Self-mixing interferometry using backside emitting vcsel diode with

Abstract

The invention relates to self-mixing interferometry using a back-emitting VCSEL diode with an integrated photodetector. Embodiments described herein include a photosensing device having a vertical cavity surface emitting laser (VCSEL), a resonant cavity photodetector (RCPD), and a tunnel junction. The VCSEL is at least partially defined by a first set of semiconductor layers disposed on the substrate. The first semiconductor layer set includes a first active region. The VCSEL is configured to emit laser light toward the substrate upon application of a first bias voltage and to undergo self-mixing interference upon receipt of its reflection or backscattering. The RCPD is vertically adjacent to the VCSEL and is at least partially defined by a second set of semiconductor layers disposed on the substrate. The second semiconductor layer set includes a second active region. The RCPD is configured to detect self-mixing interference when the second bias voltage is applied. A tunnel junction is disposed between the first active region and the second active region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a non-provisional application, which claims the benefit of U.S. Provisional Patent Application No. 63 / 540,253 filed on September 25, 2023 under 35 U.S.C. §119(e), the contents of which are incorporated herein by reference and are deemed to be fully disclosed herein. Technical Field

[0003] The embodiments relate generally to optical sensing, and more particularly to self-mixing interferometry (SMI) based optical sensing. Background Art

[0004] Electronic devices can be equipped with photoelectric sensors. For example, photoelectric sensors can be included in portable electronic devices (such as mobile phones, tablet computers, laptop computers, cameras, portable music players, portable terminals, vehicle navigation systems, robot navigation systems, electronic watches, health or fitness tracking devices, and other portable or mobile devices). Photoelectric sensors can also be included in devices (e.g., security cameras, doorbells, door locks, thermostats, refrigerators, or other household appliances) that are semi-permanently positioned (or installed) at a single location. Some of these electronic devices may include one or more input elements or surfaces, such as cameras, buttons, or touch screens, through which users can enter commands or data via touch, press, gesture, or image. Touch, press, gesture, or image can be detected by components of the electronic device (e.g., one or more photoelectric sensors), which detect presence, distance, position, motion, topology, or other parameters. The same and / or other electronic devices may additionally or alternatively include one or more sensors that can sense proximity, distance, particle velocity, or other parameters without receiving intentional user input.

[0005] Some optoelectronic sensors may include a light source (e.g., a laser) that emits a light beam toward or through an input surface. The distance, position, motion, topology, or other parameters of the input surface or an object on the opposite side of the input surface may be inferred from reflection or backscatter of the emitted light from the input surface and / or the object.

[0006] Some optoelectronic sensors may include vertical cavity surface emitting laser (VCSEL) diodes. VCSEL diodes may experience self-mixing interference, in which reflections of the laser light it emits are received back into its resonant cavity. Self-mixing interference may cause a change in the properties (such as wavelength) of the laser light generated within the resonant cavity to a different state than in the absence of the received reflection ("free emission"). In the case where the received reflection is from an input surface or object, the change in the property may be related to, for example, the displacement, distance, motion, speed, or velocity of the input surface or object that caused the reflection. Summary of the invention

[0007] The term embodiment and similar terms (e.g., specific implementations, configurations, aspects, examples, and options) are intended to refer generally to all subject matter of the present disclosure and the following claims. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the following claims. The embodiments of the present disclosure covered herein are defined by the following claims rather than by this disclosure. This disclosure is a high-level overview of various aspects of the present disclosure and introduces some concepts that are further described in the following detailed description section. This disclosure is not intended to identify the key or essential features of the claimed subject matter. This disclosure is also not intended to be used in isolation to determine the scope of the claimed subject matter. This subject matter should be understood by reference to appropriate portions of the entire specification of the present disclosure, any or all drawings, and the various claims.

[0008] Embodiments of the present disclosure relate to a photoelectric sensing device having a vertical cavity surface emitting laser (VCSEL), a resonant cavity photodetector (RCPD) and a tunnel junction. The VCSEL is at least partially defined by a first semiconductor layer set disposed on a substrate. The first semiconductor layer set includes a first active region. The VCSEL is configured to emit laser light toward the substrate when a first bias voltage is applied, and undergoes self-mixing interference when receiving a reflection or backscattering of laser light emitted from a target object. The RCPD is vertically adjacent to the VCSEL and is at least partially defined by a second semiconductor layer set disposed on the substrate. The second semiconductor layer set includes a second active region. The RCPD is configured to detect self-mixing interference during the VCSEL lasing when a second bias voltage is applied. The tunnel junction is disposed between the first active region and the second active region.

[0009] Embodiments of the present disclosure also relate to a photoelectric sensing device having a substrate, a stacked semiconductor layer set, and a grating structure arranged on the stacked semiconductor layer set. The substrate has a front side and a back side. The stacked semiconductor layer set is arranged on the front side and defines a vertical cavity surface emitting laser (VCSEL) and a resonant cavity photodetector (RCPD). The VCSEL has a first active region in its resonant cavity. The VCSEL is configured to emit a main emission toward the substrate and through the back side when a first bias voltage is applied. The RCPD has a second active region offset from the first active region.

[0010] Embodiments of the present disclosure also relate to a photoelectric sensing device having a substrate, a stacked semiconductor layer set and at least one electrical conductor. The substrate has a front side and a back side. The stacked semiconductor layer set is disposed on the front side and defines a table set. The table set includes a first set of one or more table sets and a second set of one or more table sets. Each table in the first set of one or more table sets includes a vertical cavity surface emitting laser (VCSEL) and a resonant cavity photodetector (RCPD). The VCSEL has a first active region in its resonant cavity. The VCSEL is configured to emit a main emission toward the substrate and through the back side when a first bias voltage is applied. The RCPD has a second active region offset from the first active region. The RCPD is configured to detect the self-mixing interference of the main emission in the laser cavity of the VCSEL when a second bias voltage is applied and when a reflection or backscattering of the main emission is received. At least one electrical conductor is electrically connected to an element of a first table in the first set of one or more table sets and is wired above a portion of a second table in the second set of one or more table sets.

[0011] The foregoing summary of the invention is not intended to represent every embodiment or every aspect of the present disclosure. On the contrary, the foregoing summary of the invention only provides examples of some of the novel aspects and features set forth herein. The above-mentioned features and advantages of the present disclosure and other features and advantages will be apparent from the following detailed description of representative embodiments and modes for carrying out the present invention when taken in conjunction with the accompanying drawings and the appended claims. In view of the detailed description of various embodiments made with reference to the accompanying drawings, additional aspects of the present disclosure will be apparent to those of ordinary skill in the art, and a brief description of the accompanying drawings is provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure will be easily understood by the following detailed description in conjunction with the accompanying drawings, in which like reference numerals represent like structural elements, and in which:

[0013] Figure 1A cross-sectional view of a first example structure of a back-emitting vertical cavity surface emitting laser (VCSEL) diode integrated with a resonant cavity photodetector (RCPD) according to certain aspects of the present disclosure is shown, wherein the RCPD is disposed away from the primary emission of the VCSEL diode;

[0014] Figure 2 shows a cross-sectional view of a second example structure of a back-emitting vertical cavity surface emitting laser (VCSEL) diode integrated with a resonant cavity photodetector (RCPD) according to certain aspects of the present disclosure, wherein the RCPD is disposed along the primary emission of the VCSEL diode;

[0015] Figure 3 A cross-sectional view of an example photoelectric sensing device according to certain aspects of the present disclosure is shown, the example photoelectric sensing device having Figure 1 A first example structure of a back-emitting VCSEL diode integrated with a RCPD is shown;

[0016] Figure 4 shows a cross-sectional view of a grating structure configured to be disposed on a set of stacked semiconductor layers on a substrate forming an example photoelectric sensing device in accordance with certain aspects of the present disclosure;

[0017] FIG. 5A to FIG. 5D According to certain aspects of the present disclosure Figure 4 Schematic representation of operating circuitry in an example photoelectric sensing device of the invention, the circuitry depending on whether the back emitting VCSEL diode has a cathode load or an anode drive;

[0018] Figure 6 According to certain aspects of the present disclosure Figure 4 A schematic representation of an operating circuit in an example photo-sensing device wherein the bias polarity of the RCPD is switched in the time domain;

[0019] Figure 7 A cross-sectional view of an example photoelectric sensing device according to certain aspects of the present disclosure is shown. Figure 2 A second example structure of a back-emitting VCSEL diode integrated with a RCPD is shown;

[0020] FIG. 8A to FIG. 8D According to certain aspects of the present disclosure Figure 7 Schematic representation of operating circuitry in an example photoelectric sensing device of the invention, the circuitry depending on whether the back emitting VCSEL diode has an anode drive or a cathode load;

[0021] FIG. 9A to FIG. 9BA cross-sectional view of a first example optoelectronic sensing device having an extended resonant cavity in the emitting side of a back-emitting VCSEL diode having a multi-junction structure in the optoelectronic sensing device and a corresponding schematic representation of an operating circuit are respectively shown according to certain aspects of the present disclosure;

[0022] FIG. 10A to FIG. 10B cross-sectional views of a first example photo-sensing device having multiple sets of back-emitting VCSEL diodes integrated with RCPDs and corresponding schematic representations of operating circuitry, respectively, with a first electrical connection arrangement between the multiple sets, according to certain aspects of the present disclosure;

[0023] FIG. 11A to FIG. 11B cross-sectional views of a second example photo-sensing device having multiple sets of back-emitting VCSEL diodes integrated with RCPDs and corresponding schematic representations of operating circuitry, respectively, with a second electrical connection arrangement between the multiple sets, according to certain aspects of the present disclosure;

[0024] FIG. 12A to FIG. 12B respectively showing a cross-sectional view of a second example optoelectronic sensing device having an extended resonant cavity in the emitting side of a back-emitting VCSEL diode having a multi-junction structure in the optoelectronic sensing device and a corresponding schematic representation of an operating circuit in accordance with certain aspects of the present disclosure;

[0025] FIG. 13A to FIG. 13B A first example set of photoelectric sensing devices (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A perspective view and corresponding cross-sectional view of a collection of optoelectronic sensing devices shown and described herein;

[0026] Fig.14 Shown is a reference FIG. 13A to FIG. 13B A top view of an example array of opto-sensing devices is shown and described;

[0027] FIG. 15A to FIG. 15B A second example set of photoelectric sensing devices (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A perspective view and corresponding cross-sectional view of a collection of optoelectronic sensing devices shown and described herein;

[0028] Fig.16 Shown is a reference Figures 15A to 15B A top view of an example array of opto-sensing devices is shown and described;

[0029] Fig.17 A photoelectric sensing device (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A top view of a first example layout of an optoelectronic sensing device as shown and described;

[0030] Fig.18 A photoelectric sensing device (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A top view of a second example layout of an optoelectronic sensing device as shown and described;

[0031] Fig.19 Shown is a reference Fig.18 A top view of a first array of a second example layout of opto-sensing devices shown and described;

[0032] Fig. 20 Shown is a reference Fig.18 A top view of a second array of a second example layout of opto-sensing devices shown and described; and

[0033] Fig.21 An example electrical block diagram of an electronic device with a photosensor according to certain aspects of the present disclosure is shown.

[0034] The use of cross-hatching or hatching in the drawings is generally provided to clarify boundaries between adjacent elements and also to facilitate legibility of the drawings. Thus, the presence or absence of cross-hatching or hatching does not express or indicate any preference or requirement for particular materials, material properties, element proportions, element sizes, commonality of similar illustrated elements, or any other feature, property, or property of any element shown in the drawings.

[0035] The present disclosure is susceptible to various modifications and alternative forms, and some representative embodiments have been shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that the present invention is not intended to be limited to the particular form disclosed. On the contrary, the present application is intended to cover all modifications, equivalents, and alternatives within the spirit and scope of the disclosure of the present application as defined by the appended claims.

[0036] Additionally, it should be understood that the proportions and sizes (relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, spacings, and positional relationships presented therebetween are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein, and therefore may not necessarily be presented or illustrated to scale and are not intended to indicate any preference or requirement for the embodiments illustrated to exclude the embodiments described in conjunction therewith. DETAILED DESCRIPTION

[0037] Various embodiments are described with reference to the accompanying drawings, wherein the same reference numerals are used in all the accompanying drawings to represent similar or equivalent elements. The accompanying drawings are not necessarily drawn to scale, and are only provided to illustrate aspects and features of the present disclosure. Many specific details, relationships and methods are set forth to provide a comprehensive understanding of certain aspects and features of the present disclosure, although those of ordinary skill in the relevant art will recognize that these aspects and features can be practiced in the absence of one or more of these specific details, with other relationships, or with other methods. In some cases, for the purpose of illustration, known structures or operations are not shown in detail. Various embodiments disclosed herein are not necessarily limited to the order of the actions or events illustrated, because some actions can occur in different orders and / or occur simultaneously with other actions or events. In addition, not all actions or events shown are necessary to realize certain aspects and features of the present disclosure.

[0038] For the purposes of this detailed description, unless expressly denied, and where appropriate, the singular includes the plural and vice versa. The word "including" means "including but not limited to". In addition, approximate words such as "approximately", "almost", "substantially", "approximately", etc. may be used herein to mean "at", "close to", "almost at", "within 3%-5% of...", "within an acceptable manufacturing tolerance", or any logical combination thereof. Similarly, the terms "vertical" or "horizontal" are intended to additionally include "within 3-5% of a vertical or horizontal orientation", respectively.

[0039] Additionally, directional terms, such as "top," "bottom," "upper," "lower," "front," "back," "above," "below," "above," "below," "left," "right," and the like are used with reference to the orientation of some of the components in some of the figures described below. Because components in various embodiments can be positioned in a number of different orientations, the directional terms are used for illustrative purposes only and are not limiting in any way. The directional terms are intended to be interpreted broadly and, therefore, should not be interpreted to exclude components oriented in different ways. These words are intended to refer to equivalent directions as depicted in the referenced illustrations; to be understood in the context of the objects or elements involved, such as in terms of their usual positions; or as otherwise described herein. Additionally, note that the term "signal" refers to a waveform (e.g., electrical, optical, magnetic, mechanical, or electromagnetic) that is capable of traveling through a medium such as DC, AC, a sine wave, a triangle wave, a square wave, a vibration, and the like.

[0040] In addition, as used herein, the phrase "at least one of" following a series of items in which any of the items are separated by the terms "and" or "or" modifies the list as a whole, rather than each member of the list. The phrase "at least one of" does not require selection of at least one of each of the listed items; rather, the phrase allows for a meaning that includes at least one of any of the items and / or at least one of any combination of the items and / or at least one of each of the items. For example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to only A, only B, or only C; any combination of A, B, and C; and / or one or more of each of A, B, and C. Similarly, it should be understood that the order in which the elements are presented for the combined or separated lists provided herein should not be interpreted as limiting the present disclosure to only the order provided.

[0041] Embodiments described herein relate to photoelectric sensing devices, such as those that can be used for touch or input sensors, proximity or particle sensors, or other types of sensors, and to their structures. Such photoelectric sensing devices may use one or more back-emitting vertical cavity surface emitting laser (VCSEL) diodes with integrated photodiodes, such as resonant cavity photodiodes (RCPDs), which receive lasers emitted from VCSEL diodes. Electronic devices may use such photoelectric sensing devices as part of a system for detecting displacement, distance, motion, rate, or speed of an object (or "target"). Such objects may be components of electronic devices, such as input surfaces or touch pads, or targets may be outside electronic devices; for example, photoelectric sensing devices may be part of an autofocus system of a camera and used to detect the distance of an external object or the motion of an external object. In the following, for convenience, all such possible measured kinematic parameters of a target will be referred to as "distance or motion" for short.

[0042] In a back-emitting VCSEL diode, generally speaking, laser light is emitted from a resonant cavity containing at least one active region (a pn junction surrounding its laser cavity) toward and through a substrate on which the back-emitting VCSEL diode is formed. Reflections of the emitted laser light may be received back into the resonant cavity and cause self-mixing interference in which a property of the laser light (such as wavelength) changes from the value it would have had if the reflection had not been received. The change in property may then be related to the distance or motion of the object causing the reflection.

[0043] One way the altered property may be detected is through a change in one or more electrical properties of the back emitting VCSEL diode itself, such as voltage, current, power, etc. Alternatively, the altered lasing may be received by a photodiode associated with the back emitting VCSEL diode, the photodiode having an output parameter related to the altered property of the self-mixing lasing of the VCSEL diode.

[0044] In various embodiments described herein, a back-emitting VCSEL diode can be configured to emit a primary emission from an active region through an emitting side of a photo-sensing device toward an object and toward a photodiode integrated therein when forward biased. The change in the properties of the laser light due to self-mixing with reflections from the object is then present in the primary emission received by the photodiode, which, when reverse biased, can generate a measurable electrical parameter having a value related to the changed property of the primary emission, from which the distance or motion of the object can be inferred.

[0045] In some embodiments described herein, a photodiode is integrally formed on a semiconductor substrate on which a VCSEL is formed, for example, using an epitaxial deposition technique. The photodiode may be disposed between the semiconductor substrate and the VCSEL diode, or the VCSEL diode may be disposed between the semiconductor substrate and the photodiode. Various electrical connections may be formed in or on the substrate, VCSEL diode, and / or the photodiode, to, for example, bias the VCSEL diode to receive a signal or other electrical signal from the photodiode. The VCSEL diode may have its input current (or voltage) modulated to provide a modulation of the primary emission. This type of modulation of the primary emission may allow the distance and movement of the target to be inferred.

[0046] Additional photodetector structures such as one or more gain stage layers (such as but not limited to indium gallium arsenide (InGaAs) layers, aluminum gallium arsenide (AlGaAs) layers) may be formed in the resonant cavity of the VCSEL diode to improve the absorption efficiency of the primary emission into the laser cavity of the VCSEL diode. Further, depending on the polarity of the junction, a tunnel junction may be inserted between the photodiode junction of the photodiode and the laser junction of the VCSEL diode to improve carrier injection and extraction and reduce the operating voltage of the photo-sensing device.

[0047] In some embodiments, a multi-junction structure consisting of multiple active regions (e.g., multiple pairs of barrier layers alternating with quantum well layers) and highly doped tunnel junctions interspersed therebetween can be stacked vertically in the resonant cavity of a VCSEL diode. The multi-junction structure can have one or more oxide layers formed at the top, bottom, or in the middle. Such multi-junction (MJ) VCSEL diodes can emit lasers having different characteristics from the lasers emitted by comparable single-junction (SJ) VCSEL diodes operating at similar current levels. In the case of a multi-junction structure, the MJ VCSEL diode operates at an increased voltage level (compared to a similar SJ VCSEL diode operating at a similar current level) and can provide multiple factors of increase in gain, such as output power. In addition, the center frequency of the emitted laser light can be increased, which can improve the signal-to-noise ratio (SNR) due to reduced 1 / f noise. Due to the increased efficiency and tunable range of the wavelength modulation of the emitted laser by the MJ VCSEL diode, the increased SNR and higher operating frequency can also allow for improved spatial resolution of the target through the photoelectric sensing device utilizing the MJ VCSEL diode, which in turn enables better measurement of electrical parameters related to the self-mixing interference of the emitted laser. Therefore, the multi-junction structure improves the performance of the photoelectric sensing device through faster signal transmission, wider sampling and reduced complexity.

[0048] In some embodiments, the optoelectronic sensing device having a multi-junction structure may also have an extended resonant cavity and include a substrate, the extended resonant cavity extending from the VCSEL diode to an on-chip lens (OCL) formed on the back end of the substrate. The extended resonant cavity significantly reduces the laser line width and extends the laser coherence length required for remote sensing.

[0049] In some embodiments, the photoelectric sensing device may have a semiconductor wafer or chip disposed on its front side and defining a set of mesas, wherein at least some of the mesas include a VCSEL diode with an integrated photodiode. The VCSEL diode is configured to emit a primary emission of laser light from an active region surrounding its laser cavity toward the substrate and through the back side when forward biased. The photodiode may be an RCPD having an active region offset from the active region of the VCSEL diode. The RCPD is configured to detect self-mixing interference of the primary emission when a reflection or backscattering of the primary emission is received when reverse biased. Adjacent mesas are connected to a power supply and are connected to each other via one or more electrical conductors.

[0050] Although specific optoelectronic sensing devices are shown in the figures and described below, the embodiments described herein can be used with various electronic devices, including but not limited to mobile phones, personal digital assistants, timing devices, health monitoring devices, wearable electronic devices, input devices (e.g., stylus), desktop computers, electronic glasses, etc. Although various electronic devices are mentioned, the optoelectronic sensing devices of the present disclosure can also be used in conjunction with other products and in combination with various materials.

[0051] Reference below Figure 1 to Figure 1 2. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for illustration purposes only and should not be construed as limiting.

[0052] Figure 1 A cross-sectional view of a first example structure 100 of a back-emitting vertical cavity surface emitting laser (VCSEL) diode 120 integrated with a resonant cavity photodetector (RCPD) 130 is shown, wherein the RCPD 130 is disposed in a path of a secondary emission of the VCSEL diode 120 away from a primary emission 140. The VCSEL diode 120 is formed on a semiconductor substrate 110, such as by an epitaxial deposition technique. The VCSEL diode 120 includes a first active region 128 having one or more quantum well structures. The first active region 128 forms a highly doped pn junction that allows charge carriers to pass through the pn junction when forward biased to induce lasing therefrom and toward a primary emission 140 of the substrate 110. On either side of the first active region 128, there are distributed Bragg diffraction layers formed as alternating semiconductor layers of high and low refractive indices, and the distributed Bragg diffraction layers can act as reflectors in the resonant cavity of the VCSEL diode 120.

[0053] Upon reflection and backscattering from target object 150, primary emission 140 is received into the laser cavity of first active region 128 where it undergoes self-mixing interference. As a result, the electrical properties of VCSEL diode 120 and / or primary emission 140 are altered.

[0054] RCPD 130 is formed above VCSEL diode 120, such as by epitaxial deposition techniques, and includes a second active region 138. RCPD 130 receives laser light from VCSEL diode 120 having altered electrical properties. When reverse biased, second active region 138 is configured to detect the altered electrical properties of the self-mixed laser light of VCSEL diode 120 and generate an output signal that depends on the wavelength of the self-mixed primary emission of VCSEL diode 120. The distance or motion of target object 150 that reflects or backscatters primary emission 140 can be determined based on the output signal from RCPD 130.

[0055] Figure 2 A cross-sectional view of a second example structure 200 of a back-emitting vertical cavity surface emitting laser (VCSEL) diode 220 integrated with a resonant cavity photodetector (RCPD) 230 is shown, wherein the RCPD 130 is disposed along a primary emission 240 of the VCSEL diode 220 .

[0056] RCPD 230 is formed over semiconductor substrate 210, such as by epitaxial deposition techniques, and includes a first active region 238. VCSEL diode 220 is also formed on RCPD 230 by epitaxial deposition techniques. VCSEL diode 220 includes a second active region 228 having one or more quantum well structures. Second active region 228 forms a highly doped pn junction that allows charge carriers to pass through the pn junction when forward biased to induce a primary emission 240 of laser light therefrom and toward substrate 210. On either side of second active region 228, there is a distributed Bragg diffraction layer formed as alternating semiconductor layers of high and low refractive indices, and the distributed Bragg diffraction layer can be used as a reflector in the resonant cavity of VCSEL diode 220.

[0057] Upon reflection and backscattering from target object 250, primary emission 240 is received into the laser cavity of second active region 228 where it undergoes self-mixing interference. As a result, the electrical properties of VCSEL diode 220 and / or primary emission 240 are altered.

[0058] The RCPD 230 also receives the laser light of the VCSEL diode 220 having the altered electrical properties. When reverse biased, the first active region 238 is configured to detect the altered electrical properties of the self-mixed laser light of the VCSEL diode 220 and generate an output signal that depends on the wavelength of the self-mixed primary emission 240 of the VCSEL diode 220. The distance or motion of the target object 250 receiving the primary emission 240 can be determined based on the output signal from the RCPD 230.

[0059] Figure 3A cross-sectional view of an example photoelectric sensing device 300 is shown, the example photoelectric sensing device having ( Figure 1 1 . A first example structure 100 of a back-emitting VCSEL diode integrated with an RCPD is shown. In particular, a back-emitting VCSEL diode 302 is integrated with an RCPD 312 that is disposed in a path of secondary emission away from primary emission 340 generated from the VCSEL diode 302 under forward bias. The RCPD 312 receives the altered primary emission from the VCSEL diode 302 after the primary emission 340 undergoes self-mixing interference when receiving reflection or backscattering.

[0060] The photoelectric sensing device 300 is fabricated by first depositing a stacked set of semiconductor layers on the front side 308f of the substrate 308 to form a VCSEL diode 302, and then forming a RCPD 312 on the VCSEL diode 302. An on-chip lens 330 is disposed on the back side 308r of the substrate 308, and is configured to collimate, focus, or expand the laser light emitted by the VCSEL diode 302, and to collect the returning laser light back into the laser cavity of the first active region 302 in the VCSEL diode 302 for coherent mixing.

[0061] The VCSEL diode 302 may include an emission side (or "top side") distributed Bragg reflector (hereinafter "DBR") layer 303a that serves as a first (or "emission side") reflector of the laser structure. The emission side DBR layer 303a may include a collection of alternating material pairs having different refractive indices. Each such alternating material pair will be referred to herein as a Bragg pair. One or more of the materials in the emission side DBR layer 303a may be doped to p-type and thus form a portion of the anode segment of the pn diode junction of the VCESEL diode 302. An exemplary material pair that may be used to form the emission side DBR layer 303a is aluminum gallium arsenide (AlGaAs) and gallium arsenide (GaAs).

[0062] The VCSEL diode 302 may include a base-side DBR layer 303b that serves as a second (or "base-side" or "bottom-side") reflector for the laser. The base-side DBR layer 303b may also include a collection of Bragg pairs of alternating materials having different refractive indices. One or more of the materials in the base-side DBR layer 303b may be doped to n-type and thus form part of the cathode segment of a pn diode structure. An exemplary material pair that may be used to form the base-side DBR layer 303b is aluminum arsenide and GaAs.

[0063] In some embodiments, the DBR layers 303a and 303b can be formed by semiconductor epitaxy and any one of semiconductor GaAs, AlxGa1-xAs (0 < x ≤ 1), or formed of other semiconductor materials. In other embodiments, the DBR layers 303a and 303b can be formed of dielectric materials. Examples of such dielectrics include, but are not limited to, amorphous silicon (a-Si), silicon oxide (SiO2), SiO2 / niobium pentoxide (Nb2O5), and SiO2 / tantalum pentoxide (Ta2O5). In other embodiments, the DBR layers 303a and 303b can be formed as a mixture of semiconductor materials and dielectric materials.

[0064] The VCSEL diode 302 can include an active region 307 that partially serves as a resonant cavity. In a laser diode such as the VCSEL diode 302, the active region 307 can include one or more quantum wells. In some embodiments such as Figure 3 shown, the active region 307 of the VCSEL diode 302 can be adjacent to an oxide layer 309 having holes, and the main emission 340 escapes through the holes. In some embodiments such as Figure 3 shown, the active region 307 further includes one or more gain stage layers 304 (e.g., InGaAs layer, AlGaAs layer) formed in the resonant cavity of the VCSEL diode 302 to improve the absorption efficiency of the main emission 340.

[0065] The VCSEL diode 302 can be formed by epitaxial growth of layers for each of the emission side layer 303a and the base side DBR layer 303b, the active region 307, the oxide layer 309, and possibly other layers. These various layers can be formed by epitaxial growth on the substrate 308. The power contacts 305a, 305b can be formed on the emission side layer and the base side layer of the VCSEL diode 302.

[0066] The RCPD 312 is formed on the VCSEL diode 302. In some embodiments, the RCPD 312 can include an active region 314 (offset from the active region 307 of the VCSEL diode 302) and a power contact 315a. The active region 314 can include one or more gain layers (e.g., InGaAs layer, AlGaAs layer) to improve the absorption efficiency of the changed main emission 340 after the self-mixing interference in the active region 307 of the VCSEL diode 302. The power contact 315a forms an annular or horseshoe-shaped connection on the top side of the RCPD 312. As further described with respect to Figure 4 the grating structure 320 can be vertically disposed on the set of semiconductor layers forming the RCPD 312.

[0067] One or more tunnel junctions 310 and additional gain layers 311 may be disposed between the active region 307 of the VCSEL diode 302 and the active region 314 of the RCPD 312. Depending on the polarity of the junction, the tunnel junction 310 may help improve carrier injection / extraction from the VCSEL diode 302 to the RCPD 312 and reduce the operating voltage of the photo-sensing device 300.

[0068] As an example, in one embodiment, the tunnel junction 310 of the VCSEL diode 302 may have a turn-on voltage (forward bias voltage to initiate lasing) of approximately 1.3 V, so the resulting turn-on voltage of the VCSEL diode 302 overall will become approximately 2.6 V. However, the current will remain constant for a single tunnel junction, and in one embodiment will be 0.5 mA.

[0069] The tunnel junction 310 of the VCSEL diode 302 may be formed of both a heavily doped n-type layer and a heavily doped p-type layer. Examples of n-type dopants include, but are not limited to, silicon (Si), tellurium (Te), and selenium (Se). Examples of p-type dopants include, but are not limited to, carbon (C), zinc (Zn), and beryllium (Be). The heavily doped concentration may be at least 10 18 / cm 3 The doping concentration can be as high as 10 for some dopants 20 / cm 3 , although other concentrations are possible.

[0070] like Figure 3 As shown, the current I flowing through the VCSEL diode 302 between the common power contact 305a (shared with the RCPD 312) and the power contact 305b of the VCSEL diode 302 is LD 306 generates a forward bias that generates a primary emission 340 directed toward a target object 350 through substrate 308 and on-chip lens 330. At the same time, a current I flows through RCPD 312 between common power contact 305a (shared with VCSEL diode 302) and power contact 315a of RCPD 312. PD 316 generates a reverse bias through RCPD 312. One or more controllers, such as processor 1204 described below with respect to FIG. 12, may be communicatively coupled to photo-sensing device 300 to implement a configuration for forward biasing VCSEL diode 302 and RCPD 312.

[0071] When VCSEL diode 302 is forward biased, laser light of primary emission 340 undergoes self-mixing interference in the laser cavity of active region 307 upon receiving its reflection or backscatter. RCPD 312 receives self-mixing primary emission 340 and detects altered electrical properties of primary emission 340 when reverse biased. In some embodiments, one or more controllers can be configured to switch the bias polarity of RCPD 312 to capture multiple detections of self-mixing interference in the time domain for time multiplexed sample readout, such as with respect to Figure 6 as described.

[0072] Figure 4 A cross-sectional view of a grating structure 320 is shown, which is configured to be disposed on a stacked set of semiconductor layers, such as but not limited to forming Figure 3 An example photoelectric sensing device 300 or Figure 7 The substrate of the example photoelectric sensing device 700 is as described below. The grating structure 320 can be a diffraction grating structure having a grating period greater than the wavelength of the main emission. Alternatively, the grating structure 320 can be a sub-wavelength grating structure having a grating period less than the wavelength of the main emission. The grating structure 320 is an optional feature that can have different structural variations of the features described below and may or may not be integrated in the photoelectric sensing device depending on the design requirements (such as but not limited to stabilizing the polarization of the emitted laser light).

[0073] The grating structure 320 is disposed on the top surface of the stacked semiconductor layer set, which may also include a power contact (eg, Figure 3 315a in the photoelectric sensing device 300). The grating structure 320 has a base layer 322 formed (using, for example, atomic layer deposition) of a laterally alternating arrangement of a high refractive index grating material 323 (e.g., amorphous silicon, GaAs) and a low refractive index grating material 324 (e.g., a dielectric material such as silicon oxide, aluminum oxide, silicon nitride). An optional dielectric stack 326 of alternating DBR layers and dielectric layers (e.g., silicon oxide, aluminum oxide, silicon nitride) can be disposed on the base layer 322. The collection of DBR layers in the dielectric stack 326 facilitates optical reflection of laser light from a VCSEL diode (e.g., VCSEL diode 302 of the photoelectric sensing device 300). The grating structure 320 has a conductive layer 328 formed of a metal (e.g., gold, copper) disposed on the optional dielectric stack 326. Top layer 328 electrically connects power contacts of the VCSEL diode and / or the RCPD, enhances the optical reflection of the emitted laser light, stabilizes any polarization of the emitted laser light, and also helps to bond grating structure 320 to other materials.

[0074] FIG. 5A to FIG. 5D Shows Figure 3 A schematic representation of the operating circuitry in an example photoelectric sensing device 300 is shown in FIG. Figure 5A In the embodiment of the present invention, the VCSEL diode 302 can be forward biased between the first bias node 512 and the common node 514, and the RCPD 312 can be reverse biased between the common node 514 and the second bias node 516. For example, the first bias node 512 can be driven to a positive voltage such as 0.2V, the common node 514 can be driven to a positive voltage such as 3V, and the second bias node 516 has a positive voltage such as 1.5V. The voltage of the second bias node 516 can depend on the transimpedance amplifier (TIA) or other readout circuits connected thereto. In different embodiments, different voltage levels can be used for the first bias node 512, the common node 514, and the second bias node 516, and generally speaking, the voltage at the second bias node 516 is between the voltage at the first bias node 512 and the common node 514. The forward biased VCSEL diode 302 can drive a cathode load current causing the main emission 340 to be emitted therefrom. Reverse biasing the RCPD 312 may result in the generation of a photocurrent when the RCPD 312 receives the primary emission 340 having altered properties due to self-mixing in the VCSEL diode 302. The photocurrent may be detected by a transimpedance amplifier (TIA) connected to the second bias node 516. Figure 5A In the configuration shown, the common node 514 has an n-contact, and a tunnel junction exists between the VCSEL diode 302 and the RCPD 312 .

[0075] exist Figure 5B , the VCSEL diode 302 can be forward biased between the first bias node 522 and the common node 524, and the RCPD 312 can be reverse biased between the common node 524 and the second bias node 526. For example, the first bias node 522, the common node 524, and the second bias node 526 can be driven to progressively lower positive voltages so that, generally speaking, the voltage at the common node 524 is between the voltages at the first bias node 522 and the second bias node 526. The voltage of the second bias node 526 can depend on the transimpedance amplifier (TIA) or other readout circuitry connected thereto. Although in different embodiments, different sets of positive voltage levels can be used for the first bias node 522, the common node 524, and the second bias node 526, in Figure 5BIn the example shown, the first bias node 522 can be driven to 4.3V, the common node 524 can be driven to 1.7V, and the second bias node 526 can have 0.2V. Forward biasing the VCSEL diode 302 can drive an anode current that causes the primary emission 340 to be emitted therefrom. Reverse biasing the RCPD 312 can cause the generation of a photocurrent when the RCPD 312 receives the primary emission 340 having altered properties due to self-mixing in the VCSEL diode 302. The photocurrent can be detected by a TIA connected to the second bias node 526. Figure 5A In the configuration shown, common node 524 has n contacts.

[0076] exist Figure 5C , the VCSEL diode 302 can be forward biased between the first bias node 532 and the common node 534, and the RCPD 312 can be reverse biased between the common node 534 and the second bias node 536. For example, the first bias node 532 can be driven to a positive voltage such as 2.6V, the common node 534 can be maintained at 0V or ground (GND), and the second bias node 836 can have a positive voltage such as 1.5V. The voltage of the second bias node 536 can depend on the transimpedance amplifier (TIA) or other readout circuits connected thereto. In different embodiments, different voltage levels can be used for the first bias node 532, the common node 534, and the second bias node 536, and generally speaking, the voltage at the second bias node 536 is between the voltage at the first bias node 532 and the common node 534. The forward biased VCSEL diode 302 can drive an anode current causing the main emission 340 to be emitted therefrom. Reverse biasing the RCPD 312 may result in the generation of a photocurrent when the RCPD 312 receives the primary emission 340 having altered properties due to self-mixing in the VCSEL diode 302. The photocurrent may be detected by a TIA connected to the second bias node 536. Figure 5C In the configuration shown, the common node 534 has an n-contact, and there is a native reverse junction between the VCSEL diode 302 and the RCPD 312 .

[0077] exist Figure 5C, the VCSEL diode 302 can be forward biased between a first bias node 542 and a common node 544, and the RCPD 312 can be reverse biased between a second bias node 546 and the common node 544. For example, the first bias node 542, the common node 544, and the second bias node 546 can be driven to progressively higher positive voltages so that, generally speaking, the voltage at the common node 544 is between the voltages at the first bias node 542 and the second bias node 546. The voltage at the second bias node 546 can depend on a transimpedance amplifier (TIA) or other readout circuitry connected thereto. Although in different embodiments, different sets of positive voltage levels can be used for the first bias node 542, the common node 544, and the second bias node 546, in the embodiment of the present invention, the first bias node 542, the common node 544, and the second bias node 546 can be driven to progressively higher positive voltages. Figure 5D In the example shown, the first bias node 542 can be maintained at 0V or ground (GND), the common node 544 can be driven to a positive voltage of 2.6V, and the second bias node 546 can have a positive voltage of 4.1V. Forward biasing the VCSEL diode 302 can drive a cathode load current that causes the primary emission 340 to be emitted therefrom. Reverse biasing the RCPD 312 can cause the generation of a photocurrent when the RCPD 312 receives the primary emission 340 having altered properties due to self-mixing in the VCSEL diode 302. The photocurrent can be detected by a TIA connected to the second bias node 546. Figure 5A In the configuration shown, common node 544 has a p-contact.

[0078] Figure 6 Shows Figure 3 Schematic representation of the operating circuitry in an example photo-sensing device 300 where the bias polarity of the RCPD 312 is switched in the time domain. Figure 6 , the VCSEL diode 302 can be forward biased between a first bias node 612 and a common node 614, while the RCPD 312 can be reverse biased or forward biased between the common node 614 and a second bias node 616. In different embodiments, different voltage levels can be used for the first bias node 612, the common node 614, and the second bias node 616. The forward biased VCSEL diode 302 can drive a cathode load current that causes a primary emission 340 to be emitted therefrom, which is received by the RCPD 312 having altered properties due to self-mixing in the VCSEL diode 302, which then causes the generation of a photocurrent. The photocurrent can be detected by a TIA connected to the second bias node 616. The bias polarity of the RCPD 312 can be switched in the time domain, which enables time-multiplexed sample readout of the photocurrent.

[0079] Figure 7A cross-sectional view of an example photoelectric sensing device 700 is shown having ( Figure 2 ) is a second example structure 200 of a back-emitting VCSEL diode integrated with an RCPD. In particular, a back-emitting VCSEL diode 702 is integrated with an RCPD 712 disposed along a path of a primary emission 740 of laser light generated from the VCSEL diode 702 under forward bias. The RCPD 712 receives the altered primary emission from the VCSEL diode 702 after the primary emission 740 undergoes self-mixing interference upon receiving reflections or backscattering therefrom.

[0080] The optoelectronic sensing device 700 is fabricated by first depositing a mirror layer set 710 on the front side 708f of the substrate 708. In some embodiments, the mirror layer set 710 can be a DBR layer, such as those described above. A power contact 715a can be disposed on the top surface of the mirror layer set 710 and can form a ring or horseshoe connection around the RCPD 712 deposited on the mirror layer set 710. An on-chip lens 730 is disposed on the back side 708r of the substrate 708 and is configured to collimate the laser emitted by the VCSEL diode 702 and reflect a portion of the main emission back to the first active region in the VCSEL diode 702 and the RCPD 712.

[0081] RCPD 712 is epitaxially deposited on mirror layer set 710. In some embodiments, RCPD 712 can include an active region 714 and a power contact 715b disposed on its top surface. Active region 714 can include one or more gain layers (e.g., InGaAs layer, AlGaAs layer) to improve the absorption efficiency of modified main emission 740 after it undergoes self-mixing interference in active region 707 of VCSEL diode 302. Power contact 715b forms a ring or horseshoe connection on the top side of RCPD 312.

[0082] The VCSEL diode 702 is formed on the RCPD 712, such as by epitaxial deposition techniques. The VCSEL diode 702 may include an emission side (or "top side") DBR layer 703a, which serves as a first (or "emission side") reflector of the laser structure. The emission side DBR layer 703a may include a collection of alternating material pairs having different refractive indices. One or more of the materials in the emission side DBR layer 703a may be doped to p-type and thus form a portion of the anode segment of the pn diode junction of the VCESEL diode 702. An exemplary material pair that can be used to form the emission side DBR layer 703a is AlGaAs and GaAs.

[0083] The VCSEL diode 702 may include a base - side DBR layer 703b that serves as the second (or "base - side" or "bottom - side") mirror of the laser. The base - side DBR layer 703b may also include a set of Bragg pairs of alternating materials with different refractive indices. One or more of the materials in the base - side DBR layer 703b may be doped n - type and thus form part of the cathode section of the p - n diode structure. Exemplary material pairs that can be used to form the base - side DBR layer 703b are AlAs and GaAs.

[0084] In some embodiments, the DBR layers 703a and 703b may be formed by semiconductor epitaxy and any of semiconductor GaAs, Al x Ga 1-x As (0 < x ≤ 1), or formed of other semiconductor materials. In other embodiments, the DBR layers 703a and 703b may be formed of dielectric materials. Examples of such dielectrics include, but are not limited to, amorphous silicon (a - Si), silicon oxide (SiO2), SiO2 / Nb2O5, and SiO2 / Ta2O5. In other embodiments, the DBR layers 703a and 703b may be formed as a mixture of semiconductor materials and dielectric materials.

[0085] The VCSEL diode 702 may include an active region 707 that partially serves as a resonant cavity. In a laser diode such as the VCSEL diode 702, the active region 707 may include one or more quantum wells. In some embodiments such as Figure 7 shown, the active region 707 of the VCSEL diode 702 may be adjacent to an oxide layer 709 having holes through which the main emission 740 escapes. In some embodiments such as Figure 7 shown, the active region 707 also includes one or more gain - stage layers 704 (e.g., InGaAs layer, AlGaAs layer) formed in the resonant cavity of the VCSEL diode 702 to improve the absorption efficiency of the main emission 740.

[0086] The VCSEL diode 702 may be formed by epitaxial growth of the layers for each of the emission - side DBR layer 703a and the base - side DBR layer 703b, the active region 707, and the oxide layer 709 and possibly other layers. These various layers may be formed by epitaxial growth on the RCPD 712. The power contact 705a may be formed on the emission - side and base - side layers of the VCSEL diode 702. As further described with respect to Figure 4 the grating structure 320 may be disposed on the VCSEL diode 702.

[0087] One or more tunnel junctions (such as with respect to Figure 3The tunnel junction 310 described above and the additional gain layer (such as relative to Figure 3 The described tunnel junction 311) can be disposed between the active region 707 of the VCSEL diode 702 and the active region 714 of the RCPD 712. Depending on the polarity of the junction, such a tunnel junction can help improve carrier injection / extraction from the VCSEL diode 702 to the RCPD 712 and reduce the operating voltage of the photo-sensing device 700.

[0088] like Figure 7 As shown, the current I flowing through the VCSEL diode 702 between the power contact 705a of the VCSEL diode 702 and the common power contact 715b (shared with the RCPD 712) is LD 706 generates a forward bias that generates a primary emission 740 directed toward a target object 750 through substrate 708 and on-chip lens 730. At the same time, a current I flows through RCPD 312 between common power contact 715b (shared with VCSEL diode 702) and power contact 715a of RCPD 712. PD 716 generates a reverse bias through the RCPD 712. One or more controllers, such as the processor 1204 described below with respect to FIG. 12, may be communicatively coupled to the photo-sensing device 700 to implement a configuration for forward biasing the VCSEL diode 702 and the RCPD 712.

[0089] When VCSEL diode 702 is forward biased, laser light of primary emission 740 undergoes self-mixing interference in the laser cavity of active region 707 upon receiving reflections or backscatter therefrom. RCPD 712 receives self-mixing primary emission 740 and detects altered electrical properties of primary emission 740 when reverse biased.

[0090] FIG. 8A to FIG. 8D Shows Figure 7 A schematic representation of the operating circuitry in an example photoelectric sensing device 700 is shown. Fig. 8AIn the embodiment of the present invention, the VCSEL diode 702 can be forward biased between the first bias node 812 and the common node 814, and the RCPD 712 can be reverse biased between the common node 814 and the second bias node 816. For example, the first bias node 812 can be driven to a positive voltage such as 2.6V, the common node 814 can be maintained at 0V or ground (GND), and the second bias node 816 can have a positive voltage such as 1.5V. The voltage of the second bias node 816 can depend on the transimpedance amplifier (TIA) or other readout circuits connected thereto. In different embodiments, different voltage levels can be used for the first bias node 812, the common node 814 and the second bias node 816. The forward biased VCSEL diode 702 can provide an anode drive current that causes the main emission 740 to be emitted therefrom. When the RCPD 712 receives the main emission 740 with the changed properties due to the self-mixing in the VCSEL diode 702, the reverse biased RCPD 712 can cause the generation of photocurrent. The photocurrent can be detected by a TIA connected to the second bias node 816. Fig. 8A In the configuration shown, the common node 814 has an n-contact and there is a native reverse junction between the VCSEL diode 702 and the RCPD 712 .

[0091] exist Figure 8B , the VCSEL diode 702 can be forward biased between the first bias node 822 and the common node 824, and the RCPD 712 can be reverse biased between the common node 824 and the second bias node 826. For example, the first bias node 822, the common node 824, and the second bias node 826 can be driven to progressively lower positive voltages. The voltage of the second bias node 826 can depend on the transimpedance amplifier (TIA) or other readout circuitry connected thereto. Although in different embodiments, different sets of positive voltage levels can be used for the first bias node 822, the common node 824, and the second bias node 826, in Figure 8B In the example shown, the first bias node 822 can be driven to 4.3V, the common node 824 can be driven to 1.7V, and the second bias node 826 can have 0.2V. Forward biasing the VCSEL diode 702 can drive an anode current that causes a primary emission 740 to be emitted therefrom. When the RCPD 712 receives the primary emission 740 having altered properties due to self-mixing in the VCSEL diode 702, reverse biasing the RCPD 712 can cause the generation of a photocurrent. The photocurrent can be detected by a TIA connected to the second bias node 826. Fig. 8A In the configuration shown, common node 824 has n contacts.

[0092] exist Figure 8C, VCSEL diode 702 can be forward biased between first bias node 832 and common node 834, and RCPD 712 can be reverse biased between common node 834 and second bias node 836. For example, first bias node 832 can be maintained at 0V or ground (GND), common node 834 can be driven to positive voltage 2.8V, and second bias node 836 can have positive voltage such as 1.3V. The voltage of second bias node 836 can depend on transimpedance amplifier (TIA) or other readout circuits connected thereto. In different embodiments, different voltage levels can be used for first bias node 832, common node 834 and second bias node 836. Forward biased VCSEL diode 702 can drive cathode load current causing main emission 740 to be emitted therefrom. When RCPD 712 receives main emission 740 with modified properties due to self-mixing in VCSEL diode 702, reverse biased RCPD 712 can cause generation of photocurrent. This photocurrent can be detected by a TIA connected to the second bias node 836. Figure 8C In the configuration shown, the common node 834 has an n-contact and a tunnel junction exists between the VCSEL diode 702 and the RCPD 712 .

[0093] exist Fig.8D , the VCSEL diode 702 can be forward biased between the first bias node 842 and the common node 844, and the RCPD 712 can be reverse biased between the second bias node 846 and the common node 844. For example, the first bias node 842, the common node 844, and the second bias node 846 can be driven to progressively higher positive voltages. The voltage of the second bias node 846 can depend on the transimpedance amplifier (TIA) or other readout circuitry connected thereto. Although in different embodiments, different sets of positive voltage levels can be used for the first bias node 842, the common node 844, and the second bias node 846, in Fig.8D In the example shown, the first bias node 842 can be maintained at 0V or ground (GND), the common node 844 can be driven to 2.6V, and the second bias node 546 can have 4.1V. The forward biased VCSEL diode 702 can drive a cathode load current that causes the primary emission 740 to be emitted therefrom. When the RCPD 712 receives the primary emission 740 having altered properties due to self-mixing in the VCSEL diode 702, the reverse biased RCPD 712 can cause the generation of a photocurrent. The photocurrent can be detected by a TIA connected to the second bias node 846. Fig. 8A In the configuration shown, common node 844 has a p-contact.

[0094] FIG. 9A to FIG. 9B A cross-sectional view of a first example optoelectronic sensing device 900 and a corresponding schematic representation of an operating circuit are shown, respectively, having an extended resonant cavity in the emission side of a back-emitting VCSEL diode having a multi-junction structure (MJ-VCSEL) and integrated with an RCPD, as described below. The extended resonant cavity extends from the VCSEL diode to an on-chip lens (OCL) 930 formed on the back side 908r of a substrate 908, and includes the substrate 908. In particular, Fig. 9A A back-emitting MJ-VCSEL diode 902 is shown integrated with a RCPD 912 disposed away from the path of a primary emission 940 of laser light from the MJ-VCSEL diode 902 in forward bias. The RCPD 912 receives the altered primary emission 940 from the MJ-VCSEL diode 902 after the primary emission 940 undergoes self-mixing interference upon receiving reflections or backscatter therefrom.

[0095] The photoelectric sensing device 900 is manufactured by first forming a substrate 908 (e.g., a low-loss semiconductor or dielectric material) with an extended cavity, depositing a stacked semiconductor layer set on the front side 908f of the substrate 908 to form an MJ-VCSEL diode 902 with a multi-junction structure 901, and then forming an RCPD 912 on the VCSEL diode 902. As discussed above, the extended resonant cavity significantly reduces the laser line width and extends the laser coherence length required for remote sensing. The on-chip lens 930 is arranged on the back side 908r of the substrate 908 and is configured to collimate the laser emitted by the VCSEL diode 902 and collect the laser returned from the target object toward the first active region in the VCSEL diode 902 and the RCPD 912. A reflective coating 935 made of a dielectric material can be provided on the on-chip lens 930.

[0096] Compared with Figure 3 Similar to the described embodiments, the MJ-VCSEL diode 902 may include an emission-side (or "top-side") DBR layer 903a including a set of alternating material pairs (e.g., AlGaAs, GaAs) having different refractive indices. The MJ-VCSEL diode 902 may also include a base-side DBR layer 903b also including a set of Bragg pairs of alternating materials (e.g., AlAs, GaAs) having different refractive indices. One or more materials in the emission-side DBR layer 903a and the base-side DBR layer 903b may be doped to p-type and n-type, respectively, and thus form a portion of the anode segment and cathode segment of a pn diode structure, respectively.

[0097] Between the DBR layers 903a and 903b, the MJ-VCSEL diode 902 may have a plurality of active regions 907a, 907b, 907c (e.g., a plurality of pairs of barrier layers alternating with quantum well layers) that generate laser light when stimulated by a forward bias voltage. The plurality of active regions 907a, 907b, 907c may be interspersed with highly doped tunnel junctions 910a, 910b, 910c (similar to those described above with respect to FIG. Figure 3 310 described above) to form a vertically stacked multi-junction structure 901 in the MJ-VCSEL diode 902. One or more gain layers 911a, 911b, 911c (similar to those described above with respect to Figure 3 The gain layer 311 described above can be coupled to the tunnel junctions 910a, 910b, 910c in the multi-junction structure 901, respectively. Fig. 9A In the embodiment shown, there are three active regions 907a-907c interspersed with three tunnel junctions 910a, 910b, 910c coupled to respective ones of three gain layers 911a, 911b, 911c, but it should be noted that in other embodiments, the MJ-VCSEL diode 902 can have two or more of each type of layer forming a vertical stack between the DBR layers 903a and 903b.

[0098] Typically, in MJ-VCSEL diodes with different numbers of active regions, there is a tunnel junction between each pair of consecutive active regions. Fig. 9A As shown, in the MJ-VCSEL diode 902, there is a first tunnel junction 910a between active regions 907a and 907b, and there is a second tunnel junction 910b between active regions 907b and 907c. Optionally, the MJ-VCSEL diode 902 may also include one or more tunnel junctions at locations other than between a continuous pair of active regions 907a-907c, such as a tunnel junction 910c between an active region 907c and a RCPD 912. The tunnel junctions 910a-910c of the MJ-VCSEL diode 902 may be homogeneous or heterogeneous. Semiconductor materials that can be used for the tunnel junction layer include GaAs, Al. x Ga 1-x As、In x Ga 1-x As、In x Ga 1-x P, GaAs 1-x N x In x Ga 1-x As y P 1-yFor (0 < x ≤ 1, 0 < y < 1), and other conditions known to those skilled in the art. Depending on the polarity of the junction, the tunnel junctions 910a - 910c help improve carrier injection / extraction from the MJ-VCSEL diode 902 to the RCPD 912 and reduce the operating voltage of the photosensing device 900.

[0099] The active regions 907a - c each include a plurality of barrier layers and quantum well layers. Materials that can be used for the barrier layers of the active regions 907a - c include Al x Ga 1-x As (0 < x ≤ 1), GaAs 1-x P x (0 < x ≤ 1) and other materials known to those skilled in the art. Materials that can be used for the quantum wells of the active regions 907a - c include: In x Ga 1-x As (0 < x ≤ 1), In x Ga 1-x As y N 1-y (0 < x ≤ 1, 0 < y ≤ 1), In x Ga 1-x As 1-y-z N y Sb z (0 < x ≤ 1, 0 < y < 1, 0 < z < 1, y + z < 1) and others known to those skilled in the art.

[0100] The MJ-VCSEL diode 902 includes an emission-side (or "top") oxide layer 909a that is positioned adjacent to the topmost active region 907a or on the top surface of the MJ-VCSEL diode 902, and a base-side (or "bottom") oxide layer 909c that is positioned adjacent to the bottommost active region 907c or on the bottom surface of the MJ-VCSEL diode 902. The oxide layer 909c includes a hole (or holes) through which the main emission 940 escapes. The MJ-VCSEL diode 902 may also include an additional oxide layer 909b adjacent to the active region 907b. The oxide layers 909a and 909b each include a hole (or holes) to allow the main emission 940 to pass between the active regions 907a - 907c. Other embodiments of the MJ-VCSEL diode may have no or more than one oxide layer between consecutive active regions. The holes in the oxide layers 909a - c may allow the laser generated in the active regions 907a - 907c to enter each other and enhance the generation of the main emission 940 of the laser emitted through the photosensing device 900.

[0101] In such as Fig. 9AIn some of the illustrated embodiments, each of the active regions 907a-907c also includes a corresponding one or more gain stage layers 904 (e.g., InGaAs layers, AlGaAs layers) formed in the resonant cavity of the MJ-VCSEL diode 902 to improve the reabsorption efficiency of the main emission 940 into the MJ-VCSEL diode 902.

[0102] The MJ-VCSEL diode 902 can be formed by epitaxially growing a layer of each of the emission-side DBR layer 903a, the multi-junction structure 901, and the base-side DBR layer 903b on the substrate 908. Subsequently, the RCPD 912 is also formed on the MJ-VCSEL diode 902. In some embodiments, the RCPD 912 can include an active region 914, which can include one or more gain layers (e.g., InGaAs layers, AlGaAs layers) to improve the absorption efficiency of the modified main emission 940 after the modified main emission 940 undergoes self-mixing interference in the active regions 907a-907c of the VCSEL diode 902. As shown in FIG. Figure 4 As further described, the grating structure 320 may be vertically disposed on a set of stacked semiconductor layers forming the RCPD 912 .

[0103] The MJ-VCSEL diode 902 may have a common power contact 905a (shared with the RCPD 912) disposed on or near the base-side DBR layer 903b, a first power contact 905b disposed on or near the emission-side DBR layer 903a, and a second power contact 915a disposed on the RCPD 912. The common power contact 905a, the first power contact 905b, and the second power contact 915a may form a ring or horseshoe connection around the base-side DBR layer 903b, the emission-side DBR layer 903a, and the RCPD 912, respectively.

[0104] A bias voltage may be applied to cause the laser diode current I LD 906 flows through the MJ-VCSEL diode 902 between the common power contact 905a and the first power contact 905b to generate the main emission 940. This produces the main emission 940 directed to the target object 950 through the substrate 908 and the on-chip lens 930. At the same time, the current I flows through the RCPD 912 between the common power contact 905a and the second power contact 915a of the RCPD 912. PD 916 generates a reverse bias through the RCPD 912. One or more controllers, such as the processor 1204 described below with respect to FIG. 12, may be communicatively coupled to the photo-sensing device 900 to implement configurations for forward biasing the VCSEL diode 902 and reverse biasing the RCPD 912.

[0105] When VCSEL diode 902 is forward biased, the laser light of primary emission 940 undergoes self-mixing interference in the laser cavity of active regions 907a-c upon receiving its reflection or backscatter. RCPD 912 receives self-mixing primary emission 940 and detects the altered electrical properties of primary emission 940 when reverse biased.

[0106] The MJ-VCSEL diode 902 can emit the same current as that emitted by the single junction VCSEL (SJ-VCSEL) diode 302 ( Figure 3 The MJ-VCSEL diode 902 is shown in Figure 9A and has a laser with different characteristics emitted by the MJ-VCSEL diode 902. The MJ-VCSEL diode 902 operates at an increased voltage level (compared to the SJ-VCSEL diode 302 operating at a similar current level) and can provide multiple factors of increase in gain, such as output power. In addition, the center frequency of the emitted laser can be increased, which can improve the signal-to-noise ratio (SNR) due to reduced 1 / f noise. Due to the increased efficiency and tunable range of wavelength modulation of the emitted laser of the MJ-VCSEL diode 902, the increased SNR and higher operating frequency can also allow for improved spatial resolution of the target of the photoelectric sensing device 900 with the MJ-VCSEL diode 902, which in turn enables better measurement of electrical parameters related to self-mixing interference of the emitted laser. Therefore, the multi-junction structure 901 improves the performance of the photoelectric sensing device 900 through faster signal transmission, wider sampling, and reduced complexity.

[0107] exist Fig. 9B , the VCSEL diode 902 can be forward biased between a first bias node 992 and a common node 994, and the RCPD 912 can be reverse biased between the common node 994 and a second bias node 996. For example, the first bias node 992 can be driven to a positive voltage such as 0.2V, the common node 994 can be driven to a positive voltage such as 6V, and the second bias node 996 can be driven to a positive voltage such as 4.5V. In different embodiments, different voltage levels can be used for the first bias node 992, the common node 994, and the second bias node 996. The forward biased VCSEL diode 902 can drive a cathode load current that causes primary emission 940a-940c to be emitted from the multi-junction structure 901 having active regions 907a-907c interspersed with tunnel junctions 910a-910c. When RCPD 912 receives primary emission 940a-940c having altered properties due to self-mixing in VCSEL diode 902, reverse biasing RCPD 912 can result in the generation of a photocurrent. This photocurrent can be detected by a TIA or another readout circuit connected to second bias node 996. As discussed above, Fig. 9AThe multi-junction structure 901 in the embodiment increases the tunability of thermal resistance and wavelength modulation to better measure self-mixing interference.

[0108] FIG. 10A to FIG. 10B The RCPD (with respect to Figure 3 312) integrated with multiple sets of back-emitting VCSEL diodes (similar to the RCPD 312 described above) Figure 3 1 and 10. A cross-sectional view and corresponding schematic representation of operating circuitry for a first example photo-sensing device 1000 having a first arrangement of electrical connections between groups, similar to the VCSEL diode 302 described above, which is disposed away from the primary emission path of the VCSEL diode. As described below, the photo-sensing device 1000 has a first arrangement of electrical connections between groups.

[0109] like Fig. 10A As shown, an implantation layer 1009 is formed on the front surface 1008f of the substrate 1008, and then a stacked semiconductor layer set is deposited on the implantation layer 1009 (for example, by epitaxial deposition technology) to form a first mesa set 10101, 10102, 10103 and a second mesa set 1010 a ,1010 b ,1010 c To manufacture the photoelectric sensing device 1000. Fig. 10A In the embodiment of the present invention, a set of three mesas is shown, but each set of mesas in different embodiments may include more or fewer mesas to form a corresponding number of emitters. Each of the mesas 10101, 10102, 10103 includes a corresponding back-emitting VCSEL diode 10021, 10022, 10023 integrated with a corresponding RCPD 10121, 10122, 10123 disposed thereon. A corresponding grating structure 10201, 10202, 10203 is disposed on each of the corresponding RCPDs 10121, 10122, 10123. Each of the mesas 10101, 10102, 10103 forms a corresponding emitter #1, emitter #2, emitter #3, whereby the corresponding primary emissions 10401, 10402, 10403 are emitted by the corresponding back-emitting VCSEL diodes 10021, 10022, 10023 through the corresponding on-chip lenses 10301, 10302, 10303 arranged on the back side 1008r of the substrate 1008.

[0110] Each of the respective VCSEL diodes 10021, 10022, 10023 may include a respective active region 10071, 10072, 10073 (with respect to Figure 3The respective active regions 10071, 10072, 10073 may also include respective gain stage layers 10041, 10042, 10043 (e.g., InGaAs layers, AlGaAs layers) (not shown) to improve the absorption efficiency of the respective main emission 10401, 10402, 10403. The respective RCPDs 10121, 10122, 10123 may include respective active regions 10141, 10142, 10143, which may also include one or more gain layers (e.g., InGaAs layers, AlGaAs layers) to improve the absorption efficiency of the respective modified main emission 1040. 11040210403 after it experiences self-mixing interference in the corresponding active region 1007 11007210073 - corresponding VCSEL diode 100211002210023. One or more tunnel junctions and gain layers may be disposed between the corresponding active regions 10071, 10072, 10073 of the corresponding VCSEL diodes 10021, 10022, 10023 and the corresponding active regions 10141, 10142, 10143 of the RCPDs 10121, 10122, 10123.

[0111] When the respective VCSEL diodes 10021, 10022, 10023 are forward biased, the laser light of the respective primary emission 10401, 10402, 10403, upon receiving its reflection or backscattering, undergoes self-mixing interference in the respective active regions 10071, 10072, 10073. A respective one of the RCPDs 10121, 10122, 10123 receives the respective self-mixing primary emission 10401, 10402, 10403 and detects the altered electrical properties of the respective self-mixing primary emission 10401, 10402, 10403 when reverse biased.

[0112] In some embodiments, the first set of mesas 10101, 10102, 10103 and the second set of mesas 1010 a ,1010 b ,1010 c It can be formed by epitaxially growing a common set of semiconductor layers to form trenches 1070, 1080 to define corresponding mesas, and then electrically connecting a selected number of mesas to perform different functions or provide different wiring structures. Fig. 10A In the embodiment shown in FIG. 1 , the second table set 1010 a ,1010 b ,1010c A corresponding one of the first set of mesas 10101, 10102, 10103 is adjacent to a corresponding one of the first set of mesas 10101, 10102, 10103 and is separated by a connecting trench 1070 (e.g., formed by etching through the set of stacked semiconductor layers). a can be connected to the second group of adjacent mesas 10102, 1010 b The RCPDs 10121, 10122, 10123 are separated by isolation trenches 1080 (also formed by etching through the stacked semiconductor layer set) that cut through the implant layer 1009 and provide electrical isolation between the respective active regions 10071, 10072, 10073 of the respective VCSEL diodes 10021, 10022, 10023. A conductive layer 1060 (e.g., gold, copper) is disposed on each of the grating structures 10201, 10202, 10203 on each of the respective RCPDs 10121, 10122, 10123 and is wired on the second mesa set 1010. a ,1010 b ,1010 c Each of the to provide electrical connections across the mesa set.

[0113] Each of the respective mesas 10101, 10102, 10103 includes a common power contact 10051, 10052, 10053 shared between the corresponding VCSEL diode 10021, 10022, 10023 and the corresponding RCPD 10121, 10122, 10123 disposed thereon. Fig. 10A As shown, applying a bias voltage through the corresponding common power contacts 10051, 10052, 10053 can produce a forward bias (current I LD 10061, 10062, 10063) to generate the corresponding main emission 10401, 10402, 10403 directed to the target object 1050 through the substrate 1008 and the corresponding on-chip lenses 10301, 10302, 10303. At the same time, the reverse bias (current I PD10161, 10162, 10163) facilitates the altered properties of the primary emissions 10401, 10402, 10403 due to the detection of self-mixing interference in the respective active regions 10071, 10072, 10073 of the respective VCSEL diodes 10021, 10022, 10023. One or more controllers (such as the processor 1204 described below with respect to FIG. 12) may be communicatively coupled to the photo-sensing device 1000 to implement configurations for forward biasing the respective VCSEL diodes 10021, 10022, 10023 and reverse biasing the respective RCPDs 10121, 10122, 10123.

[0114] The specific arrangement of electrical connections in the optoelectronic sensing device 1000 with the conductive layer 1160 enables individual addressability of each emitter formed by a respective one of the mesas 10101, 10102, 10103. As a result, any selection of one or more emitters (emitter #1, emitter #2, emitter #3) can be used as a sensor for detecting the distance, motion of a target object 1050 using self-mixing interference captured by respective back-emitting VCSEL diodes 10021, 10022, 10023 integrated with respective RCPDs 10121, 10122, 10123 disposed thereon.

[0115] like Fig. 10BAs shown, each of the back emitting VCSEL diodes 10021, 10022, 10023 can be forward biased between a first bias node 1092 and a common node 1094 (through a common power supply contact 10051, 10052, 10053), while the corresponding RCPD 10121, 10122, 10123 can be reverse biased between the common node 1094 and a second bias node 1096. The first bias node 1092 and the common node 1094 can have different positive voltages so that the corresponding VCSEL diodes 10021, 10022, 10023 are driven by a cathode load current that causes the corresponding primary emitters 10401, 10402, 10403 to emit therefrom. The second bias node 1096 and the common node 1094 may also have different positive voltages, whereby the respective RCPDs 10121, 10122, 10123 are reverse biased such that a photocurrent is generated when the respective RCPDs 10121, 10122, 10123 receive the respective primary emission 10401, 10402, 10403 having altered properties due to self-mixing in the VCSEL diodes 10021, 10022, 10023. The photocurrent may be detected by a TIA connected to the second bias node 1096. As described above, this arrangement enables addressability of individual emitters formed by respective back-emitting VCSEL diodes 10021, 10022, 10023 integrated with respective RCPDs 10121, 10122, 10123 disposed thereon.

[0116] FIG. 11A to FIG. 11B A cross-sectional view and a corresponding schematic representation of an operating circuit of a second example photoelectric sensing device 1100 are shown, respectively, the second example photoelectric sensing device having a RCPD (with respect to Figure 3 312) integrated with multiple sets of back-emitting VCSEL diodes (similar to the RCPD 312 described above) Figure 3 The photoelectric sensing device 1100 has a first arrangement of electrical connections between the plurality of sets, similar to the VCSEL diode 302 described above, which is disposed away from the main emission path of the VCSEL diode. As described below, the photoelectric sensing device 1100 has a first arrangement of electrical connections between the plurality of sets.

[0117] like Fig.11A As shown, an implantation layer 1109 is formed on the front surface 1108f of the substrate 1108, and then a stacked semiconductor layer set is deposited on the implantation layer 1109 (for example, by epitaxial deposition technology) to form a first mesa set 11101, 11102, 11103 and a second mesa set 1110 a ,1110 b ,1110 c To manufacture the photoelectric sensing device 1100. Fig.11A In the embodiment of the present invention, a set of three mesas is shown, but each set of mesas in different embodiments may include more or fewer mesas to form a corresponding number of emitters. Each of the mesas 11101, 11102, 11103 includes a corresponding back-emitting VCSEL diode 11021, 11022, 11023 integrated with a corresponding RCPD 11121, 11122, 11123 disposed thereon. A corresponding grating structure 11201, 11202, 11203 is disposed on each of the corresponding RCPDs 11121, 11122, 11123. Each of the mesas 11101, 11102, 11103 forms a corresponding emitter #1, emitter #2, emitter #3, whereby the corresponding primary emissions 11401, 11402, 11403 are emitted by the corresponding back-emitting VCSEL diodes 11021, 11022, 11023 through the corresponding on-chip lenses 11301, 11302, 11303 arranged on the back side 1108r of the substrate 1108.

[0118] Each of the respective VCSEL diodes 11021, 11022, 11023 may include a respective active region 11071, 11072, 11073 (with respect to Figure 3 The active region 307 described above is similar to the active region 307 described above) (not shown), which may include one or more quantum wells and may be adjacent to a corresponding oxide layer (not shown) having a hole through which the corresponding main emission 11401, 11402, 11403 escapes. The corresponding active region 11071, 11072, 11073 may also include a corresponding gain stage layer 11041, 11042, 11043 (e.g., an InGaAs layer, an AlGaAs layer) (not shown) to improve the absorption efficiency of the corresponding main emission 11401, 11402, 11403. The respective RCPDs 11121, 11122, 11123 may include respective active regions 11141, 11142, 11143, which may further include one or more gain layers (e.g., InGaAs layers, AlGaAs layers) to improve the absorption efficiency of the respective modified primary emission 11401, 11402, 11403 after self-mixing interference in the active regions 11071, 11072, 11073 of the respective VCSEL diodes 11021, 11022, 11023. The one or more tunnel junctions and gain layers may be disposed between the respective active regions 11071, 11072, 11073 of the respective VCSEL diodes 11021, 11022, 11023 and the respective active regions 11141, 11142, 11143 of the RCPDs 11121, 11122, 11123.

[0119] When the respective VCSEL diodes 11021, 11022, 11023 are forward biased, the laser light of the respective primary emission 11401, 11402, 11403, upon receiving its reflection or backscattering, undergoes self-mixing interference in the respective active regions 11071, 11072, 11073. A respective one of the RCPDs 11121, 11122, 11123 receives the respective self-mixing primary emission 11401, 11402, 11403 and, when reverse biased, detects the altered electrical properties of the respective self-mixing primary emission 11401, 11402, 11403.

[0120] In some embodiments, the first set of mesas 11101, 11102, 11103 and the second set of mesas 1110 a ,1110 b ,1110 c It can be formed by epitaxially growing a common set of semiconductor layers, forming trenches 1170, 1180 to define corresponding mesas, and then electrically connecting a selected number of mesas to perform different functions or provide different wiring structures. Fig. 10A In the embodiment shown, the second table set 1110 a ,1110 b ,1110 c A corresponding one of the mesas in the first set of mesas 11101, 11102, 11103 is adjacent to a corresponding one of the mesas in the second set of mesas 11101, 11102, 11103 and is separated by a photodetector trench 1170 (e.g., formed by etching through the stacked set of semiconductor layers) that provides electrical connection to the back end of a corresponding one of the RCPDs 11121, 11122, 11123. In addition, the first set of adjacent mesas 11101, 11102, 11103 are separated by a photodetector trench 1170 (e.g., formed by etching through the stacked set of semiconductor layers). a The second group of adjacent mesas 11102 and 1110 can be connected by oxidation trench 1180. b Separation (also formed by etching through the stacked semiconductor layer set), the oxide trench provides electrical isolation between the respective active regions 11071, 11072, 11073 of the respective VCSEL diodes 11021, 11022, 11023. The respective grating structures 11201, 11202, 11203 on each of the respective RCPDs 11121, 11122, 11123 and on the second mesa set 1110 a ,1110 b ,1110 c A conductive layer 1160 (eg, gold, copper) is disposed on each of the mesas to provide electrical connections across the set of mesas.

[0121] The photoelectric sensing device 1100 includes a common power contact 1105 disposed on the injection layer 1109 and shared by the corresponding back-emitting VCSEL diodes 11021, 11022, 11023 and the corresponding RCPDs 11121, 11122, 11123 disposed thereon. Fig.11A As shown, the bias voltage applied through the common power contact 1105 can produce a forward bias (current I LD 11061, 11062, 11063) to generate respective primary emissions 11401, 11402, 11403 directed toward target object 1150 through substrate 1108 and respective on-chip lenses 11301, 11302, 11303. At the same time, a reverse bias (current I PD 11161, 11162, 11163) facilitates the altered nature of the primary emissions 11401, 11402, 11403 due to the detection of self-mixing interference in the respective active regions 11071, 11072, 11073 of the respective VCSEL diodes 11021, 11022, 11023. One or more controllers, such as the processor 1204 described below with respect to FIG. 12, may be communicatively coupled to the photo-sensing device 1100 to implement configurations for forward biasing the respective VCSEL diodes 11021, 11022, 11023 and reverse biasing the respective RCPDs 11121, 11122, 11123.

[0122] The specific arrangement of electrical connections in the optoelectronic sensing device 1100 with the conductive layer 1160 enables individual addressability of each emitter formed by a respective one of the mesas 11101, 11102, 11103. As a result, any selection of one or more emitters (emitter #1, emitter #2, emitter #3) can be used as a sensor for detecting the distance, motion of a target object 1150 using self-mixing interference captured by respective back-emitting VCSEL diodes 11021, 11022, 11023 integrated with respective RCPDs 11121, 11122, 11123 disposed thereon.

[0123] like Fig. 11BAs shown, each of the back emitting VCSEL diodes 11021, 11022, 11023 can be forward biased (through a common power contact 1105) between a first bias node 1192 and a common node 1194, while the corresponding RCPD 11121, 11122, 11123 can be reverse biased between the first bias node 1192 and the second bias node 1196. The first bias node 1192 and the common node 1194 can have different positive voltages so that the corresponding VCSEL diodes 11021, 11022, 11023 are driven by a cathode load current that causes the corresponding primary emitters 11401, 11402, 11403 to emit therefrom. The first bias node 1192 and the second bias node 1196 may also have different positive voltages, whereby the respective RCPDs 11121, 11122, 11123 are reverse biased such that a photocurrent is generated when the respective RCPDs 11121, 11122, 11123 receive the respective primary emission 11401, 11402, 11403 having altered properties due to self-mixing in the VCSEL diodes 11021, 11022, 11023. The photocurrent may be detected by a TIA connected to the second bias node 1196. As discussed above, this arrangement enables addressability of individual emitters formed by the respective back-emitting VCSEL diodes 11021, 11022, 11023 integrated with the respective RCPDs 11121, 11122, 11123 disposed thereon.

[0124] FIG. 12A to FIG. 12B A cross-sectional view and corresponding schematic representation of operating circuitry of a second example photo-sensing device 1200 having an extended resonant cavity in the emitting side of a back-emitting MJ-VCSEL diode and integrated with an RCPD, as described herein, are shown, respectively. FIG. 12A to FIG. 12B The second example of the photoelectric sensing device 1200 shown and described can have improved performance. In particular, the photoelectric sensing device 1200 can have a relatively more stable polarization and be more stable in the optical mode than other photoelectric sensing devices. In some cases, the photoelectric sensing device 1200 can have a relatively higher signal strength for the RCPD output signal compared to other photoelectric sensing devices.

[0125] The extended resonant cavity of the photoelectric sensing device 1200 extends from the RCPD to the OCL 1230 formed on the back side 1208r of the substrate 1208 and includes the substrate 1208. In particular, Fig. 12AA back emitting MJ-VCSEL diode 1202 is shown integrated with a RCPD 1212 disposed in the path of a primary emission 1240 of laser light from the MJ-VCSEL diode 1202 in forward bias. The RCPD 1212 receives the modified primary emission 1240 from the MJ-VCSEL diode 1202 after the primary emission 1240 undergoes self-mixing interference upon receiving reflection or backscattering.

[0126] The photoelectric sensing device 1200 is manufactured by first forming a substrate 1208 (e.g., a low-loss semiconductor or dielectric material) with an extended cavity, forming an RCPD 1212 on the front side 1208f of the substrate, and then depositing a stacked semiconductor layer set on the RCPD 1212 to form an MJ-VCSEL diode 1202 with a multi-junction structure. As discussed above, the extended resonant cavity significantly reduces the laser line width and extends the laser coherence length required for remote sensing. The OCL 1230 is disposed on the back side 1208r of the substrate 1208 and is configured to collimate the laser emitted by the VCSEL diode 1202 and collect the laser returned from the target object toward the first active region in the VCSEL diode 1202 and the RCPD 1212. A reflective coating 1235 made of a dielectric material may be disposed on the OCL 1230. In other examples, a dielectric (multilayer) DBR may be disposed on the OCL 1230 to form a reflector for the extended resonant cavity.

[0127] In some examples, OCL 1230 can be formed by etching substrate 1208 to produce a curved mirror. For example, OCL 1230 can be formed using grayscale lithography, or OCL 1230 can be formed using reflowed photoresist. In other examples, OCL 1230 can be formed from a dielectric material by a reflow process. In some examples, OCL 1230 can be a dielectric material or an organic material.

[0128] In some examples, a reflective coating may be deposited on the OCL 1230 to form a reflector for the extended cavity of the optoelectronic sensing device 1200. In other examples, a dielectric (multilayer) DBR structure may be deposited on the OCL 1230 to form a reflector for the extended cavity of the optoelectronic sensing device 1200.

[0129] The photoelectric sensing device 1200 may include an emission side (or "top side") DBR layer 1203a, which includes a set of pairs of alternating materials (e.g., AlGaAs, GaAs) having different refractive indices. Additionally, the MJ-VCSEL diode 1202 may also include a base side DBR layer 1203b, which also includes a set of Bragg pairs of alternating materials (e.g., AlAs, GaAs) having different refractive indices. One or more materials in the emission side DBR layer 1203a and the base side DBR layer 1203b may be doped to p-type and n-type, respectively, and thus form a portion of the anode segment and cathode segment of the pn diode structure, respectively.

[0130] The MJ-VCSEL diode 1202 may have multiple active regions 1207a, 1207b, 1207c (e.g., multiple pairs of barrier layers alternating with quantum well layers) that generate laser light when stimulated by a forward bias voltage. The multiple active regions 1207a, 1207b, 1207c may be interspersed with highly doped tunnel junctions 1210a and 1210b (similar to those described above with respect to FIG. Figure 3 12) to form a vertically stacked multi-junction structure in the MJ-VCSEL diode 1202. One or more gain layers 1211a, 1211b (similar to those described above with respect to Figure 3 The gain layer 311 described above can be coupled to the tunnel junctions 1210a, 1210b in the multi-junction structure in the MJ-VCSEL diode 1202, respectively. Fig. 12A In the embodiment shown, there are three active regions 1207a-1207c interspersed with two tunnel junctions 1210a, 1210b coupled to respective ones of the two gain layers 1203a, 1203b, but it should be noted that in other embodiments, the MJ-VCSEL diode 1202 can have two or more than three of each type of layer forming a vertical stack between the DBR layers 1211a and 1211b.

[0131] Typically, in MJ-VCSEL diodes with different numbers of active regions, there is a tunnel junction between each pair of consecutive active regions. Fig. 12AAs shown, in the MJ-VCSEL diode 1202, there is a first tunnel junction 1210a between the active regions 1207a and 1207b, and a second tunnel junction 1210b between the active regions 1207b and 1207c. Optionally, the MJ-VCSEL diode 902 may also include one or more tunnel junctions (not shown) at positions other than between a consecutive pair of active regions 1207a - 1207c. The tunnel junctions 1210a, 1210b of the MJ-VCSEL diode 1202 can be homogenous or heterogenous. Semiconductor materials that can be used for the tunnel junction layer include GaAs, Al. x Ga 1-x As, In x Ga 1-x As, In x Ga 1-x P, GaAs 1-x N x In x Ga 1- x As y P 1-y For (0 < x ≤ 1, 0 < y < 1), and other cases known to those skilled in the art. Depending on the polarity of the junction, the tunnel junctions 1210a, 1210b can help improve carrier injection / extraction from the MJ-VCSEL diode 1202 to the RCPD 1212, and reduce the operating voltage of the photoelectric sensing device 1200.

[0132] The active regions 1207a - 1207c respectively contain multiple barrier layers and quantum well layers. Materials that can be used for the barrier layers of the active regions 1207a - 1207c include Al x Ga 1-x As (0 < x ≤ 1), GaAs 1-x P x (0 < x ≤ 1) and other materials known to those skilled in the art. Materials that can be used for the quantum wells of the active regions 1207a - 1207c include: In x Ga 1-x As (0 < x ≤ 1), In x Ga 1-x As y N 1-y (0 < x ≤ 1, 0 < y ≤ 1), In x Ga 1-x As 1-y-z N y Sb z (0 < x ≤ 1, 0 < y < 1, 0 < z < 1, y + z < 1) and others known to those skilled in the art.

[0133] The MJ-VCSEL diode 1202 includes an emission side (or "top") oxide layer 1209a, which is positioned adjacent to the topmost active region 1207a or on the top surface of the MJ-VCSEL diode 1202, and a base side (or "bottom") oxide layer 1209c, which is positioned adjacent to the bottommost active region 1207c or on the bottom surface of the MJ-VCSEL diode 1202. The oxide layer 1209c includes a hole (or multiple holes) through which the main emission 1240 escapes. The MJ-VCSEL diode 1202 may also include an additional oxide layer 1209b adjacent to the active region 1207b. The oxide layers 1209a and 1209b each include a hole (or multiple holes). To allow the main emission 1240 to pass between the active regions 1207a-1207c. Other embodiments of the MJ-VCSEL diode may have no or more than one oxide layer between consecutive active regions. The holes in the oxide layers 1209 a - 1209 c may allow laser light generated in the active regions 1207 a - 1207 c to enter each other and enhance the generation of a primary emission 1240 of laser light emitted by the photo-sensing device 1200 .

[0134] In such Fig. 12A In some of the illustrated embodiments, each of the active regions 1207a, 1207b, 1207c also includes corresponding one or more gain stage layers 1204a, 1204b, 1204c (e.g., InGaAs layers, AlGaAs layers) formed in the resonant cavity of the MJ-VCSEL diode 1202 to improve the reabsorption efficiency of the main emission 1240 into the MJ-VCSEL diode 1202.

[0135] The emission side DBR layer 1203a and then the RCPD 1212 may be formed by epitaxially growing these layers on the substrate 1208, including the front side 1208f of the substrate 1208. Subsequently, the MJ-VCSEL diode 1202 may be formed by epitaxially growing on the RCPD 1212. The base side DBR layer 1203b may be formed by epitaxially growing on the MJ-VCSEL diode 1202.

[0136] In some embodiments, the RCPD 1212 may include an active region 1214, which may include one or more gain layers (e.g., InGaAs layers, AlGaAs layers) to improve the absorption efficiency of the modified main emission 1240 after it undergoes self-mixing interference in the active regions 1207a-1207c of the VCSEL diode 902.

[0137] The MJ-VCSEL diode 1202 may have a common power contact 1205a (shared with the RCPD 1212) disposed on or near the RCPD 1212, a first power contact 1205b disposed on or near the emission-side DBR layer 1203a, and a second power contact 1215a disposed on or near the base-side DBR layer 1203b. The common power contact 1205a, the first power contact 1205b, and the second power contact 1215a may form a ring or horseshoe connection around the base-side DBR layer 1203b, the emission-side DBR layer 903a, and the RCPD 912, respectively.

[0138] As the applied laser diode voltage V LD As a result, a bias voltage can be applied so that the laser diode current I LD 1216 flows through the MJ-VCSEL diode 1202 between the common power contact 1205a and the second power contact 1215a to generate the main emission 1240. This produces the main emission 1240 directed to the target object (not shown) through the substrate 1208 and the OCL 1230. At the same time, as the applied photodiode voltage V PD As a result, the current I flowing through the RCPD 1212 between the common power contact 1205a and the first power contact 1205b of the RCPD 1212 is PD 1206 generates a reverse bias through RCPD 1212. One or more controllers, such as the following about Fig.21 The processor 2104 is depicted as being communicatively coupled to the photo-sensing device 1200 to implement configurations for forward biasing the VCSEL diode 1202 and reverse biasing the RCPD 1212 .

[0139] When VCSEL diode 1202 is forward biased, the laser light of primary emission 1240 undergoes self-mixing interference in the laser cavity of active regions 1207a-1207c upon receiving its reflection or backscatter. RCPD 1212 receives the self-mixed primary emission 1240 and detects the altered electrical properties of primary emission 1240 when reverse biased.

[0140] The MJ-VCSEL diode 1202 can emit the same current as that emitted by a single junction VCSEL (SJ-VCSEL) diode 302 ( Figure 3The MJ-VCSEL diode 1202 is a laser diode having laser light with different characteristics than the SJ-VCSEL diode 302 (shown in FIG. 1 ). The MJ-VCSEL diode 1202 operates at an increased voltage level (compared to the SJ-VCSEL diode 302 operating at a similar current level) and can provide multiple factors of increase in gain, such as output power. In addition, the center frequency of the emitted laser light can be increased, which can improve the SNR due to reduced 1 / f noise. Due to the increased efficiency and tunable range of wavelength modulation of the emitted laser light of the MJ-VCSEL diode 1202, the increased SNR and higher operating frequency can also allow for improved spatial resolution of the target of the photoelectric sensing device 1200 having the MJ-VCSEL diode 1202, which in turn enables better measurement of electrical parameters related to self-mixing interference of the emitted laser light. Therefore, the multi-junction structure in the MJ-VCSEL diode 1202 improves the performance of the photoelectric sensing device 1200 through faster signal transmission, wider sampling, and reduced complexity.

[0141] exist Fig. 12B , the VCSEL diode 1202 can be forward biased between the first bias node 1292 and the common node 1294, and the RCPD 1212 can be reverse biased between the common node 1294 and the second bias node 1296. For example, the first bias node 1292 can be driven to a positive voltage, the common node 1294 can be driven to a lower positive voltage (e.g., ground), and the second bias node 1296 can also be driven at a positive voltage. In different embodiments, different voltage levels can be used for the first bias node 2392, the common node 1294, and the second bias node 1296. The forward biased VCSEL diode 902 can drive a cathode load current that causes the primary emission 940a-940c to be emitted from the multi-junction structure 1201 having active regions 1207a-1207c interspersed with tunnel junctions 1210a-1210c. When RCPD 1212 receives primary emissions 1240a-1240c having altered properties due to self-mixing in VCSEL diode 1202, reverse biasing RCPD 1212 can result in the generation of a photocurrent. The photocurrent can be detected by a TIA or another readout circuit connected to second bias node 1296. As discussed above, Fig. 12A The multi-junction structure 1201 in the embodiment increases the tunability of thermal resistance and wavelength modulation to better measure self-mixing interference.

[0142] Fig.13A A photoelectric sensing device (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A perspective view of a first example collection of optoelectronic sensing devices shown and described. Fig.13AAn example is generally depicted in which a collection of photo-sensing devices 1320 (a block of photo-sensing devices) share common photodiode block contacts and common block contacts, and each photo-sensing device has an individual (eg, addressable) power contact for a VCSEL diode.

[0143] The first example set of photo-sensing devices depicts eight examples of photo-sensing devices 1320 arranged in two rows and four columns. Each photo-sensing device 1320 may be an example of photo-sensing device 1200.

[0144] Each photo sensing device 1320 has an associated power contact 1316. The power contact 1316 is a conductive material (e.g., a p-contact) that is electrically coupled to a first bias node of the VCSEL of the photo sensing device 1320. In some examples, the power contact 1316 is an example of the first bias node 1292 and / or the second power contact 1215a.

[0145] The collection of photo-sensing devices share a common contact 1312 for the group block. The common contact 1312 is a conductive material that is electrically coupled to both the node of the VCSEL and the node of the RCPD, such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B More particularly described. In some examples, common contact 1312 is an example of common node 1294 and / or common power contact 1205a.

[0146] The collection of photo-sensing devices share a common photodiode contact 1314 for the group. The common photodiode contact 1314 is a conductive material (eg, an n-contact) that is electrically coupled to a node of the RCPD, such as a reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B In some examples, common photodiode contact 1314 is an example of second bias node 1296 and / or first power supply contact 1205b.

[0147] The common contact 1312, the common photodiode contact 1314, and the power contact 1316 are configured and oriented to be accessible to contact with a conductor, thereby providing an electrical signal to and from a contact of another device to which the photoelectric sensing device can be bonded. As further described herein, the first side of the collection of photoelectric sensing devices is the light emitting surface of the device, and the first side is on the opposite side of the common contact 1312, the common photodiode contact 1314, and the power contact 1316. In some specific implementations, this arrangement of contacts can provide contacts to a two-dimensional addressable point set, such as from a driver for the photoelectric sensing device. In some cases, wire bonds and pads outside the array can be reduced or eliminated as a result. Additionally, the number of emitters per array can be increased, and large arrays of emitters can be utilized.

[0148] Fig. 13B Shown through Fig.13A 13. A cross-sectional view of cross-section A of FIG. As shown, the layers of the photo-sensing device 1320 are generally electrically coupled to a common contact 1312, a common photodiode contact 1314, and a power contact 1316. The common contact 1312 may form a ring around a central portion of the photo-sensing device 1320.

[0149] Fig.14 A top view of an example sense array 1400 including a set of photo-sensing devices 1410 is shown. Fig.14 An example die architecture including an array of photo-sensing devices is generally depicted, wherein each set (or block) of photo-sensing devices shares common contacts and common photodiode contacts.

[0150] The set of photoelectric sensing devices 1410 may be a reference FIG. 13A to FIG. 13B An example of a collection of photo-sensing devices shown and described. Common contact 1412, common photodiode contact 1414, and power contact 1416 associated with photo-sensing device 1420 may be examples of common contact 1312, common photodiode contact 1314, and power contact 1316 associated with photo-sensing device 1320. Photo-sensing device 1410 may be part of a larger block 1402 of photo-sensing devices.

[0151] In some examples, the sensing array 1400 can be a single die. The sensing array 1400 includes twenty-eight of thirty-two blocks 1402 of photo-sensing devices arranged in a set of fourteen rows 1404 and two columns (including a first column 1406 and a second column 1408). Each block 1402 (a block of photo-sensing devices) shares a common contact 1412 and a common photodiode contact 1414, and each photo-sensing device 1420 has a separate (e.g., addressable) power contact 1416 for a VCSEL diode.

[0152] As further described above, the contacts of the sense array 1400 are on the face opposite the light emitting face of the device and are configured and oriented to be accessible for contact with another device (such as a driver). Each photo-sensing device 1420 can have a width 1422 and a length 1424, including an area for the photo-sensing device 1420. Because a block of photo-sensing devices 1420 can share a single contact in the common contacts 1412 and a single contact in the common photodiode contacts 1414, the area of ​​the block 1402 can be reduced relative to other photo-sensing device architectures. For example, an architecture of a sense array with an equal number of photo-sensing devices, in which the contacts are routed to the periphery of the die, can result in a larger area than the area of ​​the sense array 1400. Similarly, an architecture of a sense array with an equal number of photo-sensing devices, in which three contacts are provided for each photo-sensing device, can also result in a larger area than the area of ​​the sense array 1400.

[0153] Fig.15A A second example set of photoelectric sensing devices (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B A perspective view of a collection of optoelectronic sensing devices shown and described. Fig.15A An example is generally depicted in which each photo-sensing device 1520 has an isolated photodiode. That is, each photodiode can be individually addressed and read out, for example, as described in reference FIG. 13A to FIG. 14 The blocks of photodiodes shown and described for common readout are reversed.In addition, each photo-sensing device 1520 has a separate (eg, addressable) power contact for the VCSEL diode.

[0154] The first example set of photo-sensing devices depicts six examples of photo-sensing devices 1520 arranged in two rows and three columns. Each photo-sensing device 1520 can be an example of photo-sensing device 1200. In some examples, each photo-sensing device 1520 can be isolated from adjacent photo-sensing devices 1520 by a trench structure (e.g., an insulating trench). Each photo-sensing device 1520 can be an example of photo-sensing device 1200.

[0155] Each photo sensing device 1520 has an associated power contact 1516. The power contact 1516 is a conductive material (e.g., a p-contact) electrically coupled to a first bias node of the VCSEL of the photo sensing device 1520. In some examples, the power contact 1516 is an example of the first bias node 1292 and / or the second power contact 1215a.

[0156] Each photo-sensing device 1520 also has an associated common contact 1512. The common contact 1512 is a conductive material electrically coupled to a node of the VCSEL and a node of the RCPD, such as a reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B In some examples, common contact 1512 is an example of common node 1294 and / or common power contact 1205a.

[0157] Each photo-sensing device 1520 also has an associated photodiode contact 1514. The photodiode contact 1514 is a conductive material (eg, an n-contact) electrically coupled to a node of the RCPD, as shown in FIG. FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B In some examples, the photodiode contact 1514 is an example of the second bias node 1296 and / or the first power contact 1205b.

[0158] The common contact 1512, the photodiode contact 1514, and the power contact 1516 are configured and oriented to be accessible to contact with a conductor to provide an electrical signal to and from a contact of another device to which the photoelectric sensing device can be bonded. As further described herein, the first side of the set of photoelectric sensing devices is the light emitting side of the device, and the first side is on the opposite side of the common contact 1512, the photodiode contact 1514, and the power contact 1516. In some specific implementations, this arrangement of contacts can provide contacts to a two-dimensional addressable point set, such as from a driver for the photoelectric sensing device. In some cases, wire bonds and pads outside the array can be reduced or eliminated as a result. Additionally, the number of emitters per array can be increased, and large arrays of emitters can be utilized.

[0159] Fig. 15B Shown through Fig.15A 15. A cross-sectional view of cross-section B of FIG. As shown, the layers of the photo-sensing device 1520 are generally electrically coupled to a common contact 1512, a common photodiode contact 1514, and a power contact 1516. The common contact 1512 may form a ring around a central portion of the photo-sensing device 1520.

[0160] Fig.16 Shown is a reference Figures 15A to 15B A top view of an example sensing array 1600 of a photo-sensing device is shown and described. Fig.15A An example die architecture including an array of photo-sensing devices where three contacts of each photo-sensing device are individually accessible is generally depicted.

[0161] The photoelectric sensing device 1620 may be a reference FIG. 15A to FIG. 15BAn example of a photo-sensing device 1520 is shown and described. The common contact 1612, the common photodiode contact 1614, and the power contact 1616 associated with the photo-sensing device 1520 may be examples of the common contact 1512, the common photodiode contact 1514, and the power contact 1516 associated with the photo-sensing device 1520. The photo-sensing device 1620 may be part of a larger sense array 1600.

[0162] In some examples, the sensing array 1600 can be a single die. The sensing array 1300 includes thirty optical sensing devices arranged in a set of five rows 1601 and six columns 1606. Each optical sensing device has individual (e.g., addressable) contacts, including a common contact 1612, a common photodiode contact 1614, and a power contact 1616.

[0163] As further described above, the contacts of the sense array 1600 are on the face opposite the light emitting face of the device and are configured and oriented to be accessible for contact with another device (such as a driver). Each photo-sensing device 1620 can have a width 1622 and a length 1624, including an area for the photo-sensing device 1620. Because the photo-sensing devices 1420 can be directly accessed from an attached device (e.g., a driver chip), the area of ​​the sense array 1600 can be reduced relative to other photo-sensing device architectures. For example, an architecture of a sense array with an equal number of photo-sensing devices in which the contacts are routed to the periphery of the die can result in a larger area than the area of ​​the sense array 1600.

[0164] Fig.17 A photoelectric sensing device (eg, reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B 1700. The photoelectric sensing device 1710 may be a top view of a first example layout 1700 of a photoelectric sensing device as shown and described in the drawings. FIG. 9A to FIG. 9B , FIG. 12A to FIG. 12B , FIG. 15A to FIG. 16 An example of one of the photoelectric sensing devices shown and described. Fig.17 An example layout of an example of a photo-sensing device is generally depicted in which common contact 1712 and photodiode contact 1714 each form a ring around a central portion of photo-sensing device 1710. Photo-sensing device 1710 may have an area defined by length 1722 and width 1724.

[0165] The common contact 1712, the photodiode contact 1714, and the power contact 1716 associated with the photo-sensing device 1710 may be examples of common contacts, common photodiode contacts, and power contacts associated with another photo-sensing device described herein, such as the common contact 1512, common photodiode contact 1514, and power contact 1516 associated with the photo-sensing device 1520. The photo-sensing device 1520 may be formed as part of a larger sensing array, such as the sensing array 1600.

[0166] The common contacts 1712 may generally form a first ring around the power contacts 1716 of the photo-sensing devices 1710. A portion of the common contacts 1712 may extend away from the power contacts 1716 and be exposed so that the common contacts may contact a conductor to form an electrical connection (e.g., to a chip driver to be bonded to an array of photo-sensing devices 1710). The unexposed portions of the common contacts 1712 (e.g., including the ring portions closest to the power contacts 1716) may be covered with a dielectric to protect the contacts and prevent short circuits.

[0167] Similarly, the photodiode contacts 1714 can generally form a second ring around the common contact 1712 and the first ring of power contacts 1716 for the photo-sensing device 1710. A portion of the photodiode contacts 1714 can extend away from the power contacts 1716 and be exposed so that the common contact can contact the conductor to form an electrical connection. The unexposed portions of the photodiode contacts 1714 (e.g., the ring portions including the first ring closest to the common contact 1712 and the power contacts 1716) can be covered with a dielectric to protect the contacts and prevent short circuits.

[0168] Fig.18 A photoelectric sensing device (such as reference FIG. 9A to FIG. 9B or FIG. 12A to FIG. 12B 00100 is a top view of a second example layout 1800 of an optoelectronic sensing device as shown and described herein. Fig.18 An example layout of an example of a photo-sensing device is generally depicted in which the common contact 1712 forms a first half of a ring around a central portion of the photo-sensing device 1810, and the photodiode contact 1714 forms a second half of a ring around a central portion of the photo-sensing device 1810. In some examples, the first half of the ring and the second half of the ring can be in the same plane. In other examples, at least a portion of the first half of the ring can be in a different plane than at least a portion of the second half of the ring.

[0169] Common contact 1712, photodiode contact 1714, and power contact 1716 associated with photo-sensing device 1810 may be examples of common contacts, common photodiode contacts, and power contacts associated with another photo-sensing device described herein.Photo-sensing device 1820 may be formed as part of a larger sensing array.

[0170] The common contact 1712 can generally form a first half of a ring around the power contact 1716 of the photoelectric sensing device 1810. A portion of the common contact 1712 can extend away from the power contact 1716 and be exposed so that the common contact can contact the conductor to form an electrical connection. The unexposed portion of the common contact 1712 (e.g., the first half of the ring portion including the closest to the power contact 1716) can be covered with a dielectric to protect the contact and prevent short circuits.

[0171] Similarly, the photodiode contact 1714 can generally form a second half of a ring around the power contact 1716 of the photo-sensing device 1810. A portion of the photodiode contact 1714 can extend away from the power contact 1716 and be exposed so that the common contact can contact the conductor to form an electrical connection. The unexposed portion of the photodiode contact 1714 (e.g., the second half of the ring portion including the closest to the power contact 1716) can be covered with a dielectric to protect the contact and prevent short circuits.

[0172] The photo-sensing device 1810 can have an area defined by a length 1822 and a width 1824. One or both of the length 1822 or the width 1824 of the photo-sensing device 1810 can be less than the length 1722 or the width 1724 of the photo-sensing device 1710 for an otherwise similar or equivalent photo-sensing device. In general, the single split ring structure shown and described with reference to the photo-sensing device 1810 can have a relatively smaller area (e.g., and relatively higher density) than the two ring structures shown and described with reference to the photo-sensing device 1710.

[0173] Although the second example layout 1800 shows a first half of the ring for the common contact 1712 and a second half of the ring for the photodiode contact 1714, the ring can be divided according to different ratios. For example, the contact area of ​​the photo-sensing device 1810 can be adjusted by changing the relative contact area, such as by contacting one or the other contact between the common contact 1712 and the photodiode contact 1714 by a larger or smaller amount than half of the ring.

[0174] Fig.19 Shown is a reference Fig.18 A top view of a first array 1900 of a second example layout of opto-sensing devices is shown and described. Fig.19 A square or rectangular pattern (eg, a grid or array) of photo-sensing devices 1810 is generally depicted, where a unit area is based on a width 1922 and a length 1924. The photo-sensing devices 1810 may be as shown and described with reference to the second example layout 1800.

[0175] Fig. 20 Shown is a reference Fig.18 A top view of a second array 2000 of a second example layout of opto-sensing devices is shown and described. Fig. 20 A hexagonal pattern (eg, a grid or array) of photo-sensing devices (including photo-sensing device 2010 and photo-sensing device 2020 ) is generally depicted, where a unit area is based on a width 2022 and a length 2024 .

[0176] The photo-sensing device 2010 and the photo-sensing device 2020 can be similar to the photo-sensing device 1810 in the second example layout 1800, but have some differences. In particular, the photo-sensing device 2010 can include the same central portion and an open ring around the central portion, including a first half of the ring portion closest to the power contact 1716 and a second half of the ring portion closest to the power contact 1716. However, the portion of the common contact 1712 extending away from the power contact 1716 and the portion of the photodiode contact 1714 extending away from the power contact 1716 can be at different locations for the photo-sensing device 2010. In particular, these portions can be generally configured to allow for a hexagonal pattern for the second array 2000. In some examples, the layout of the photo-sensing device 2010 is the same as the layout of the photo-sensing device 2020, but rotated 180 degrees. In other examples, the locations of the common contact 1712 and the photodiode contact 1714 for the photo-sensing device 2020 may be different (eg, swapped) for the photo-sensing device 2010 .

[0177] In some examples, the unit area (based on width 2022 and length 2024) of the photo-sensing device 2010 can be smaller than the unit area (based on width 1922 and length 1924) of the photo-sensing device 1810. Therefore, in some examples, for the same number of devices, the second array 2000 of photo-sensing devices can be smaller (e.g., denser, smaller pitch) than the first array 1900 of photo-sensing devices.

[0178] Fig.21 A photoelectric sensor (such as reference Figure 32100). The electronic device 2100 may take the form of a handheld or portable device (e.g., a smart phone, a tablet computer, or an electronic watch), a navigation system for a vehicle, or the like. The electronic device 2100 may include an optional display 2102 (e.g., a light-emitting display), a processor 2104, a power supply 2106, a memory 2108 or a storage device, a sensor system 2110, and an optional input / output (I / O) mechanism 2112 (e.g., an input / output device and / or an input / output port). The processor 2104 may control some or all operations of the electronic device 2100. The processor 2104 may communicate directly or indirectly with substantially all components of the electronic device 2100. For example, a system bus or other communication mechanism 2114 may provide communication between the processor 2104, the power supply 2106, the memory 2108, the sensor system 2110, and / or the input / output mechanism 2112.

[0179] The processor 2104 may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor 2104 may be a microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), or a combination of such devices. As described herein, the term "processor" is intended to encompass a single processor or processing unit, multiple processors, multiple processing units, or one or more other appropriately configured computing elements.

[0180] In some embodiments, components of the electronic device 2100 may be controlled by multiple processors. For example, selected components of the electronic device 2100 may be controlled by a first processor, and other components of the electronic device 2100 may be controlled by a second processor, wherein the first processor and the second processor may or may not communicate with each other.

[0181] The power supply 2106 can be implemented using any device capable of providing energy to the electronic device 2100. For example, the power supply 2106 can include one or more disposable or rechargeable batteries. Additionally or alternatively, the power supply 2106 can include a power connector or power cord that connects the electronic device 2100 to another power source (such as a wall outlet).

[0182] The memory 2108 can store electronic data that can be used by the electronic device 2100. For example, the memory 2108 can store electronic data or content, such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, data structures or databases, image data, maps, or focus settings. The memory 2108 can be configured as any type of memory. By way of example only, the memory 2108 can be implemented as a random access memory, a read-only memory, a flash memory, a removable memory, other types of storage elements, or a combination of such devices.

[0183] The electronic device 2100 may also include one or more optoelectronic sensors defining a sensor system 2110. The sensors may be positioned substantially anywhere on the electronic device 2100. The sensors may be configured to sense substantially any type of characteristic, such as, but not limited to, touch, force, pressure, electromagnetic radiation (e.g., light), heat, movement, relative motion, biometric data, distance, and the like. For example, the sensor system 2110 may include a touch sensor, a force sensor, a heat sensor, a position sensor, an optical or optical sensor, an accelerometer, a pressure sensor (e.g., a pressure transducer), a gyroscope, a magnetometer, a health monitoring sensor, and the like. Additionally, the one or more sensors may utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasonic, piezoelectric, and thermal sensing technologies.

[0184] The I / O mechanism 2112 can transmit and / or receive data from a user or another electronic device. The I / O device may include a display, a touch sensing input surface such as a tracking pad, one or more buttons (e.g., a graphical user interface "home" button or one of the buttons described herein), one or more cameras (including one or more image sensors), one or more microphones or speakers, one or more ports such as a microphone port, and / or a keyboard. Additionally or alternatively, the I / O device or port can transmit electrical signals via a communication network (such as a wireless and / or wired network connection). Examples of wireless and wired network connections include, but are not limited to, cellular networks, Wi-Fi, Bluetooth, IR, and Ethernet connections. The I / O mechanism 2112 can also provide feedback (e.g., tactile output) to the user.

[0185] For the purpose of explanation, the foregoing description uses specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to those skilled in the art after reading this description that specific details are not required to practice the described embodiments. Therefore, for the purpose of illustration and description, the foregoing description of the specific embodiments described herein is presented. They are not intended to be exhaustive or to limit the embodiments to the disclosed precise forms. It will be apparent to those of ordinary skill in the art after reading this description that, in view of the above teachings, many modifications and variations are possible.

[0186] Although the disclosed embodiments have been shown and described with respect to one or more specific implementations, equivalent changes and modifications will occur to or become known to those skilled in the art upon reading and understanding this specification and the accompanying drawings. In addition, although specific features of the invention have been disclosed with respect to only one of several specific implementations, such features may be combined with one or more other features of other specific implementations, as may be desirable and advantageous for any given or specific application.

[0187] Although various embodiments of the present disclosure have been described above, it should be understood that they have been presented only by way of example and not limitation. Without departing from the spirit or scope of the present disclosure, many changes may be made to the disclosed embodiments according to the disclosure herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the examples described above. On the contrary, the scope of the present disclosure should be defined according to the following claims and their equivalents.

Claims

1. A photoelectric sensing device, comprising: a vertical cavity surface emitting laser (VCSEL) diode, the VCSEL diode being at least partially defined by a first set of semiconductor layers disposed on a substrate, the first set of semiconductor layers including a first active region; a resonant cavity photodetector (RCPD) vertically adjacent to the VCSEL diode and at least partially defined by a second set of semiconductor layers disposed on the substrate, the second set of semiconductor layers including a second active region; as well as A tunnel junction is disposed between the first active region of the first semiconductor layer set and the second active region of the second semiconductor layer set, wherein: The VCSEL diode is configured to emit laser light toward the substrate when a first bias voltage is applied, and to undergo self-mixing interference when receiving reflection or backscattering of the emitted laser light; and The RCPD is configured to detect self-mixing interference during lasing by the VCSEL diode when a second bias voltage is applied. 2 . The photoelectric sensing device of claim 1 , wherein the VCSEL diode is disposed between the substrate and the RCPD. 3 . The photoelectric sensing device of claim 1 , wherein the RCPD is disposed between the substrate and the VCSEL diode.

4. The photoelectric sensing device according to claim 3, further comprising: a first power contact disposed on or near one or more of the second set of semiconductor layers; a second power contact disposed on or near one or more of the first set of semiconductor layers; as well as A common power contact is disposed on or near a layer between the first active region of the first semiconductor layer set and the second active region of the second semiconductor layer set.

5. The photoelectric sensing device according to claim 4, wherein: The photoelectric sensing device is a first photoelectric sensing device in a block of an array of multiple photoelectric sensing devices, each of the multiple photoelectric sensing devices sharing a common photodiode block contact coupled to the second power contact, and sharing a common block contact for the VCSEL diode coupled to the common power contact.

6. The photoelectric sensing device according to claim 4, wherein: The photo-sensing device is a first photo-sensing device in an array of a plurality of photo-sensing devices, each of the plurality of photo-sensing devices having a photodiode contact coupled to the second power contact and a common contact for the VCSEL diode coupled to the common power contact.

7. The photoelectric sensing device according to claim 1, further comprising: A controller is configured to switch the bias polarity of the RCPD to capture multiple detections of the self-mixing interference in the time domain for time-division multiplexed sample readout.

8. A photoelectric sensing device, comprising: a substrate having a front side and a back side; A set of stacked semiconductor layers, the set of stacked semiconductor layers being disposed on the front side and defining: a vertical cavity surface emitting laser (VCSEL) diode having a first active region within a resonant cavity thereof, the VCSEL diode being configured to emit a primary emission toward the substrate and through the back surface when a first bias voltage is applied; and a resonant cavity photodetector (RCPD) having a second active region offset from the first active region; as well as A grating structure is disposed on the stacked semiconductor layer set.

9. The photoelectric sensing device according to claim 8, wherein: The VCSEL diode is forward biased during the main emission period; light emitted by the VCSEL diode during primary emission undergoes self-mixing interference in a resonant cavity of the VCSEL diode upon receiving a reflection or backscatter of the primary emission; and The RCPD is configured to detect self-mixing interference during a primary emission period by the VCSEL diode when a second bias voltage is applied. 10 . The photoelectric sensing device according to claim 8 , wherein the grating structure is vertically disposed on the RCPD.

11. The photoelectric sensing device of claim 8, wherein the VCSEL diode further comprises a multi-junction stack within a resonant cavity of the VCSEL diode, the multi-junction stack comprising one or more gain stage layers interconnected with one or more vertically stacked tunnel junction layers.

12. The photoelectric sensing device of claim 11, wherein the VCSEL diode further comprises one or more oxide layers formed on a top surface of the VCSEL diode, on a bottom surface of the VCSEL diode, or within the multi-junction stack, each of the one or more oxide layers defining one or more oxide holes.

13. The optoelectronic sensing device of claim 11, wherein the substrate defines at least a portion of an extended laser cavity separated from a multi-junction stack of the VCSEL diode by a set of distributed Bragg reflector (DBR) layers formed on the substrate.

14. The optoelectronic sensing device of claim 8, wherein the RCPD comprises one or more gain stage layers disposed within a resonant cavity of the RCPD, the one or more gain stage layers comprising InGaAs.

15. The photoelectric sensing device according to claim 8, further comprising: an on-chip lens disposed on a back side of the substrate; and A reflective coating is disposed on the on-chip lens and is configured to reflect a portion of the primary emission back toward the first active region. 16 . The photoelectric sensing device of claim 8 , wherein the grating structure is filled with a dielectric material, the dielectric material comprising one of: silicon oxide, aluminum oxide, and silicon nitride.

17. A photoelectric sensing device, comprising: a substrate having a front side and a back side; a set of stacked semiconductor layers disposed on the front side and defining a set of mesas, the set of mesas comprising: A first set of one or more mesas, each mesas in the first set of one or more mesas comprising: a vertical cavity surface emitting laser (VCSEL) diode having a first active region within a resonant cavity of the VCSEL diode, the VCSEL diode being configured to emit a primary emission toward the substrate and through the back surface when a first bias voltage is applied; and a resonant cavity photodetector (RCPD) having a second active region offset from the first active region and configured to detect self-mixing interference of the primary emission in a laser cavity of the VCSEL diode upon receiving reflection or backscattering of the primary emission when a second bias voltage is applied; a second set of one or more decks; and At least one electrical conductor is electrically connected to an element of a first mesa of the first set of one or more mesas and is routed over a portion of a second mesa of the second set of one or more mesas.

18. The photoelectric sensing device of claim 17, wherein at least two adjacent mesas are operatively isolated by a trench etched through the stacked set of semiconductor layers, and an electrical conductor of the at least one electrical conductor is disposed in the trench.

19. The photoelectric sensing device of claim 18, wherein the trench extends through the set of stacked semiconductor layers and into the substrate.

20. The photoelectric sensing device of claim 17, wherein the at least one electrical conductor enables the RCPDs in the first set of the one or more mesas to be individually addressable.

Images