e.g., operability, temperature) of IR system 6200.

[0075] e. At least one light source 6780 operable to emit light onto the FOV of the electro-optical system 6299. A portion of the light from the light source 6780 is reflected from objects within the FOV and captured by the plurality of PSs 6202. This light may be used (e.g., by the processor 6720) to generate an image or another model of the object. Any suitable type of light source (e.g., a pulsed light source, a continuous light source, a modulated light source, an LED light source, a laser light source) may be used. Optionally, the operation of the light source 6780 may be controlled by a controller (e.g., the controller 6270).

[0076] f. At least one optical interface 6794 for directing light from one or more light sources 6780 to part or all of the FOV of the electro-optical detection system 6299. While the optical interface 6794 is illustrated as a single lens, those skilled in the art will appreciate that any suitable combination of optical components may be used, such as, but not limited to, lenses, mirrors, prisms, optical fibers, filters, beam splitters, retarders, etc. Such optical components may be fixed or movable (particularly in a controllable manner); g. At least one filter 6770 for manipulating light collected from part or all of the FOV before it reaches the plurality of PSs 6202. Such a filter may include a physical barrier, a spectral filter, a polarizer, a retarder, or any other suitable type of filter. The filter 6770 may be part of the detector array (e.g., implemented as one or more layers on the same wafer) or may be external to the detector array. The filter 6770, if implemented, may be fixed or variable (e.g., a moving shutter). Optionally, the operation of the filter 6770, if variable, may be controlled by a controller (e.g., controller 6270).

[0077] h. At least one controller 6270 for controlling, synchronously or otherwise, the operation of any one or more of the other components of the electro-optical system 6299 (e.g., photodetectors, light sources, readout circuitry). Note that any functionality of the controller 6270 may be implemented by an external controller (e.g., on a separate processor of the electro-optical system 6270 that is not directly connected to the photodetectors, or by an auxiliary system such as a controller of an autonomous vehicle in which the electro-optical system 6299 is installed). Optionally, the controller 6270 may be implemented as one or more processors fabricated on the same wafer as the other components of the IR system 6200 (e.g., multiple PSs 6202). Optionally, the controller 6270 may be implemented as one or more processors on a printed circuit board (PCB) connected to such wafer. Other suitable controllers may also be implemented as the controller 6270. Optionally, controller 6270 may include (or consist of) controller 6830 described above, although this is not required.

[0078] i. At least one memory module 6740 for storing at least one detection signal (e.g., if different) among the plurality of detection signals output by the plurality of PSs and / or readout circuits 6710, as well as detection information generated by the processor 6720 by processing the plurality of detection signals.

[0079] j. At least one power source 6760 (e.g., a battery, an AC power adapter, a DC power adapter). The power source may provide power to multiple PSs, to an amplifier, or to any other components of the photodetector device.

[0080] k.Hard casing 6798 (or any other type of structural support).

[0081] Optionally, the processor of the electro-optical system 6299 may be further configured to process the detection data such that the presence of at least one object within the FOV is determined.

[0082] 7 is a flowchart illustrating an example of a method 6300 according to the subject matter of this disclosure. Method 6300 is a method for sensing light from an FOV. Referring to the examples in the accompanying drawings, method 6300 may optionally be performed by IR system 6200 or by electro-optical system 6299.

[0083] Step 6310 includes applying a first voltage combination to (a) a first doped region of the Si layer of the PS, (b) a second doped region of the Si layer of the PS having an opposite doping polarity, and (c) a doped region of the Ge region of the PS connected to the Si layer to enable transfer of charge carriers from the Ge region to the Si layer. By applying the first voltage combination, charge carriers of the same polarity as the second doped region are forced to move from the Ge region toward the second doped region of the Si layer. CCSPs are then collected in the second doped region via a readout electrode electrically coupled to the second doped region. Step 6310 includes applying the first voltage combination for a sampling duration of the PS.

[0084] Step 6320 includes providing a second voltage combination to the first doped region of the Si layer, the second doped region of the Si layer of the PS, and the doped region of the Ge region. By providing the second voltage combination, the aforementioned charge carrier forcing is attenuated, thereby ceasing signal collection by the PS. Step 6320 includes providing the second voltage combination for a pause duration of the PS. While not required, the pause duration may begin immediately upon the end of the sampling duration.

[0085] The first and second voltage combinations can differ from one another in (a) the voltage(s) applied to the first doped region of the Si layer, (b) the voltage(s) applied to the second doped region of the Si layer, (c) the voltage(s) applied to the Ge region, or (d) any combination of two or more of (a), (b), and (c). At at least the first voltage combination, a photodiode including the first and second doped regions is biased for collection of charge carriers resulting from absorption of photons.

[0086] Optionally, diode 6230 is maintained in reverse bias for the duration of the sampling period, and optionally for the entire continuous operation of PS 6202. V C V A , diode 6230 is maintained in reverse bias. Optionally, diode 6230 is maintained at zero bias (or substantially zero bias) during the sampling duration, and optionally during the entire continuous operation of PS 6202. Optionally, during the sampling duration, and optionally during the entire continuous operation of PS 6202, V C ≧V A is.

[0087] Stage 6330 of method 6300 includes reading, by a readout circuit electrically connected to the PS, the electrical signals collected during at least a particular sampling duration to determine a detected signal for the PS during the sampling duration. Stage 6330 is performed after stage 6310 is completed. Stage 6330 may also be performed during and / or after stage 6320. The detected signals may be used to generate an image, for example, by combining multiple detected signals of multiple PSs, each PS pointing toward an instantaneous FOV within the system's FOV.

[0088] Stages 6310, 6320, and 6330 may be repeated in batches to collect various detection signals corresponding to the amount of IR light impinging on the Ge region of the IR light detection system. The sampling duration and pause duration may be kept the same between any two consecutive instances of the repetition, although one or both of these durations may be changed.

[0089] Stages 6310, 6320, and 6330 may be performed for each of multiple PSs of the IR sensor, and method 6300 may include generating an image (or other detection model, such as a depth map for lidar or spectrographic analysis) representative of objects within the FOV in response to multiple detection signals of the various PSs. The sampling durations of the various PSs may be consistent with one another or may be different from one another.

[0090] A method for detecting IR radiation by a PS such as PS6202 is disclosed, which includes the following steps: a. providing a first region voltage to a first doped region of the PS and a second region voltage to a second region of the PS, wherein the PS is: (i) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (ii) a Si layer including a diode, the diode including a first doped region of a first polarity and a second doped region of a second polarity opposite to the first polarity; wherein the first doped region is located between the second doped region and the absorber doped region.

[0091] b. providing an activation voltage to the Ge region for a sampling duration of PS while providing the first region voltage and the second region voltage, the activation voltage forcing charge carriers of a second polarity to migrate from the Ge region toward a photodiode, where CCSP is collected in the photodiode via a readout electrode electrically coupled to the second doped region.

[0092] c. stopping signal collection by the photosites after the end of the sampling duration by providing a resting voltage to the Ge photosensitive region that attenuates forced migration of the CCSPs toward the photodiode. d. Optionally, reading the electrical signals collected during at least a particular sampling duration by a readout circuit electrically connected to the PS to determine a detection signal for the PS during said sampling duration.

[0093] e. Any step discussed with respect to method 6300 or variations thereof.

[0094] 8 is a cross-sectional view illustrating an example of an IR light detection system PS6402 according to an embodiment of the disclosed subject matter. PS6402 is similar to PS6202 but has a different readout mechanism. While in PS6202 readout is implemented via an electrode connected to a pole of the photodiode (of second polarity), in PS6402 readout is implemented via a transfer gate 6410 connecting between a storage well 6430 (of second polarity) and a floating diffusion 6420 (of second polarity). Charge carriers generated in Ge region 6492 (specifically, in doped region 6494 of Ge region 6492) are selectively collected into storage well 6430 during an active period of the PS based on the voltage difference between Ge region 6492 and first doped region 6440. During the collection phase, the transmission gate 6410 may keep the storage well 6430 isolated from the floating diffusion 6420 so that all CCSP coming from the Ge region 6492 is collected during the sampling time of the PS. At a later time (e.g., during the off time during the modulation voltage), the transmission gate 6410 may connect the storage well 6430 and the floating diffusion 6420 so that the charge collected in the storage well 6430 may transfer to the floating diffusion 6420. The charge is read out from the floating diffusion 6420 by at least one electrode 6460. The storage well 6430 may be a pinned layer (also referred to as a “pinned area”) underlying a pinning layer 6450 (also referred to as a “pinning area”) of the opposite polarity (first polarity). Optionally, a third layer 6470 (also referred to as "third region 6470") may be pinned below the storage well, which has a different doping of the first polarity with respect to the Si layer in which it resides.

[0095] In the illustrated example, modulation is implemented on the first doped region 6440. The voltage on the Ge region 6492 and the readout electrode is held constant. It should be noted, however, that any suitable type of modulation may be used to modulate the voltage on any one or more of these electrodes, as long as the relative voltage between the electrodes changes over time.

[0096] Note that the "charge storage region" may appear as a pinned photodiode, but the collected charge comes from a remote Ge region compared to any part of the charge storage region. An appropriate filter may be implemented to bring charge generation to Si (e.g., one that blocks some parts of the PS6402, a spectral bandpass or highpass filter that passes SWIR light but not visible or NIR light, etc.).

[0097] FIG. 9 includes a state diagram 50 illustrating the applied states (sampling mode vs. idle mode) for voltage modulation on one or more of the electrodes connected to the Ge region and the electrodes connected to the first doped region and the applied states (connected, i.e., charge readout, or disconnected) for the transmission gate during successive sampling cycles, according to an embodiment of the presently disclosed subject matter. In the illustrated example, multiple illumination pulses are emitted (at times t1-t6), and charge indicative of the amount of reflected light from each pulse is accumulated for three consecutive pulses before being read from the storage well via floating diffusion. The sampling window may begin upon the emission of a pulse (e.g., as in the case where pulses are emitted at t1, t2, and t3), or after a delay period or before the emission of a pulse (e.g., as in the case where pulses are emitted at t4, t5, and t6). Note that some sampling durations may be performed without connection to a pulse (e.g., to measure a dark calibration frame). The sampling cycles may be of equal duration, for example, as illustrated in FIG. 9, but this need not be the case. The sampling durations of the various sampling cycles may be constant, for example, as illustrated in FIG. 9, but this need not be the case. The pause durations of the various sampling cycles may be constant, for example, as illustrated in FIG. 9, but this need not be the case. The duration of the sampling cycle may optionally be determined with respect to the frame rate of the IR system of which the PS6402 is a component. For example, for a frame rate of 60 fps, the duration of the multiple sampling cycles may each be 1 / 60 seconds, and each may contain charge collected from one or more pulses. If each frame in the 60 fps example requires multiple exposures, the sampling cycles may be much shorter than this and need not necessarily be of equal length.The sampling cycles may optionally be synchronized with illumination by the associated illumination source (if any). For example, an IR system may be combined with at least one illumination source (e.g., laser, light-emitting diode (LED)) in a single electro-optical system (e.g., camera, LIDAR, spectrograph), and the sampling durations may begin upon emission of light by the at least one light source. Each sampling duration may be associated with a single illumination span, multiple illumination spans (e.g., in some pulsed illumination embodiments), or asynchronous with illumination (e.g., when no illumination or constant illumination is implemented). The sampling durations and / or sampling cycles of the various PSs 6402 may be synchronized (e.g., starting at the same time), cascaded (e.g., various columns of multiple PSs in a photodetector array may be triggered one after the other), or otherwise modulated. The sampling durations may be varied in various embodiments of the present disclosure. Optionally, one or more of the sampling durations of at least one PS 6202 is shorter than 10 nanoseconds. Optionally, one or more of the at least one sampling duration of PS6202 is between 10 and 100 nanoseconds. Optionally, one or more of the at least one sampling duration of PS6202 is between 100 and 500 nanoseconds. Optionally, one or more of the at least one sampling duration of PS6202 is between 0.5 and 5 microseconds. Optionally, one or more of the at least one sampling duration of PS6402 is longer than 5 microseconds.

[0098] FIG. 10 illustrates a PS 6404 according to an embodiment of the disclosed subject matter. All of the components of PS 6402 described above are included in PS 6404. PS 6404 includes an additional doped region 6480 that is modulated with respect to the Ge region, which may be used to redirect charge carriers of a second polarity away from storage well 6430 during idle times in a sampling cycle (e.g., whenever doped region 6440 is “off,” doped region 6480 may be “on,” and vice versa; however, other modulations may be implemented). Note that, optionally, additional doped region 6480 is not modulated with respect to the Ge region, but rather has a relatively small, constant voltage difference with respect to the Ge region. During idle times, this low DC offset is sufficient to attract the respective charge carriers, but is overcome by a higher modulation voltage during the sampling duration. Note that similar additional doped regions with corresponding modulations may also be implemented in the PS6402 (optionally illustrated in FIG. 2, where V R is shown).

[0099] FIG. 11 shows a photosite 6406 according to an embodiment of the presently disclosed subject matter. All of the components of PS 6404 described above are included in PS 6404. Photosite 6406 includes additional storage, floating diffusion, readout electrodes, and other components for reading out charge carriers of a second polarity when they are collected away from first storage well 6430. Such a configuration may be used, for example, for time-of-flight measurements, in which the relative amount of charge collected on each of the two sides may indicate the phase of the returning light and, therefore, the distance to an object reflecting the light. A controller may toggle the readout between two readout complexes (left and right of the Ge region in the figure).

[0100] 12A is a top view of an example of a PS 6406 (for clarity, only some of the components are shown). Voltages applied to the different doped regions are transmitted through the respective electrodes (or combinations of electrodes).

[0101] FIG. 12B shows a top view of an example of PS6408 (only some of the components are shown for clarity). Voltages applied to the different doped regions are transmitted through their respective electrodes (or combinations of electrodes). All of the components of PS6406 described above are included in PS6408. PS6408 includes an additional doped region 6790 (further labeled "OFF time charge removal") that is modulated with respect to Ge region 6492 and can be used to divert charge carriers of a second polarity away from both storage wells during idle times in the sampling cycle. For example, charge carriers of a second polarity may be toggled between the first and second storage wells when a reflected pulse of light is detected by PS6408, and may be diverted toward a third doped region (at the top of the figure) when a reflected pulse is not expected or desired. The transmission gates can be turned on simultaneously (e.g., if two readout circuits are used) or consecutively (e.g., if a single readout circuit reads both sides at different times) for readout when charge is directed toward that third doped region.

[0102] It should be noted that any variations, implementations, features, and components described above with respect to PS6202 may be applied, mutatis mutandis, to PS6402, PS6404, PS6406, and PS6408. It should be noted that any variations, implementations, configurations, and components described above with respect to IR system 6200 may be implemented, mutatis mutandis, for any IR system in which PS6402, PS6404, PS6406, or PS6408 is implemented.

[0103] 13A, 13B, and 13C illustrate a cross-sectional view (FIG. 13A) and a top view (FIG. 13B) of an example photosite 6502, in accordance with an embodiment of the presently disclosed subject matter. Similar to the PSs described above, a group of one or more PSs 6502 may be incorporated into an IR photodetection system operable to detect IR radiation. Such a system may be substantially similar to system 6299, but may include PS 6502 in place of PS 6202, mutatis mutandis. Each PS 6502 includes a Ge photosensitive region 6520 operable to generate e-h pairs in response to impinging IR photons. The Ge photosensitive region 6520 includes an absorber-doped region 6522 doped to have a first polarity (e.g., positively charged). Each PS 6502 also includes a Si layer 6510 upon which a plurality of readout structures 6570 are implemented. Each readout structure 6570 includes (a) a remotely doped region 6534 doped to have a second polarity, and (b) an intermediate doped region 6532 disposed between the respective remotely doped region 6534 and the Ge photosensitive region 6520 (optionally, between the absorber-doped region 6522 and the respective remotely doped region 6534). The intermediate doped region 6532 is doped to have a second polarity opposite to the first polarity. The intermediate doped region 6532 of a particular readout structure 6570 is disposed between the respective remotely doped region 6534 and the Ge photosensitive region 6520 when at least a portion of the intermediate doped region 6532 is disposed on a line between a first point on the respective remotely doped region 6534 and a second point on the Ge photosensitive region 6520. Optionally, each location L on at least half of the intermediate doped region 6532 (or a larger portion of the intermediate doped region 6532, e.g., >60%, >70%, >80%, >90%, >95%) n , point A on each remote doped region 6534 n and point B on the Ge photosensitive region 6520 n and at position L n are these two points (A n and B n ) can be selected to be located on the line connecting the

[0104] Note that although the operation of PS6502 differs from that of PS6202, each readout structure 6570 associated with a Ge photosensitive region 6520 may operate similarly to the Ge region 6220, the first doped region 6232 (which in this embodiment corresponds to a respective intermediate doped region 6532), and the second doped region 6234 (which in this embodiment corresponds to a respective remote doped region 6534) (usually only during a portion of the runtime of PS6502). When operating similarly to PS6502, the flow of charge carriers between the Ge regions and each readout structure 6570 behaves similarly to the sampling phase of PS6502 (even though there may be some differences (e.g., with respect to the relative voltages of all electrodes while affecting other readout structures 6570, etc.)). Optionally (e.g., as shown in FIG. 13C), PS 6502 may include a guard ring 6592 (or trenching) that completely, incompletely, or partially surrounds PS 6592 (or a portion thereof). Many uses and methods of implementation are known to those skilled in the art and will not be disclosed herein for the sake of brevity.

[0105] Some IR systems of the PS 6502 further include a controllable power supply (partially represented by a controllable power supply unit 6540) operable to provide a controlled voltage to the Ge photosensitive region 6520 (and possibly to portions thereof, such as, for example, the absorber-doped region 6522), as well as to (e.g., all of) the remotely doped regions 6534 and intermediately doped regions 6532 of the various readout structures. The voltage may be provided to the various regions via appropriate electrodes, such as, but not limited to, electrode 6535, electrode 6533, and electrode 6521. Note that some of the regions supplied with voltage by the controllable power supply may receive a constant (or substantially constant) voltage, while some of these regions are provided with a controllable (e.g., modulated) voltage that varies over time. In the example shown in FIG. 13A , a modulated voltage is provided to the intermediate doped regions (6532A and 6532B in the illustrated example) by variable power unit 6540, but this is by way of example only. As shown, charge readout from the readout structure 6570 may occur via connection 6560 (e.g., via electrode 6535 through which a voltage is applied to the remotely doped region 6534). This may be connected, for example, to the readout circuitry of an IR electro-optical system incorporating multiple PSs 6502. During the sampling duration of the readout structure 6570 (see further examples below), charge carriers of the second polarity are repelled by the voltage applied to the Ge region 6522 and attracted to the voltage applied to the active intermediate doped region 6532. These charge carriers pass through the active intermediate doped region 6532 and move towards the remotely doped region 6234 of the active readout structure 6570 using drift velocity (e.g., due to a voltage applied between the intermediate doped region and the remotely doped region, for example, in optional depletion region 6580 (illustrated only in FIG. 13A )).

[0106] 13D shows an example of a PS 6502 having four separate readout structures 6570, namely, number 6570A, number 6570B, number 6570C, and number 6570D. As illustrated in FIG. 13D, optionally, the PS 6502 may include multiple readout modules 6598, each associated with one or more readout structures 6570 and operable to apply signal processing to signals provided by the respective readout structures 6570. Such signal processing may include, for example, amplification, noise reduction, and any other suitable signal processing technique. Alternatively or additionally, the PS 6502 may include multiple modules that affect signal collection by a particular PS (e.g., at the location of module 6598 in the figure). For example, a PS 6502 may include a module that modifies the control voltages supplied to multiple PSs 6502 (e.g., columns of a sensor array) with respect to the requirements of the particular PS 6502 (e.g., depending on the temperature of the particular PS, depending on its characteristic dark noise, etc.) Optionally, the PS 6502 may include an internal trench 6596 (or guard ring) that separates the readout structure 6570 from the readout module 6598 or electrically isolates it from other modules described above.

[0107] Returning to the controllable power supply, it should be noted that different voltage schemes may be applied by the controllable power supply to the various electrodes of any one or more PSs 6502, such that charges (and thereby detection signals) are alternately read by the various readout structures 6570 of any such single PS 6502. For example, the controllable power supply of a PS 6502 may optionally be operable (e.g., by pre-configuration, by run-time determination of a controller, etc.) to maintain the following voltage schemes, e.g., to achieve the objectives discussed below. It should be noted that reference numbers in the following discussion are provided as non-limiting examples with respect to Figures 13B, 13C, and 13D.

[0108] a. During the first sampling duration, 1. Maintaining relative voltages (a) on the Ge photosensitive region, (b) on a first remotely doped region of the first readout structure, and (c) on a first intermediately doped region of the first readout structure such that charge carriers of a second polarity are forced by a first tensile force to migrate from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein CCSPs are collected in the first readout structure via a first readout electrode electrically coupled to the first remotely doped region; and 2. Maintain a voltage on the multiple doped regions of the first group of multiple readout structures such that the tensile force exerted on charge carriers of the second polarity toward each of the multiple remote doped regions of the first group of multiple readout structures, including the remainder of the multiple readout structures other than the first readout structure (e.g., one readout structure in the example of Figure 13B, three readout structures in the example of Figure 13D), is less than half of the first tensile force.

[0109] b. Over a second sampling duration (later than, but not necessarily immediately after, the first sampling duration); 1. maintaining relative voltages on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure such that charge carriers of a second polarity (CCSP) are forced by a second tensile force to migrate from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein the CCSP are collected in the second readout structure via a second readout electrode electrically coupled to the second remotely doped region; and 2. Maintaining a voltage on the plurality of doped regions of the second group of the plurality of readout structures such that a pulling force exerted on charge carriers of the second polarity toward each of the plurality of remote doped regions of the second group of the plurality of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half of the second pulling force. c. Over a third sampling duration (after the second sampling duration, but not necessarily immediately thereafter): 1. Maintaining relative voltages on the Ge region, the first remotely doped region, and the first intermediately doped region such that charge carriers of a second polarity (CCSPs) are forced by a third tensile force to migrate from the Ge photosensitive region toward a first readout structure, wherein the CCSPs are collected in the first readout structure via a first readout electrode; and 2. Maintaining a voltage on the plurality of doped regions of the first group of the plurality of readout structures for a third sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the plurality of remote doped regions of the first group of the plurality of readout structures is less than half of the third pulling force.

[0110] The alternation between reading from the first readout structure and reading from the second readout structure may continue with the same principles. Note that the disclosed process may further accommodate reading of more than two readout structures (e.g., four readout structures in the example of FIG. 13D ). Additional readout structures may be read, for example, between phases b2 and c1. During readout, a similar voltage scheme may be applied to the selected readout structure (e.g., similar to phase b1, mutatis mutandis) and to each group of the remaining readout structures (e.g., similar to phase b2, mutatis mutandis). Also, note that in a PS 6502 including more than two PSs, a cyclic readout order may be maintained (e.g., ABCDABCDABCD), but this is not necessarily the case, and any other order for reading from the various readout structures 6570 may be implemented (e.g., ABCDBDACDABC, ABABCDCDABABCDCD). Additionally, optionally, a controllable power supply module may apply appropriate voltages to simultaneously read out two or more readout structures 6570 (e.g., 6570A and 6570B) while reducing the pulling force towards one or more remaining photosite structures (e.g., 6570C and 6570D). The sampling cycles may be of the same duration, but this need not be the case. The sampling durations of the various readout structures may be identical to one another, but this need not be the case.

[0111] Referring to the tensile forces discussed above, it is clear that different charge carriers will experience different tensile forces towards the doped regions at the same time (e.g., when known voltages are applied to different portions of PS 6502). However, a single charge carrier will experience different tensile forces towards different readout structures 6570, and the relative magnitudes of these forces exerted on any given charge carrier can be compared.

[0112] It should be noted that while the illustrated PS6502 shows the polarity in which the absorber-doped region 6522 is doped to have a positive polarity, the reversed polarity can also be implemented (i.e., the absorber-doped region 6522 is doped to have a negative polarity, and the rest of the polarity in PS6502 is also reversed). It should also be noted that while PS6502 and PS6202 differ from one another, one skilled in the art would be able to implement the expanded description of PS6202, its components, and its method of operation, mutatis mutandis, for the purpose of understanding PS6502, its components, and its method of operation.

[0113] 13B , PS 6502 may include an optional doped region 6590 that is modulated with respect to Ge region 6520 and may be used to divert charge carriers of a second polarity away from readout structure 6570 (e.g., during idle times in a sampling cycle). For example, charge carriers of a second polarity may be toggled between readout structure 6502 when a reflected pulse of light is detected by PS 6502, and diverted toward doped region 6590 when a reflected pulse is not expected or desired. Optionally, a doped region of opposite polarity (shown at 6594) may be disposed between Ge region 6520 and doped region 6590, and voltages applied to doped region 6590 and doped region 6594 may be applied in the same manner as readout structure 6570 (e.g., via electrodes connected thereto, not numbered in the figure). That is, structure 6588, including region 6590 and region 6594, may optionally be operated similarly to readout structure 6570 (e.g., when charge dumping is required), where doped region 6590 corresponds to region 6534 and region 6594 corresponds to region 6532.

[0114] Figure 14A shows the relative voltages that may be applied to various regions of the PS6502 during its operation. A is the voltage supplied to the Ge region 6520 (or a portion thereof) that may function as an anode. Ais the voltage supplied to the Ge region 6520 (or a portion thereof) that may function as an anode. C is the voltage supplied to the remote doped region 6534 (or a portion thereof) of a particular readout structure 6570, which may function as a cathode. M is the voltage supplied to the intermediate doped region 6532 (or a portion thereof), which may function as a controllable motion-inducing structure. When the readout structure is in an active detection mode (e.g., corresponding to stages a and c of the first readout structure described above), the relationship between the voltage applied to the Ge region 6520 and the voltages applied to the various doped regions of that readout structure 6570 may follow the following rules: V C (active) ≥ V M (Active)>V A (active). For inactive readout structures, the following rules may be applied at the same time: C (inactive)>V A (inactive) and V A (inactive) ≥ V M(inactive). The convention in FIG. 14A relates to the doping polarity shown in FIGS. 13A-13D. If the opposite doping polarity is implemented (e.g., if doped region 6522 is negatively doped), the convention in FIG. 14B can be used. FIG. 14C shows example relationships between voltages applied to the various electrodes (labeled C1, M1, A, M2, and C2 at the top of the figure) when PS 6502 is not read at all (two examples are given, labeled "OFF" and "OFF strong"), when readout occurs via the left readout structure (labeled "Read out from RO1"), and when readout occurs via the right readout structure (labeled "Read out from RO2"). H represents high voltage and L represents low voltage. Note that some differences may be implemented between the various regions assigned the same voltage designation (i.e., "H" or "L"). For example, in an active readout structure, different voltages may be applied to C1 and M1 (e.g., 1.7 volts and 1.8 volts) to increase the number of charge carriers of the second polarity detected in the remotely doped region. When referring to voltages applied to various regions of the PS6502 (and other PSs described herein), it should be noted that various levels of voltage may be used in various implementations. Exemplary voltages may be on the order of magnitude of 1 V to 10 V, although this need not be the case. For example, the voltages applied to various doped regions on the PS may be within one or more of the following ranges (where ± represents a positive or negative voltage, depending on the implementation): 0 V to ±0.25 V, ±0.25 V to ±0.5 V, ±0.5 V to ±1 V, ±1 V to ±1.5 V, ±1.5 V to ±2.5 V, ±2.5 V to ±5 V, and ±5 V to ±10 V. Other voltages may also be applied. For example, referring to the example of FIG. 14C, the low voltage (denoted as "L") may be in the range of 0V to 0.25V, while the high voltage (denoted as "H") may be in the range of 1V to 1.5V.In the above description, the voltages applied to the various PSs are described based on the forces exerted on the charge carriers within the PSs as a result of the respective voltages. However, the voltages may be determined more directly. For example, the voltage applied to the modulation electrodes (e.g., to the intermediate doped regions in the example of FIG. 14C ) of the active readout structure 6570 during a sampling duration (e.g., the first sampling duration, or any other sampling duration) may be 10 times or more greater than any voltage applied to the modulation electrodes (e.g., any intermediate doped regions) of the first group of readout structures (e.g., in idle mode) averaged over the respective sampling durations. This relationship between voltages may be implemented, mutatis mutandis, in the PS 6502 even if the pulling forces exerted on the charge carriers are different from those described above.

[0115] The PS 6502 includes a single Ge region 6520 connected to one (or more) associated electrodes 6521. However, unlike a PS 6502 that includes only a single anode and a single cathode, the PS 6502 includes multiple sets of first and second doped regions 6532 and 6534, as well as associated components (e.g., electrodes). Each set of doped regions and associated components is designated by a capital letter subscript associated with that set. For example, the first doped region 6532 of set A is designated 6532A, and the first doped region 6532 of set B is designated 6532B. Note that while only a single combination of polarities is shown in the figure, other combinations of doped regions and charge carrier polarities, particularly those with opposite polarities, may also be implemented. Note also that the polarities of the doped regions of the various readout structures may differ from one readout structure to another within a single PS 6502.

[0116] 15, 16, 17, and 18 illustrate a photodetector array 9010 having an N-tap PS 9020 according to an embodiment of the presently disclosed subject matter. FIGS. 15 and 16 illustrate an embodiment of a two-tap PDA 9010, where each photosite has two detection structures 9030 that are alternately activated. FIGS. 17 and 18 illustrate an embodiment of a four-tap PDA 9010, where each photosite has four detection structures 9030 that can be activated in a round-robin or any other manner. Note that the following discussion may apply to a PDA 9010 having a three-tap PS 9020, an eight-tap PS 9020, or any other N-tap PS, where N is a natural number greater than 1. The PS 9020 may be, for example, a PS 9502, or any other type of multi-tap photosite discussed in this disclosure, or any other type of N-tap photosite (e.g., a silicon-only N-tap photosite for the visible region of the electromagnetic spectrum).

[0117] Prior art implementations of photodetector arrays with N-tap photosites are implemented in a rectangular tiling. Each PS is identical to its neighbors, and the various detection / readout structures of different PSs are activated in the same manner across all PSs in the array (e.g., in a 4-tap PDA, a synchronized clockwise modulated detection scheme would simultaneously activate all of the top-left detection structures of the various PSs, followed by simultaneously activating all of the top-right detection structures of the various PSs, followed by simultaneously activating all of the bottom-right detection structures of the various PSs, followed by simultaneously activating all of the bottom-left detection structures of the various PSs). Figures 15-18 show a PDA 9010 with an N-tap PS 9020 in which multiple readout structures 9030 are activated non-identically. Figure 18 shows a possible circuit for controlling the PS 9020 of a 4-tap PDA 9010 in a manner 9060, described below.

[0118] 19 illustrates a method 9060 for detecting light coming from a field of view of a PDA including multiple PSs, according to an embodiment of the presently disclosed subject matter. Each PS includes multiple readout structures operable to collect charge carriers generated by the PS in response to light impinging on the reflected PS. The various readout structures of any single PS (e.g., as described above with respect to PS 9502) are controllable to instantly collect signals of different instantaneous levels in response to light impinging on the PS. Referring to the embodiment described with respect to the previous figures, the PS may be PS 9502 or any type of N-tap Si PS (not including Ge).

[0119] The following discussion relates to adjacent photosites. Each photosite includes at least a first readout structure (e.g., 9030A) and a second readout structure (e.g., 9030B). The first readout structures of adjacent photosites are adjacent to each other, and the second readout structures of adjacent photosites are spaced apart. For example, the distance between the second readout structures of adjacent PSs may be at least three times greater than the distance between the first readout structures of adjacent PSs. For example, the distance between the second readout structures of adjacent PSs may be at least one (or at least two) readout structure widths greater than the distance between the first readout structures of adjacent PSs. For example, the distance between the second readout structures of adjacent PSs may be greater than the width of the PSs of the PDA.

[0120] Stage 9062 includes controlling the collection scheme of adjacent PSs (e.g., by applying appropriate voltages to various regions of the PSs, including various portions of the various readout structures) so that the first readout structures of the adjacent PSs are activated simultaneously (i.e., set to detection mode). Optionally, stage 9062 may also include controlling the collection scheme of adjacent PSs so that the second readout structure of the adjacent photosite is set to idle simultaneously with the activation of the first readout structure (e.g., applying a reduced force that attracts charge carriers of the detected polarity toward the second readout structure, or applying a repelling force that repels such charge carriers away from the second readout structure).

[0121] Step 9064, performed after step 9062, includes controlling the collection scheme of adjacent photosites (e.g., by applying appropriate voltages to various regions of the photosite, including various portions of the various readout structures) so that the second readout structures of the adjacent photosites are simultaneously activated (i.e., set to detection mode). Optionally, step 9062 may also include controlling the collection scheme of adjacent photosites so that the first readout structure of the adjacent photosite is simultaneously set to idle (e.g., applying a reduced force that attracts charge carriers of the detected polarity toward the first readout structure, or applying a repulsive force that repels such charge carriers away from the first readout structure) simultaneously with activation of the second readout structure.

[0122] Optionally, steps 9062 and 9064 may be repeated to collect additional signals. Optionally, steps 9062 and / or 9064 also include controlling the collection strategy of adjacent photosites such that one or more readout structures (e.g., third readout structure, fourth readout structure, etc., 9030C, 9040D, etc.) of each photosite are set to idle simultaneously with activation of the respective first or second readout structure. Note that for photosites including three or more readout structures, additional steps similar to 9062 and 9064 may be included mutatis mutandis for the additional readout structures. As discussed above, when a photosite having three or more readout structures is implemented and one or more readout structures are activated more than once in detecting the photosite (e.g., in a single frame of the PDA), any order, round robin or otherwise, may be implemented (e.g., ABCDABCDABCD, ABCDBDACDABC, ABABCDCDABABCDCD). If various photosites include structures (e.g., structure 6588 described above) for discarding charge carriers without reading them and without them reaching other readout structures, additional optional steps similar to 9062 and 9064 may be included, mutatis mutandis, to drive the associated charge carriers towards this structure.

[0123] Stage 9062 has been performed at least once (1≦T1 times), and after stage 9062 has been performed at least once (1≦T2 times), method 9060 may optionally continue with stage 9066 of determining detected signals for each of the first readout structures corresponding to signals collected by each of the first readout structures during instance T1, and with stage 9068 of determining detected signals for each of the second readout structures corresponding to signals collected by each of the second readout structures during instance T2. The determined detected signals may be combined (e.g., aggregated), for example, for each detection frame of the PDA.

[0124] Optionally, method 9060 may continue with at least one of optional steps 9070, 9072, and 9074.

[0125] Stage 9070 includes generating an image of at least a portion of the PDA's FOV based on the detection signals determined for each of the readout structures, where the number of detection signals for each photosite is less than the number of photosite readout structures (e.g., a single detection value is determined for each photosite based on data collected by two, three, four, or more photosite readout structures). Optionally, stage 9070 may include determining one or more detection signals for a group of multiple photosites, where the total number of detection signals determined for the group of multiple photosites is less than the number of readout structures (RO structures, ROS) in each photosite. For example, for a group of four N-tap photosites, R, G, and B color signals are determined.

[0126] Optional step 9072 includes determining a distance to an object within the FOV based on a comparison between a first detected signal of a first readout structure of a photosite and a second detected signal of a second readout structure of the same photosite, each of the first detected signal and the second detected signal being determined based on multiple measurements performed during multiple instances of step 9062 or step 9064, respectively. For example, step 9072 may be performed by implementing a current assisted photonic demodulator (CAPD) technique, many of which are known in the art.

[0127] Optional step 9074 includes determining the distance to the object in the FOV based on a first detection signal of a first readout structure of a photosite, a second detection signal of a second readout structure of the same photosite, and possibly further detection signals (if any) of further readout structures of the same photosite. Each detection signal is based on a single instance (i.e., T1=1, T2=1, etc.), and each detection signal is measured sequentially (optionally with some overlap) after the emission of an illumination pulse. The magnitude of the various detection signals and their temporal relationship to the timing of the pulse emission indicate the distance to the object. An example is provided below.

[0128] It should be noted that simultaneous activation of adjacent readout structures of adjacent photosites 9020 can be used to reduce crosstalk between adjacent photosites and to reduce the amount of pulling force exerted by the active readout structures of adjacent photosites that is exerted in a direction opposite to that of the active readout structure of the photosite in question (or in other inappropriate directions). Also, it should be noted that although the second readout structures of method 9060 are described as being spaced apart from one another, these photosites may be adjacent to other second readout structures of other adjacent photosites, as illustrated, for example, in Figures 15 and 17.

[0129] 20A and 20B are cross-sectional views illustrating example photosites 7502 and 7504 of an IR light detection system according to an embodiment of the disclosed subject matter. Photosites 7502 and 7504 may be combined in any suitable IR light detection system described above, or in any other type of IR light detection system requiring one or more photosites (e.g., camera, LIDAR, spectrograph). Both photosites 7502 and 7504 include a Ge region 7510 on top of a Si layer 7520 that includes a pinned layer 7522 (illustrated as a negatively doped layer) and a pinning layer 7524 (illustrated as a positively doped layer). Both pinned layer 7522 and pinning layer 7524 are partially below Ge region 7510.

[0130] The pinned layer 7522, and optionally the pinning layer 7524, are connected to the floating diffusion 7540 via a transmission gate 7530. Charge carriers generated in the Ge region 7510 (particularly in the doped region 7512 of the Ge region 7510) are collected in the pinned layer 7522 (also referred to as a storage well). During the collection phase, the transmission gate 7530 may keep the storage well 7522 isolated from the floating diffusion 7540 so that all charge carriers coming from the Ge region 7510 are collected during the sampling time of each photosite. At a later time (e.g., during the off-time of each photosite), the transmission gate 7530 may connect the storage well 7522 and the floating diffusion 7540 so that the charge collected in the storage well 7522 is transferred to the floating diffusion 7540. The charge is read out from the floating diffusion 7540 by at least one electrode. An optional third doped layer 7526 (similar to layer 6470, considering minor differences) is illustrated in Figure 20B. Note that the oppositely doped region 7542 may be located adjacent to the floating diffusion 7540, for example, as illustrated in Figure 20B. A similar oppositely doped region may be implemented adjacent to any one or more of the floating diffusions 7540 described above. Charge may be read from the floating diffusion via a suitable readout electrode 7550 connected to the floating diffusion 7540.

[0131] Also shown in Figure 20B is another option of including doped regions 7512 for Ge region 7510. Optionally, Ge region 7510 may include doped regions on any side (e.g., top, sides, edges, etc.) of Ge region 7510, which may optionally cover the entire exposed surface (i.e., above the Si layer) of Ge region 7510, or a portion thereof. Note that a similar implementation of doped regions in a Ge region may be implemented, mutatis mutandis, in any of the photosites described above.

[0132] FIG. 21 illustrates a photosite 7506 according to an embodiment of the presently disclosed subject matter. All of the components of photosites 7502 and 7504 described above are contained within photosite 7506. Photosite 7506 includes an additional floating diffusion 7540, a readout electrode 7550, and other components for reading out charge carriers of a second polarity as they are concentrated away from storage well 7522. Such a configuration may be used, for example, for time-of-flight measurements. In this case, the relative amount of charge collected on each of the two sides may indicate the phase of the returning light and, therefore, the distance to the object reflecting the light. One example of a technique that may be used to determine distance based on the charge collected from various floating diffusions of a single photosite connected to a single Ge region is the CAPD technique described above. Other examples are provided below. A controller (not shown) may toggle the readout between two readout complexes (also referred to as "readout structures" and located to the left and right of Ge region 7510 in the figure). 21, photosite 7506 is shown as having two floating diffusions 7540, each connected to a storage well 7522 via a respective transfer gate 7530. However, it should be noted that photosite 7506 may be implemented with three or more floating diffusions 7540, each connected to a storage well 7522 via a respective transfer gate 7530. For example, three or four floating diffusions may be implemented in a triangular or rectangular photosite 7506, respectively.

[0133] With respect to photosite 6402, photosite 6404, photosite 6406, photosite 6408, photosite 7502, photosite 7504, and photosite 7506 (and all other photosites described above), it should be noted that the same photosites may be implemented with polarities that are reversed from those illustrated in the figures. That is, regions / portions shown with negative polarity may be implemented as positively doped, and regions / portions shown with positive doping may be implemented as negatively doped. It should also be noted that the doping levels (e.g., -, +, ++) of various regions may vary in different embodiments.

[0134] 22 illustrates a method 7600 for detecting IR radiation according to an embodiment of the presently disclosed subject matter. With reference to the embodiments of the accompanying drawings, method 7600 may optionally be performed by any one of photosite 7502, photosite 7504, and photosite 7506, mutatis mutandis.

[0135] Step 7610 of method 7600 includes modulating a voltage to at least one region of a photosite (PS) selected from the group consisting of a first doped region of the PS, a Ge photosensitive region of the PS, and a floating diffusion of the PS, where the photosite includes at least (a) a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity, and (b) a Si layer including the first doped region, a storage well, a floating diffusion, and a transfer gate. The modulating step according to step 7610 includes at least the following steps:

[0136] Stage 7620 involves forcing charge carriers of the second polarity to migrate from the Ge photosensitive region towards the storage well by providing a voltage across the Ge photosensitive region, the first doped region and the floating diffusion.

[0137] At another time, step 7630 includes providing another voltage to the Ge photosensitive region, the first doped region, and the floating diffusion to weaken the forced migration of CCSP toward the storage well, thereby stopping signal collection by the storage well.

[0138] Step 7640 involves intermittently transferring charge carriers of a second polarity from the storage well through the transfer gate to the floating diffusion, where the charge carriers of the second polarity are read out via a readout electrode electrically coupled to the floating diffusion.

[0139] Optionally, method 7600 may further include reading the electrical signal collected at the floating diffusion by a readout circuit electrically connected to the photosite to determine a detection signal for the photosite during a particular sampling duration.

[0140] Various steps of method 7600 may be performed for each of a plurality of photosites of an IR sensor, and method 7600 may include generating an image (or other detection model, such as a depth map for lidar or spectrographic analysis) representative of objects within the FOV in response to the detection signals of the various photosites. The sampling durations of the various photosites may be consistent with one another or may differ from one another.

[0141] Any of the variations discussed with respect to photosite 7502, photosite 7504, and photosite 7506 (as well as with respect to the equivalent components of any other photosites described above) may be implemented, mutatis mutandis, in the performance of method 7600.

[0142] When method 7600 is performed for a photosite including two or more floating diffusions connected to a Ge region by respective transfer gates (e.g., as described above with respect to photosite 7506), stages 7620, 7630, and 7640 may be performed separately for each of the floating diffusions (e.g., alternately, in a round-robin manner, or in any other desired order). Although not required, a first instance of stage 7640 may be performed after the first instances of stages 7620 and 7630 are performed to transfer charge carriers of a second polarity from the storage well through the first transfer gate to the first floating diffusion (where the charge carriers of the second polarity are read out via a first readout electrode electrically connected to the first floating diffusion). Following the first instance of step 7640, second instances of steps 7620 and 7630 may be performed, followed by a second instance of step 7640 in which charge carriers of a second polarity are transferred from the storage well via a second transfer gate to a second floating diffusion where they are read out via a second readout electrode electrically connected to the second floating diffusion. If desired, subsequent instances of steps 7620, 7630, and 7640 may be performed to transfer charge carriers of a second polarity toward additional floating diffusions at a first time and / or to transfer charge carriers of a second polarity toward the floating diffusions at additional times.

[0143] Optionally, method 7600 may further include reading the electrical signals collected at the floating diffusions by a readout circuit electrically connected to the photosites to determine a detection signal for the photosites during a particular sampling duration. The detection signal may be used, for example, to determine a brightness value for a pixel in an image of the FOV. When photosites with multiple floating diffusions are used, electrical signals may be read from each of the multiple floating diffusions via appropriate electrodes. These signals may be used, for example, to determine the distance to an object within the FOV.

[0144] 23 illustrates a method 7700 for detecting IR radiation, according to an embodiment of the presently disclosed subject matter. Referring to the embodiment of the accompanying drawings, the method 7700 may optionally be performed by a photosite 6502.

[0145] The method 7700 includes providing a controlled voltage to a plurality of regions of a photosite, the photosite comprising at least: a. a Ge photosensitive region operable to generate eh pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region doped to have a first polarity; b. a plurality of doped regions of a plurality of readout structures implemented on the Si layer of the photosite, the plurality of doped regions including, for each of the plurality of readout structures, (i) a remote doped region doped to have a second polarity, and (ii) an intermediate doped region disposed between the remote doped region and the Ge photosensitive region, the intermediate doped region being doped to have a second polarity opposite to the first polarity; Includes:

[0146] The process of providing a controlled voltage is used at different times for different ends and includes at least step 7710, step 7720, step 7730, step 7740, step 7750, and step 7760.

[0147] Stage 7710 includes maintaining a relative voltage on the Ge photosensitive region, on a first remotely doped region of the first readout structure, and on a first intermediately doped region of the first readout structure for a first sampling duration such that charge carriers of a second polarity are forced by a first tensile force to migrate from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein CCSPs are collected in the first readout structure via a first readout electrode electrically connected to the first remotely doped region.

[0148] Step 7720 includes maintaining a voltage on the plurality of doped regions of the first group of the plurality of readout structures for a first sampling duration so that a tensile force applied to charge carriers of a second polarity toward each of the plurality of remote doped regions of the first group of the plurality of readout structures, including the remainder of the plurality of readout structures other than the first readout structure, is less than half the first tensile force.

[0149] Stage 7730 includes maintaining a relative voltage on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure for a second sampling duration that is later than the first sampling duration, such that charge carriers of a second polarity are forced by a second tensile force to migrate from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein CCSPs are collected in the second readout structure via a second readout electrode electrically connected to the second remotely doped region; Step 7740 includes maintaining a voltage on the plurality of doped regions of the second group of readout structures for a second sampling duration so that a tensile force applied to charge carriers of a second polarity toward each of the plurality of remote doped regions of the second group of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half the second tensile force.

[0150] Stage 7750 includes maintaining the relative voltages on the Ge region, the first remotely doped region, and the first intermediately doped region for a third sampling duration that is later than the second sampling duration, such that a third tensile force forces charge carriers of a second polarity to migrate from the Ge photosensitive region toward the first readout structure, where the charge carriers of the second polarity are collected via the first readout electrode at the first readout structure.

[0151] Step 7760 includes maintaining a voltage on the plurality of doped regions of the first group of the plurality of readout structures for a third sampling duration such that a tensile force applied to charge carriers of a second polarity toward each of the plurality of remote doped regions of the first group of the plurality of readout structures is less than half of the third tensile force.

[0152] Optionally, the first voltage applied to the first intermediate doped region during the first sampling duration is 10 times or more greater than any voltage applied to any intermediate doped region of the first group of the plurality of readout structures averaged over the first duration.

[0153] Optionally, the method 7700 may be performed for multiple photosites simultaneously.

[0154] Optionally, method 7700 may further include providing a voltage to multiple regions of the photosite during a discarding-duration such that charge carriers of a second polarity are driven from the photosite towards the electrode where they are discarded without being read out.

[0155] As mentioned above, various techniques can be used to determine depth based on the output of one or more photosites. The following discussion discusses systems and methods that can be used to determine the distance of multiple objects in the FOV of a SWIR electro-optical system, as well as other electro-optical systems sensitive to other portions of the electromagnetic spectrum.

[0156] 24 illustrates a method 5500 for generating a depth image of a scene based on detection by a short-wave infrared (SWIR) electro-optical imaging system (SEI system), according to an embodiment of the subject matter of this disclosure. The SEI system may be any of the systems described above or any other suitable SWIR electro-optical system (e.g., sensor, camera, lidar, etc.). Method 5500 may be performed by one or more processors in the SEI system, by one or more processors external to the SEI system, or by a combination of both.

[0157] Stage 5510 includes obtaining a plurality of detection signals of the SEI system, each detection signal indicating the amount of light from a particular direction within the FOV of the SEI system captured by at least one FPA detector of the SEI system over a respective detection time frame (i.e., the detection time frame during which the respective detection signal is captured, e.g., measured from the triggering of illumination by an associated light source such as a laser). The at least one FPA includes a plurality of individual photosites, each including a Ge element where impinging photons are converted into a detected charge in the Ge element. Note that method 5500 can be performed with any type of photosite that has the characteristic of high dark current, even if it includes other elements other than Ge.

[0158] For each of a plurality of directions within the FOV, various detection signals (of the aforementioned plurality of detection signals) indicate the level of reflected SWIR illumination from various distance ranges along that direction. An example is provided in diagram 5710 of FIG. 25, which shows the timing of three different detection signals arriving from the same direction within the FOV. The y-axis (ordinate) in the diagram indicates the level of response of the detection system to reflected photons arriving from the associated direction. The reflected illumination originates from one or more light sources (e.g., lasers, LEDs) optionally controlled by the same processor that controls the FPA, and is reflected from a portion of the FOV (e.g., corresponding to a spatial volume detectable by a single photosite). Note that the various detection signals may be associated with similar but not completely overlapping portions of the FOV (e.g., if the sensor, scene, or intermediate optics are moving in time between the two, the detection signals from the same photosite may be reflected from somewhat different angles within the FOV in different detection time windows associated with different detection signals).

[0159] See the example of FIG. 25. Note that diagram 5710 does not show the detection level of each signal, but rather shows the response of the detection signal to photons reflected from a perfect reflector at various times from the start of light emission. Diagram 5720 shows three objects positioned at different distances from the SEI system. Note that in many cases, only one object in each direction—the object closest to the SEI system—will be detected at each time. However, in some scenarios, more than one object may be detected (e.g., if the foreground object is partially transparent or does not block light from the entire photosite). Diagram 5730 shows the levels of three return signals in a direction where one of multiple objects is present (e.g., a person in the near field, a dog in the mid-field, and a tree in the far field). (The choice of object is arbitrary; only light reflected from a portion of each object is typically detected by a single photosite.) Light returning from an object at distance D1 is represented by a figure of a person for three different detection signals (corresponding to different detection timing windows and different ranges from the SEI system). Similarly, the detection signal levels corresponding to light reflected from an object at distance D2 and an object at distance D3 are correspondingly represented by dog ​​and tree symbols. As shown in diagram 5740, reflections from objects located at given distances can be converted into tuples (or any other representation of data, e.g., any suitable form of direction-associated data structure (DADS)) indicating relative levels of detection signals in different time windows. In the illustrated example, each number in the tuple indicates the signal level detected in one detection window. The detection level representation in the tuple may be corrected for distance from the sensor (because reflected light from the same object attenuates with distance), but this is not necessarily so. In the illustrated example, three partially overlapping time windows are used, but any number of time windows may be used. The number of time windows may be the same for various regions of the FOV, but is not necessarily so.

[0160] Stage 5520 includes processing the detection signals to determine a three-dimensional (3D) detection map including a plurality of 3D locations within the FOV at which a plurality of objects are detected. The processing includes compensating for dark current (DC) levels accumulated during collection of the detection signals from the plurality of Ge elements. The compensating also includes applying different degrees of dark current compensation to the detection signals detected by different photosites of at least one focal place array. Referring to the examples in the accompanying drawings, the different detection signals may be obtained at different times by different readout structures of any of the suitable photosites described above. Alternatively, the detection signals may be obtained by a group of interconnected photosites, as discussed in more detail below. Other embodiments may also be used.

[0161] In addition to or instead of compensating for accumulated dark current, the processing step may include compensating for high integration noise levels and / or readout noise levels during readout of the plurality of detected signals. The compensating step may include applying varying degrees of noise level compensation to the plurality of detected signals detected by different photosites of the at least one focal place array.

[0162] Compensation for dark current collection, compensation for read noise, and / or compensation for integrated noise may be performed in any suitable manner, for example, by using any combination of one or more of software, hardware, and firmware. In particular, compensation for dark current collection may be implemented using any combination or any portion of any one or more of the systems, methods, and computer program products described above. Some non-limiting examples of systems, methods, and computer program products that can be used to apply multiple degrees of dark current compensation to multiple detection signals detected by various photosites of at least one focal place array and to compensate for dark current are described above with reference to FIGS. 12A-35.

[0163] In some embodiments, the compensating step may be performed during acquisition of the detection signals (e.g., at the sensor hardware level), and the processing step may be performed on detection signals that have already been compensated for dark current accumulation (e.g., as discussed in patent applications published by the present applicant, TriEye LTD, Tel Aviv).

[0164] Regarding the compensating step in step 5520, optionally, the compensating step may include subtracting a first dark current compensation offset from a first detection signal detected by a first photosite corresponding to a first detection range, and subtracting a second dark current compensation offset different from the first dark current compensation offset from a second detection signal detected by a first photosite corresponding to a second detection range that is farther away from the SEI system than the first detection range.

[0165] Optionally, method 5500 may include coordinating active illumination (e.g., by at least one light source of the SEI system) and acquisition of the plurality of detection signals. Optionally, method 5500 may include (a) triggering emission of first illumination (e.g., laser, LED) in coordination with start of exposure of a first gated image in which a plurality of first detection signals are detected for various of the plurality of directions, (b) triggering emission of second illumination (e.g., laser, LED) in coordination with start of exposure of a second gated image in which a plurality of second detection signals are detected for various of the directions, and (c) triggering emission of third illumination (e.g., laser, LED) in coordination with start of exposure of a third gated image in which a plurality of third detection signals are detected for various of the directions. In such a case, the processing according to Stage 5520 optionally includes determining, based on at least one detection signal from each of the first, second, and third images, a presence of a first object at a first 3D position in a first one of the various directions, and determining, based on at least one detection signal from each of the first, second, and third images, a presence of a second object at a second 3D position in a second one of the various directions, where a distance of the first object from the SEI system is at least twice a distance of the second object from the SEI system.

[0166] Optionally, applying different degrees of DC compensation to the plurality of detected signals detected by different photosites of the at least one FPA may include using detected dark current levels of different reference photosites that are shielded from light coming from the FOV.

[0167] Optionally, the compensating step may include applying different degrees of DC compensation to a plurality of detected signals simultaneously detected by different photosites of the at least one FPA.

[0168] Referring to integrated noise and readout noise, it is noted that compensation for such noise may be correlated by at least one processor executing method 5500 with the number of illumination pulses used to illuminate portions of the FOV during acquisition of each detected signal. Different numbers of illumination pulses may introduce significant non-linearities in the detected signal, which are optionally corrected for as part of processing prior to determining the distances / 3D positions of various objects within the FOV.

[0169] With reference to the use of DADS to determine the distance / 3D position of various objects within the FOV, it is noted that different transformation functions (e.g., tuples) of DADS to distance can be used for different directions within the FOV to compensate for, for example, non-uniformity of detection channels across the FOV (e.g., of the sensor and / or detected object), non-uniformity of illumination (e.g., non-uniformity of the light source or non-uniformity of the optical system using multiple light sources), etc.

[0170] As described above, various detection signals from the same direction within the FOV correspond to different detection windows, which may be at the same distance or at different distances. For example, a detection window may correspond to a distance range of approximately 50 m (e.g., between 80 m and 130 m from the SEI system). In various examples, some or all of the detection windows used to determine the distance / 3D position of an object within the FOV may be at distances ranging from 0.1 m to 10 m, 5 m to 25 m, 20 m to 50 m, 50 m to 100 m, 100 m to 250 m, etc. The distance ranges associated with various detection signals may overlap. For example, a first detection window may detect return light from an object at a distance between 0 m and 50 m from the SEI system, a second window may correspond to an object at a distance between 25 m and 75 m, and a third window may correspond to an object at a distance between 50 m and 150 m.

[0171] Method 5500 may be performed by one or more processors, such as, but not limited to, any of the systems described above. A system for generating a depth image of a scene based on detections from a short-wave infrared (SWIR) electro-optical imaging system (SEI system) is disclosed. The system includes at least one processor configured to: (i) obtain a plurality of detection signals of the SEI system, where each detection signal indicates an amount of light from a particular direction within a FOV of the SEI system captured by at least one FPA detector of the SEI system over a respective detection time frame, the at least one FPA including a plurality of individual photosites, each photosite including a Ge element where impinging photons are converted into detected charges therein, and for each of a plurality of directions within the FOV, different detection signals indicate reflected SWIR illumination levels from different distance ranges along the direction; and (ii) process the plurality of detection signals such that a three-dimensional (3D) detection map is determined, the detection map including a plurality of 3D locations within the FOV where a plurality of objects are detected. wherein the processing step includes compensating for dark current (DC) levels accumulated during collection of the plurality of detection signals from the plurality of Ge elements, and the compensating step includes applying different degrees of DC compensation to the plurality of detection signals detected by different photosites of the at least one FPA.

[0172] Optionally, the compensating step may include subtracting a first DC compensation offset from a first detection signal detected by a first DE corresponding to a first detection range, and subtracting a second DC compensation offset different from the first DC compensation offset from a second detection signal detected by a first DE corresponding to a second detection range that is farther away from the SEI system than the first detection range.

[0173] Optionally, the at least one processor may be further configured to perform the steps of: (a) triggering emission of a first illumination in coordination with the start of exposure of a first gated image in which a plurality of first detection signals are detected for various of the plurality of directions; (b) triggering emission of a second illumination in coordination with the start of exposure of a second gated image in which a plurality of second detection signals are detected for various of the directions; and (c) triggering emission of a third illumination in coordination with the start of exposure of a third gated image in which a plurality of third detection signals are detected for various of the directions. In such a case, as part of determining the 3D detection map, the at least one processor may be further configured to: (a) determine, based on at least one detection signal from each of the first, second, and third images, a presence of a first object at a first 3D position within a first one of the various directions; and (b) determine, based on at least one detection signal from each of the first, second, and third images, a presence of a second object at a second 3D position within a second one of the various directions, where the distance of the first object from the SEI system is at least twice the distance of the second object from the SEI system. The gated image (or its equivalent) may be achieved by utilizing various readout structures of the PDA's multiple photosites, for example, by any of the methods described above.

[0174] Optionally, applying different degrees of DC compensation to the plurality of detection signals detected by different photosites of the at least one FPA includes using detected dark current levels of different reference photosites that are shielded from light coming from the FOV. Optionally, compensating may include applying different degrees of DC compensation to the plurality of detection signals simultaneously detected by different photosites of the at least one FPA. Optionally, one or more processors (and possibly all processors) of the at least one processor may be part of an SEI system.

[0175] With reference to the preceding diagram, method 5500, and any combination of two or more of its steps, may be performed by any of the processors described above with respect to the preceding diagram. With reference to the preceding diagram, method 4600, and any combination of two or more of its steps, may be performed by any of the processors described above with respect to the preceding diagram. It should be noted that while method 5500 and related systems have been discussed in connection with generating a depth image of a scene based on the detection of a SWIR electro-optic imaging system, similar methods and systems may be used, mutatis mutandis, to generate a depth image of a scene based on the detection of an electro-optic imaging system having high dark current or other noise and interference characteristics to the signal, even when operating in other portions of the electromagnetic spectrum.

[0176] 26A-26C illustrate a sensor 5200 according to an embodiment of the subject matter of the present disclosure. The sensor 5200 is operable to detect depth information of objects within its FOV. It should be noted that the sensor 5200 may be a variation of any of the sensors described above (under any aspect) with the adaptations discussed below (including a controller 5250 and its functionality, and associated switches). Many of the details, options, and variations described above with respect to the various sensors will not be repeated for the sake of brevity, but may be implemented in the sensor 5200, mutatis mutandis.

[0177] The sensor 5200 includes an FPA 5290 that includes a plurality of photosites 5212, each operable to detect light coming from a view IFOV of a PS. The various PSs 5212 are oriented in different directions within an FOV 5390 of the sensor 5200. For example, with reference to the FOV 5390 of FIG. 30 , a first PS 5212(a) may be oriented toward the first IFOV 5312(a), a second PS 5212(b) may be oriented toward the second IFOV 5312(b), and a third PS 5212(c) may be oriented toward the third IFOV 5312(c). The portion of the FOV 5390 collectively detectable by a readout group of multiple PSs (collectively designated 5210, including PSs 5212(a), PS 5212(b), and PS 5212(c)) is designated 5310. Note that any type of PS 5312 may be implemented, including, for example, a single photodiode or multiple photodiodes. The various PSs 5212 in a single readout group 5210 (and optionally, the various PSs 5212 across the FPA 5290) may be substantially duplications of each other, but this is not necessarily the case, and various types of PSs 5212 may optionally be implemented in a single FPA 5290 and even in a single readout group 5210. The various PSs 5212 in a single readout group 5210 (and, optionally, the various PSs 5212 across FPA 5290) may be sensitive to the same portion(s) of the electromagnetic spectrum or to different portions of the electromagnetic spectrum. Any one or more of the types of PSs described elsewhere in this disclosure (e.g., described above) may be implemented as a PS 5212.

[0178] Note that, optionally, all of the multiple PSs 5212 in a single read group 5210 are physically adjacent (proximate) to one another (i.e., each PS 4212 in the read group 5210 is physically adjacent to at least one other PS 5212 in the read group 5210 such that at least one continuous path is formed through adjacent PSs 5212 between any two PSs 5212 in the read group 5210). However, non-contiguous read groups may be implemented (e.g., if some PSs 5212 in the FPA 5290 are defective, if some PSs 5212 in the FPA 5290 are unused (e.g., to save power), or for any other reason). If the FPA 5290 includes two or more read groups 5210, the read groups 5210 may (but do not necessarily have to) include the same number of PSs 5212, may (but do not necessarily have to) include the same type of PSs 5212, and may (but do not necessarily have to) be arranged in the same geometric configuration (e.g., in a 1x3 array, as shown in the examples of Figures 28A and 28B).

[0179] The sensor 5200 includes at least one readout set 5240, which includes multiple readout circuits 5242. Each of the multiple readout circuits 5242 in a single readout set 5240 is connected to the same readout group 5210 of multiple PSs 5212 of the FPA 5290 by multiple switches 5232 (collectively referred to as 5230). The readout circuit 5242 reads signals from the one or more PSs 5212 connected to it and outputs data (e.g., analog or digital) indicative of the level of light received by each of the one or more PSs 5212. The output data may be provided to a processor, communicated to another system, stored in a memory module, or used in any other manner. The various readout circuits 5242 of a single readout set are connected to the various PSs 5122 of the respective readout groups 5210 and are operable to output an electrical signal indicative of the amount of light impinging on the PSs 5212 of the readout groups 5210 when the readout groups 5210 are connected to their respective readout circuits 5242 through at least one switch of the plurality of switches 5230. It should be noted that the switches 5232 may be implemented with any suitable switching technology, such as any combination of one or more transistors. The switches 5232 may, but are not necessarily, implemented as part of the FPA 5290. For example, some or all of the switches 5232 may be included in a readout wafer that is electrically (and optionally, physically) connected to the FPA 5290. The readout circuit 5242 may, but is not necessarily implemented as part of the FPA 5290. For example, some or all of the readout circuits of the plurality of readout circuits 5242 may be included on a readout wafer that is electrically (and optionally also physically) connected to the FPA 5290.

[0180] In addition, the sensor 5200 also includes at least one controller 5250 configured and operable to change the switching states of the plurality of switches 5230 such that different readout circuits 5242 of a readout set 5240 are connected to a readout group 5210 (i.e., multiple PSs 5212 of a readout group 5210) at different times to expose the different readout circuits 5242 to illumination light reflected from objects located at different distances from the sensor 5200. The illumination light may be emitted by a light source 5260 included in the sensor 5200 or a light source 5260 included in any electro-optical system (e.g., camera, telescope, spectrometer) in which the sensor 5200 is implemented. The illumination light may also be emitted by another light source associated with the sensor 5200 (whether controlled by the light source or by a common controller therewith) or by any other light source.

[0181] Sensor 5200 also includes a processor 5220 configured to obtain a plurality of electrical signals from readout set 5240 indicative of detected levels of reflected light collected from a plurality of IFOVs of a plurality of PSs 5212 in readout group 5210 to determine object depth information indicative of the object's distance from sensor 5200. Such an object may be, for example, a tower 5382 in the background of FOV 5390, or a tree 5384 in the foreground of FOV 5390. For example, method 5500, or any of the techniques described above (e.g., with respect to FIGS. 24 and 37), may be implemented by processor 5200.

[0182] 26A, 26B, and 26C show the same sensor 5200 in various switching states of readout set 5240. Readout set 5240 is connected to readout group 5210, which in the illustrated example includes three PSs (PS 5212(a), PS 5212(b), and PS 5212(c)). In FIG. 38A, readout circuit 5242 is not connected to any of the PSs 5212, in which case readout is not possible. In FIG. 38B, a single readout circuit 5242(a) is connected to all three PSs 5212 in readout group 5210. This allows the single readout circuit 5242 to read signals indicative of light impinging on all three PSs 5212. For example, all of the multiple PSs 5212 may be sequentially connected to one readout circuit 5242 at a time, such that at various times during a sampled frame, light collected by all of the multiple PSs 5212 of a readout group 5210 at all times is measured by various readout circuits 5242 at various times. One such example is provided in diagram 5410 of FIG.

[0183] In FIG. 26C , an appropriate subgroup of multiple readout circuits (including readout circuit 5242(b) and readout circuit 5242(c) in the illustrated example) is connected to all of the multiple PSs 5212 in the readout group 5210. This allows the multiple readout circuits 5242 to read signals indicative of light impinging on all three PSs 5212. The connection of two readout circuits 5212 to a readout group 5210 is illustrated in diagrams 5420 and 5430 of FIG. 27. Depending on the requirements of the implementation, more than two readout circuits 5212 may optionally be connectable to a readout group 5210. One implementation example of connecting multiple readout circuits 5212 to a single readout group 5210 is at the transition time between two different detection time windows of different detection signals (e.g., as described above with respect to FIGS. 24 and 25 ).

[0184] For example, at various times during a sampled frame, all of the plurality of PSs 5212 may be connected sequentially to one readout circuit 5242 at a time, such that light collected by all of the plurality of PSs 5212 of a readout group 5210 at all times is measured by various readout circuits 5242 at various times. An example of such is provided in diagram 5410 of FIG. 27. In other embodiments, only one readout circuit 5242 is connected to the plurality of PSs 5212 of a readout group 5210 at some times, while two or more readout circuits 5242 are connected in parallel to the plurality of PSs 5212 of a readout group 5210. An example of such is provided in diagrams 5420 and 5430 of FIG. 27. In yet other examples, various subsets of the plurality of readout circuits 5242 may be connected in parallel to the plurality of PSs 5212 of a readout group 5210 at various times. Note that for all of the options, there can optionally be idle times when no readout circuits 5242 are connected to the PSs 5212 of a readout group 5210. Examples of such are provided in diagrams 5440 and 5450 of Figure 27. Diagram 5460 of Figure 27 illustrates situations where various combinations of connections are implemented in a single frame—in a single readout circuit 5242, in multiple readout circuits 5242—and where no readout circuits 5242 are connected to a readout group 5210 at various times during the sensor sensing duration.

[0185] 28A-28C illustrate a sensor 5200 according to an embodiment of the presently disclosed subject matter. Optionally, the switching network 5230 includes switchable circuitry that allows individual readout circuits 5242 to be connected to individual PSs 5212 at some times, and to multiple PSs 5212 simultaneously at other times. In the illustrated embodiment, in FIG. 28B, readout circuit 5242(ROC1) is connected to all three PSs 5212(a), 5212(b), and 5212(c). Meanwhile, in FIG. 28C, the same readout circuit 5242(ROC1) is connected to only one PS 5242(a), while the other two readout circuits 5242(ROC2) and 5242(ROC3) are each connected to a single PS 5212. It should be noted that the detection operating parameters (e.g., photodiode bias, amplification gain, etc.) may be different in these two detection states, e.g., to accommodate different amounts of light collected by the PS5212.

[0186] Sensor 5200 is operable to detect depth information of objects within its FOV. It is noted that sensor 5200 may be a variation of any of the sensors described above (under any aspect) with the adaptations discussed below (including controller 5250 and its functionality, and associated switches). Many of the details, options, and variations described above with respect to the various sensors will not be repeated for the sake of brevity, but may be implemented in sensor 5200, mutatis mutandis.

[0187] Additionally, the sensor 5200 may operate in other detection modes that provide detection outputs that do not include depth information. For example, in some detection modes, the sensor 5200 may operate as a camera that provides a 2D image in which various detection values ​​indicate the amount of light reflected from a portion of the FOV within one (or more) detection durations. Note that such detection modes may, but need not, involve active illumination of the FOV.

[0188] 29 illustrates a sensor 5200 according to an embodiment of the subject matter of the present disclosure. As with other diagrams of a sensor 5200, it will be apparent that the number of PSs 5212 in the sensor may vary significantly from the illustrated diagram, for example, in the range of thousands, millions, etc.

[0189] FIG. 30 shows an FOV 5390 of an electro-optical system and multiple instantaneous FOVs 5312 according to an embodiment of the disclosed subject matter.

[0190] 31A and 31B illustrate various examples of a sensor 5200 according to embodiments of the subject matter of this disclosure. The examples of Figures 31A and 31B show light rays arriving from an FOV toward a readout group of multiple PSs (collectively designated 5210), as well as optional light rays emitted toward the FOV from an optional light source 5260. As with other diagrams of a sensor 5200, it will be apparent that the number of PSs 5212 in the sensor may vary significantly from the illustrated diagram, for example, in the thousands, millions, etc.

[0191] With respect to sensor 5200 and the systems, methods, and sensors described with respect to FIGS. 24-31B , it should be noted that multiple PSs including multiple readout structures (also referred to as “readout compounds”) may be implemented in place of multiple PSs to detect signals indicative of light arriving from an instantaneous FOV at different times. For example, a first readout structure (e.g., readout structure 6570, readout structure 9030, or floating diffusion 7540 acting as a readout structure, etc.) may be used to detect signal S1 of FIG. 25 , a second readout structure of the same PS may be used to detect signal S2 of FIG. 25 , and a third readout structure of the same PS may be used to detect signal S3 of FIG. 25 . For any of the systems and methods discussed with respect to FIGS. 24-31B that utilize a combination of multiple PSs to detect signals from the same portion of the FOV at different times, an equivalent system or method utilizing multiple readout structures of any single PS disclosed in this disclosure to detect signals from the same portion of the FOV at different times may be implemented, mutatis mutandis.

[0192] This disclosure also includes the following numbered clauses:

[0193] 1. 1. An infrared (IR) light detection system operable to detect IR radiation, comprising: at least one photosite (PS), a germanium (Ge) photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; a silicon (Si) layer including a diode, the Si layer including a first doped region of the first polarity and a second doped region of a second polarity opposite to the first polarity; wherein the first doped region is located between the second doped region and the absorber doped region; and at least one power supply operable to provide a first region voltage to the first doped region and a second region voltage to the second doped region; 1. A controllable power supply, comprising: providing an activation voltage to the Ge photosensitive region for a sampling duration of the PS, the activation voltage forcing charge carriers of the second polarity (CCSP) to migrate from the Ge photosensitive region toward the photodiode, the CCSP being collected in the photodiode via a readout electrode electrically coupled to the second doped region; Stopping signal collection by the PS after the end of the sampling duration by providing a rest voltage to the Ge photosensitive region that reduces the forced migration of the CCSP toward the photodiode. a controllable power source operable to: An IR light detection system, including:

[0194] 2. 10. The IR light detection system of claim 1, wherein the amplitude of the resting voltage is at least 10 times smaller than the amplitude of the activation voltage.

[0195] 3. The IR light detection system of claim 1 , wherein the sampling duration is less than 10 nanoseconds.

[0196] 4. 10. The IR light detection system of claim 1, wherein IR photons from the field of view of the IR light detection sensor pass through the Si layer before being absorbed in the Ge photosensitive region.

[0197] 5. (a) the Ge photosensitive region and the photodiode; (b) between at least one of said power sources; The IR light detection system of claim 1 further comprising a passivation layer.

[0198] 6. An electro-optical detection system comprising the IR light detection system according to any one of claims 1 to 5, Multiple photo sites and at least one optical interface for directing light from a field of view of the electro-optical detection system to the IR light detection sensor; a readout circuit operable to read at least one electrical signal from each of a plurality of said photosites corresponding to the number of photons captured by said Ge photosensitive region during said sampling duration of said respective photosite; a processor operable to process detection data provided by the readout circuitry indicative of a plurality of the electrical signals such that an IR image of the field of view is provided; an electro-optical detection system comprising:

[0199] 7. The electro-optical detection system of claim 6 , wherein the processor is further configured to process the detection data such that the presence of at least one object within the field of view is determined.

[0200] 8. 1. An infrared (IR) light detection system operable to detect IR radiation, comprising: at least one photosite, a Ge photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; a silicon (Si) layer including a first doped region, a storage well, a floating diffusion, and a transfer gate; at least one photosite, at least one controllable power supply operable to modulate a voltage to at least one of the first doped region, the Ge photosensitive region, and the floating diffusion; A control device, at one time, forcing charge carriers of the second polarity (CCSP) to migrate from the Ge photosensitive region toward the storage well by providing a voltage across the Ge photosensitive region, the first doped region, and the floating diffusion; At another time, providing another voltage to the Ge photosensitive region, the first doped region, and the floating diffusion reduces the forced migration of the CCSP toward the storage well, thereby stopping signal collection by the storage well; and intermittently transferring charge carriers of the second polarity from the storage well through the transfer gate to the floating diffusion, where the charge carriers are read out via a readout electrode electrically coupled to the floating diffusion. a controller operable to control at least one of the controllable power supply and the transmission gate such that An IR light detection system, including:

[0201] 9. 10. The IR light detection system of claim 8, wherein the storage well is at least partially pinned under a pinned layer of opposite polarity.

[0202] 10. 10. An IR light detection system according to claim 8 or claim 9, wherein at said other time, the charge carriers of the second polarity are discarded from the photosite without being read out.

[0203] 11. 10. The IR light detection system of claim 8 or claim 9, wherein the storage well is disposed between the first doped region and the floating diffusion.

[0204] 12. 10. The IR light detection system of claim 8 or claim 9, wherein the first doped region is disposed between the storage well and the Ge photosensitive region.

[0205] 13. 10. The IR light detection system of claim 8 or claim 9, wherein the sampling duration is less than 10 nanoseconds.

[0206] 14. 10. The IR light detection system of claim 8 or claim 9, wherein IR photons from the field of view of the IR light detection sensor pass through the Si layer before being absorbed in the Ge photosensitive region.

[0207] 15. (a) the Ge photosensitive region and the photodiode; (b) between at least one of said power sources; 10. The IR light detection system of claim 8 or claim 9, further comprising a passivation layer.

[0208] 16. 1. An infrared (IR) light detection system operable to detect IR radiation, comprising: at least one photosite, a germanium (Ge) photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region doped to have a first polarity; A silicon (Si) layer having a plurality of readout structures implemented thereon, each readout structure comprising: a remote doped region doped to have a second polarity; an intermediate doped region disposed between the remote doped region and the Ge photosensitive region, the intermediate doped region being doped to have a second polarity opposite to the first polarity; a Si layer including at least one photosite, a controllable power supply operable to provide a controlled voltage to the Ge photosensitive region and the remotely doped region and the intermediately doped region of each readout structure of the plurality of readout structures; maintaining relative voltages on the Ge photosensitive region, on a first remotely doped region of the first readout structure, and on a first intermediately doped region of the first readout structure for a first sampling duration such that charge carriers of the second polarity (CCSPs) are forced by a first tensile force to move from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein the CCSPs are collected in the first readout structure via a first readout electrode electrically coupled to the first remotely doped region; maintaining a voltage on the plurality of doped regions of the first group of readout structures for the first sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the plurality of remotely doped regions of the first group of readout structures, including the remainder of the plurality of readout structures other than the first readout structure, is less than half of the first pulling force; maintaining a relative voltage on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure for a second sampling duration that is later than the first sampling duration, such that charge carriers of a second polarity (CCSP) are forced by a second tensile force to move from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein the CCSP are collected in the second readout structure via a second readout electrode electrically coupled to the second remotely doped region; maintaining a voltage on the doped regions of the second group of readout structures for the second sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the remotely doped regions of a second group of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half of the second pulling force; maintaining relative voltages on the Ge photosensitive region, the first remotely doped region, and the first intermediately doped region for a third sampling duration that is later than the second sampling duration, such that charge carriers of the second polarity (CCSPs) are forced by a third tensile force to migrate from the Ge photosensitive region toward the first readout structure, wherein the CCSPs are collected at the first readout structure via the first readout electrode; and maintaining a voltage on the doped regions of the first group of readout structures for the third sampling duration such that a pulling force applied to charge carriers of the second polarity toward each of the remotely doped regions of the first group of readout structures is less than half of the third pulling force; a controllable power source operable to: An IR light detection system, including:

[0209] 17. 17. The IR light detection system of claim 16, wherein a first voltage applied to a first intermediate doped region during the first sampling duration is greater than or equal to 10 times any voltage applied to any intermediate doped region of the first group of multiple readout structures averaged over the first duration.

[0210] 18. 18. The IR light detection system of claim 16 or 17, wherein IR photons from the field of view of the IR light detection sensor pass through the Si layer before being absorbed in the Ge photosensitive region.

[0211] 19. (a) the Ge photosensitive region and the photodiode; (b) between at least one of said power sources; 18. The IR light detection system of claim 16 or claim 17, further comprising a passivation layer.

[0212] 20. 18. The IR light detection system of claim 16 or claim 17, further comprising at least one optically active layer bonded to a polished side of the Si layer positioned opposite to a side of the Si layer on which the Ge photosensitive region extends.

[0213] twenty one. 1. A method for detecting infrared (IR) radiation, comprising: providing a first domain voltage to a first doped region of a photosite (PS) and a second domain voltage to a second region of said PS, wherein said PS: a germanium (Ge) photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; a silicon layer including a diode, the diode including a first doped region of the first polarity and a second doped region of a second polarity opposite to the first polarity; wherein the first doped region is located between the second doped region and the absorber doped region; providing an activation voltage to the Ge photosensitive region for a sampling duration of the photosite while providing the first region voltage and the second region voltage, the activation voltage forcing charge carriers of the second polarity (CCSP) to migrate from the Ge photosensitive region toward the photodiode, the CCSP being collected in the photodiode via a readout electrode electrically coupled to the second doped region; and ceasing signal collection by the photosites after the end of the sampling duration by providing a rest voltage to the Ge photosensitive region that attenuates forced migration of the CCSPs toward the photodiodes. A method comprising:

[0214] twenty two. The method of claim 21 , wherein the photosites are photosites of an IR photodetector system.

[0215] twenty three. 1. A method for detecting infrared (IR) radiation, comprising: modulating a voltage to at least one region of a photosite (PS); the region is selected from the group consisting of a first doped region of the PS, a germanium (Ge) photosensitive region of the PS, and a floating diffusion of the PS; The PS comprises at least (a) a Ge photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region having a first polarity; (b) a silicon layer including the first doped region, a storage well, the floating diffusion, and a transfer gate; Including, The modulating step includes: at one time, forcing the charge carriers of the second polarity (CCSP) to migrate from the Ge photosensitive region toward the storage well by providing a voltage across the Ge photosensitive region, the first doped region, and the floating diffusion; At another time, providing another voltage to the Ge photosensitive region, the first doped region, and the floating diffusion to attenuate the forced migration of the CCSP toward the storage well, thereby stopping signal collection by the storage well; and intermittently transferring charge carriers of the second polarity from the storage well through the transfer gate to the floating diffusion, wherein the CCSP is read at the floating diffusion via a readout electrode electrically coupled to the floating diffusion. A method comprising:

[0216] twenty four. The method of claim 23 , wherein the photosites are IR photodetector photosites.

[0217] twenty five. 25. The method of claim 23 or claim 24, wherein the amplitude of the resting voltage is at least 10 times smaller than the amplitude of the activation voltage.

[0218] 26. 1. A method for detecting infrared (IR) radiation, comprising: providing a controlled voltage to multiple regions of the photosite (PS); Including, The PS is a germanium (Ge) photosensitive region operable to generate electron-hole pairs in response to impinging IR photons, the Ge photosensitive region including an absorber-doped region doped to have a first polarity; a plurality of doped regions of a plurality of readout structures implemented on a silicon layer of the photosite, for each of the plurality of readout structures: (a) a remote doped region doped to have a second polarity; (b) an intermediate doped region disposed between the remote doped region and the Ge photosensitive region, the intermediate doped region being doped to have a second polarity opposite to the first polarity; a plurality of doped regions of a plurality of readout structures, including: Including, The providing step comprises: maintaining relative voltages on the Ge photosensitive region, on a first remotely doped region of the first readout structure, and on a first intermediately doped region of the first readout structure for a first sampling duration such that charge carriers of the second polarity (CCSPs) are forced by a first tensile force to move from the Ge photosensitive region toward a first readout structure of the plurality of readout structures, wherein the CCSPs are collected in the first readout structure via a first readout electrode electrically coupled to the first remotely doped region; maintaining a voltage on the doped regions of the first group of readout structures for the first sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the remotely doped regions of the first group of readout structures, including the remainder of the plurality of readout structures other than the first readout structure, is less than half of the first pulling force; maintaining a relative voltage on the Ge photosensitive region, on a second remotely doped region of the second readout structure, and on a second intermediately doped region of the second readout structure for a second sampling duration that is later than the first sampling duration, such that charge carriers of a second polarity (CCSP) are forced by a second tensile force to migrate from the Ge photosensitive region toward a second readout structure of the plurality of readout structures, wherein the CCSP are collected in the second readout structure via a second readout electrode electrically coupled to the second remotely doped region; maintaining a voltage on the doped regions of the second group of readout structures for the second sampling duration such that a pulling force exerted on charge carriers of the second polarity toward each of the remotely doped regions of a second group of readout structures, including the remainder of the plurality of readout structures other than the second readout structure, is less than half of the second pulling force; maintaining relative voltages on the Ge photosensitive region, the first remotely doped region, and the first intermediately doped region for a third sampling duration that is later than the second sampling duration, such that charge carriers of the second polarity (CCSPs) are forced by a third tensile force to migrate from the Ge photosensitive region toward the first readout structure, wherein the CCSPs are collected at the first readout structure via the first readout electrode; and maintaining a voltage on the doped regions of the first group of readout structures for the third sampling duration such that a pulling force applied to charge carriers of the second polarity toward each of the remotely doped regions of the first group of readout structures is less than half of the third pulling force. A method comprising:

[0219] 27. 27. The method of claim 26, wherein a first voltage applied to a first intermediate doped region during the first sampling duration is greater than or equal to 10 times any voltage applied to any intermediate doped region of the first group of multiple readout structures averaged over the first duration.

[0220] 28. 28. A method according to claim 26 or claim 27, performed on multiple photosites simultaneously.

[0221] 29. 28. The method of claim 26 or 27, further comprising providing a voltage to a plurality of regions of the photosite during a discard duration such that charge carriers of the second polarity are driven from the photosite through an electrode towards the electrode where they are discarded without being read out.

[0222] 30. 1. A method for generating a depth image of a scene based on detection of a short-wave infrared (SWIR) electro-optical imaging system (SEI system), comprising: obtaining a plurality of detection signals of the SEI system, each detection signal indicative of an amount of light from a particular direction within a field of view (FOV) of the SEI system captured by at least one focal plane array (FPA) detector of the SEI system over a respective detection time frame, the at least one FPA including a plurality of individual photosites, each photosite including a germanium (Ge) element at which impinging photons are converted into detected charges in the Ge element, and for each of a plurality of directions within the FOV, different detection signals indicative of reflected SWIR illumination levels from different distance ranges along that direction; and processing the plurality of detection signals such that a three-dimensional (3D) detection map is determined that includes a plurality of 3D locations within the FOV at which a plurality of objects are detected; Including, the processing step includes compensating for a dark current (DC) level accumulated during collection of the plurality of detection signals from the plurality of germanium elements; The method, wherein the compensating step includes applying different degrees of DC compensation to a plurality of detected signals detected by different photosites of at least one of the FPAs.

[0223] 31. The compensating step includes: subtracting a first DC compensation offset from a first detection signal detected by a first DE corresponding to a first detection range; subtracting a second DC compensation offset different from the first DC compensation offset from a second detection signal detected by a first photosite corresponding to a second detection range that is farther from the SEI system than the first detection range; 31. The method of claim 30, comprising:

[0224] 32. triggering emission of a first illumination in coordination with the initiation of exposure of a first gated image in which a plurality of first detection signals are detected for different ones of the plurality of directions; triggering the emission of a second illumination in coordination with the initiation of exposure of a second gated image in which a plurality of second detection signals are detected for different of said directions; triggering the emission of a third illumination in coordination with the initiation of exposure of a third gated image in which a plurality of third detection signals are detected for different of said directions; further comprising The treating step comprises: determining a presence of a first object at a first 3D position within a first one of the various directions based on at least one detection signal from each of the first image, the second image, and the third image; determining a presence of a second object at a second 3D position within a second one of the various directions based on at least one detection signal from each of the first image, the second image, and the third image; Including, 31. The method of claim 30, wherein a distance of the first object from the SEI system is at least twice a distance of the second object from the SEI system.

[0225] 33. a sensor operable to detect depth information of an object, a focal plane array (FPA) including a plurality of photosites, each photosite operable to detect light coming from an instantaneous field of view (IFOV) of that photosite, different photosites being oriented in different directions within the field of view of the sensor; a readout set of a plurality of readout circuits, each of which is coupled by a plurality of switches to a readout group of a plurality of photosites of the FPA, the readout set of a plurality of readout circuits operable to output an electrical signal indicative of an amount of light impinging on a plurality of the photosites of the readout group when the readout group is connected to a respective readout circuit through at least one of the plurality of switches; a control device operable to change a plurality of switching states of a plurality of said switches such that different readout circuits of said readout set are coupled to said readout group at different times to expose different readout circuits to reflections of illumination light from a plurality of objects located at different distances from said sensor; a processor configured to obtain a plurality of electrical signals from the readout set indicative of detected levels of reflected light collected from a plurality of the IFOVs of the readout group of a plurality of photosites to determine depth information relating to the object indicative of a distance of the object from the sensor; and a sensor.

[0226] With respect to the PSs described above, and all PSs discussed throughout this disclosure, any of those PSs may optionally include a guard ring (not shown) or trenching that completely, incompletely, or partially surrounds the PS (or a portion thereof). Such partial or complete trenching or guard rings are not shown in the diagrams for clarity and simplicity. Many uses and methods of implementation are known to those skilled in the art and are not disclosed herein for the sake of brevity.

[0227] However, other modifications, variations, and alternatives are also possible. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0228] In the claims, any reference signs placed between parentheses shall not be construed as limiting the scope of the claim. The word "comprising" does not exclude the presence of other elements or steps than those recited in a claim. Furthermore, as used herein, the words "a" or "an" are defined as one or more than one. Also, the use of introductory phrases such as "at least one" and "one or more" in the claims shall not be construed as implying that the introduction of another claim element with the indefinite article "a" or "an" limits any particular claim containing such introduced claim element to a disclosure containing only one such element, even if the same claim also contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an." The same applies to the use of definite articles. Unless otherwise specified, the terms "first" and "second", etc. are used to arbitrarily distinguish between the elements designated by such terms. As such, these terms are not intended to necessarily indicate a chronological or other priority between such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

[0229] While particular configurations for the present disclosure have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all modifications and variations that fall within the true spirit of the present disclosure. It will be understood that the above-described embodiments are given by way of example, and that various configurations and combinations of these configurations are susceptible to change and modification. While various embodiments have been shown and described, there is no intention to limit the present disclosure by such disclosure. Rather, it will be understood that the intention is to cover all modifications and alternative configurations that fall within the scope of the present disclosure, as defined by the appended claims. [Brief explanation of the drawings]

[0230] [Figure 1A] 1 is a cross-sectional view of an embodiment of a photosite of an IR light detection system. [Figure 1B] FIG. 1B illustrates the attenuation of charge carrier movement during the pause duration in the system of FIG. 1A. [Figure 1C] FIG. 1B illustrates the movement of charge carriers during a sampling duration in the system of FIG. 1A. [Figure 2A] 1 is a cross-sectional view of an embodiment of a photosite of an IR light detection system. [Figure 2B] FIG. 2B illustrates the attenuation of charge carrier movement during the pause duration in the system of FIG. 2A. [Figure 2C] FIG. 2B illustrates the movement of charge carriers during the sampling duration in the system of FIG. 2A. [Figure 3A] FIG. 1 is a top view showing two example photosites. [Figure 3B] FIG. 1 is a top view showing two example photosites. [Figure 4] The voltages applied to the photosite electrodes during successive sampling cycles are shown. [Figure 5] 1 shows an IR light detection system. [Figure 6] FIG. 1 is a block diagram illustrating an electro-optical system including an IR light detection system. [Figure 7] 1 is a flow chart illustrating an example of a method for sensing light from a field of view. [Figure 8] FIG. 1 is a cross-sectional view of a photosite of an IR light detection system. [Figure 9] The conditions applied to the voltage modulation on one or more electrodes of the photosite and the conditions applied to the transmission gate during successive sampling cycles are shown. [Figure 10] Shows photosites. [Figure 11] Shows photosites. [Figure 12A] FIG. 1 is a top view of a photosite. [Figure 12B] FIG. 2 is a top view of an example photosite. [Figure 13A] 1 shows a cross-sectional view and a top view of a photosite. [Figure 13B] 1 shows a cross-sectional view and a top view of a photosite. [Figure 13C] 1 shows a cross-sectional view and a top view of a photosite. [Figure 13D] An example of a PS with four separate readout structures is shown. [Figure 14A] The relative voltages that can be applied to various regions of the photosite during its operation are shown. [Figure 14B] The relative voltages that can be applied to various regions of the photosite during its operation are shown. [Figure 14C] 1 illustrates exemplary relationships between voltages applied to various electrodes in various operating states. [Figure 14D] 1 illustrates exemplary relationships between voltages applied to various electrodes in various operating states. [Figure 15] 1 shows a photodetector array with N-tap photosites. [Figure 16] 1 shows a photodetector array with N-tap photosites. [Figure 17]1 shows a photodetector array with N-tap photosites. [Figure 18] 1 shows a photodetector array with N-tap photosites. [Figure 19] 1 illustrates a method for detecting light coming from the field of view of a photodetector array that includes a plurality of photosites. [Figure 20A] 1 is a cross-sectional view of an embodiment of a photosite of an IR light detection system. [Figure 20B] 1 is a cross-sectional view of an embodiment of a photosite of an IR light detection system. [Figure 21] Shows photosites. [Figure 22] A method for detecting IR radiation is presented. [Figure 23] A method for detecting IR radiation is presented. [Figure 24] A method for generating a depth image of a scene based on the detection of a SWIR electro-optical imaging system is presented. [Figure 25] The timing of three different detected signals coming from the same direction within the FOV is shown. [Figure 26A] 1 shows the sensor in various operating states. [Figure 26B] 1 shows the sensor in various operating states. [Figure 26C] 1 shows the sensor in various operating states. [Figure 27] Includes various timing diagrams. [Figure 28A] 1 shows the sensor in various operating states. [Figure 28B] 1 shows the sensor in various operating states. [Figure 28C] 1 shows the sensor in various operating states. [Figure 29] The sensor is shown. [Figure 30] 1 shows the field of view of the electro-optical system, and multiple instantaneous FOVs. [Figure 31A] 1 illustrates various examples of sensors according to embodiments of the presently disclosed subject matter. [Figure 31B]1 illustrates various examples of sensors according to embodiments of the presently disclosed subject matter.

Claims

1. 1. A method for generating a depth image of a scene based on detection of a short-wave infrared (SWIR) electro-optical imaging system (SEI system), comprising: obtaining a plurality of detection signals of the SEI system, each detection signal indicative of an amount of light from a particular direction within a field of view (FOV) of the SEI system captured by at least one focal plane array (FPA) detector of the SEI system over a respective detection time frame, the at least one FPA detector including a plurality of individual photosites, each photosite including a germanium (Ge) element at which impinging photons are converted into detected charges in the Ge element, and for each of a plurality of directions within the FOV, different detection signals indicative of reflected SWIR illumination levels from different distance ranges along that direction; and processing the plurality of detection signals such that a three-dimensional (3D) detection map is determined that includes a plurality of 3D locations within the FOV at which a plurality of objects are detected; Including, The method, wherein the processing step includes compensating for dark current (DC) levels accumulated during collection of the plurality of detection signals from the plurality of Ge elements.

2. The method of claim 1 , wherein the compensating step comprises applying different degrees of DC compensation to multiple detected signals simultaneously detected by different photosites of at least one of the FPA detectors.

3. 3. The method of claim 2, wherein applying different degrees of DC compensation comprises using detected dark current levels of different reference photosites shielded from light coming from the FOV.

4. The compensating step includes: subtracting a first DC compensation offset from a first detection signal detected by a first photosite corresponding to a first detection range; subtracting a second DC compensation offset different from the first DC compensation offset from a second detection signal detected by the first photosite corresponding to a second detection range that is farther from the SEI system than the first detection range; The method of claim 1 , comprising:

5. triggering emission of a first illumination in coordination with the initiation of exposure of a first gated image in which a plurality of first detection signals are detected for different ones of the plurality of directions; triggering the emission of a second illumination in coordination with the initiation of exposure of a second gated image in which a plurality of second detection signals are detected for different of said directions; triggering the emission of a third illumination in coordination with the start of exposure of a third gated image in which a plurality of third detection signals are detected for different of said directions; The method of claim 1 further comprising:

6. said step of processing a plurality of said detection signals so as to determine a three-dimensional (3D) detection map, said step comprising: determining a presence of a first object at a first 3D position within a first direction of the various directions based on at least one detection signal from each gated image of the first gated image, the second gated image, and the third gated image; determining a presence of a second object at a second 3D position within a second one of the various directions based on at least one detection signal from each gated image of the first gated image, the second gated image, and the third gated image; further comprising The method of claim 5 , wherein the distance of the first object from the SEI system is at least twice the distance of the second object from the SEI system.

7. 1. A system for generating a depth image of a scene based on detection of a short-wave infrared (SWIR) electro-optical imaging system (SEI system), comprising: obtaining a plurality of detection signals of the SEI system, each detection signal indicative of an amount of light from a particular direction within a field of view (FOV) of the SEI system captured by at least one focal plane array (FPA) detector of the SEI system over a respective detection time frame, the at least one FPA detector including a plurality of individual photosites, each photosite including a germanium (Ge) element at which impinging photons are converted into detected charges in the Ge element, and for each of a plurality of directions within the FOV, different detection signals indicative of reflected SWIR illumination levels from different distance ranges along that direction; and processing the plurality of detection signals such that a three-dimensional (3D) detection map is determined that includes a plurality of 3D locations within the FOV at which a plurality of objects are detected; at least one processor configured to execute The processing step includes compensating for dark current (DC) levels accumulated during collection of the detection signals from the Ge elements.

8. 8. The system of claim 7, wherein the compensating step comprises applying different degrees of DC compensation to multiple detected signals simultaneously detected by different photosites of at least one of the FPA detectors.

9. 9. The system of claim 8, wherein applying different degrees of DC compensation comprises using detected dark current levels of different reference photosites shielded from light coming from the FOV.

10. The compensating step includes: subtracting a first DC compensation offset from a first detection signal detected by a first photosite corresponding to a first detection range; subtracting a second DC compensation offset different from the first DC compensation offset from a second detection signal detected by the first photosite corresponding to a second detection range that is farther from the SEI system than the first detection range; The system of claim 7, comprising:

11. At least one of the processors triggering emission of a first illumination in coordination with the initiation of exposure of a first gated image in which a plurality of first detection signals are detected for different ones of the plurality of directions; triggering the emission of a second illumination in coordination with the initiation of exposure of a second gated image in which a plurality of second detection signals are detected for different of said directions; triggering the emission of a third illumination in coordination with the start of exposure of a third gated image in which a plurality of third detection signals are detected for different of said directions; The system of claim 7 , further configured to:

12. At least one of the processors may, as part of determining the three-dimensional (3D) detection map, (a) detecting a presence of a first object at a first 3D position within a first direction of the various directions based on at least one detection signal from each gated image of the first gated image, the second gated image, and the third gated image; (b) the presence of a second object at a second 3D position within a second one of the various directions based on at least one detection signal from each gated image among the first gated image, the second gated image, and the third gated image; and and further configured to determine The system of claim 11 , wherein the distance of the first object from the SEI system is at least twice the distance of the second object from the SEI system.

13. a sensor operable to detect depth information of an object, a focal plane array (FPA) including a plurality of photosites, each photosite operable to detect light coming from an instantaneous field of view (IFOV) of that photosite, different photosites being oriented in different directions within the sensor's field of view; a readout set of a plurality of readout circuits, each of which is coupled by a plurality of switches to a readout group of a plurality of photosites of the FPA, the readout set of a plurality of readout circuits operable to output an electrical signal indicative of an amount of light impinging on a plurality of the photosites of the readout group when the readout group is connected to a respective readout circuit through at least one of the plurality of switches; a control device operable to change a plurality of switching states of a plurality of said switches such that different readout circuits of said readout set are coupled to said readout group at different times to expose different readout circuits to reflections of illumination light from a plurality of objects located at different distances from said sensor; a processor configured to obtain a plurality of electrical signals from the readout set indicative of detected levels of reflected light collected from a plurality of the IFOVs of the readout group of a plurality of photosites to determine depth information relating to the object indicative of a distance of the object from the sensor; a sensor.

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