Broadband back-illuminated electromagnetic radiation detector

Abstract

An electromagnetic radiation detector includes an InP substrate having a first surface opposite a second surface; a first InGaAs electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths; a set of one or more buffer layers stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the first set of electromagnetic radiation wavelengths; a second InGaAs electromagnetic radiation absorber stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths; and an immersion condenser lens formed on the second surface and configured to direct electromagnetic radiation through the InP substrate and toward the first and second InGaAs electromagnetic radiation absorbers.

Description

[0001] Cross-reference to related applications

[0002] This Patent Cooperation Treaty (PCT) patent application claims priority to U.S. Provisional Patent Application No. 63 / 059,862, filed July 31, 2020, and U.S. Non-Provisional Patent Application No. 17 / 385,813, filed July 26, 2021, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The described implementation scheme relates to the detection of electromagnetic radiation, and more specifically to the detection of electromagnetic radiation over broadband. Background Technology

[0004] Sensors are found in many electronic devices today, including smartphones, computers (e.g., tablets or laptops), wearable devices (e.g., smartwatches, smartwatches, or health monitors), game controllers, navigation systems (e.g., vehicle navigation systems or robot navigation systems), and more. Sensors can sense the presence of an object, distance to the object, proximity to the object, movement of the object (e.g., whether the object is moving, or the speed, acceleration, or direction of the object's movement), composition of the object, and so on, in various ways.

[0005] One type of sensor available is an electromagnetic radiation detector (or equivalently, an electromagnetic radiation sensor, an optical sensor, or an optical detector). Some electromagnetic radiation detectors can be configured to sense a wide bandwidth of electromagnetic radiation wavelengths, while others can be configured to sense a narrow bandwidth or multiple different bandwidths of electromagnetic radiation wavelengths. Sometimes, there is a need to develop a novel electromagnetic radiation detector to sense one or more specific electromagnetic radiation wavelength bands, or to effectively sense one or more specific electromagnetic radiation bands (e.g., with a sufficiently high signal-to-noise ratio (SNR)). Summary of the Invention

[0006] Embodiments of the systems, apparatuses, methods, and devices described in this disclosure relate to broadband back-illuminated electromagnetic radiation detectors. In some embodiments, broadband electromagnetic radiation detectors are described. For the purposes of this specification, a broadband electromagnetic radiation detector is a detector capable of detecting electromagnetic radiation wavelengths in the spectral wavelength range of 0.5 micrometers (μm) or larger. In some embodiments, short-wave infrared (SWIR) electromagnetic radiation detectors are described. For the purposes of this specification, SWIR electromagnetic radiation is considered to be electromagnetic radiation in the range of about 0.7 μm to about 3.0 μm. Although many of the disclosed examples relate to broadband and / or SWIR electromagnetic radiation detectors, the systems, apparatuses, methods, and devices described herein can be configured to detect a wide range of electromagnetic radiation wavelengths, including wavelengths within a narrow band and / or wavelengths outside of SWIR electromagnetic radiation.

[0007] In a first aspect, this disclosure describes an electromagnetic radiation detector. The electromagnetic radiation detector may include an indium phosphide (InP) substrate having a first surface opposite a second surface; a first indium gallium arsenide (InGaAs) electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths; a set of one or more buffer layers stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the electromagnetic radiation wavelengths in the first set; a second InGaAs electromagnetic radiation absorber stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths; and an immersion focusing lens formed on the second surface and configured to guide electromagnetic radiation through the InP substrate and direct it to the first and second InGaAs electromagnetic radiation absorbers. The second set of electromagnetic radiation wavelengths may include at least some electromagnetic radiation wavelengths not in the first set of electromagnetic radiation wavelengths.

[0008] In a second aspect, this disclosure describes an electromagnetic radiation detection system. The system may include a substrate, a first electromagnetic radiation emitter, a second electromagnetic radiation emitter, and a detection circuit. On a first surface of the substrate, a first electromagnetic radiation absorber, a second electromagnetic radiation absorber, and a buffer positioned between the first and second electromagnetic radiation absorbers may be present. The detection circuit may be configured to operate the first and second electromagnetic radiation emitters and detect, respectively: first electromagnetic radiation emitted by the first electromagnetic radiation emitter by reading a first current generated by the first electromagnetic radiation absorber; and second electromagnetic radiation emitted by the second electromagnetic radiation emitter by reading a second current generated by the second electromagnetic radiation absorber.

[0009] In a third aspect, this disclosure describes an electronic device. The electronic device may include: a housing; an electromagnetic radiation emitter configured to emit electromagnetic radiation through the housing; and an electromagnetic radiation detector configured to receive electromagnetic radiation reflected from a target. The electromagnetic radiation detector may further include: a substrate having a first surface opposite a second surface; a first electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths; a buffer stacked on the first electromagnetic radiation absorber and configured to absorb at least some of the electromagnetic radiation wavelengths in the first set; and a second electromagnetic radiation absorber stacked on the buffer and configured to absorb a second set of electromagnetic radiation wavelengths. The second set of electromagnetic radiation wavelengths may include at least some electromagnetic radiation wavelengths not in the first set.

[0010] In addition to the exemplary aspects and embodiments described herein, further aspects and embodiments will become apparent from the accompanying drawings and by studying the following description. Attached Figure Description

[0011] This disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings, wherein similar reference numerals denote similar structural elements, and wherein:

[0012] Figure 1 It is a graph showing the transmittance of various electromagnetic radiation wavelengths in the atmospheric environment.

[0013] Figure 2A A first example of an InGaAs detector is shown;

[0014] Figure 2B References are shown Figure 2A The exemplary responsivity of the absorber described for the InGaAs detector;

[0015] Figure 3A As shown in the reference Figure 2A An exemplary responsivity of a particular embodiment of the generally constructed InGaAs detector described;

[0016] Figure 3B References are shown Figure 3A Exemplary detection capabilities of a specific implementation described;

[0017] Figure 4A A second example of an InGaAs detector is shown;

[0018] Figure 4B References are shown Figure 4A The exemplary responsivity of the absorber described for the InGaAs detector;

[0019] Figure 5A As shown in the reference Figure 4A An exemplary responsivity of a particular embodiment of the generally constructed InGaAs detector described;

[0020] Figure 5B References are shown Figure 5A Exemplary detection capabilities of a specific implementation described;

[0021] Figure 6A As shown in the reference Figure 4A An exemplary responsivity of another specific embodiment of the InGaAs detector with the general construction described;

[0022] Figure 6B References are shown Figure 6A Exemplary detection capabilities of a specific implementation described;

[0023] Figure 7A An exemplary use of a back-illuminated InGaAs detector with an immersion focusing lens is shown;

[0024] Figure 7B An exemplary use of a back-illuminated InGaAs detector incorporating an emitter unit is shown;

[0025] Figures 8A to 11 Various exemplary contact arrangements for InGaAs detectors are shown;

[0026] Figure 12A and Figure 12B An example of a device including a set of sensors is shown;

[0027] Figure 13A and Figure 13B Another example of a device including a set of sensors is shown;

[0028] Figure 14 An example of an earbud including a set of sensors is shown;

[0029] Figure 15 An exemplary elevation view of a system that may include an electromagnetic radiation emitter and a detector in an electronic device is shown; and

[0030] Figure 16 An example electrical block diagram of an electronic device is shown.

[0031] The use of crosshairs or shading in the accompanying drawings is generally provided to clarify the boundaries between adjacent elements and also to improve the readability of the drawings. Therefore, the presence or absence of crosshairs or shading does not indicate or suggest any preference or requirement for a particular material, material properties, element proportions, element dimensions, commonalities of similar illustrated elements, or any other feature, property, or characteristic of any element shown in the accompanying drawings.

[0032] Additionally, it should be understood that the proportions and dimensions (relative or absolute) of various features and elements (as well as their sets and groups), and the boundaries, spacing, and positional relationships therebetween, are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein, and are therefore unnecessarily presented or shown for scaling and are not intended to indicate any preference or requirement for the illustrated embodiments to exclude embodiments in conjunction with them. Detailed Implementation

[0033] Reference will now be made specifically to the representative embodiments shown in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to a single preferred embodiment. Rather, it is intended to cover alternative forms, modifications, and equivalents that may be included within the substance and scope of the embodiments defined by the appended claims.

[0034] While the construction and techniques described herein can be applied to electromagnetic radiation detectors tailored for detection across a wide range of electromagnetic radiation wavelengths, the described techniques have a specific suitability for broadband SWIR electromagnetic radiation detectors and are described primarily with reference to broadband SWIR electromagnetic radiation detectors. Most electromagnetic radiation in this wavelength range is minimally absorbed by atmospheric components such as water, oxygen, and carbon dioxide; therefore, this range is well-suited for sensing other materials or components (e.g., particulate matter, skin, blood, etc.).

[0035] Some of the constructions and techniques described in this article can also increase SNR. For example, some constructions and techniques can increase SNR by reducing dark current.

[0036] One type of electromagnetic radiation detector is the InGaAs detector. Some InGaAs detectors comprise an InGaAs layer (electromagnetic radiation absorber) epitaxially grown on a substrate (e.g., an InP substrate) in a lattice-matched configuration. Although this type of electromagnetic radiation detector has low dark current and high SNR, its usable absorption range (or detection range) can be limited.

[0037] To extend the absorption range of InGaAs detectors to longer electromagnetic radiation wavelengths, one or more buffer layers can be grown on a substrate, and an InGaAs layer (electromagnetic radiation absorber) can be grown on these buffer layers in an alattice-matched configuration. This InGaAs detector can be configured to receive electromagnetic radiation through its front side (i.e., with front illumination (FSI) or front illumination configuration) or through its back side (i.e., with back illumination (BSI) or back illumination configuration). The FSI configuration eliminates light loss due to substrate or buffer absorption and is easy to fabricate. In the BSI configuration, the InGaAs detector receives electromagnetic radiation through the detector's substrate before the radiation is projected onto the InGaAs layer. These types of InGaAs detectors can have an absorption range that includes wavelengths longer than those of InGaAs detectors with lattice-matched InGaAs layers. However, the absorption of shorter wavelengths is sacrificed in the BSI configuration because these wavelengths tend to be absorbed by the buffer layers before reaching the InGaAs layer. The detector's ability to detect shorter wavelengths can also be more significantly affected by dark current.

[0038] To extend the bandwidth of the electromagnetic radiation detector while maintaining a good SNR across most or all of its absorption range, two InGaAs electromagnetic radiation absorbers can be stacked on an InP substrate instead of a single one. To "tune" the detector and extend its bandwidth, one or more buffer layers can be grown between the InGaAs electromagnetic radiation absorbers. Because the buffer layers can have high absorption in the same wavelength range as the InGaAs electromagnetic radiation absorber closest to the InP substrate, the detector can be used in a BSI configuration. Thus, wavelengths that might be absorbed by the buffer layers are first absorbed by the InGaAs electromagnetic radiation absorber closest to the InP substrate. By absorbing wavelengths within the absorption range of the InGaAs electromagnetic radiation absorber closest to the InP substrate, the buffer layers enable more distant InGaAs electromagnetic radiation absorbers to primarily absorb wavelength ranges that do not overlap with the wavelength ranges absorbed by the closer InGaAs electromagnetic radiation absorbers and the buffer layers. In some embodiments of this type of electromagnetic radiation detector, a second set of one or more buffer layers can be grown between the InP substrate and the nearest InGaAs electromagnetic radiation absorber to adjust the wavelength range absorbed by the nearest InGaAs electromagnetic radiation absorber. The absorption on / off state of each InGaAs electromagnetic radiation absorber can be adjusted by varying the number or thickness of the buffer layer, or by modifying the material or doping of the buffer layer and / or the InGaAs electromagnetic radiation absorber, or otherwise. Different on / off states can provide advantages in various sensing applications (e.g., different sensing ranges, different levels of dark current and SNR, different responsivity or detection capabilities, etc.). An additional advantage achieved by an InGaAs detector in a BSI configuration with two InGaAs electromagnetic radiation absorbers is the simplified InGaAs electromagnetic radiation absorber construction, which sometimes helps improve signal absorption. BSI-configured InGaAs detectors also have a higher electrical connection density, which can be useful for InGaAs detectors used in detector arrays.

[0039] In some implementations, the detectors described in the preceding paragraphs can be used in the FSI configuration.

[0040] In some implementations, an immersion focusing lens can be formed on the back side of the InGaAs detector in a BSI configuration, i.e., on the surface of the detector that does not support the InGaAs electromagnetic radiation absorber. This allows for the reception and focusing of more electromagnetic radiation onto the detector, which has a smaller footprint (i.e., a smaller surface area). In some cases, the immersion focusing lens can provide an improvement in electromagnetic radiation focusing efficiency equal to the square of the refractive index of the detector substrate (e.g., approximately a 10-fold increase in focusing efficiency for a detector with an InP substrate).

[0041] In some cases, the detectors described herein can be used to detect different wavelengths of electromagnetic radiation emitted by the same or different electromagnetic radiation emitters simultaneously or sequentially.

[0042] refer to Figures 1 to 16 These and other techniques are described herein. However, those skilled in the art will readily understand that the detailed descriptions given herein with respect to the accompanying drawings are for illustrative purposes only and should not be construed as limiting.

[0043] Directional terms such as “top,” “bottom,” “upper,” “lower,” “front,” “rear,” “above,” “below,” “above,” “below,” “left,” “right,” etc., are used with reference to the orientation of some components in some of the figures described below. Because components in various embodiments may be positioned in multiple different orientations, directional terms are for illustrative purposes only and are not intended to be limiting in any way. Directional terms are intended to be interpreted broadly and should therefore not be construed as excluding components oriented in different ways. Furthermore, as used herein, the phrase “at least one of” following a series of items separated by the terms “and” or “or” modifies the list as a whole, not 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 the inclusion of at least one of any item in the list and / or at least one of any combination of items and / or at least one of each item in the list. For example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer 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 of elements presented with respect to the combined or separate lists provided herein should not be construed as limiting this disclosure to the order provided.

[0044] As used herein, “substrate” refers to a block or mass of common material. As used herein, “layer” refers to one or more materials that are generally, but not necessarily, parallel to the top and / or bottom surfaces of a substrate or another layer. As used herein, a component, material, or layer “stacked” on another component, material, or layer may be formed directly on the other component, material, or layer, or may be attached to and separated from that other component, material, or layer by sharing one or more other components, materials, or layers in a “stack.” The terms “on” and “directly on” are used interchangeably herein.

[0045] Figure 1This is graph 100, which shows the transmittance of various electromagnetic radiation wavelengths in the atmosphere. The horizontal axis of graph 100 shows the electromagnetic radiation wavelength (in μm), and the vertical axis shows the transmittance (in percentage (%)). A transmittance of less than 100% for a specific wavelength means that the atmosphere absorbs at least a portion of the electromagnetic radiation with that wavelength.

[0046] Figure 1 The diagram also shows a block representation of atmospheric environment 102 and some molecules in atmospheric environment 102 that absorb electromagnetic radiation of a specific wavelength (in some cases, interfere with or suppress the intended sensing operation). Figure 1 The molecules shown include water (H2O), oxygen (O2), and carbon dioxide (CO2).

[0047] In some cases, detecting a wide range of SWIR wavelengths can be useful. For example, detecting a range (or ranges) of SWIR wavelengths including those between approximately 1.4 μm-1.5 μm and approximately 2.5 μm can be useful. This range includes two windows where SWIR wavelengths are not absorbed (or conversely, transmitted). The first window or range that transmits SWIR wavelengths extends from approximately 1.4 μm-1.5 μm to approximately 1.85 μm. The second window or range that transmits SWIR wavelengths extends from approximately 2.0 μm to approximately 2.5 μm. These windows / ranges are within... Figure 1 As shown in the figure, the SWIR wavelength between these two windows (i.e., the SWIR wavelength from about 1.85 μm to about 2.0 μm) is absorbed by water.

[0048] InGaAs electromagnetic radiation detectors (hereinafter referred to as InGaAs detectors, or simply detectors) can be used to detect SWIR wavelengths in the range of approximately 1.4 μm–2.5 μm. However, at least conventionally, InGaAs detectors with a single absorber BSI configuration cannot detect SWIR wavelengths at the lower end of this range with high SNR. A new type of SWIR electromagnetic radiation detector is needed to detect electromagnetic radiation over a wider range of SWIR wavelengths using a single detector, or to detect different ranges of SWIR wavelengths using a single detector. Although InGaAs detectors with an FSI configuration can detect a wider range of SWIR wavelengths and are not subject to buffer absorption, immersion condenser lenses cannot be formed on FSI-configured InGaAs detectors. InGaAs detectors with immersion condenser lenses will generally be able to achieve higher SNRs by focusing the received electromagnetic radiation wavelengths into a smaller area than would otherwise be possible.

[0049] In some cases, the techniques described herein can be used to construct electromagnetic radiation detectors capable of detecting electromagnetic radiation wavelengths in other spectral ranges. These other ranges may include ranges with SWIR wavelengths, ranges that overlap with SWIR wavelengths, or ranges that do not intersect with SWIR wavelengths.

[0050] Figure 2A A first example of an InGaAs detector 200 is shown. The detector 200 includes an InP substrate 202 having a first surface 204 opposite a second surface 206. A plurality of InGaAs electromagnetic radiation absorbers 208, 210 and other structures (e.g., a group of one or more buffer layers 212) may be formed on the first surface 204, and electromagnetic radiation 214 may be received in the detector 200 by means of electromagnetic radiation 214 projected onto and passing through the second surface 206. The reception of the electromagnetic radiation 214 through the second surface 206 and its subsequent propagation through the InP substrate 202 before being projected onto the InGaAs electromagnetic radiation absorbers 208, 210 stacked on the first surface 204 make the detector 200 a back-illuminated InGaAs detector.

[0051] The first InGaAs electromagnetic radiation absorber 208 may be stacked on the first surface 204 of the InP substrate 202, and more specifically, may be epitaxially grown directly on the first surface 204 as a lattice-matched InGaAs layer (i.e., a layer lattice-matched to the InP substrate). A pn ​​junction may be formed in the first InGaAs electromagnetic radiation absorber 208 via implantation and / or doping during epitaxial growth.

[0052] One or more buffer layers 212 may be stacked on the first InGaAs electromagnetic radiation absorber 208. More specifically, and in some embodiments, each buffer layer may be grown directly on the first InGaAs electromagnetic radiation absorber 208 or on another buffer layer within the buffer layers 212. Each buffer layer may be, for example, an InAsP layer, and each successive buffer layer may be grown in a hierarchical configuration such that the lattice constant transitions from a first value of the first InGaAs electromagnetic radiation absorber 208 to a second value of the second InGaAs electromagnetic radiation absorber 210.

[0053] The second InGaAs electromagnetic radiation absorber 210 may be stacked on the set of one or more buffer layers 212, and more specifically, may be epitaxially grown directly on one of the buffer layers. The second InGaAs electromagnetic radiation absorber 210 may be grown on the buffer layer as a lattice-matched InGaAs layer (i.e., as a layer lattice-matched to the InP substrate 202 (e.g., an extended or strained InGaAs layer)), but may have a lattice constant substantially matching that of the buffer layer on which it is grown. Therefore, the second InGaAs electromagnetic radiation absorber 210 may experience a lattice constant environment (and thus performance) typically associated with an isolated absorber. A pn ​​junction may be formed in the second InGaAs electromagnetic radiation absorber 210 via implantation, doping during epitaxial growth, and / or diffusion doping. The pn junction may also be formed in the InAsP capping layer, rather than within the InGaAs electromagnetic radiation absorber 210 itself.

[0054] The second InGaAs electromagnetic radiation absorber 210 may have a smaller band gap than the group of one or more buffer layers 212.

[0055] When electromagnetic radiation 214 is projected onto the second surface 206 of the InP substrate 202, some or all of the electromagnetic radiation 214 can pass through the InP substrate 202 and be absorbed by the first InGaAs electromagnetic radiation absorber 208. For example, a first set of electromagnetic radiation wavelengths (e.g., a first electromagnetic radiation wavelength range) can pass through the InP substrate 202 and be absorbed by the first InGaAs electromagnetic radiation absorber 208. Some of the electromagnetic radiation 214 projected onto the first InGaAs electromagnetic radiation absorber 208 can pass through the first InGaAs electromagnetic radiation absorber 208 without being absorbed or with minimal absorption, and be absorbed by the set of one or more buffer layers 212. The electromagnetic radiation absorbed by the set of one or more buffer layers 212 may include at least some of the electromagnetic radiation wavelengths in the first set of electromagnetic radiation wavelengths. The electromagnetic radiation absorbed by the set of one or more buffer layers 212 may also include other electromagnetic radiation wavelengths. Some of the electromagnetic radiation projected onto the first InGaAs electromagnetic radiation absorber 208 can also pass through the set of one or more buffer layers 212 and be projected onto the second InGaAs electromagnetic radiation absorber 210. At least some of the electromagnetic radiation (e.g., a second set of electromagnetic radiation wavelengths, such as a second electromagnetic radiation wavelength range) can be absorbed by the second InGaAs electromagnetic radiation absorber 210. The second set of electromagnetic radiation wavelengths may include at least some electromagnetic radiation wavelengths that are not in the first set of electromagnetic radiation wavelengths, and in some cases, may include only electromagnetic radiation wavelengths that are not in the first set of electromagnetic radiation wavelengths. The second set of electromagnetic radiation wavelengths typically includes wavelengths longer than the first set of wavelengths.

[0056] In some embodiments, a first InGaAs electromagnetic radiation absorber 208 may be configured to absorb electromagnetic radiation wavelengths in the range of about 1.4 μm to about 1.7 μm, and a second InGaAs electromagnetic radiation absorber 210 may be configured to absorb electromagnetic radiation wavelengths in the range of about 1.7 μm to about 2.5 μm. For the purposes of this specification, a material or layer (such as an electromagnetic radiation absorber) is considered to “absorb” an electromagnetic radiation wavelength if it has a responsivity of 0.5 amperes per watt (A / W) or greater (and preferably 0.6 A / W or 0.7 A / W or greater). Or, in the case of a buffer or buffer layer, if the buffer or buffer layer has an equivalent absorption in some arbitrary unit (au). Also for the purposes of this specification, “about” a particular electromagnetic radiation wavelength is considered to be within + / - 50 nanometers (nm) of that particular electromagnetic radiation wavelength.

[0057] Figure 2B References are shown Figure 2A An exemplary responsivity of 220 is described for the absorber of the InGaAs detector.

[0058] The first InGaAs electromagnetic radiation absorber 208 has a first responsivity 222 and can absorb a specific electromagnetic radiation wavelength range around the first electromagnetic radiation wavelength 224.

[0059] The second InGaAs electromagnetic radiation absorber 210 has a second responsivity 226 and can absorb a specific range of electromagnetic radiation wavelengths around the second electromagnetic radiation wavelength 228. As shown, the second InGaAs electromagnetic radiation absorber 210 can typically absorb electromagnetic radiation wavelengths longer than the first InGaAs electromagnetic radiation absorber 208. Because electromagnetic radiation is first projected onto the first InGaAs electromagnetic radiation absorber 208 and only after passing through the first InGaAs electromagnetic radiation absorber 208 is it projected onto the second InGaAs electromagnetic radiation absorber 210, fewer electromagnetic radiation wavelengths (or in some cases no electromagnetic radiation wavelengths) of the electromagnetic radiation absorbed by the first InGaAs electromagnetic radiation absorber 208 can be projected onto the second InGaAs electromagnetic radiation absorber 210 (and absorbed by the second InGaAs electromagnetic radiation absorber). In other embodiments, the absorption ranges of the first InGaAs electromagnetic radiation absorber 208 and the second InGaAs electromagnetic radiation absorber 210 may not overlap (e.g., they may not intersect).

[0060] The set of one or more buffer layers 212 is associated with absorption (or buffer loss) 230. The absorption range of the one or more buffer layers 212 may overlap with some or all of the absorption range of the first InGaAs electromagnetic radiation absorber 208, and in some cases may overlap with some (but not all) of the absorption range of the second InGaAs electromagnetic radiation absorber 210. Because electromagnetic radiation is first projected onto the first InGaAs electromagnetic radiation absorber 208, and only after being projected onto the one or more buffer layers 212, electromagnetic radiation within the absorption range of the first InGaAs electromagnetic radiation absorber 208 can be absorbed by the first InGaAs electromagnetic radiation absorber 208 before being absorbed by the one or more buffer layers 212, thereby avoiding the effect of buffer absorption loss on the first InGaAs electromagnetic radiation absorber 208. In addition, the set of one or more buffer layers 212 can absorb some or all of the electromagnetic radiation that can be absorbed by the first InGaAs electromagnetic radiation absorber 208 but is not absorbed by the first InGaAs electromagnetic radiation absorber 208, so that the responsivity of the second InGaAs electromagnetic radiation absorber 210 is more specifically tuned to an absorption range that does not overlap with the absorption range of the first InGaAs electromagnetic radiation absorber (although some overlap in the wavelengths of the electromagnetic radiation absorbed by the first InGaAs electromagnetic radiation absorber 208 and the second InGaAs electromagnetic radiation absorber 210 is possible and even possible).

[0061] Figure 3A As shown in the reference Figure 2A An exemplary response of 300 is given for a particular embodiment of the InGaAs detector with the general construction described. Figure 3B An exemplary detection capability 310 of a specific implementation is shown. For example... Figure 3A As shown, the first InGaAs electromagnetic radiation absorber 208 has a responsivity 302 with absorption cutoff at approximately 1.7 μm and may have an absorption range extending below 1.2 μm (and in some cases extending to the beginning of the spectrum). The second InGaAs electromagnetic radiation absorber 210 has a responsivity 304 extending from approximately 1.4 μm to approximately 2.5 μm when the absorption is turned on at approximately 1.7 μm. Therefore, the responsivity 302, 304 of the first InGaAs electromagnetic radiation absorber 208 and the second InGaAs electromagnetic radiation absorber 210 intersect at approximately 1.7 μm (i.e., have an alternation point).

[0062] The set of one or more buffer layers 212 is associated with absorption (or buffer loss) 306, which overlaps with a portion of the responsivity 302 of the first InGaAs electromagnetic radiation absorber.

[0063] like Figure 3B As shown, the detection capability 312 (in Jones) of the first InGaAs electromagnetic radiation absorber 208 is higher below approximately 1.7 μm (as seen between the first InGaAs electromagnetic radiation absorber 208 and the second InGaAs electromagnetic radiation absorber 210), and the detection capability 314 of the second InGaAs electromagnetic radiation absorber 210 is higher between approximately 1.7 μm and 2.5 μm. Reference Figure 3A and Figure 3B The advantage of the described InGaAs detector lies in the fact that the first InGaAs electromagnetic radiation absorber of the InGaAs detector is lattice-matched to the InP substrate of the InGaAs detector, and there is no buffer layer that could interfere with the first InGaAs electromagnetic radiation absorber by, for example, increasing dark current, which could interfere with the readout of the current generated by the first InGaAs electromagnetic radiation absorber in response to the absorption of electromagnetic radiation within its absorption range. Furthermore, shorter wavelength (i.e., larger bandgap) semiconductors typically have low dark current densities.

[0064] In some cases, it may be desirable to adjust the range of electromagnetic radiation wavelengths to which the absorber responds (i.e., the range of electromagnetic radiation wavelengths absorbed by the absorber). In some cases, the responsivity of an InGaAs electromagnetic radiation absorber further away from the InP substrate can be adjusted by changing the number or thickness of one or more buffer layers that separate the InP substrate from the InGaAs electromagnetic radiation absorber located earlier in the electromagnetic radiation propagation path. In some cases, the responsivity of an InGaAs electromagnetic radiation absorber can be adjusted by using a set of one or more additional buffer layers to separate the InGaAs electromagnetic radiation absorber located closest to the InP substrate from the InP substrate, as shown below for example. Figure 4A and Figure 4B As described. In some cases, the responsivity of the InGaAs electromagnetic radiation absorber can be adjusted by changing the composition or growth method of the InGaAs electromagnetic radiation absorber and / or by adjusting the number, thickness, or type of the buffer layer separating the InGaAs electromagnetic radiation absorber from the InP substrate or other InGaAs electromagnetic radiation absorbers.

[0065] Figure 4AA second example of an InGaAs detector 400 is shown. The detector 400 includes an InP substrate 402 having a first surface 404 opposite a second surface 406. A plurality of InGaAs electromagnetic radiation absorbers 408, 410 and other structures (e.g., one or more sets of buffer layers 412, 414) may be formed on the first surface 404, and electromagnetic radiation 416 may be received in the detector 400 by means of electromagnetic radiation 416 projected onto and passing through the second surface 406. The reception of electromagnetic radiation 416 through the second surface 406 and its subsequent propagation through the InP substrate 402 before being projected onto the InGaAs electromagnetic radiation absorbers 408, 410 stacked on the first surface 404 make the detector 400 a back-illuminated InGaAs detector.

[0066] One or more buffer layers 412 in the first group may be stacked on the first surface 404 of the InP substrate 402. More specifically, and in some embodiments, each buffer layer in the first group may be epitaxially grown directly on the InP substrate 402 or epitaxially grown on another buffer layer in the buffer layer 412. Each buffer layer may be, for example, an InAsP layer, and each successive buffer layer may be grown in a hierarchical configuration to transform the lattice constant from a first value of the InP substrate 402 to a second value of the first InGaAs electromagnetic radiation absorber 408.

[0067] A first InGaAs electromagnetic radiation absorber 408 may be stacked on a first set of one or more buffer layers 412, wherein the buffer layers 412 are disposed between the InP substrate 402 and the first InGaAs electromagnetic radiation absorber 408. More specifically, and in some embodiments, the first InGaAs electromagnetic radiation absorber 408 may be epitaxially grown directly on a buffer layer in the first set of one or more buffer layers 412 as a short lattice-mismatched InGaAs layer (i.e., as a layer lattice-mismatched with the InP substrate), but may have a lattice constant substantially matching that of the buffer layer on which it is grown. Thus, the first InGaAs electromagnetic radiation absorber 408 may experience a lattice constant environment (and therefore performance) typically associated with an isolated absorber. A pn ​​junction may be formed in the first InGaAs electromagnetic radiation absorber 408 via implantation, doping during epitaxial growth, and / or diffusion doping. The pn junction may also be formed in an InAsP capping layer, rather than in the InGaAs electromagnetic radiation absorber 410 itself.

[0068] A second group of one or more buffer layers 414 may be stacked on the first InGaAs electromagnetic radiation absorber 408. More specifically, and in some embodiments, each buffer layer in this group may be epitaxially grown directly on the first InGaAs electromagnetic radiation absorber 408 or epitaxially grown on another buffer layer in the buffer layer 414. Each buffer layer may be, for example, an InAsP layer, and each successive buffer layer may be grown in a hierarchical configuration such that the lattice constant transitions from a first value of the first InGaAs electromagnetic radiation absorber 408 to a second value of the second InGaAs electromagnetic radiation absorber 410.

[0069] The second InGaAs electromagnetic radiation absorber 410 may be stacked on a second set of one or more buffer layers 414, wherein the buffer layers 414 are disposed between the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410. More specifically, and in some embodiments, the second InGaAs electromagnetic radiation absorber 410 may be epitaxially grown on a buffer layer in one of the second set of one or more buffer layers 414 as a long or extended lattice-mismatched InGaAs layer (i.e., as a layer that is not lattice-matched with the InP substrate 402 (e.g., an extended or strained InGaAs layer)), but may have a lattice constant substantially matching that of the buffer layer on which it is grown. Thus, the second InGaAs electromagnetic radiation absorber 410 may experience a lattice constant environment (and therefore performance) typically associated with an isolated absorber. A pn ​​junction may be formed in the second InGaAs electromagnetic radiation absorber 410 via implantation, doping during epitaxial growth, and / or diffusion doping. The pn junction can also be formed in the InAsP capping layer, rather than in the InGaAs electromagnetic radiation absorber 410 itself.

[0070] The first InGaAs electromagnetic radiation absorber 408 may have a larger band gap than the first group of one or more buffer layers 412. Similarly, the second InGaAs electromagnetic radiation absorber 410 may have a larger band gap than the second group of one or more buffer layers 414. This allows each InGaAs electromagnetic radiation absorber 408, 410 to absorb longer wavelengths of electromagnetic radiation that are absorbed by layers closer to the InP substrate 402.

[0071] When electromagnetic radiation 416 is projected onto the second surface 406 of the InP substrate 402, some or all of the electromagnetic radiation 416 can pass through the InP substrate 402 and be absorbed by the first InGaAs electromagnetic radiation absorber 408. For example, a first set of electromagnetic radiation wavelengths (e.g., a first electromagnetic radiation wavelength range) can pass through the InP substrate 402 and be absorbed by the first InGaAs electromagnetic radiation absorber 408. This set of electromagnetic radiation wavelengths absorbed by the first InGaAs electromagnetic radiation absorber 408 can be affected by the absorption range of the first set of one or more buffer layers 412. For example, electromagnetic radiation wavelengths absorbed by the first set of buffer layers 412 will not be projected onto the first InGaAs electromagnetic radiation absorber 408. In some cases, the first set of one or more buffer layers 412 can be used to adjust (or tune) one or both boundaries of the electromagnetic radiation wavelength range absorbed by the first InGaAs electromagnetic radiation absorber 408.

[0072] Some electromagnetic radiation 416 projected onto the first InGaAs electromagnetic radiation absorber 408 may pass through the first InGaAs electromagnetic radiation absorber 408 without being absorbed or with minimal absorption, and be absorbed by one or more second-group buffer layers 414. The electromagnetic radiation absorbed by the one or more second-group buffer layers 414 may include at least some of the electromagnetic radiation wavelengths in the first group of electromagnetic radiation wavelengths. The electromagnetic radiation absorbed by the one or more second-group buffer layers 414 may also include other electromagnetic radiation wavelengths. Some electromagnetic radiation projected onto the first InGaAs electromagnetic radiation absorber 408 may also pass through the one or more second-group buffer layers 414 and be projected onto the second InGaAs electromagnetic radiation absorber 410. At least some of this electromagnetic radiation (e.g., second-group electromagnetic radiation wavelengths, such as a second electromagnetic radiation wavelength range) may be absorbed by the second InGaAs electromagnetic radiation absorber 410. The second-group electromagnetic radiation wavelengths may include at least some electromagnetic radiation wavelengths not in the first group of electromagnetic radiation wavelengths, and in some cases, may include only electromagnetic radiation wavelengths not in the first group of electromagnetic radiation wavelengths. The second-group electromagnetic radiation wavelengths typically include wavelengths longer than the first group of wavelengths.

[0073] In some embodiments, a first InGaAs electromagnetic radiation absorber 408 may be configured to absorb electromagnetic radiation wavelengths in the range of about 1.4 μm to about 1.9 μm or 2.0 μm, and a second InGaAs electromagnetic radiation absorber 410 may be configured to absorb electromagnetic radiation wavelengths in the range of about 1.9 μm or 2.0 μm to about 2.5 μm. The cutoff of the absorption range of the first InGaAs electromagnetic radiation detector is configured in the range of about 1.85 μm to about 2.0 μm (i.e., the band where electromagnetic radiation is mainly absorbed by water, as referenced). Figure 1(As discussed) and configuring the absorption range of the second InGaAs electromagnetic radiation detector to be switched on within the same range places the alternation between absorber responsivity within the electromagnetic radiation wavelength range that can perform less useful sensing (at least in some applications).

[0074] Figure 4B References are shown Figure 4A An exemplary responsivity of 420 is described for the absorber of the InGaAs detector.

[0075] The first InGaAs electromagnetic radiation absorber 408 has a first responsivity 422 and can absorb a specific electromagnetic radiation wavelength range around a first electromagnetic radiation wavelength 424.

[0076] The second InGaAs electromagnetic radiation absorber 410 has a second responsivity 426 and can absorb a specific range of electromagnetic radiation wavelengths around the second electromagnetic radiation wavelength 428. As shown, the second InGaAs electromagnetic radiation absorber 410 can typically absorb electromagnetic radiation wavelengths longer than the first InGaAs electromagnetic radiation absorber 408. Because electromagnetic radiation is first projected onto the first InGaAs electromagnetic radiation absorber 408 and only after passing through the first InGaAs electromagnetic radiation absorber 408 is it projected onto the second InGaAs electromagnetic radiation absorber 410, fewer electromagnetic radiation wavelengths (or in some cases no electromagnetic radiation wavelengths) of the electromagnetic radiation absorbed by the first InGaAs electromagnetic radiation absorber 408 can be projected onto the second InGaAs electromagnetic radiation absorber 410 (and absorbed by the second InGaAs electromagnetic radiation absorber). In other embodiments, the absorption ranges of the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410 may not overlap (e.g., they may not intersect).

[0077] The first group of one or more buffer layers 412 is associated with absorption (or buffer loss) 430. The absorption range of the first group of one or more buffer layers 412 is negligible and is generally outside the absorption range of the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410.

[0078] The second group of one or more buffer layers 414 is associated with absorption (or buffer loss) 432. The absorption range of the second group of one or more buffer layers 414 may overlap with some or all of the absorption range of the first InGaAs electromagnetic radiation absorber 408, and in some cases may overlap with some (but not all) of the absorption range of the second InGaAs electromagnetic radiation absorber 410. Because electromagnetic radiation is first projected onto the first InGaAs electromagnetic radiation absorber 408, and only after being projected onto the first InGaAs electromagnetic radiation absorber 408, is projected onto the second group of one or more buffer layers 414, electromagnetic radiation within the absorption range of the first InGaAs electromagnetic radiation absorber 408 can be absorbed by the first InGaAs electromagnetic radiation absorber 408 before being absorbed by the second group of one or more buffer layers 414, thereby avoiding the effect of buffer absorption loss on the first InGaAs electromagnetic radiation absorber 408. Additionally, the second set of one or more buffer layers 414 can absorb some or all of the electromagnetic radiation that can be absorbed by the first InGaAs electromagnetic radiation absorber 408 but is not absorbed by the first InGaAs electromagnetic radiation absorber 408, such that the responsivity of the second InGaAs electromagnetic radiation absorber 410 is more specifically tuned to an absorption range that does not overlap with the absorption range of the first InGaAs electromagnetic radiation absorber (although some overlap in the wavelengths of the electromagnetic radiation absorbed by the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410 is possible and even possible).

[0079] Figure 5A As shown in the reference Figure 4A An exemplary response of 500 is given for a particular embodiment of the InGaAs detector with the general construction described. Figure 5B An exemplary detection capability 510 for a specific implementation is shown.

[0080] like Figure 5A As shown, the first InGaAs electromagnetic radiation absorber 408 has a responsivity 502 with absorption cutoff at approximately 1.9 μm and may have an absorption range extending to approximately 1.2 μm. The second InGaAs electromagnetic radiation absorber 410 has a responsivity 504 extending from approximately 1.4 μm to approximately 2.5 μm when the absorption is turned on at approximately 1.9 μm. Therefore, the responsivity 502 and 504 of the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410 intersect at approximately 1.9 μm (i.e., have an alternation point).

[0081] The first group of one or more buffer layers 412 is associated with absorption (or buffer loss) 506 that is typically outside the responsivity of the first InGaAs electromagnetic radiation detector 408 and the second InGaAs electromagnetic radiation detector 410, and the second group of one or more buffer layers 414 is associated with absorption (or buffer loss) 508 that partially overlaps with the responsivity 502 of the first InGaAs electromagnetic radiation absorber and the responsivity 504 of the second InGaAs electromagnetic radiation absorber.

[0082] like Figure 5B As shown, the detection capability 512 (in Jones) of the first InGaAs electromagnetic radiation absorber 408 is higher between about 1.2 μm and 1.9 μm (as between the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410), and the detection capability 514 of the second InGaAs electromagnetic radiation absorber 410 is higher between about 1.9 μm and 2.5 μm.

[0083] refer to Figure 5A and Figure 5B An advantage of the described InGaAs detector is that the alternation point between the first and second InGaAs electromagnetic radiation absorbers of the InGaAs detector lies in the moisture absorption band (e.g., between approximately 1.85 μm and approximately 2.0 μm, as shown in the reference). Figure 1 Within the described range. In other words, the alternation point is located at the electromagnetic radiation wavelength (or wavelength range) where sensing is less useful.

[0084] Figure 6A As shown in the reference Figure 4A An exemplary response of 600 is given by another specific embodiment of the InGaAs detector with the general construction described. Figure 6B An exemplary detection capability 610 for a specific implementation is shown.

[0085] like Figure 6A As shown, the first InGaAs electromagnetic radiation absorber 408 has a responsivity 602 with absorption cutoff at approximately 2.1 μm and may have an absorption range extending to approximately 1.4 μm. The second InGaAs electromagnetic radiation absorber 410 has a responsivity 604 extending from approximately 1.6 μm to approximately 2.5 μm when the absorption is turned on at approximately 2.1 μm. Therefore, the responsivity 602 and 604 of the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410 intersect at approximately 2.1 μm (i.e., have an alternation point).

[0086] The first group of one or more buffer layers 412 is associated with an absorption (or buffer loss) 606 that overlaps with a portion of the responsivity of the first InGaAs electromagnetic radiation detector 408, and the second group of one or more buffer layers 414 is associated with an absorption (or buffer loss) 608 that overlaps with a portion of the responsivity of the first InGaAs electromagnetic radiation absorber 602 and the responsivity of the second InGaAs electromagnetic radiation absorber 604.

[0087] like Figure 6B As shown, the detection capability 612 (in Jones) of the first InGaAs electromagnetic radiation absorber 408 is higher between about 1.4 μm and 2.1 μm (as between the first InGaAs electromagnetic radiation absorber 408 and the second InGaAs electromagnetic radiation absorber 410), and the detection capability 614 of the second InGaAs electromagnetic radiation absorber 410 is higher between about 2.1 μm and 2.5 μm.

[0088] refer to Figure 6A and Figure 6B An advantage of the described InGaAs detector is that its first InGaAs electromagnetic radiation absorber has a cutoff at electromagnetic radiation wavelengths longer than other InGaAs detectors described herein. When electromagnetic radiation passes through wavelengths within the range of interest that are not absorbed by the buffer layer of the first InGaAs electromagnetic radiation absorber (e.g., when the buffer layer absorbs only electromagnetic radiation wavelengths below 1.4 μm), less dark current can exist that interferes with the readout of the current generated by the first InGaAs electromagnetic radiation absorber in response to the absorption of electromagnetic radiation within its absorption range. This limitation on the absorption range of the buffer layer, which is closer to the InP substrate, constrains the composition of the buffer layer (e.g., InAsP composition), and thus the achievable lattice constant, and thus the composition of the first electromagnetic radiation absorber (e.g., InGaAs composition), and thus the long-wavelength cutoff of the first electromagnetic radiation absorber. This design ensures that at any wavelength of interest, the responsivity of no absorber is reduced by buffer absorption.

[0089] In some implementation schemes, such as reference Figure 2A or Figure 4A The InGaAs detector of the general construction described may include one or more additional InGaAs electromagnetic radiation absorbers stacked on one or more additional sets of one or more buffer layers. For example, the InGaAs detector may include a third InGaAs electromagnetic radiation absorber stacked on a third set of one or more buffer layers, which may be stacked on a second InGaAs electromagnetic radiation absorber of the detector.

[0090] In some embodiments, the detector may include a substrate, a buffer layer, and / or an electromagnetic radiation absorber with other materials. For example, the substrate may be formed of gallium arsenide (GaAs), cadmium telluride (CdTe), or silicon (Si). In the case of GaAs, CdTe, or Si substrates, the electromagnetic radiation absorber may in some cases be formed of mercury cadmium telluride (HgCdTe).

[0091] Figure 7A An exemplary use of a back-illuminated InGaAs detector 700 with an immersion condenser lens 702 is shown. In some examples, the InGaAs detector 700 may include a reference... Figures 2A to 6B One or more of the figures in the diagram depict InGaAs electromagnetic radiation absorbers and buffer layers.

[0092] The InGaAs detector 700 may have a plurality of InGaAs electromagnetic radiation absorbers (i.e., two or more InGaAs electromagnetic radiation absorbers) and one or more sets of buffer layers stacked (e.g., grown) on a first surface 706 of an InP substrate 708, these buffer layers being collectively designated 704. The InP substrate 708 may have a second surface 710 on which an immersion condenser lens 702 is formed (e.g., etched), such that the InGaAs electromagnetic radiation absorbers and buffer layers 704 are immersed in a continuous high refractive index medium (i.e., the InP substrate 708). The immersion condenser lens 702 improves the transmission of electromagnetic radiation 712 through the InP substrate 708 of the InGaAs detector 700.

[0093] The immersion focusing lens 702 can receive electromagnetic radiation 712 through the second surface 710 (which may be a convex surface) of the InP substrate 708 and focus the electromagnetic radiation onto the InGaAs electromagnetic radiation absorber and buffer layer 704.

[0094] In some cases, the InGaAs detector 700 may be used as a single (e.g., standalone) detector unit. In other cases, the InGaAs detector 700 may be one of the detector units in an array (e.g., a one-dimensional or two-dimensional array) of InGaAs detectors 700, 714, or detector units. For example, different InGaAs detectors 700, 714 may share a common InP substrate 708 (as shown) and / or other components, or may be manufactured individually (or co-manufactured and subsequently cut) and mounted on a carrier substrate or within a housing.

[0095] In some cases, and such as Figure 7BAs shown, the InGaAs detector 700 can be used as a detector unit and is positioned near the transmitter unit. The transmitter unit may include an electromagnetic radiation emitter 716, which is stacked on or positioned near the surface 718 of the lens 720 and configured to emit electromagnetic radiation through the lens 720. For example, the lens 720 may collimate, diffuse, or focus the electromagnetic radiation emitted by the electromagnetic radiation emitter 716. The electromagnetic radiation emitter 716 may emit electromagnetic radiation within, throughout, or including the electromagnetic radiation range that can be absorbed by the InGaAs detector 700. In some embodiments, the lens 720 may not be provided.

[0096] Figures 8A to 11 Various exemplary contact arrangements for InGaAs detectors are shown. For example, a contact arrangement for an InGaAs detector similar to the one described with reference to FIG4 is shown. However, various contact arrangements can be used for any InGaAs detector described herein.

[0097] Figure 8A A plan view of a 3-contact InGaAs detector 800 is shown, and Figure 8B A top cross-sectional view of an InGaAs detector 800 is shown. The InGaAs detector 800 includes an InP substrate 802, on which one or more optional first buffer layers (collectively referred to as first buffers 804) are stacked. A first InGaAs electromagnetic radiation absorber 806 is stacked on the first buffer 804 (i.e., the first buffer 804 is disposed between the InP substrate 802 and the first InGaAs electromagnetic radiation absorber 806), or is stacked on the InP substrate 802 without the first buffer 804. A second set of one or more buffer layers (collectively referred to as second buffers 808) is stacked on the first InGaAs electromagnetic radiation absorber 806, and a second InGaAs electromagnetic radiation absorber 810 is stacked on the second buffer 808 (i.e., the second buffer 808 is disposed between the first InGaAs electromagnetic radiation absorber 806 and the second InGaAs electromagnetic radiation absorber 810).

[0098] A first InGaAs electromagnetic radiation absorber may be electrically disposed between a first electrical contact 812 and a second electrical contact 814, wherein the first electrical contact 812 and the second electrical contact 814 are used to electrically bias the first InGaAs electromagnetic radiation absorber 806 and sense a first current generated by the first InGaAs electromagnetic radiation absorber 806. In some embodiments, the first electrical contact 812 may be deposited on a first buffer 804, and the second electrical contact 814 may be deposited on a second buffer 808. In other embodiments, the first electrical contact 812 may be deposited on, for example, an InP substrate 802, or the second electrical contact 814 may be deposited on the first InGaAs electromagnetic radiation absorber 806.

[0099] A second InGaAs electromagnetic radiation absorber may be electrically disposed between a second electrical contact 814 and a third electrical contact 816, wherein the second electrical contact 814 and the third electrical contact 816 are used to electrically bias the second InGaAs electromagnetic radiation absorber 810 and sense a second current generated by the second InGaAs electromagnetic radiation absorber 810. In some embodiments, the third electrical contact 816 may be deposited on the second InGaAs electromagnetic radiation absorber 810.

[0100] like Figure 8A As shown, the first buffer 804 may extend over the entire InP substrate 802, or over a portion of the InP substrate 802 that is larger than each of the first InGaAs electromagnetic radiation absorber 806, the second InGaAs electromagnetic radiation absorber 810, and the second buffer 808. The first electrical contact 812 is shown extending along three sides of the first InGaAs electromagnetic radiation absorber 806, but in other embodiments, it may be positioned only adjacent to one side of the first InGaAs electromagnetic radiation absorber 806, or may surround the first InGaAs electromagnetic radiation absorber 806 or have other configurations. Although the periphery of all substrate, buffer, and absorber components is... Figure 8A The elements are shown as rectangles or squares, but the perimeter of these elements may alternatively have any shape.

[0101] Figure 9A A plan view of a 2-contact InGaAs detector 900 is shown, and Figure 9BA top cross-sectional view of an InGaAs detector 900 is shown. The InGaAs detector 900 includes an InP substrate 902, on which one or more optional first buffer layers (collectively referred to as first buffers 904) are stacked. A first InGaAs electromagnetic radiation absorber 906 is stacked on the first buffer 904 (i.e., the first buffer 904 is disposed between the InP substrate 902 and the first InGaAs electromagnetic radiation absorber 906), or is stacked on the InP substrate 902 without the first buffer 904. A second set of one or more buffer layers (collectively referred to as second buffers 908) is stacked on the first InGaAs electromagnetic radiation absorber 906, and a second InGaAs electromagnetic radiation absorber 910 is stacked on the second buffer 908 (i.e., the second buffer 908 is disposed between the first InGaAs electromagnetic radiation absorber 906 and the second InGaAs electromagnetic radiation absorber 910).

[0102] A first InGaAs electromagnetic radiation absorber 906 and a second InGaAs electromagnetic radiation absorber 910 may be electrically disposed between a first electrical contact 912 and a second electrical contact 914, wherein the first electrical contact 912 and the second electrical contact 914 are used to electrically bias the first InGaAs electromagnetic radiation absorber 906 in a positive direction and sense a current corresponding to the total current generated by the first InGaAs electromagnetic radiation absorber 906. Alternatively, the first electrical contact 912 and the second electrical contact 914 may be used to electrically bias the second InGaAs electromagnetic radiation absorber 910 in a negative direction and sense a current corresponding to the total current generated by the second InGaAs electromagnetic radiation absorber 910. In other embodiments, and depending on the implantation or doping of the first InGaAs electromagnetic radiation absorber 906 and the second InGaAs electromagnetic radiation absorber 910, electrical contacts 912 and 914 can be used to bias and read the first InGaAs electromagnetic radiation absorber 906 and the second InGaAs electromagnetic radiation absorber 910 in opposite directions. In some embodiments, the first electrical contact 912 may be deposited on the first buffer 904, and the second electrical contact 914 may be deposited on the second InGaAs electromagnetic radiation absorber 910.

[0103] like Figure 9AAs shown, the first buffer 904 may extend over the entire InP substrate 902, or over a portion of the InP substrate 902 that is larger than each of the first InGaAs electromagnetic radiation absorber 906, the second InGaAs electromagnetic radiation absorber 910, and the second buffer 908. The first electrical contact 912 is shown extending along three sides of the first InGaAs electromagnetic radiation absorber 906, but in other embodiments, it may be positioned only adjacent to one side of the first InGaAs electromagnetic radiation absorber 906, or may surround the first InGaAs electromagnetic radiation absorber 906 or have other configurations. Although the periphery of all substrate, buffer, and absorber components is... Figure 9A The elements are shown as rectangles or squares, but the perimeter of these elements may alternatively have any shape.

[0104] Figure 10 An elevation view of an InGaAs detector 1000 is shown, in which a first InGaAs electromagnetic radiation absorber 1006 and a second InGaAs electromagnetic radiation absorber 1010 are configured back-to-back with photodiodes. The InGaAs detector 1000 includes an InP substrate 1002, on which a first set of one or more buffer layers (collectively referred to as first buffer 1004) are stacked. The first InGaAs electromagnetic radiation absorber 1006 is stacked on the first buffer 1004 (i.e., the first buffer 1004 is disposed between the InP substrate 1002 and the first InGaAs electromagnetic radiation absorber 1006). A second set of one or more buffer layers (collectively referred to as second buffer 1008) is stacked on the first InGaAs electromagnetic radiation absorber 1006, and the second InGaAs electromagnetic radiation absorber 1010 is stacked on the second buffer 1008 (i.e., the second buffer 1008 is disposed between the first InGaAs electromagnetic radiation absorber 1006 and the second InGaAs electromagnetic radiation absorber 1010). The capping layer 1012 is stacked on the second InGaAs electromagnetic radiation absorber 1010 (i.e., the second InGaAs electromagnetic radiation absorber 1010 is disposed between the second buffer 1008 and the capping layer 1012).

[0105] Each of the first InGaAs electromagnetic radiation absorber 1006 and the second InGaAs electromagnetic radiation absorber 1010 may be an n-doped (or n-type) InGaAs electromagnetic radiation absorber. Each of the first buffer 1004 and the second buffer 1008 may include one or more indium arsenide (InAsP) layers, wherein the first buffer 1004 includes one or more p-doped (or p-type) InAsP layers, and wherein the second buffer 1008 includes one or more n-doped (or n-type) InAsP layers. The InGaAs electromagnetic radiation absorbers 1006, 1010, buffers 1004, 1008, and capping layer 1012 thus form a pnnp layer structure including back-to-back photodiodes. A forward bias (or alternatively, a reverse bias) applied to the pnnp layer structure enables readout of the first InGaAs electromagnetic radiation absorber 1006 (or the second InGaAs electromagnetic radiation absorber 1010).

[0106] In an alternative embodiment, the InGaAs electromagnetic radiation absorbers 1006, 1010, buffer layers 1004, 1008, and capping layer 1012 may be implanted or doped to form an nppn, nBn, or pBp layer structure including back-to-back photodiodes.

[0107] Figure 11 An elevation view of an InGaAs detector 1100 is shown, comprising two photodetectors, a first InGaAs electromagnetic radiation absorber 1106 and a second InGaAs electromagnetic radiation absorber 1110, configured to face the same direction and connected by a tunnel junction. The InGaAs detector 1100 includes an InP substrate 1102, on which one or more buffer layers (collectively referred to as first buffers 1104) are stacked. The first InGaAs electromagnetic radiation absorber 1106 is stacked on the first buffer 1104 (i.e., the first buffer 1104 is disposed between the InP substrate 1102 and the first InGaAs electromagnetic radiation absorber 1106). A second set of one or more buffer layers (collectively referred to as second buffers 1108) is stacked on the first InGaAs electromagnetic radiation absorber 1106, and the second InGaAs electromagnetic radiation absorber 1110 is stacked on the second buffer 1108 (i.e., the second buffer 1108 is disposed between the first InGaAs electromagnetic radiation absorber 1106 and the second InGaAs electromagnetic radiation absorber 1110). The capping layer 1112 is stacked on the second InGaAs electromagnetic radiation absorber 1110 (i.e., the second InGaAs electromagnetic radiation absorber 1110 is disposed between the second buffer 1108 and the capping layer 1112).

[0108] Each of the first InGaAs electromagnetic radiation absorber 1106 and the second InGaAs electromagnetic radiation absorber 1110 may be an n-doped (or n-type) InGaAs electromagnetic radiation absorber. Each of the first buffer 1104 and the second buffer 1108 may include one or more indium arsenide (InAsP) layers, wherein the first buffer 1104 includes one or more n-doped (or n-type) InAsP layers, and wherein the second buffer 1108 includes one or more n-doped (or n-type) InAsP layers and one or more p-doped (or p-type) InAsP layers. The InGaAs electromagnetic radiation absorbers 1106, 1110, buffers 1104, 1108, and capping layer 1112 thus form a pnpn layer structure including a stacked photodiode with a tunnel junction. Unlike the reference Figure 10 The described InGaAs detector, with its tunnel junction, allows photocurrent to be read out from two InGaAs electromagnetic radiation absorbers 1106 and 1110 with the same bias polarity, which would require different bias voltages to extract photocurrent from different InGaAs electromagnetic radiation absorbers.

[0109] Figure 12A and Figure 12B An example of a device 1200 (electronic device) including a set of sensors is shown. The sensors can be used, for example, to obtain biometric information (e.g., heart rate, respiratory rate, blood pressure, blood flow rate, blood oxygenation, blood glucose level, etc.) from the wearer or user of the device 1200, or to determine the state of the device 1200 (e.g., whether the device 1200 is being worn or the tightness of the device 1200). The size and shape factors of the device, as well as the inclusion of a strap 1204 (e.g., a wristband), indicate that the device 1200 is an electronic watch, fitness monitor, or health diagnostic device. However, the device 1200 may alternatively be any type of wearable device. Figure 12A A front isometric view of device 1200 is shown, and Figure 12B A rear isometric view of device 1200 is shown.

[0110] Device 1200 may include a body 1202 (e.g., a watch body) and a strap 1204. Body 1202 may include input or selection devices, such as a crown 1218 or a button 1220. Strap 1204 may be attached to a housing 1206 of body 1202 and may be used to attach body 1202 to a user's body part (e.g., arm, wrist, leg, ankle, or waist). Body 1202 may include a housing 1206 that at least partially surrounds display 1208. In some embodiments, housing 1206 may include sidewalls 1210 that may support a front cover 1212 (…). Figure 12A ) and / or back cover 1214 ( Figure 12BThe front cover 1212 may be positioned above the display 1208 and may provide a window through which the display 1208 can be viewed. In some embodiments, the display 1208 may be attached to (or adjacent to) the sidewall 1210 and / or the front cover 1212. In alternative embodiments of the device 1200, the display 1208 may not be included and / or the housing 1206 may have an alternative configuration.

[0111] Display 1208 may include one or more light-emitting elements, including, for example, light-emitting elements defining a light-emitting diode (LED) display, an organic LED (OLED) display, a liquid crystal display (LCD), an electroluminescent (EL) display, or other types of displays. In some embodiments, display 1208 may include one or more touch sensors and / or force sensors, or associated therewith, which are configured to detect touch and / or force applied to the surface of the front cover 1212.

[0112] In some embodiments, the sidewalls 1210 of the housing 1206 may be formed of one or more metals (e.g., aluminum or stainless steel), polymers (e.g., plastics), ceramics, or composite materials (e.g., carbon fiber). The front cover 1212 may be formed, for example, using one or more of glass, crystal (e.g., sapphire), or transparent polymers (e.g., plastics), which allows a user to view the display 1208 through the front cover 1212. In some cases, a portion of the front cover 1212 (e.g., the peripheral portion of the front cover 1212) may be coated with an opaque ink to cover components included within the housing 1206. In some cases, all external components of the housing 1206 may be formed of a transparent material, and components within the device 1200 may be covered or uncovered by opaque ink or opaque structures within the housing 1206.

[0113] The rear cover 1214 may be formed of the same material used to form the sidewall 1210 or the front cover 1212. In some cases, the rear cover 1214 may be part of an integral element that also forms the sidewall 1210. In other cases, and as shown, the rear cover 1214 may be a multi-part rear cover, such as a rear cover having a first rear cover portion 1214-1 attached to the sidewall 1210 and a second rear cover portion 1214-2 attached to the first rear cover portion 1214-1. In some cases, the second rear cover portion 1214-2 may have a circular periphery and an arcuate outer surface 1216 (i.e., an outer surface 1216 with an arcuate profile).

[0114] The front cover 1212, the rear cover 1214, or the first rear cover portion 1214-1 can be mounted to the side wall 1210 using fasteners, adhesives, seals, gaskets, or other components. When present, the second rear cover portion 1214-2 can be mounted to the first rear cover portion 1214-1 using fasteners, adhesives, seals, gaskets, or other components.

[0115] A display stack or device stack (hereinafter referred to as a "stack") including display 1208 may be attached (or adjacent to) the inner surface of front cover 1212 and extend into the internal volume of device 1200. In some cases, the stack may include a touch sensor (e.g., a grid of capacitive, resistive, strain-based, ultrasonic, or other types of touch sensing elements) or other layers of optical, mechanical, electrical, or other types of components. In some cases, the touch sensor (or part of a touch sensor system) may be configured to detect touches applied to the outer surface of front cover 1212 (e.g., to the display surface of device 1200).

[0116] In some cases, the force sensor (or part of a force sensor system) may be located within an internal volume below and / or to the side of the display 1208 (and in some cases, within a device stack). The force sensor (or force sensor system) may be triggered in response to a touch sensor detecting one or more touches on the front cover 1212 (or one or more locations of one or more touches on the front cover 1212), and may determine the magnitude of the force associated with each touch, or the magnitude of the force associated with the entire set of touches. The force sensor (or force sensor system) may optionally trigger the operation of the touch sensor (or touch sensor system), or may be used independently of the touch sensor (or touch sensor system).

[0117] Device 1200 may include various sensors. In some embodiments, device 1200 may have a port 1222 (or a set of ports) on one side (or elsewhere) of housing 1206, and an ambient pressure sensor, an ambient temperature sensor, an internal / external differential pressure sensor, a gas sensor, a particulate matter concentration sensor, or an air quality sensor may be located in or near port 1222.

[0118] In some cases, one or more skin-facing sensors 1226 may be included within device 1200. Skin-facing sensors may transmit or receive signals and sense conditions via housing 1206 (or back cover 1214). For example, in some embodiments, one or more such sensors may include multiple electromagnetic radiation emitters (e.g., visible light and / or IR emitters) and / or multiple electromagnetic radiation detectors (e.g., visible light and / or IR detectors, such as any InGaAs detector described herein). Sensors may be used, for example, to obtain biometric information (e.g., heart rate, respiratory rate, blood pressure, blood flow rate, blood oxygenation, blood glucose level, etc.) from the wearer or user of device 1200, or to determine the state of device 1200 (e.g., whether device 1200 is being worn or the tightness of device 1200).

[0119] Device 1200 may include a circuitry 1224 (e.g., a processor and / or other components) configured to determine or extract, at least in part, signals received directly or indirectly from one or more sensors of the device, such as biometric parameters of the user of the device and / or the state of device 1200. In some embodiments, circuitry 1224 may be configured to transmit the determined or extracted parameters or state via an output device of device 1200. For example, circuitry 1224 may cause indications to be displayed on display 1208, output via audio or haptic feedback, transmitted via a wireless communication interface or other communication interface, etc. Circuitry 1224 may additionally or alternatively maintain or alter one or more settings, functions, or aspects of device 1200, in some cases including content displayed on display 1208.

[0120] Figure 13A and Figure 13B Another example of a device 1300 (electronic device) including a set of sensors is shown. The sensors can be used, for example, to obtain biological information from a user of the device 1300, determine parameters of the device 1300's environment (e.g., air quality), or determine the distance to a target or object or the composition of the target or object. The size and shape factors of the device (including the ratio of the length of its long side to the length of its short side) indicate that the device 1300 is a mobile phone (e.g., a smartphone). However, the size and shape factors of the device are arbitrarily chosen, and the device 1300 may alternatively be any portable electronic device, including, for example, a mobile phone, tablet computer, portable computer, portable music player, portable terminal, vehicle navigation system, robot navigation system, or other portable or mobile device. The device 1300 may also be a device that is semi-permanently located (or installed) in a single location (e.g., a door lock, thermostat, refrigerator, or other appliance). Figure 13A A front isometric view of device 1300 is shown, and Figure 13B A rear isometric view of device 1300 is shown. Device 1300 may include a housing 1302 that at least partially surrounds a display 1304. Housing 1302 may include or support a front cover 1306 or a rear cover 1308. Front cover 1306 may be positioned above display 1304 and may provide a window through which a user can view display 1304 (including images displayed thereon). In some embodiments, display 1304 may be attached to (or adjacent to) housing 1302 and / or front cover 1306.

[0121] Display 1304 may include one or more light-emitting elements or pixels, and in some cases may be an LED display, OLED display, LCD, EL display, laser projector, or another type of electronic display. In some embodiments, display 1304 may include one or more touch sensors and / or force sensors, or associated therewith, which are configured to detect touch and / or force applied to the surface of front cover 1306.

[0122] Various components of housing 1302 may be formed of the same or different materials. For example, the sidewalls 1318 of housing 1302 may be formed of one or more metals (e.g., stainless steel), polymers (e.g., plastics), ceramics, or composite materials (e.g., carbon fiber). In some cases, sidewalls 1318 may be multi-segment sidewalls including a set of antennas. Antennas may form structural components of sidewalls 1318. Antennas may be structurally coupled (to each other or to other components) and electrically isolated (to each other or to other components) through one or more non-conductive segments of sidewalls 1318. The front cover 1306 may be formed, for example, using one or more of glass, crystal (e.g., sapphire), or transparent polymers (e.g., plastics), which allows a user to view display 1304 through the front cover 1306. In some cases, a portion of the front cover 1306 (e.g., the peripheral portion of the front cover 1306) may be coated with an opaque ink to cover components included within housing 1302. The rear cover 1308 may be formed using the same material as that used to form the sidewalls 1318 or the front cover 1306, or it may be formed using one or more different materials. In some cases, the rear cover 1308 may be part of an integral element that also forms the sidewalls 1318 (or, in the case that the sidewalls 1318 are multi-segmented, those portions of the sidewalls 1318 are non-conductive). In other embodiments, all external components of the housing 1302 may be formed of a transparent material, and components within the device 1300 may be covered or uncovered by opaque ink or opaque structures within the housing 1302.

[0123] The front cover 1306 can be mounted to the side wall 1318 to cover the opening defined by the side wall 1318 (i.e., the opening to the internal volume in which various electronic components of the device 1300 (including the display 1304) can be positioned). The front cover 1306 can be mounted to the side wall 1318 using fasteners, adhesives, seals, gaskets, or other components.

[0124] A display stack or device stack (hereinafter referred to as a "stack") including display 1304 (and in some cases front cover 1306) may be attached (or adjacent to) the inner surface of front cover 1306 and extend into the internal volume of device 1300. In some cases, the stack may also include a touch sensor (e.g., a grid of capacitive, resistive, strain-based, ultrasonic, or other types of touch sensing elements) or other layers of optical, mechanical, electrical, or other types of components. In some cases, the touch sensor (or part of a touch sensor system) may be configured to detect touches applied to the outer surface of front cover 1306 (e.g., to the display surface of device 1300).

[0125] The stack may also include a sensor 1316 or an array thereof, wherein the sensor is positioned in front of or behind the light-emitting element of the display 1304 or distributed within the light-emitting element. In some cases, the array of sensor 1316 may extend across an area equal in size to the area of ​​the display 1304. Alternatively, the array of photodetectors 1316 may extend across an area smaller or larger than the area of ​​the display 1304, or may be positioned entirely adjacent to the display 1304. Although the array of sensor 1316 is shown as having rectangular boundaries, the array may alternatively have boundaries with different shapes, including, for example, irregular shapes. The array of sensor 1316 may be configured in various ways as an ambient light sensor, a light-emitting element (e.g., OLED), a health sensor (e.g., an aging sensor), a touch sensor, a proximity sensor, a biometric sensor (e.g., a fingerprint sensor or a facial recognition sensor), a camera, a depth sensor, and so on. The array of sensor 1316 may additionally or alternatively serve as a proximity sensor for determining whether an object (e.g., a finger, face, or stylus) is near the front cover 1306. In some implementations, the array of sensors 1316 can provide stacked touch sensing capabilities (i.e., touch sensors).

[0126] In some cases, the force sensor (or part of a force sensor system) may be located within an internal volume below and / or to the side of the display 1304 (and in some cases, within a stack). The force sensor (or force sensor system) may be triggered in response to a touch sensor detecting one or more touches on the front cover 1306 (or indicating one or more locations of one or more touches on the front cover 1306), and may determine the magnitude of the force associated with each touch, or the magnitude of the force associated with the entire set of touches.

[0127] like Figure 13A As shown, device 1300 may include various other components. For example, the front of device 1300 may include one or more forward-facing cameras 1310 (including one or more image sensors), a speaker 1312, a microphone, or other components 1314 (e.g., audio components, imaging components, and / or sensing components) configured to transmit signals to or receive signals from device 1300. In some cases, the forward-facing camera 1310 may be configured to operate as a biometric or facial recognition sensor, alone or in combination with other sensors. Additionally or alternatively, an array of sensors 1316 may be configured to operate as a forward-facing camera 1310, a biometric sensor, or a facial recognition sensor.

[0128] Device 1300 may also include buttons or other input devices positioned along a sidewall 1318 of device 1300 and / or on the rear surface of the device. For example, a volume button or multifunction button 1320 may be positioned along the sidewall 1318 and, in some cases, may extend through an opening in the sidewall 1318. The sidewall 1318 may include one or more ports 1322 that allow air (but not liquid) to flow into and out of device 1300. In some embodiments, one or more sensors may be located in or near the ports 1322. For example, an ambient pressure sensor, an ambient temperature sensor, an internal / external differential pressure sensor, a gas sensor, a particulate matter concentration sensor, or an air quality sensor may be located in or near the ports 1322.

[0129] In some embodiments, the rear surface of device 1300 may include a rear-facing camera 1324. A flash or light source 1326 may also be positioned along the rear of device 1300 (e.g., close to the rear-facing camera). In some cases, the rear surface of device 1300 may include multiple rear-facing cameras.

[0130] In some cases, sensor 1316, forward camera 1310, rear camera 1324, and / or other sensors located on the front, rear, or side of device 1300 may transmit or receive signals or sense conditions through housing 1302 (including front cover 1306, rear cover 1308, or sidewall 1318). For example, in some embodiments, one or more such sensors may include multiple electromagnetic radiation emitters (e.g., visible light and / or IR emitters) and / or multiple electromagnetic radiation detectors (e.g., visible light and / or IR detectors, such as any InGaAs detector described herein).

[0131] Device 1300 may include a circuitry 1328 (e.g., a processor and / or other components) configured to determine or extract, at least in part, parameters of the device's environment (e.g., air quality) or the composition of a target or object, in response to signals received directly or indirectly from one or more sensors in the device's sensors. In some embodiments, circuitry 1328 may be configured to transmit the determined or extracted parameters or status via an output device of device 1300. For example, circuitry 1328 may cause indications to be displayed on display 1304, output via audio or haptic feedback, transmitted via a wireless communication interface or other communication interface, etc. Circuitry 1328 may additionally or alternatively maintain or alter one or more settings, functions, or aspects of device 1300, in some cases including content displayed on display 1304.

[0132] Figure 14 An example of an earbud 1400 (electronic device) including a set of sensors 1408 is shown. The earbud 1400 may include a housing 1402. The housing 1402 may hold a speaker 1410 that can be inserted into a user's ear, an optional microphone 1404, and a circuitry 1406 for acquiring audio from the microphone 1404, transmitting audio to the speaker 1402, and transmitting audio between the speaker 1402, the microphone 1404, and one or more remote devices. The circuitry 1406 may wirelessly communicate with the remote devices (e.g., via a wireless communication interface, using, for example, Wi-Fi). It can communicate via cellular radio communication protocols or via one or more lines (e.g., via wired communication interfaces such as Universal Serial Bus (USB) communication interfaces). In addition to transmitting audio, the circuit system 1406 can also transmit or receive commands, etc.

[0133] Sensor 1408 can be used, for example, to determine the proximity of a user to earbud 1400 or speaker 1410, or to receive input from the user. In some cases, the sensor can be used to identify user gestures (e.g., swiping or pressing gestures) made on the surface of earbud 1400 or in free space near earbud 1400. Sensor 1408 may include skin-facing and / or non-skin-facing sensors. In some embodiments, one or more such sensors may include multiple electromagnetic radiation emitters (e.g., visible light and / or IR emitters) and / or multiple electromagnetic radiation detectors (e.g., visible light and / or IR detectors, such as any InGaAs detector described herein).

[0134] The circuit system 1406 may include a processor and / or other components configured to determine or extract information related to user proximity, user input, etc., in at least part of a response to signals received directly or indirectly from one or more sensors in the sensor 1408. In some embodiments, the circuit system 1406 may be configured to transmit the determined or extracted parameters or states via an output device of the earpiece 1400. For example, the circuit system 1406 may cause indications to be output via a speaker 1410 or a haptic device, transmitted via a wireless communication interface or other communication interface, etc. The circuit system 1406 may additionally or alternatively maintain or modify one or more settings, functions, or aspects of the earpiece 1400, in some cases including content output via the speaker 1410.

[0135] Figure 15 An exemplary elevation view of a system 1500 that may include an electromagnetic radiation emitter and detector in an electronic device is shown. In some cases, system 1500 may be included in a wearable device (such as a reference optics unit). Figures 12A to 12B , Figures 13A to 13B or Figure 14 (Described in the context of wearable devices).

[0136] For example, in Figure 15 The image shows two electromagnetic radiation emitters 1502 and 1504 and one electromagnetic radiation detector 1506. When combined with a reference... Figure 12A and Figure 12B In the described wearable device, transmitters 1502 and 1504 may be positioned and / or oriented to emit electromagnetic radiation 1512 toward a target (e.g., the wrist or other body part 1508 of the user of the wearable device). Similarly, detector 1506 may be positioned and / or oriented to receive electromagnetic radiation 1514 returned (e.g., reflected or scattered) from hair, skin, or internal structures of the wrist or other body part 1508.

[0137] Detector 1506 may be configured similarly to any detector described herein (e.g., an InGaAs detector) and may include two or more electromagnetic radiation absorbers.

[0138] Emitters 1502 and 1504 may emit the same or different electromagnetic radiation wavelengths and may have the same or different configurations (e.g., both may be lasers, one may be a laser and the other may be an LED, etc.). In some embodiments, emitters 1502 and 1504 may be configured to emit different electromagnetic radiation wavelengths, and detector 1506 may be configured to detect different electromagnetic radiation wavelengths. If different electromagnetic radiation absorbers of the detector are configured to detect different and non-overlapping electromagnetic radiation wavelength ranges, emitters 1502 and 1504 may be activated to simultaneously emit their different electromagnetic radiation wavelengths, and detector 1506 may separately receive and quantify the electromagnetic radiation received from each of emitters 1502 and 1504. Thus, detector 1506 can operate as a spectrometer with two or more resolvable spots.

[0139] The detection circuit 1510 can be configured to operate transmitters 1502 and 1504 at the same or different times, and to read the current generated by the first electromagnetic radiation absorber and the second electromagnetic radiation absorber after simultaneous emission from transmitters 1502 and 1504, overlapping emission from transmitters 1502 and 1504, or non-overlapping (i.e., time-spaced) emission from transmitters 1502 and 1504.

[0140] Figure 16 An example electrical block diagram of electronic device 1600 is shown, which may be implemented as a reference in some cases. Figures 12A to 12B , Figures 13A to 13B or Figure 14 The described device. Electronic device 1600 may include electronic display 1602 (e.g., a light-emitting display), processor 1604, power supply 1606, memory 1608 or storage device, sensor system 1610 or input / output (I / O) mechanism 1612 (e.g., input / output device, input / output port, or haptic input / output interface). Processor 1604 may control some or all of the operations of electronic device 1600. Processor 1604 may communicate directly or indirectly with some or all other components of electronic device 1600. For example, system bus or other communication mechanism 1614 may provide communication between electronic display 1602, processor 1604, power supply 1606, memory 1608, sensor system 1610 and I / O mechanism 1612.

[0141] Processor 1604 can be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions, whether such data or instructions are in the form of software or firmware or otherwise encoded. For example, processor 1604 may include a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a controller, or a combination of such devices. As described herein, the term "processor" is intended to cover a single processor or processing unit, multiple processors, multiple processing units, or one or more other suitably configured computing elements. In some cases, processor 1604 may be provided as a reference. Figures 12A to 15 The circuit system described is part or all of it.

[0142] It should be noted that components of electronic device 1600 may be controlled by multiple processors. For example, selectable components of electronic device 1600 (e.g., sensor system 1610) may be controlled by a first processor and other components of electronic device 1600 (e.g., electronic display 1602) may be controlled by a second processor, wherein the first processor and the second processor may or may not communicate with each other.

[0143] The power source 1606 can be implemented using any device capable of providing power to the electronic device 1600. For example, the power source 1606 may include one or more batteries or rechargeable batteries. Additionally or alternatively, the power source 1606 may include a power connector or power cord for connecting the electronic device 1600 to another power source, such as a wall power outlet.

[0144] Memory 1608 may store electronic data that can be used by electronic device 1600. For example, memory 1608 may 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, and data structures or databases. Memory 1608 may include any type of memory. By way of example only, memory 1608 may include random access memory, read-only memory, flash memory, removable memory, other types of storage elements, or combinations of these memory types.

[0145] The electronic device 1600 may also include a sensor system 1610, which includes sensors positioned at virtually any location on the electronic device 1600. In some cases, the sensor system 1610 may include, as referenced... Figures 2A to 15The sensor system 1610 may be configured to sense one or more types of electromagnetic radiation emitters and detectors, as described in any of the above descriptions, generally positioned and / or configured. The sensor system 1610 may be configured to sense one or more types of parameters, such as, but not limited to, vibration; light; touch; force; heat; movement; relative motion; user biometric data (e.g., biological parameters); air quality; proximity; location; connectivity; type of matter; and so on. For example, the sensor system 1610 may include one or more of the following: thermal sensors, position sensors, proximity sensors, light or optical sensors (e.g., electromagnetic radiation emitters and / or detectors), accelerometers, pressure transducers, gyroscopes, magnetometers, health monitoring sensors, and air quality sensors. Additionally, the sensor system 1610 may utilize any suitable sensing technology, including but not limited to interferometry, magnetic, pressure, capacitance, ultrasonic, resistive, optical, acoustic, piezoelectric, or thermal techniques.

[0146] I / O mechanism 1612 can transmit or receive data from a user or another electronic device. I / O mechanism 1612 may include an electronic display 1602, a touch-sensing input surface, a crown, one or more buttons (e.g., a graphical user interface "home" button), one or more cameras (including under-display cameras), one or more microphones or speakers, one or more ports such as microphone ports, and / or a keyboard. Additionally or alternatively, I / O mechanism 1612 may transmit electronic signals via communication interfaces such as wireless, wired, and / or optical communication interfaces. Examples of wireless and wired communication interfaces include, but are not limited to, cellular and Wi-Fi communication interfaces.

[0147] The foregoing description uses specific nomenclature to provide a thorough understanding of the described embodiments for the purpose of explanation. However, it will be apparent to those skilled in the art that, after reading this specification, the specific details are not required to practice the described embodiments. Therefore, the foregoing description of specific embodiments described herein is presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to those skilled in the art that, after reading this specification and in light of the teachings above, many modifications and variations are possible.

[0148] As described above, one aspect of this technology may be the collection and use of data from various sources. This disclosure contemplates that, in some cases, the collected data may include personal information data (e.g., biometric information) that uniquely identifies or can be used to identify, locate, or diagnose specific individuals. Such personal information data may include demographic data, location-based data, telephone numbers, email addresses, home addresses, data or records related to a user's health or fitness level (e.g., vital sign measurements, medication information, exercise information), date of birth, or any other identifying information or personal information.

[0149] This disclosure recognizes that the use of such personal information data in the techniques of this invention can be beneficial to users. For example, personal information data can be used to activate or deactivate various functions of a user's device, or to collect performance metrics of the user's device or user. Furthermore, this disclosure also contemplates other uses of personal information data that are beneficial to users. For example, health and fitness data can be used to provide insights into a user's overall health status, or can be used as positive feedback for individuals using technology to pursue health goals.

[0150] This disclosure anticipates that entities responsible for collecting, analyzing, disclosing, transmitting, storing, or otherwise using such personal information data will comply with established privacy policies and / or privacy practices. Specifically, such entities should implement and adhere to privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy and security of personal information data. Such policies should be easily accessible to users and should be updated as data collection and / or use change. Personal information from users should be collected for the entity's lawful and reasonable purposes and not shared or sold outside of these lawful uses. Furthermore, such collection / sharing should be conducted only after obtaining informed consent from users. Additionally, such entities should consider taking any necessary steps to protect and safeguard access to such personal information data and ensure that others with access to such personal information data comply with their privacy policies and processes. Furthermore, such entities may be subject to third-party assessments to demonstrate their compliance with widely accepted privacy policies and practices. Additionally, policies and practices should be adapted to the specific types of personal information data collected and / or accessed, and to applicable laws and standards, including specific considerations regarding jurisdiction. For example, in the United States, the collection or access to certain health data may be governed by federal and / or state laws, such as the Health Insurance Portability and Accountability Act (“HIPAA”); while health data in other countries may be subject to other regulations and policies and should be handled accordingly. Therefore, different privacy practices should be maintained for different types of personal data in each country.

[0151] Regardless of the foregoing, this disclosure also contemplates implementation schemes that allow users to selectively block the use or access to personal information data. That is, this disclosure contemplates providing hardware and / or software components to prevent or block access to such personal information data. For example, with regard to advertising delivery services, the technology of this invention can be configured to allow users to opt-in or opt-out at any time during or after service registration to participate in the collection of personal information data. In another example, users can choose not to provide emotion-related data for a targeted content delivery service. In yet another example, users can choose to limit the length of time emotion-related data is retained, or completely prohibit the development of underlying emotional states. In addition to providing opt-in and opt-out options, this disclosure also contemplates providing notifications related to access to or use of personal information. For example, users can be notified when downloading an application that their personal information data will be accessed, and then reminded again just before the application accesses the personal information data.

[0152] Furthermore, the purpose of this disclosure is to manage and process personal information data to minimize the risk of unintentional or unauthorized access or use. Once data is no longer needed, this risk can be minimized by limiting data collection and deleting data. Additionally, and where applicable, including in certain health-related applications, data deidentification can be used to protect user privacy. Where appropriate, deidentification can be facilitated by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of stored data (e.g., collecting location data at the city level rather than the address level), controlling how data is stored (e.g., aggregating data across users), and / or other methods.

[0153] Therefore, while this disclosure broadly covers the use of personal information data to implement one or more of the various disclosed embodiments, it is also contemplated that various embodiments can be implemented without access to such personal information data. That is, various embodiments of the present invention will not be rendered inoperable due to the absence of all or part of such personal information data. For example, preferences can be inferred based on non-personal information data or a minimal amount of personal information, such as content requested by a device associated with a user, other non-personal information available to the content delivery service, or publicly available information, thereby selecting content and delivering it to the user.

Claims

1. An electromagnetic radiation detector, comprising: An indium phosphide (InP) substrate having a first surface opposite to a second surface; A first indium gallium arsenide (InGaAs) electromagnetic radiation absorber is stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths. A set of one or more buffer layers, the set of one or more buffer layers being stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the electromagnetic radiation wavelengths of the first set of electromagnetic radiation wavelengths; The second InGaAs electromagnetic radiation absorber is stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths. and An immersion-type condenser lens is formed on the second surface and configured to guide electromagnetic radiation through the InP substrate and direct it to the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber; wherein... The second group of electromagnetic radiation wavelengths includes at least some electromagnetic radiation wavelengths that are not in the first group of electromagnetic radiation wavelengths; as well as The first responsivity of the first InGaAs electromagnetic radiation absorber and the second responsivity of the second InGaAs electromagnetic radiation absorber have an alternation point at the electromagnetic radiation wavelength within the moisture absorption band of 1.85µm to 2.0µm.

2. The electromagnetic radiation detector according to claim 1, wherein: The group or more buffer layers are the first group or more buffer layers; and The electromagnetic radiation detector further includes a second set of one or more buffer layers directly disposed on the InP substrate between the InP substrate and the first InGaAs electromagnetic radiation absorber.

3. The electromagnetic radiation detector according to claim 1, wherein: At least the InP substrate, the first InGaAs electromagnetic radiation absorber, the group of one or more buffer layers, the second InGaAs electromagnetic radiation absorber, and the immersion focusing lens define at least a first detector unit; and The electromagnetic radiation detector further includes a detector unit array, which includes the first detector unit. Each detector unit in the detector unit array includes at least the InP substrate, the first InGaAs electromagnetic radiation absorber, the group of one or more buffer layers, and different portions of the second InGaAs electromagnetic radiation absorber.

4. The electromagnetic radiation detector according to claim 1, wherein the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber are configured as two photodetectors facing the same direction and connected by a tunnel junction.

5. The electromagnetic radiation detector according to claim 1, wherein the one or more buffer layers comprise one or more indium arsenide (InAsP) layers.

6. The electromagnetic radiation detector according to claim 2, wherein the second group of one or more buffer layers comprises one or more indium arsenide (InAsP) layers.

7. The electromagnetic radiation detector according to claim 1, wherein the first responsivity of the first InGaAs electromagnetic radiation absorber and the second responsivity of the second InGaAs electromagnetic radiation absorber have an alternation point at an electromagnetic radiation wavelength of 1.9 micrometers.

8. An electromagnetic radiation detection system, comprising: substrate; On the first surface of the substrate, First indium gallium arsenide (InGaAs) electromagnetic radiation absorber; Second InGaAs electromagnetic radiation absorber; and A buffer, wherein the buffer is positioned between the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber; First electromagnetic radiation emitter; Second electromagnetic radiation emitter; and A detection circuit, configured to operate the first electromagnetic radiation emitter and the second electromagnetic radiation emitter, and respectively The first electromagnetic radiation emitted by the first electromagnetic radiation emitter is detected by reading the first current generated by the first InGaAs electromagnetic radiation absorber. as well as The second electromagnetic radiation emitted by the second electromagnetic radiation emitter is detected by reading the second current generated by the second InGaAs electromagnetic radiation absorber; wherein... The first responsivity of the first InGaAs electromagnetic radiation absorber and the second responsivity of the second InGaAs electromagnetic radiation absorber have an alternation point at the electromagnetic radiation wavelength within the moisture absorption band of 1.85µm to 2.0µm.

9. The electromagnetic radiation detection system according to claim 8, wherein the detection circuit is configured to simultaneously operate the first electromagnetic radiation emitter and the second electromagnetic radiation emitter, and simultaneously detect the first electromagnetic radiation and the second electromagnetic radiation emitted by the first electromagnetic radiation emitter and the second electromagnetic radiation emitted by the second electromagnetic radiation emitter, respectively.

10. The electromagnetic radiation detection system according to claim 8, wherein the detection circuit is configured to operate the first electromagnetic radiation emitter and the second electromagnetic radiation emitter at different times, and simultaneously detect the first electromagnetic radiation and the second electromagnetic radiation emitted by the first electromagnetic radiation emitter and the second electromagnetic radiation emitter, respectively.

11. The electromagnetic radiation detection system according to claim 8, wherein the buffer is a first buffer, and the electromagnetic radiation detection system further comprises: On the first surface of the substrate, The second buffer is positioned between the substrate and the first InGaAs electromagnetic radiation absorber.

12. The electromagnetic radiation detection system according to claim 8, further comprising: On the second surface of the substrate opposite to the first surface, An immersion condenser lens is configured to guide electromagnetic radiation through the substrate and direct it to the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber.

13. The electromagnetic radiation detection system according to claim 8, wherein the first absorption range of the first InGaAs electromagnetic radiation absorber and the second absorption range of the second InGaAs electromagnetic radiation absorber do not overlap.

14. The electromagnetic radiation detection system according to claim 8, wherein the first responsivity of the first InGaAs electromagnetic radiation absorber and the second responsivity of the second InGaAs electromagnetic radiation absorber have an alternation point at electromagnetic radiation wavelengths in the range of 1.9µm to 2.0µm.

15. The electromagnetic radiation detection system of claim 8, wherein the buffer comprises one or more indium arsenide (InAsP) layers.

16. An electronic device comprising: case; An electromagnetic radiation emitter configured to emit electromagnetic radiation through the housing; and An electromagnetic radiation detector, configured to receive electromagnetic radiation reflected from a target; wherein, The electromagnetic radiation detector includes: A substrate having a first surface opposite to a second surface; A first buffer, which is directly stacked on the first surface; A first indium gallium arsenide (InGaAs) electromagnetic radiation absorber is stacked on the first buffer and configured to absorb a first set of electromagnetic radiation wavelengths. A second buffer, stacked on top of the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the electromagnetic radiation wavelengths from the first set of electromagnetic radiation wavelengths; and A second InGaAs electromagnetic radiation absorber, stacked on the second buffer and configured to absorb a second set of electromagnetic radiation wavelengths; wherein... The second set of electromagnetic radiation wavelengths includes at least some electromagnetic radiation wavelengths that are not in the first set of electromagnetic radiation wavelengths; and The first responsivity of the first InGaAs electromagnetic radiation absorber and the second responsivity of the second InGaAs electromagnetic radiation absorber have an alternation point at the electromagnetic radiation wavelength within the moisture absorption band of 1.85µm to 2.0µm.

17. The electronic device according to claim 16, wherein: The substrate is an indium phosphide (InP) substrate.

18. The electronic device of claim 16, wherein each of the first buffer and the second buffer comprises one or more indium arsenide (InAsP) layers.

19. The electronic device of claim 16, further comprising: The first electrical contact is located on the first buffer; The second electrical contact is located on the second InGaAs electromagnetic radiation absorber; and The third electrical contact is located on the second buffer.

20. The electronic device of claim 16, further comprising: The first electrical contact is located on the first buffer; and The second electrical contact is located on the second InGaAs electromagnetic radiation absorber; wherein... The first and second electrical contacts are forward biased or reverse biased to read the current generated by the first InGaAs electromagnetic radiation absorber or the second InGaAs electromagnetic radiation absorber.

21. The electronic device of claim 16, further comprising: A capping layer is stacked on the second InGaAs electromagnetic radiation absorber; wherein... The cover layer, the second InGaAs electromagnetic radiation absorber, the second buffer, and the first InGaAs electromagnetic radiation absorber are configured as pnnp, nppn, or pnpn layer structures.

22. The electronic device according to claim 16, wherein: The housing has a back panel configured to face the user's skin when the electronic device is worn on a part of the user's body; and The electronic device also includes a strap configured to attach the housing to the body part.

Images