Optoelectronic device

Abstract

The present disclosure relates to a time-of-flight sensor comprising a light emitter configured to emit light into an image scene, a reference sensor configured to detect light emitted by the light emitter, and an array of signal receiving sensors separated from the light emitter by an optical barrier, all on the same base substrate. The optical barrier is configured to prevent light emitted by the light emitter from reaching the array of signal receiving sensors directly, wherein the array of signal receiving sensors is configured to detect light reflected by the image scene. The reference sensor and the array of signal receiving sensors are based on semiconductor nanoparticles.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to European Patent Application No. 22305725.8, filed on 17 May 2022, the contents of which are incorporated herein by reference in their entirety to the fullest extent permitted by law. Technical Field

[0003] This disclosure relates generally to the field of optoelectronic devices, and more specifically to time-of-flight sensors and related methods. Background Technology

[0004] Time-of-flight sensors involve the use of a transmitter and a receiver sensor. The transmitter emits light into a scene to illuminate at least a portion of the scene, and the receiver sensor detects the reflected light returning from the scene. Bulk semiconductor materials (such as silicon or III-V materials) are commonly used to construct single-photon avalanche diodes (SPADs), which are typically used in the receiver sensor. These bulk materials tend to be associated with high dark currents at room temperature. Silicon is also limited when time-of-flight sensors are intended to operate in the short-wave infrared band. Therefore, further development is needed.

[0005] There is a need in the art to address the shortcomings of known time-of-flight sensors caused by the use of the aforementioned materials. Summary of the Invention

[0006] One embodiment provides a time-of-flight sensor including a light emitter, a reference sensor, and a signal receiving sensor array located on the same substrate. The light emitter is configured to emit light into an image scene, the reference sensor is configured to detect the light emitted by the light emitter, and the signal receiving sensor array is separated from the light emitter by an optical barrier. The optical barrier is configured to prevent light emitted by the light emitter from directly reaching the signal receiving sensor array, wherein the signal receiving sensor array is configured to detect light reflected from the image scene. The reference sensor and the signal receiving sensor array are based on semiconductor nanoparticles.

[0007] One embodiment provides a method for manufacturing a time-of-flight sensor, the method comprising forming on the same base substrate a light emitter configured to emit light into an image scene, a reference sensor configured to detect the light emitted by the light emitter, and a signal receiving sensor array separated from the light emitter by an optical barrier. The optical barrier is configured to prevent light emitted by the light emitter from directly reaching the signal receiving sensor array, wherein the signal receiving sensor array is configured to detect light reflected from the image scene. The reference sensor and the signal receiving sensor array are based on semiconductor nanoparticles.

[0008] According to one embodiment, the light emitter may be based on semiconductor nanoparticles.

[0009] According to one embodiment, the light emitter may be a vertical cavity surface-emitting laser.

[0010] According to one embodiment, the signal receiving sensor array may include multiple pixels, and each pixel of the reference sensor and the signal receiving sensor may include components made of InSb and InAs. x P x or InAs or InAs x Sb x The semiconductor nanoparticle layer is formed.

[0011] According to one embodiment, each sensor may include a semiconductor nanoparticle layer, a hole transport layer, an electron transport layer, and electrodes.

[0012] According to one embodiment, the hole transport layer may include molybdenum oxide and / or the electron transport layer may include zinc oxide.

[0013] According to one embodiment, the signal receiving sensor and / or reference sensor may include a matrix of pixels, each pixel having a first electrode and a second electrode. The first electrode of the pixel of the signal receiving sensor and / or reference sensor may include a conductive layer that is partially transparent to all pixels, and the second electrode is insulated from the second electrode of each other pixel of the signal receiving sensor and / or reference sensor.

[0014] According to one embodiment, the partially transparent conductive layer may be common to both the signal receiving sensor and the reference sensor.

[0015] According to one embodiment, the reference sensor may include a first device substrate, and the signal receiving sensor includes a second device substrate, the first device substrate and the second device substrate being mounted on a base substrate.

[0016] According to one embodiment, the partially transparent conductive layers of the signal receiving sensor and the reference sensor may be different and insulated from each other. The sensor may include at least one polarization circuit configured to apply a first voltage between a first electrode and a second electrode of a pixel of the reference sensor, and to apply a second voltage between the first electrode and the second electrode of a pixel of the signal receiving sensor, the first voltage being different from the second voltage.

[0017] Another embodiment provides a mobile communication device that includes a touch display screen and a sensor such that the touch display screen covers the sensor.

[0018] According to one embodiment, the touch display screen can be an organic light-emitting diode (OLED) display.

[0019] Another embodiment could be a facial ID sensor that includes such a sensor.

[0020] Another embodiment provides a method for measuring time-of-flight using such a sensor, the method comprising applying a first voltage between a first electrode and a second electrode of a pixel of a reference sensor via a polarization circuit, and applying a second voltage different from the first voltage between a first electrode and a second electrode of a pixel of a signal receiving sensor. The method further comprises modifying the first voltage based on a signal output from the reference sensor and / or modifying the second voltage based on a signal output from the signal receiving sensor. Attached Figure Description

[0021] The above-described features and advantages, as well as other features and advantages, will be described in detail in the following description of specific embodiments, which are illustrated but not limited by the accompanying drawings, in which:

[0022] Figure 1 This is a schematic cross-sectional view of an optoelectronic device according to an exemplary embodiment of the present disclosure;

[0023] Figure 2 This is an example embodiment based on the present disclosure. Figure 1 An enlarged cross-sectional view of the signal receiving sensor or reference sensor;

[0024] Figure 3 This is a schematic cross-sectional view of an optoelectronic device according to another exemplary embodiment of the present disclosure;

[0025] Figure 4 This is a schematic cross-sectional view of an optoelectronic device according to another exemplary embodiment of the present disclosure;

[0026] Figure 5 This is a schematic cross-sectional view of an optoelectronic device according to another exemplary embodiment of the present disclosure;

[0027] Figure 6 This is a schematic cross-sectional view of an optoelectronic device according to yet another exemplary embodiment of the present disclosure;

[0028] Figure 7 It is a graph showing the change of quantum efficiency of the signal receiving sensor and the reference sensor with the applied bias voltage;

[0029] Figure 8 It is based on the instructions for use of optoelectronic devices. Figure 1 or Figure 3 A block diagram of the functional blocks of an optoelectronic device;

[0030] Figure 9 It is based on the instructions for use of optoelectronic devices. Figure 4 , Figure 5 or Figure 6 A block diagram of the functional blocks of an optoelectronic device;

[0031] Figure 10 This is based on another usage method description for optoelectronic devices. Figure 4 , Figure 5 or Figure 6 A block diagram of the functional blocks of an optoelectronic device;

[0032] Figure 11 yes Figure 7 , Figure 8 or Figure 9 Example embodiment of a voltage bias regulator;

[0033] Figure 12 This is a diagram showing time-domain stacking distortion; and

[0034] Figure 13 This is a diagram showing the mitigation of temporal stacking distortion. Detailed Implementation

[0035] In different figures, similar features are designated by similar reference numerals. In particular, common structural and / or functional features in different embodiments may have the same reference numerals and may have the same structure, dimensions, and material properties.

[0036] For clarity, the operation and elements that help to understand the embodiments described herein have been detailed and described in detail.

[0037] Unless otherwise stated, when referring to two elements connected together, this means there is no direct connection of any intermediate element other than a conductor, and when referring to two elements coupled together, this means that the two elements can be connected, or they can be coupled via one or more other elements.

[0038] In the following disclosure, unless otherwise stated, reference is made to the orientation shown in the figures when referring to absolute position qualifiers (such as the terms “front”, “back”, “top”, “bottom”, “left”, “right”, etc.) or relative position qualifiers (such as the terms “above”, “below”, “higher”, “lower”, etc.) or orientation qualifiers (such as “horizontal”, “vertical”, etc.).

[0039] Unless otherwise specified, the expressions “approximately,” “roughly,” “basically,” and “on the order of” indicate within 10%, and preferably within 5%.

[0040] Figure 1 This is a schematic cross-sectional view of an optoelectronic device 100 according to an exemplary embodiment of the present disclosure.

[0041] Optoelectronic device 100 is, for example, a time-of-flight (ToF) sensor; in other words, the device is designed to measure distances via ToF. For example, device 100 is a direct ToF sensor. For example, optoelectronic device 100 is configured for use in an imager or image sensor to generate a depth image representing a scene, sometimes called a depth map.

[0042] For example, Figure 1 The optoelectronic device 100 includes a base substrate 122. The base substrate 122 is, for example, a silicon substrate such as a silicon integrated circuit or silicon chip, or a printed circuit board or other type of substrate.

[0043] The optoelectronic device 100 includes, for example, a light emitter 108 mounted on a surface 114 (such as the upper surface) of a base substrate 122. The light emitter 108 is configured to emit light 118 into the image scene 50 and, for example, toward a reference sensor 106. The reference sensor 106 is also mounted on the surface 114, for example, and is configured to detect the light emitted by the light emitter 108.

[0044] For example, the optoelectronic device 100 also includes a signal receiving sensor 104 mounted on surface 114. The signal receiving sensor 104 is separated from the light emitter 108, for example, by an optical barrier 126.

[0045] For example, the base substrate 122 also includes a control circuit 112. The control circuit 112 is coupled to the light emitter 108, the reference sensor 106 and the signal receiving sensor 104, for example, via connection pads (not shown) located on the surface 114 of the base substrate 122.

[0046] The optical barrier 126 is configured, for example, to prevent light emitted by the light emitter 108 from directly reaching the signal receiving sensor 104. Figure 1 In this example, the optical barrier 126 is disposed between the upper surface 114 of the base substrate 122 and the inner surface of the packaging unit 102, for example, the base substrate 122 is fixed in the packaging unit 102. In this example, the optical barrier 126 is further disposed between the signal receiving sensor 104 and the reference sensor 106. The packaging unit 102 includes, for example, a first aperture 110 and a second aperture 113.

[0047] For example, the first aperture 110 is configured to provide a transparent opening through which at least a portion of the light emitted by the light emitter 108 is allowed to pass to illuminate the image scene 50. The first aperture 110 is aligned, for example, with the emitting surface of the light emitter 108. For example, the first aperture 110 is filled with, for example, a transparent window made of glass, a diffuser, or a lens (not shown).

[0048] For example, the second aperture 113 is configured to provide an opening to allow the return light 124 emitted by the light emitter 108 and reflected by the scene 50 to enter the encapsulation unit 102.

[0049] For example, a reference photodetector 106 is arranged in the packaging unit 102 to receive light emitted by the transmitter, for example, through a direct optical path and / or through reflection 130 on the inner surface of the packaging unit 102.

[0050] The signal receiving sensor 104 has, for example, two or more electrodes. In one example, a top electrode is disposed on the top surface 128 of the signal receiving sensor 104. The top electrode is connected to the connection pads of the base substrate 122, for example, via bonding wires 120. One or more other electrodes of the signal receiving sensor 104 are disposed, for example, on the underside of the signal receiving sensor 104 and coupled to the control circuitry 112 via one or more connection pads of the base substrate 122.

[0051] The reference sensor 106 has, for example, two or more electrodes. In one example, a top electrode is disposed on the top surface 132 of the reference sensor 106. The top electrode is connected to the connection pads of the base substrate 122, for example, via bonding wires 120. One or more other electrodes of the reference sensor 106 are disposed, for example, on the underside of the reference sensor and coupled to the control circuitry 112 via one or more connection pads of the base substrate 122.

[0052] The light emitter 108 has, for example, two or more electrodes. In one example, a top electrode is disposed on the top surface 138 of the light emitter 108. The top electrode is connected to the connection pads of the base substrate 122, for example, via bonding wire 116. One or more other electrodes of the light emitter 108 are disposed, for example, on the underside of the light emitter 108 and coupled to the control circuitry 112 via one or more connection pads of the base substrate 122.

[0053] According to one example, reference sensor 106 and / or signal receiving sensor 104 are based on semiconductor nanoparticles. More specifically, reference sensor 106 and / or signal receiving sensor 104, for example, both include one or more layers of semiconductor nanoparticles.

[0054] The light emitter 108 is, for example, based on semiconductor nanoparticles. More specifically, the light emitter 108 includes, for example, one or more layers of semiconductor nanoparticles. In another example, the light emitter 108 is a vertical-cavity surface-emitting laser (VCSEL).

[0055] The reference sensor 106 may include one or more pixels. The signal receiving sensor 104 may be formed by a pixel array.

[0056] Each pixel of the reference sensor 106 and the signal receiving sensor 104, and the light emitter 108 in the case of semiconductor nanoparticles, includes, for example, a stacked layer comprising electrodes from a base substrate (e.g., electrodes in the form of interconnects disposed in or on the surface of the base substrate), an optional electron transport layer, a semiconductor nanoparticle layer, an optional moisture barrier, an optional hole transport layer, and electrodes. Several layers of the reference sensor 106, the signal receiving sensor 104, and the emitter 108 are at least partially transparent to the wavelength of light emitted by the emitter. More specifically, the layer located between the semiconductor nanoparticle layer and the scene is at least partially transparent to the wavelength of light emitted by the emitter.

[0057] Semiconductor nanoparticles are nanomaterial structures that, under electrical excitation corresponding to their band gap, emit photons due to the generation and subsequent recombination of electron-hole pairs within the semiconductor nanoparticles. Similarly, when photons are incident on a nanomaterial structure, electron-hole pairs can be generated. In this way, emitting elements such as LEDs (light-emitting diodes) and detection elements such as photodetectors can be created based on semiconductor nanoparticles.

[0058] Semiconductor nanoparticles include a semiconductor core. If the semiconductor nanoparticle is part of a light emitter, the size or shape, composition, and shape of the core determine the wavelength of the emitted light; or if the semiconductor nanoparticle is part of a photodetector, the size or shape, composition, and shape of the core determine the wavelength of the absorbed light that generates electron-hole pairs. Semiconductor nanoparticles may also include a shell, preferably made of a semiconductor material, surrounding the core to protect and passivate it. For example, semiconductor nanoparticles may also include ligands, organic aliphatic compounds, organometallic or inorganic molecules that extend from the shell and passivate, protect, and functionalize the semiconductor surface.

[0059] The semiconductor nanoparticles in one or more layers of semiconductor nanoparticles in reference sensor 106, signal receiving sensor 104, and transmitter 108 can be of several types. For example, the semiconductor nanoparticles can be quantum dots, in other words, semiconductor nanoparticles having a substantially spherical core. Semiconductor nanoparticles can also be quantum wires or quantum rods, in other words, semiconductor nanoparticles having a core extending in one direction, for example, in a substantially cylindrical form. Semiconductor nanoparticles can also be quantum wells, in other words, semiconductor nanoparticles having a core having a substantially layered form, in other words, in a parallelepiped form.

[0060] For example, the core is made of materials or alloys of materials including: CdSe, CdS, CdTe, CdSeS, CdTeSe, AgS, ZnO, ZnS, ZnSe, CuInS, CuInSe, CuInGaS, CuInGaSe, PbS, PbSe, PbSeS, PbTe, InAsSb, InAs, InSb, InGaAs, InP, InGaP, InAlP, InGaAlP, InZnS, InZnSe, InZnSeS, HgTe, HgSe, HgSeTe, Ge, Si. For example, the outer shell may be made of materials or alloys of materials such as: CdSe, CdS, CdTe, CdSeS, CdTeSe, AgS, ZnO, ZnS, ZnSe, CuInS, CuInSe, CuInGaS, CuInGaSe, PbS, PbSe, PbSeS, PbTe, InAsSb, InAs, InSb, InGaAs, InP, InGaP, InAlP, InGaAlP, InZnS, InZnSe, InZnSeS, HgTe, HgSeTe, Ge, and Si. The choice of material depends on the desired wavelength.

[0061] According to some embodiments, one or more semiconductor nanoparticle layers of the reference sensor 106, the signal receiving sensor 104, and the transmitter 108 (where it is a semiconductor nanoparticle transmitter) are, for example, made of InAs, InSb, or InAs. x P x or InAs x Sb x Formation. In fact, the inventors have discovered that these materials are particularly advantageous for time-of-flight devices due to the relatively high rate at which charge is photogenerated and transported to the pixel electrodes. Furthermore, both materials exhibit good absorption in the short-wave infrared (SWIR) range; for example, InAs is particularly sensitive to light in the 800 nm to 1600 nm wavelength range, and InAsSb is particularly sensitive to light in the 1000 nm to 5000 nm wavelength range.

[0062] For SWIR photosensing or luminescence, i.e., wavelengths between 1 μm and 2.5 μm, the core size is preferably less than 20 nm, for example, in the range of 2 nm to 15 nm. In the case of quantum dots, the diameter of each quantum dot is preferably in the range of 2 nm to 15 nm. For example, the semiconductor nanoparticles of reference sensor 106, signal receiving sensor 104, and / or transmitter 108 comprise octahedral quantum dots, each with a diameter between 1 nm and 3 nm; truncated octahedral quantum dots, each with a diameter between 3 nm and 4 nm; or cubic octahedral quantum dots, each with a diameter of 4 nm or greater and, for example, between 4 nm and 7 nm.

[0063] A time-of-flight sensor operating in SWIR was obtained, for example, by using semiconductor nanoparticles and by comparing the light level received by signal receiving sensor 104 with the signal output of reference sensor 106.

[0064] Suitable for implementation Figure 1 Further details of the semiconductor nanoparticle-based light emitter and sensor 110 and / or sensor 106, 108 are described in U.S. Patent Application Publication No. 2022 / 0165797, the contents of which are incorporated herein by reference to the fullest extent permitted by law.

[0065] Figure 2 This is an example embodiment based on the present disclosure. Figure 1 An enlarged cross-sectional view of an example of a signal receiving sensor 104. For example, Figure 1 The reference sensor 106 in the middle is implemented by a similar structure.

[0066] exist Figure 2 In the example, the signal receiving sensor 104 includes an array of pixels 230. Pixels 230 include, for example, a top electrode 202, which is common to all pixels, and is wire-bonded to connection pads 203 of a base substrate 122. Pixels 230 are formed, for example, by a stack comprising, in order from the top electrode 202 to the base substrate 122, a conductive layer 206 transparent to the common portions of each pixel 230, an optional hole transport layer 208 common to each pixel 230, an optional moisture barrier layer (not shown) common to each pixel 230, a semiconductor nanoparticle layer 210 common to each pixel 230, an optional electron transport layer 215, and a lower electrode layer 235 including a lower electrode for each pixel 230. Figure 2Three such lower electrodes 220, 224, and 226 are shown. According to one example, the partially transparent conductive layer 206 is an indium tin oxide (ITO) layer, the hole transport layer 208 is a molybdenum oxide (MoO3) layer, the moisture barrier layer is an aluminum oxide (Al2O3) layer, the electron transport layer 215 is made of zinc oxide, and the lower electrodes 220, 224, and 226 are all formed by optional diffusion barrier layers of titanium or titanium nitride and / or tantalum or tantalum nitride placed on copper pillars.

[0067] A partially transparent conductive layer 206 is located, for example, on the top surface 214 of the hole transport layer 208. Figure 2 In this example, the insulating material portion 227 is arranged to contact the side 240 of the stack composed of layers 208, 210, and 215, and a portion of the upper surface 114 of the base substrate 122 adjacent to the stack composed of layers 208, 210, and 215. In this example, a partially transparent conductive layer 206 is further arranged, for example, to cover the insulating material portion 227. In this example, the top electrode 202 is positioned on a portion of the partially transparent conductive layer 206 covering the insulating material portion 227.

[0068] For example, the electron transport layer 215 of each pixel 230 is connected to a corresponding lower electrode among the lower electrodes 220, 224, 226. Each lower electrode 220, 224, 226 is connected, for example, to a connection pad located on, for example, the upper surface 114 of the base substrate 122. The lower electrodes 220, 224, 226 are, for example, copper pillars. According to an example embodiment, the top of the copper pillar has a diffusion barrier layer comprising, for example, titanium nitride and / or tantalum nitride and / or an alloy comprising nickel. In other words, the diffusion barrier layer provides, for example, an interface between the copper pillars of the lower electrodes 220, 224, 226 and the electron transport layer 215. According to an example embodiment, the lower electrodes 220, 224, 226 are electrically insulated from each other by, for example, an insulating layer 222 of silicon dioxide. Adjacent pixels 230 are, for example, laterally defined by the space between adjacent lower electrodes 220, 224, 226. For example, an insulating layer 228 covers the lower electrodes facing outwards from the device. Figure 2 The electrodes 220 and 226 in the example are located on the sides 221 and 231. According to one example, when the base substrate is a silicon chip, the lower electrode is formed in the base substrate. According to one example, the insulating layer 228 is silicon dioxide or a low-k insulator.

[0069] A layer 210 comprising semiconductor nanoparticles is sandwiched, for example, between an optional electron transport layer 215 and an optional hole transport layer 208. The hole transport layer 208 comprises, for example, molybdenum oxide, nickel oxide, or copper oxide. The electron transport layer 215 comprises, for example, zinc oxide, titanium oxide, or doped zinc oxide or doped titanium oxide. According to one example, the semiconductor nanoparticle layer is sandwiched between a barrier layer and an aluminum oxide (Al₂O₃) layer with a thickness less than 2 nm, the barrier layer being formed, for example, by a titanium and / or tantalum layer disposed on a copper electrode. The aluminum oxide (Al₂O₃) layer is covered, for example, by a molybdenum oxide (MoO₃) layer, which in turn is covered, for example, by an indium tin oxide layer.

[0070] As described above, according to one example, the semiconductor nanoparticle layer 210, the hole transport layer 208, and the partially transparent conductive layer 206 are common to each pixel 230. According to another example, the electron transport layer 215 is located on each lower electrode or on a diffusion barrier layer covering the lower electrodes. According to another example, the electron transport layer 215 is common to each pixel 230. Therefore, the pixel boundary between adjacent pixels 230 is defined by the arrangement of the lower electrodes 220, 224, 226, and in particular by the distance between two adjacent lower electrodes among the lower electrodes 220, 224, 226. Once electron-hole pairs are generated in the semiconductor nanoparticle layer 210, charge is transferred to the nearest lower electrode 220, 224, 226. Several electron-hole pairs are generated using several incident photons corresponding to the returned light and transferred to the respective lower electrodes 220, 224, 226.

[0071] In another example, not shown, microlenses are arranged on a partially transparent conductive layer 206. For example, each microlens is approximately aligned with a corresponding lower electrode 220, 224, 226 in order to focus incident photons toward the region of the semiconductor nanoparticle layer 210 aligned with the corresponding lower electrode among the lower electrodes 220, 224, 226.

[0072] The partially transparent conductive layer 206 is made of, for example, indium tin oxide, doped zinc oxide, a translucent metal, or graphene. Electrodes 202 and bonding pads allow a voltage to be applied between the anode and cathode of the reference sensor 106 and / or the signal receiving sensor 104 (in other words, between the top electrode 202 and the lower electrodes 220, 224, 226) via control circuitry 112. Control circuitry 112 is configured, for example, to detect the current flowing through each of the lower electrodes 220, 224, 226 in order to detect light arriving at each pixel.

[0073] Figure 3 This is a schematic cross-sectional view of an optoelectronic device 300 according to another exemplary embodiment of the present disclosure.

[0074] For example, optoelectronic device 300 has the same characteristics as... Figure 1 The optoelectronic device 100 has some similar features, and specifically includes a similar basic substrate 122, packaging unit 102, and light emitter 108. Figure 3 In the example, the signal receiving sensor 104 and / or the reference sensor 106 have, for example, a hole transport layer, semiconductor nanoparticles, an electron transport layer, and a lower electrode layer, respectively similar to Figure 2 The example layers are 208, 210, 215, and 235.

[0075] exist Figure 3 In the example, signal receiving sensor 104 and reference sensor 106 are part of the same unit, and insulating material portion 306 covers side 240 of signal receiving sensor 104, side 340 of reference sensor 106, and a portion of the upper surface 114 of the base substrate 122 located between side 240 and 340. Figure 3 In the example, the partially transparent conductive layer 316 is, for example, Figure 2 As in the example, it is arranged as the top layer of the stack of the signal receiving sensor and the reference sensor, and is also arranged, for example, to cover the insulating material portion 306 between the signal receiving sensor 104 and the reference sensor 106. Thus, layer 316 forms, for example, a single layer common to both the signal receiving sensor 104 and the reference sensor 106.

[0076] Although Figure 3 In the embodiments, both the signal receiving sensor 104 and the reference sensor 106 include an array of pixels 230, but in an example not shown, the signal receiving sensor 104 is implemented as an array of pixels 230, and the reference sensor 106 has a single lower electrode instead of a lower electrode array, and therefore the reference sensor 106 includes a single light receiving area.

[0077] exist Figure 3 In this example, the top electrode 322 is disposed on and connected to the partially transparent conductive layer 316, such that a single electrode serves simultaneously as both the signal receiving sensor 104 and the reference sensor 106. Wire bonding connections 350 electrically connect the top electrode 322 to the connection pads 360 of the base substrate 122, for example. The wire bonding of the light emitter 108 to the base substrate 122 is similar to, for example, wire bonding with, the base substrate 122. Figure 1 For example, and for clear reasons in Figure 3 Not shown in the image.

[0078] exist Figure 3 In the example, the optical barrier 326 is disposed between the upper surface of the partially transparent conductive layer 316 and the inner surface of the encapsulation unit 102.

[0079] Figure 4This is a schematic cross-sectional view of an optoelectronic device 400 according to another exemplary embodiment of the present disclosure.

[0080] For example, optoelectronic device 400 has the same characteristics as... Figure 1 The optoelectronic device 100 shares some similar features and specifically includes a similar packaging unit 102, optical barrier 126, light emitter 108, and base substrate 122. The signal receiving sensor 104 is similar to... Figure 2 The difference lies in that the lower electrode layer 235 is included in the device substrate 410, which is mounted, for example, on the upper surface 114 of the base substrate 122. For example, the signal receiving sensor 104 is remotely assembled with the device substrate 410, and then the device substrate 410 is mounted on the base substrate 122. For example, the reference sensor 106 is similar... Figure 2 The signal receiving sensor 104 differs in that its lower electrode layer 235 is included in a device substrate 406, which is mounted, for example, on the upper surface 114 of a base substrate 122. For example, the reference sensor 106 is remotely assembled with the device substrate 406, and then the device substrate 406 is mounted on the base substrate 122.

[0081] The top electrodes 202 of the signal receiving sensor 104 and the reference sensor 106 are respectively similar to Figure 2 Examples include, and for instance, connections to corresponding connection pads 203 via corresponding wire bonding. For example, each connection pad 203 is disposed on the upper surface of the device substrates 410, 406, or, in an example not shown, on the upper surface 114 of the base substrate 122.

[0082] Figure 5 This is a schematic cross-sectional view of an optoelectronic device 500 according to another exemplary embodiment of the present disclosure.

[0083] For example, optoelectronic device 500 is similar to Figure 4 The optoelectronic device 400 differs in that the lower electrodes 220, 224, 226 and insulating layers 222, 228 of the signal receiving sensor 104 and the reference sensor 106 are not separately included within device substrates 410 and 406, but are included within the same device substrate 510, which is mounted, for example, on the upper surface 114 of a base substrate. The signal receiving sensor 104 and the reference sensor 106 are, for example, remotely assembled on the device substrate 510 and then mounted on the base substrate 122. Figure 5 In some examples, control circuitry 112 is included in device substrate 510.

[0084] For example, Figure 5An optical barrier 126 is disposed between the upper surface 512 of the device substrate 510 and the inner surface of the packaging unit 102.

[0085] The optoelectronic device 500 allows the acquisition of the signal receiving sensor 104 and the reference sensor 106 in a manner different from the first technique used to acquire the light emitter 108.

[0086] Figure 6 This is a schematic cross-sectional view of an optoelectronic device 600 according to yet another exemplary embodiment of the present disclosure.

[0087] Optoelectronic device 600 is similar to Figure 4 The optoelectronic device 400 differs in that the control circuit 112 is not included in the base substrate 122. Instead, the device substrate 410 includes the control circuit 112, which is arranged, for example, to control the signal receiving sensor 104. A reference sensor 106 is mounted, for example, on another device substrate 606 that includes the control circuit 112. The control circuit 112 is arranged, for example, to control the reference sensor 106. Figure 6 In one example, light emitter 108 is mounted on the same device substrate 606 as reference sensor 106. Control circuitry 612 is arranged, for example, to control light emitter 108.

[0088] Figure 7 This is a graph showing the quantum efficiency (quantum efficiency (%)) of the signal receiving sensor 104 and the reference sensor 106 as a function of the bias voltage (applied bias voltage (V)) applied between their top and bottom electrodes. It can be seen that the higher the bias voltage, the higher the quantum efficiency, although the quantum efficiency plateaus above a certain voltage. Furthermore, a higher bias voltage leads to higher energy consumption.

[0089] For example, the bias voltage applied to the signal receiving sensor 104 and the reference sensor 106 is controlled to achieve an appropriate trade-off between quantum efficiency and energy consumption.

[0090] In the first example, the signal receiving sensor 104 and the reference sensor 106 are biased by the same bias voltage. For example, at least in Figure 3 In one embodiment, sensors 104 and 106 share a common top electrode 322 and a common partially transparent conductive layer 316. In this case, sensors 104 and 106 operate, for example, at the same first operating point 702 representing an intermediate value of the applied voltage.

[0091] In the second example, the signal receiving sensor 104 and the reference sensor 106 are biased by different bias voltages. For example, in Figure 1 , Figure 4 , Figure 5 and Figure 6 In some embodiments, this is possible, where sensors 104 and 106 are separate and do not share a common top electrode 202 or layer 206. In this case, signal receiving sensor 104 operates, for example, at a second operating point 104, where the bias voltage is, for example, higher than the bias voltage at the first operating point 702, resulting in a relatively high sensitivity level for signal receiving sensor 104. In some embodiments, this bias voltage is adjusted independently of the bias voltage of reference sensor 106 to obtain the desired signal-to-noise ratio (SNR) and distance linearity without saturating the return array. Reference sensor 106 operates, for example, at a third operating point 706, where the applied bias voltage is, for example, lower than the bias voltage at the first operating point 702. In some embodiments, the third operating point of reference sensor 106 is variable and controlled by a feedback loop. It will be noted that in various embodiments, reference sensor 106 is arranged on one side of light emitter 108 and is not optically insulated from light emitter 108. The amount of light received by the reference sensor 106 from the light emitter 108 is therefore higher than the amount of returned light received by the signal receiving sensor 104. Reducing the voltage bias of the reference sensor 106 allows for a reduction in the risk of saturation of the reference sensor 106, thereby improving linearity and signal-to-noise ratio. Furthermore, this results in a reduction in the power consumption of the reference sensor 106.

[0092] Figure 8 This is based on the usage instructions for optoelectronic devices 100 and 300. Figure 1 or Figure 3 A block diagram of the functional blocks of an optoelectronic device.

[0093] exist Figure 8 In the example, for instance, a bias voltage setting 810 (voltage setting) (e.g., a fixed level) is applied to a low-dropout (LDO) regulator or switch 820 to obtain an regulated bias voltage at the output of the LDO regulator or switch 820. The voltage setting 810 is provided, for example, by a portion of control circuitry 112, and the LDO regulator or switch 820 forms, for example, a portion of control circuitry 112.

[0094] The regulated bias voltage at the output of the LDO regulator or switch 820 is provided to the signal receiving sensor 104 and the reference sensor 106, for example, to the partially transparent conductive layer 206. Figure 2 ) or 316 ( Figure 3 ).

[0095] The optical signal received by the reference sensor 106 results in a reference signal output, which is measured by a dedicated readout chain 814 (reference readout chain).

[0096] The optical signal received by the signal receiving sensor 104 results in a return signal output, which is measured, for example, by a dedicated readout chain 816 (receive readout chain).

[0097] In one example, readout chains 814 and 816 form part of control circuit 112.

[0098] The signals measured by readout chains 814 and 816 are then compared and used to calculate the differential distance 818 (differential distance calculation), for example, by calculating the time of flight. For example, the optical transmitter 108 is configured to emit optical pulses, and the readout chains 814 and 816 are configured to detect the reception times of the optical pulses received by the reference readout chain 814 and the receiving readout chain 816, respectively. The differential distance calculation 818 involves, for example, calculating the time difference between the reception times of the signal receiving sensor 104 and the reference sensor 106 for a given optical pulse.

[0099] In one example, the signal read from reference sensor 106 is further analyzed 820 (reference optical power calculation), for example, to calculate the optical power of the light emitted by optical emitter 108. For example, the optical power of the light emitted by optical emitter 108 is monitored for safety reasons.

[0100] In one example, differential distance measurement 818 and / or reference optical power calculation 820 are implemented by control circuitry 112.

[0101] Figure 9 It is based on the instruction manual for optoelectronic devices 400, 500, or 600. Figure 4 , Figure 5 or Figure 6 A block diagram of the functional blocks of an optoelectronic device.

[0102] Figure 9 Examples are similar to Figure 8 The difference is that the LDO regulator or switch 820 is replaced by LDO regulators 912 and 916, which allows different bias voltages to be applied to the reference sensor 106 and the signal receiving sensor 104. These different bias voltages are applied, for example, to the transparent conductive layer 206 of the corresponding portions of the reference sensor 106 and the signal receiving sensor 104. Figure 9 In the example, a bias voltage setting 910 (reference voltage setting) is provided, for example, to an LDO regulator 912 (an LDO regulator for reference bias) to obtain a first regulated bias voltage. For example, the reference sensor voltage bias setting is modified based on an optical power calculation performed in a previous calculation. For example, if the optical power is found to be above a certain threshold, which, for example, risks causing saturation of the reference sensor 106, the reference bias voltage setting 910 is correspondingly reduced to decrease the sensitivity of the reference sensor 106. Figure 9 In the example, another voltage bias setting 914 (receive voltage setting) is provided, for example, to an LDO regulator 916 (an LDO regulator for receive bias) to obtain an regulated bias voltage applied to the signal receiving sensor 104.

[0103] Voltage settings 910 and 914 are provided, for example, by a portion of control circuit 112, and LDO regulators 912 and 916 are, for example, part of control circuit 112.

[0104] Figure 10 This is according to another usage instruction for optoelectronic devices 400, 500, or 600. Figure 4 , Figure 5 or Figure 6 A block diagram of the functional blocks of an optoelectronic device.

[0105] Figure 10 Examples are similar to Figure 9 The difference is that, in this example, an regulated bias voltage generated by the LDO regulator 916 is provided to multiple arrays 1010 (1 to N) of pixels 230 of the signal receiving sensor 104. This allows for multi-region imaging.

[0106] Figure 11 Schematic illustration Figures 8-10 Example embodiments of LDO regulators 820, 912, and 916.

[0107] Figure 11 Example LDO regulators 820, 912, 916 include, for example, an operational amplifier 1116 that receives voltage settings 810, 910, 914 for a reference sensor 106 and / or a signal receiving sensor 104 at its non-inverting input. Operational amplifier 1116 is coupled to, for example, a power supply voltage rail, via which it is powered. The output of operational amplifier 1116 is coupled to the gate of transistor 1114. The source of transistor 1114 is coupled to the power supply voltage rail. The drain of transistor 1114 provides an regulated bias voltage at the output of LDO regulators 820, 912, 916. Furthermore, the drain of transistor 1114 is coupled to the inverting input of operational amplifier 1116.

[0108] exist Figure 11 In the example, current source 1110 is coupled between the drain of transistor 1114 and the ground voltage rail, and provides a load for transistor 1114 that is independent of the amount of light received by sensor(s). Another current source 1112 represents the load for signal receiving sensor 104 and / or reference sensor 106, which depends on the amount of light received by signal receiving sensor 104 and / or reference sensor 106.

[0109] Figure 12 This is a diagram illustrating temporal stacking distortion. Specifically, Figure 12 The solid line illustrates the change in signal strength (intensity) over time received by signal receiving sensor 104, and the dashed line illustrates the change in signal strength over time received by reference sensor. It is assumed that the object is at zero distance, and therefore the signal receiving sensor should receive pulses simultaneously with the reference sensor. However, due to the high signal level, time-domain distortion occurs, resulting in the clipping of the reference pulse. The average or median level of the pulse detected by the reference sensor is therefore offset from the pulse received by the signal receiving sensor by a time error (error).

[0110] Figure 13 This is a diagram illustrating the mitigation of temporal stacking distortion. Specifically, Figure 13 The curve is similar to Figure 12 The graph shows a case where the bias voltage of the reference sensor 106 is adjusted independently of the bias voltage of the signal receiving sensor 104, thereby avoiding saturation of the reference sensor and avoiding time-domain distortion.

[0111] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these embodiments can be combined, and other variations will readily conceive of by those skilled in the art. In particular, for example, Figure 4 The control circuit 112 is implemented in the device substrates 406 and 410, rather than in the base substrate. In another example, Figure 5 The control circuit 112 is implemented, for example, in the base substrate, rather than in the device substrate. In another example, Figure 6 The control circuits 112 and 612 are implemented, for example, in the base substrate 122, rather than inside the device substrates 410 and 606.

[0112] In another example, the receive voltage setting 914 is further adjusted based on the signal receive readout value.

[0113] Finally, based on the functional description provided above, the actual implementation of the embodiments and variations described herein is within the capabilities of those skilled in the art. In particular, the adjustment of the bias voltage can be implemented using other circuitry. Furthermore, the time-of-flight calculation 818 can be implemented using different methods, such as those based on direct TOF or indirect TOF methods.

[0114] Each of devices 100, 300, 400, 500 and 600 is, for example, a facial ID sensor, in other words, a device configured to recognize faces.

[0115] Devices 100, 300, 400, 500, and 600 are implemented, for example, under the touch display of a mobile communication device, such as an organic light-emitting diode (OLED) touchscreen. If the semiconductor nanoparticles are designed to operate in the SWIR domain, the light emitted or returned by the light emitter 108 will not be absorbed or will be partially absorbed by the touchscreen, especially in cases where the touchscreen is based on an OLED. This has the advantage of avoiding the generation of white spots on the screen.

[0116] Optoelectronic devices 100, 300, 400, 500, and 600 are implemented, for example, in medical, health, or wellness sensors, such as for detecting the deformable movement of blood vessels.

Claims

1. A time-of-flight sensor, comprising the following items located on the same basic substrate: A light emitter is configured to emit light into the image scene; A reference sensor is configured to detect light emitted by the light emitter; as well as The signal receiving sensor array is separated from the light emitter by an optical barrier; The light emitter mentioned above is based on semiconductor nanoparticles; Each of the reference sensors and each sensor in the signal receiving sensor array includes a semiconductor nanoparticle layer, a hole transport layer, an electron transport layer, and electrodes; The optical barrier is configured to prevent light emitted by the light emitter from directly reaching the signal receiving sensor array; The signal receiving sensor array is configured to detect light reflected from the image scene. The signal receiving sensor array and the reference sensor comprise a matrix of pixels, each pixel having a first electrode and a second electrode; The first electrode of the pixel of the signal receiving sensor array and the reference sensor includes a conductive layer that is transparent to the common portion of each pixel in the pixel, and the second electrode is insulated from the second electrode of each other pixel of the signal receiving sensor array and the reference sensor.

2. The time-of-flight sensor according to claim 1, wherein the light emitter is a vertical-cavity surface-emitting laser.

3. The time-of-flight sensor according to claim 1, wherein the signal receiving sensor array comprises a plurality of pixels, and wherein each pixel of the reference sensor and the signal receiving sensor array has a composition of InSb, InAs x P x or InAs or InAs x Sb x The semiconductor nanoparticle layer is formed.

4. The time-of-flight sensor of claim 1, wherein the hole transport layer comprises molybdenum oxide and the electron transport layer comprises zinc oxide.

5. The time-of-flight sensor of claim 1, wherein the partially transparent conductive layer is common to both the signal receiving sensor array and the reference sensor.

6. The time-of-flight sensor of claim 5, wherein the reference sensor includes a first device substrate, and the signal receiving sensor array includes a second device substrate, the first device substrate and the second device substrate being mounted on the base substrate.

7. The time-of-flight sensor of claim 1, wherein the partially transparent conductive layers of the signal receiving sensor array and the reference sensor are independently adjustable and insulated from each other; and The time-of-flight sensor further includes at least one polarization circuit configured to apply a first voltage between a first electrode and a second electrode of a pixel of the reference sensor, and to apply a second voltage between a first electrode and a second electrode of a pixel of the signal receiving sensor array, wherein the first voltage is different from the second voltage.

8. A mobile communication device, comprising a touch display screen and including a time-of-flight sensor according to claim 1, wherein the touch display screen covers the time-of-flight sensor.

9. The mobile communication device according to claim 8, wherein the touch display screen is an organic light-emitting diode display.

10. A facial recognition sensor, comprising the time-of-flight sensor according to claim 1.

11. A method for measuring flight time using the time-of-flight sensor according to claim 1, comprising: A first voltage is applied between the first and second electrodes of the pixel of the reference sensor through a polarization circuit, and a second voltage is applied between the first and second electrodes of the pixel of the signal receiving sensor. as well as The first voltage is modified based on the signal output of the reference sensor.

12. The method of claim 11, wherein both the reference sensor and the signal receiving sensor comprise a semiconductor nanoparticle layer, a hole transport layer, an electron transport layer, and an electrode; and wherein the hole transport layer comprises molybdenum oxide and / or the electron transport layer comprises zinc oxide.

13. The method of claim 11, further comprising modifying the second voltage based on the signal output of the signal receiving sensor.

14. The method of claim 13, wherein the second voltage is different from the first voltage.

15. A method for measuring flight time using the time-of-flight sensor according to claim 1, comprising: A first voltage is applied between the first and second electrodes of the pixel of the reference sensor through a polarization circuit, and a second voltage is applied between the first and second electrodes of the pixel of the signal receiving sensor. as well as The second voltage is modified based on the signal output of the signal receiving sensor.

16. The method of claim 15, wherein both the reference sensor and the signal receiving sensor comprise a semiconductor nanoparticle layer, a hole transport layer, an electron transport layer, and an electrode; and wherein the hole transport layer comprises molybdenum oxide and / or the electron transport layer comprises zinc oxide.

17. The method of claim 15, wherein the second voltage is different from the first voltage.

Images