CN111885321A - Germanium-silicon image sensor, acquisition module and TOF depth camera - Google Patents
Germanium-silicon image sensor, acquisition module and TOF depth camera Download PDFInfo
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- CN111885321A CN111885321A CN202010699707.1A CN202010699707A CN111885321A CN 111885321 A CN111885321 A CN 111885321A CN 202010699707 A CN202010699707 A CN 202010699707A CN 111885321 A CN111885321 A CN 111885321A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
- H04N25/63—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to dark current
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
- H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
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Abstract
The invention discloses a germanium-silicon image sensor, which comprises a pixel array consisting of a plurality of pixels; wherein the pixel includes: a read-in unit, a buffer direct injection structure unit, a demodulation unit, and a read-out unit; the read-in unit comprises a germanium photodiode configured to convert an optical signal incident to the sensor into an electric charge signal; the buffer direct injection structure unit is connected with the germanium photodiode, is configured to reduce the input impedance of the charge signal and provide a stable bias voltage, and transmits the charge signal to the demodulation unit; the demodulation unit configured to cause the charge signal to generate a plurality of voltage signals according to a plurality of exposure control transistors, respectively; the readout unit is configured to read the voltage signal. The germanium-silicon image sensor can reduce the input resistance of a reading circuit, improve the injection efficiency, realize stable bias voltage and reduce dark current.
Description
Technical Field
The invention relates to the technical field of image sensors, in particular to a germanium-silicon image sensor, an acquisition module and a TOF depth camera.
Background
Distance measurement may be performed on a target using a Time of Flight (TOF) principle to obtain a depth image containing a depth value of the target, and TOF depth cameras based on the Time of Flight principle have been widely used in the fields of consumer electronics, unmanned driving, AR/VR, and the like. TOF depth cameras achieve accurate ranging by measuring the round-trip time of flight of light pulses between a transmitting/receiving device and a target object.
TOF depth cameras typically use photodiodes to detect optical signals, convert the optical signals into electrical signals, and read out by readout circuitry. In general, materials absorb light at various wavelengths depending on the material's associated bandgap energy, with materials having lower bandgap energies having higher absorption coefficients at long wavelengths. At room temperature, silicon has a bandgap energy of 1.12eV and germanium of 0.66eV, whereas a germanium-silicon alloy may have a bandgap energy between 0.66eV and 1.12eV depending on the germanium-silicon composition ratio. Since silicon has too low an absorption coefficient for light sources above 1000nm in wavelength, optical signals cannot be converted into electrical signals, while germanium is an effective absorbing material for near infrared wavelengths.
Germanium has higher light absorption efficiency and higher mobility compared with silicon, and can increase the bandwidth of a device, thereby allowing a TOF depth camera to use higher modulation frequency and improving the depth measurement precision; in addition, germanium does not need to use a photosensitive layer with enough depth to improve the absorption efficiency of an absorption wavelength section, and germanium or silicon-germanium alloy can adopt a shallower photosensitive area to realize higher light absorption efficiency, so that crosstalk between adjacent pixels is reduced, the modulation contrast is improved, and higher depth measurement precision is realized.
In prior art pixel circuits for silicon germanium based image sensors, a silicon layer is adjacent to a silicon germanium layer, transistors are arranged on the surface of the silicon layer, while source/drain regions are electrically connected to photodetectors, which advantageously have good sensitivity and absorption for long wavelength radiation by being arranged in the silicon germanium layer. However, the circuit structure of the readout unit of the pixel circuit is generally a direct injection structure, and due to the influence of the internal resistance of the photodetector, the photocurrent generated by the photodetector is shunted by the internal resistance of the photodetector, so that the injection efficiency of the readout unit circuit is not high.
The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.
Disclosure of Invention
The present invention is directed to a germanium-silicon image sensor, an acquisition module and a TOF depth camera, so as to solve at least one of the above problems of the related art.
In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:
a germanium-silicon image sensor comprises a pixel array composed of a plurality of pixels; wherein the pixel includes: a read-in unit, a buffer direct injection structure unit, a demodulation unit, and a read-out unit;
the read-in unit comprises a germanium photodiode configured to convert an optical signal incident to the sensor into an electric charge signal;
the buffer direct injection structure unit is connected with the germanium photodiode, is configured to reduce the input impedance of the charge signal and provide a stable bias voltage, and transmits the charge signal to the demodulation unit;
the demodulation unit configured to cause the charge signal to generate a plurality of voltage signals according to a plurality of exposure control transistors, respectively;
the readout unit is configured to read the voltage signal.
In some embodiments, the buffer direct injection structural unit comprises an amplifier and an NMOS transistor; the source electrode of the NMOS transistor is respectively connected with the output end of the read-in unit and the input end of the demodulation unit; the positive input end of the amplifier is connected with a direct-current bias power supply, the negative input end of the amplifier is connected with the output end of the read-in unit, the output end of the amplifier is connected with the grid electrode of the NMOS transistor, and the amplifier is configured to reduce the impedance of the NMOS transistor.
In some embodiments, the hybrid bonding unit is connected to the output end of the read-in unit and the input end of the buffer direct injection structure unit, and configured to implement physical structure bonding between a single silicon layer wafer and a germanium-silicon layer wafer, and transmit the charge signal subjected to photoelectric conversion on the germanium-silicon layer wafer to the single silicon layer buffer direct injection structure unit.
In some embodiments, the demodulation unit further includes a first integration capacitor and a second integration capacitor configured to integrate voltages generated by the plurality of exposure control transistors, respectively.
In some embodiments, the readout unit includes a source follower transistor and a selection transistor; wherein the selection transistor is configured to control an output of the voltage signal.
In some embodiments, the germanium photodiode includes a photodetector buried in a silicon germanium layer, the photodetector configured to convert an optical signal incident to an image sensor into a charge signal.
In some embodiments, the readout unit comprises a first readout unit and a second readout unit configured to read voltages of the first integration capacitance and the second integration capacitance, respectively.
In some embodiments, the readout unit further comprises a transfer transistor, which is connected to the demodulation unit and the readout unit, respectively, and configured to transfer the charges collected by the first and second integration capacitors to the readout unit in a time-sharing manner.
The other technical scheme of the embodiment of the invention is as follows:
an acquisition module comprises a lens unit and the germanium-silicon image sensor in any embodiment.
The embodiment of the invention adopts another technical scheme that:
a TOF depth camera, comprising:
the emission module is configured to emit a light beam to a target object;
the acquisition module according to the foregoing embodiment is configured to acquire at least a part of the reflected light signal reflected by the target object;
and the control and processor is respectively connected with the transmitting module and the collecting module, and synchronizes trigger signals of the transmitting module and the collecting module so as to calculate the time required for the light beam to be transmitted by the transmitting module and received by the collecting module.
The technical scheme of the invention has the beneficial effects that:
compared with the prior art, the germanium-silicon image sensor can reduce the input resistance of a reading circuit, improve the injection efficiency, realize stable bias voltage and reduce dark current.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a TOF depth camera according to one embodiment of the present disclosure;
fig. 2 is a schematic block diagram of a pixel of a sige image sensor according to an embodiment of the present invention;
FIG. 3 is a circuit diagram of a pixel of a SiGe image sensor in accordance with one embodiment of the present invention;
fig. 4 is another circuit diagram of a pixel of a sige image sensor according to an embodiment of the present invention;
FIG. 5 is another circuit diagram of a pixel of a SiGe image sensor in accordance with one embodiment of the present invention;
fig. 6 is another circuit diagram of a pixel of a sige image sensor according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. The connection may be for fixation or for circuit connection.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a TOF depth camera according to an embodiment of the present invention. The TOF depth camera 10 includes a transmit module 11, an acquisition module 12, and a control and processor 13. The emission module 11 provides an emission beam 30 to emit to a target space to illuminate an object 20 in the space, at least a part of the emission beam 30 is reflected by the object 20 to form a reflected beam 40, and at least a part of the reflected beam 40 is collected by the collection module 12; control and processor 13 are connected with emission module 11 and collection module 12 respectively, and the trigger signal of synchronous emission module 11 and collection module 12 is sent out and is gathered module 12 receipt required time in order to calculate the light beam by emission module 11, and the time of flight t between transmission beam 30 and the reflected light beam 40 promptly, and further, the distance D of target object can be calculated by the following formula:
D＝c·t/2 (1)
where c is the speed of light.
The emitting module 11 includes a light source, a light source driver (not shown), and the like. The light source may be a light source such as a Light Emitting Diode (LED), an Edge Emitting Laser (EEL), a Vertical Cavity Surface Emitting Laser (VCSEL), or a light source array composed of a plurality of light sources, and the light beam emitted by the light source may be visible light, infrared light, ultraviolet light, or the like.
The collection module 12 includes an image sensor 121, a lens unit, a filter (not shown), and the like. Wherein the lens unit receives and images at least part of the light beam reflected by the object on the image sensor 121, and the filter selects a narrow-band filter matched with the wavelength of the light source for suppressing background light noise of the rest wave bands. The image sensor may be an image sensor array of Charge Coupled Devices (CCD), Complementary Metal Oxide Semiconductor (CMOS), Avalanche Diodes (AD), Single Photon Avalanche Diodes (SPAD), etc., with an array size representing the resolution of the depth camera, e.g., 320 x 240, etc.
Generally, the image sensor 121 includes a pixel array composed of a plurality of pixels, each of which includes a plurality of taps (for storing and reading or transferring charge signals generated by incident photons under the control of respective electrodes). For example, a pixel may include 3 taps that time-divisionally accumulate and read charge signal data generated by a photodetector according to a modulation signal. The pixels will be described in detail later with reference to fig. 2, 3, and 4.
The control and processor 13 may be a separate dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, etc. including a CPU, a memory, a bus, etc., or may include a general-purpose processing circuit, such as when the TOF depth camera is integrated into an intelligent terminal, such as a mobile phone, a television, a computer, etc., the processing circuit of the terminal may be at least a part of the control and processor 13.
In some embodiments, the control and processor 13 is configured to provide a modulation signal (emission signal) required when the light source emits laser light, and the light source emits a pulse light beam to the object to be measured under the control of the modulation signal; the control and processor 13 also supplies a demodulation signal (acquisition signal) of a tap in each pixel of the image sensor 121, the tap acquires a charge signal generated by the pulse beam reflected back by the object under the control of the demodulation signal, and calculates a phase difference based on the electric signal to obtain the distance of the object 20. For example, in the case of a pixel with 2 taps, the distance expression of the object is calculated as follows:
wherein c is the speed of light; t is the laser pulse width of a single exposure period; q1, Q2 are the total charge amount of the 2 taps, respectively.
In TOF depth camera applications, the phase difference between emitted light pulses and detected light pulses may be used to determine depth information of a three-dimensional object. For example, a two-dimensional array of pixels may be used to reconstruct a three-dimensional image of a three-dimensional object, where each pixel may include one or more photodiodes for deriving phase information of the three-dimensional object. In some implementations, the TOF depth camera uses a light source having a wavelength in the Near Infrared (NIR) range. For example, a Light Emitting Diode (LED) may have a wavelength of 850nm, 940nm, 1050nm, or 1310 nm. Among these, photodiodes may use silicon as an absorbing material, but silicon is an inefficient absorbing material for NIR wavelengths. To collect NIR light, the photosensitive region of the photodiode is set deep, generating photo-carriers deep in the silicon substrate (e.g., greater than 10um deep), which can slowly drift and/or diffuse to the photodiode junction to reduce the bandwidth of the device. In addition, photodiode operation is typically controlled using small voltage swings to minimize power consumption, which can only produce small lateral/vertical electric fields over large absorption regions for deep absorption regions (e.g., 10um in diameter), which affects the drift rate of photo-carriers that sweep across the entire absorption region. Thus, the device bandwidth is further limited. For TOF depth cameras using NIR wavelengths, photodiodes using germanium-silicon as an absorbing material may solve the technical problem described above.
As an embodiment of the present invention, the image sensor in the TOF depth camera shown in fig. 1 is a sige image sensor, which forms a semiconductor stack including a silicon layer and a silicon germanium layer, forms a photodetector in the silicon germanium layer, and forms a readout circuit having source/drain regions on the silicon layer, the source/drain regions being buried in the surface of the silicon layer and electrically connected to the photodetector, and the readout circuit employs a buffered direct injection structure, thereby reducing the input resistance of the readout circuit, improving the injection efficiency, and achieving a stable detector bias voltage and low dark current.
Referring to fig. 2-4, a sige image sensor pixel circuit is described in detail later, and in the embodiment of the present invention, a two-tap example is used as an example, and the sige image sensor pixel circuit includes a read-in unit 50, a buffer direct injection structure unit 60, a demodulation unit 70, and a readout unit 80. It should be understood that the embodiment of the present invention takes two taps as an example, but the present invention is not limited to the case of two taps, and the present invention should fall within the protection scope of the present invention as long as the main concept of the present invention is adopted.
The read-in unit 50 includes a germanium photodiode 501; among other things, the germanium photodiode 501 includes a photodetector (not shown) buried in a silicon germanium layer, the photodetector being configured to convert an optical signal incident to the image sensor into a charge signal.
In fig. 3, two-way buffer direct injection structure unit 60 is connected to germanium photodiode 501, configured to reduce the input impedance of the charge signal and provide a stable bias voltage, and transmit the charge signal to demodulation unit 70. The buffer direct injection structure unit 60 includes an amplifier and an NMOS transistor, sources of the NMOS transistor are respectively connected to an output terminal of the read-in unit 50 and an input terminal of the demodulation unit 70, a positive input terminal of the amplifier is connected to a dc bias power supply, a negative input terminal of the amplifier is connected to an output terminal of the read-in unit 50, and an output terminal of the amplifier is connected to a gate of the NMOS transistor, and is configured to reduce impedance of the NMOS transistor.
A demodulation unit 70 configured to cause the charge signal to generate a first voltage signal and a second voltage signal according to a first exposure control transistor (MG1) and a second exposure control transistor (MG2), respectively; the demodulation unit 70 further comprises a first integrating capacitor CAAnd a second integrating capacitor CBConfigured to integrate voltages generated by the first exposure control transistor (MG1) and the second exposure control transistor (MG2), respectively.
The readout unit 80 includes a source follower transistor (SF) and a selection transistor (SEL); wherein, the selection transistor (SEL) controls the output of the voltage signal, when the selection transistor (SEL) is turned on, the integral voltage signal kept on the integral capacitance is output to the following processing circuit; when the selection transistor is turned off, the integrated voltage held on the integration capacitor is not output. The processing circuitry (not shown) may include, for example, an ADC, which converts the electrical signal collected by the tap (tap) into a digital signal to calculate the distance of the target from the TOF depth camera 10 according to equation (1).
In one embodiment, the readout unit 80 includes a first readout unit (not numbered) and a second readout unit (not numbered) configured to read voltages of the first integration capacitance CA and the second integration capacitance CB, respectively.
In one embodiment, as shown in fig. 4, to reduce the area and power consumption of the pixel, the pixel employs a shared buffer direct injection structure 60, which directs the current to the modulation capacitor for integration, and the electrons collected by the two taps are read out by respective readout circuits to calculate the distance.
In one embodiment, as shown in fig. 5, the sensor pixel circuit further comprises a transfer Transistor (TX) connected to the demodulation unit 70 and the readout unit 80, respectively, and configured to time-share the first integrating capacitor CAAnd a second integrating capacitor CBAfter the collected charges are converted into voltageTransmitted to the readout unit 80, and the readout unit 80 time-divisionally reads out the first integration capacitance CAAnd a second integrating capacitor CBThe voltage of (c). It can be understood that the voltages accumulated and converted by different taps are read out through the same readout unit 80 by the transmission Transistor (TX), so that the fill factor of the pixel is improved, and the gain error in depth caused by process deviation of different readout units, such as the gain error caused by the source follower transistor (SF), is avoided, thereby reducing the subsequent calibration work.
In one embodiment, the sensor pixel circuit further includes a reset transistor (RST) respectively connected to the buffer direct injection structure unit 60 and the demodulation unit 70, configured to reset the voltage of the integration capacitor according to a reset control signal; after the exposure is finished, the exposure signals Clk of the two taps are closedAAnd ClkBIntegrated in the integrating capacitances of the two taps, respectively, and finally read out by the readout unit 80.
In one embodiment, the sensor pixel circuit further includes a Hybrid Bonding unit (HB) respectively connected to the output end of the reading unit 50 and the input end of the buffer direct injection structure unit 60, and configured to implement physical structure Bonding between the single silicon layer wafer and the germanium-silicon layer wafer, so that the germanium photodiode buried in the silicon-germanium layer can collect near-infrared incident light by using a stacking process, the quantum efficiency of the pixel unit is improved, and the charge signal photoelectrically converted in the germanium-silicon layer wafer is transmitted to the single silicon layer buffer direct injection structure unit 70 through the Hybrid Bonding unit.
In the embodiment of the present invention, the buffer direct injection structure unit 60 is composed of an amplifier and an NMOS transistor, wherein the source of the NMOS transistor is connected to the output terminal of the read-in unit 50 and the input terminal of the demodulation unit 70, the positive input terminal of the amplifier is connected to the dc bias power supply, the negative input terminal is connected to the output terminal of the read-in unit 50, and the output terminal is connected to the gate of the NMOS transistor, so that the input impedance can be reduced through negative feedback, and the injection efficiency can be improved. The larger the open-loop gain of the amplifier is, the smaller the input impedance thereof is, and the higher the injection efficiency is, and at the same time, the buffer direct injection structure unit 60 provides a stable bias voltage for the read-in unit 60, so that the dark current change caused by the bias voltage change can be avoided, and the dark current characteristic is improved.
In one embodiment, as shown in fig. 6, the modulation section and the buffer direct injection structure unit can be made together, and CLKA and CLKB are both high-speed small-swing signals, thereby greatly reducing the power consumption of the modulation signal driving circuit.
In some embodiments, the readout unit 90 also includes a Correlated Double Sampling (CDS) circuit (not shown) in which the output of a pixel can be measured twice: once under known conditions and once under unknown conditions, the values measured under known conditions may be subtracted from the values measured under unknown conditions to generate values having a known relationship to the measured physical quantity, representing the photoelectron charge of the particular part of the pixel receiving the light. By using correlated double sampling, noise can be reduced by removing the reference voltage of the pixel (such as the pixel voltage after being reset) from the signal voltage of the pixel at the end of each integration period.
It should be noted that the above embodiment has been described only by taking 2 taps as an example, and the same is true for a plurality of taps. The image sensor described in the above embodiments can solve the problem of low injection efficiency of the readout unit in the prior art, and the application of the image sensor to the acquisition module 12 included in the TOF depth camera 10 in the embodiment of fig. 1 does not mean that the image sensor can only be applied to the TOF depth camera, and any other devices that directly or indirectly utilize the scheme should be included in the protection scope of the present invention.
As another embodiment of the present invention, an electronic device is further provided, where the electronic device includes the germanium-silicon image sensor described in any of the foregoing embodiments; the electronic device may be a desktop, desktop-mounted device, portable device, wearable device, or in-vehicle device, as well as a robot, among others. In particular, the device may be a laptop or an electronic device to allow gesture recognition or biometric recognition. In other examples, the device may be a head-mounted device to obtain distance information of the user's surroundings, identify objects or hazards in the user's surroundings to ensure safety, e.g., a virtual reality system that obstructs the user's vision of the environment, may detect objects or hazards in the surroundings to provide the user with warnings about nearby objects or obstacles. In other examples, the device may be applied to the field of unmanned driving and the like.
It is to be understood that the foregoing is a more detailed description of the invention, and that specific embodiments are not to be considered as limiting the invention. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention.
In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.
Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. One of ordinary skill in the art will readily appreciate that the above-disclosed, presently existing or later to be developed, processes, machines, manufacture, compositions of matter, means, methods, or steps, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims (10)
1. A germanium-silicon image sensor is characterized by comprising a pixel array formed by a plurality of pixels; wherein the pixel includes: a read-in unit, a buffer direct injection structure unit, a demodulation unit, and a read-out unit;
the read-in unit comprises a germanium photodiode configured to convert an optical signal incident to the sensor into an electric charge signal;
the buffer direct injection structure unit is connected with the germanium photodiode, is configured to reduce the input impedance of the charge signal and provide a stable bias voltage, and transmits the charge signal to the demodulation unit;
the demodulation unit configured to cause the charge signal to generate a plurality of voltage signals according to a plurality of exposure control transistors, respectively;
the readout unit is configured to read the voltage signal.
2. The silicon germanium image sensor of claim 1, wherein: the buffer direct injection structure unit comprises an amplifier and an NMOS transistor; wherein the content of the first and second substances,
the source electrode of the NMOS transistor is respectively connected with the output end of the read-in unit and the input end of the demodulation unit;
the positive input end of the amplifier is connected with a direct-current bias power supply, the negative input end of the amplifier is connected with the output end of the read-in unit, the output end of the amplifier is connected with the grid electrode of the NMOS transistor, and the amplifier is configured to reduce the impedance of the NMOS transistor.
3. The silicon germanium image sensor of claim 1, wherein: the mixed bonding unit is respectively connected with the output end of the reading-in unit and the input end of the buffer direct injection structure unit, is configured to realize physical structure bonding of the single silicon layer wafer and the germanium-silicon layer wafer, and transmits charge signals of the germanium-silicon layer wafer after photoelectric conversion to the single silicon layer buffer direct injection structure unit.
4. The silicon germanium image sensor of claim 1, wherein: the demodulation unit further includes a first integration capacitor and a second integration capacitor configured to integrate voltages generated by the plurality of exposure control transistors, respectively.
5. The silicon germanium image sensor of claim 1, wherein: the readout unit includes a source follower transistor and a selection transistor; wherein the selection transistor is configured to control an output of the voltage signal.
6. The silicon germanium image sensor of claim 1, wherein: the germanium photodiode includes a photodetector buried in a silicon germanium layer, the photodetector configured to convert a light signal incident to the image sensor into a charge signal.
7. The silicon germanium image sensor of claim 4, wherein: the readout unit includes a first readout unit and a second readout unit configured to read voltages of the first integration capacitance and the second integration capacitance, respectively.
8. The silicon germanium image sensor of claim 4, wherein: the charge transfer circuit further comprises a transfer transistor which is respectively connected with the demodulation unit and the readout unit and is configured to transfer the charges collected by the first integration capacitor and the second integration capacitor to the readout unit in a time-sharing manner.
9. The utility model provides an acquisition module which characterized in that: a germanium-silicon image sensor comprising a lens unit and as claimed in any one of claims 1 to 8.
10. A TOF depth camera, comprising:
the emission module is configured to emit a light beam to a target object;
the acquisition module of claim 9, configured to acquire at least a portion of the reflected light signal reflected back through the target object;
and the control and processor is respectively connected with the transmitting module and the collecting module, and synchronizes trigger signals of the transmitting module and the collecting module so as to calculate the time required for the light beam to be transmitted by the transmitting module and received by the collecting module.
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| CN202010699707.1A CN111885321B (en) | 2020-07-17 | 2020-07-17 | Germanium-silicon image sensor, acquisition module and TOF depth camera |
| PCT/CN2021/085048 WO2022012091A1 (en) | 2020-07-17 | 2021-04-01 | A germanium silicon image sensor, a collection module, and a tof depth camera |
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| WO2022012091A1 (en) * | 2020-07-17 | 2022-01-20 | 深圳奥芯微视科技有限公司 | A germanium silicon image sensor, a collection module, and a tof depth camera |
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| CN2754070Y (en) * | 2004-10-22 | 2006-01-25 | 重庆大学 | Background current inhibition reading-out circuit for infrared focal plane array |
| US20180233521A1 (en) * | 2015-08-04 | 2018-08-16 | Artilux Corporation | Germanium-silicon light sensing apparatus ii |
| CN108700649A (en) * | 2016-02-29 | 2018-10-23 | 赛峰电子与防务公司 | Equipment for detecting laser facula |
| CN110663114A (en) * | 2017-04-13 | 2020-01-07 | 奥特逻科公司 | Germanium-silicon light sensing device II |
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| CN111885321B (en) * | 2020-07-17 | 2023-04-07 | 深圳奥辰光电科技有限公司 | Germanium-silicon image sensor, acquisition module and TOF depth camera |
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| CN2754070Y (en) * | 2004-10-22 | 2006-01-25 | 重庆大学 | Background current inhibition reading-out circuit for infrared focal plane array |
| US20180233521A1 (en) * | 2015-08-04 | 2018-08-16 | Artilux Corporation | Germanium-silicon light sensing apparatus ii |
| CN108700649A (en) * | 2016-02-29 | 2018-10-23 | 赛峰电子与防务公司 | Equipment for detecting laser facula |
| CN110663114A (en) * | 2017-04-13 | 2020-01-07 | 奥特逻科公司 | Germanium-silicon light sensing device II |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2022012091A1 (en) * | 2020-07-17 | 2022-01-20 | 深圳奥芯微视科技有限公司 | A germanium silicon image sensor, a collection module, and a tof depth camera |
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| CN111885321B (en) | 2023-04-07 |
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