Optical sensor and detector for optical detection

Abstract

To provide an optical sensor, a detector including the optical sensor for an optical detection of at least one object, a manufacturing method of the optical sensor, and applications of the optical detector.SOLUTION: An optical sensor 110 includes a substrate 124 attached to a circuit carrier device 142, a layer 112 of a photoconductive material 114 directly or indirectly applied to the substrate 124, electrical contacts 136 and 136', in contact with the layer 112, and a cover 116 covering accessible surfaces of the layer 112 and the substrate 124. The cover 116 is an amorphous cover comprising a metal-containing compound 120, and at least one of the substrate 124 and the cover 116 is optically transparent in the wavelength range. The optical sensor 110 provides increased protection against possible degradation due to humidity and / or oxygen over time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical sensor and a detector having such an optical sensor for optical detection, in particular optical detection of optical radiation, in particular optical radiation in the infrared spectral range, in particular relating to sensing at least one of the transmittance, absorption, emission, and reflectance provided by at least one light beam, or for determining the position of at least one object, in particular the position of at least one object relating to the depth or both the depth and width of the at least one object. Furthermore, the present invention relates to a method for manufacturing the optical sensor and various uses of the optical sensor and detector. Such devices, methods, and uses can be employed in various fields of security technology. However, further applications are also possible. [Background technology]

[0002] Various detectors for optically detecting at least one object are known based on optical sensors. WO 2012 / 110924 A1 discloses a detector including at least one optical sensor, which exhibits at least one sensor area. The optical sensor is designed to generate at least one sensor signal in response to illumination of the sensor area. According to the FIP effect described therein, the sensor signal depends on the geometry of the illumination, particularly the beam cross section of the illumination on the sensor area, assuming the total illumination power is the same. The detector further includes at least one evaluation device designed to generate at least one item of geometric information from the sensor signal, particularly at least one item of geometric information related to the illumination and / or the object.

[0003] WO 2014 / 097181 A1 discloses a method and a detector for determining the position of at least one object using at least one lateral optical sensor and at least one longitudinal optical sensor. Preferably, a stack of longitudinal optical sensors is employed, particularly for determining the longitudinal position of an object with high accuracy and unambiguity. WO 2014 / 097181 A1 further discloses a human-machine interface, an entertainment device, a tracking system, and a camera, each of which includes at least one such detector for determining the position of at least one object.

[0004] WO2016 / 120392A1 discloses another type of material suitable for a longitudinal optical sensor, where the sensor area of ​​the longitudinal optical sensor comprises a photoconductive material, and the electrical conductivity of the photoconductive material depends on the beam cross section of the light beam in the sensor area, assuming the total power of irradiation is the same. Therefore, the longitudinal sensor signal depends on the electrical conductivity of the photoconductive material. Preferably, the photoconductive material is selected from lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), cadmium telluride (CdTe), indium phosphide (InP), cadmium sulfide (CdS), cadmium selenide (CdSe), indium antimonide (InSb), mercury cadmium telluride (HgCdTe; MCT), copper indium sulfide (CIS), copper indium gallium selenide (CIGS), zinc sulfide (ZnS), zinc selenide (ZnSe), or copper zinc tin sulfide (CZTS). Furthermore, solid solutions and / or doped variants thereof are also possible. Furthermore, a lateral photosensor having a sensor region is disclosed, the sensor region comprising a layer of photoconductive material, preferably embedded between two transparent conductive oxide layers and at least two electrodes. Preferably, at least one of the electrodes is a split electrode having at least two partial electrodes, the lateral sensor signal provided by which is indicative of the x and / or y position of the incident light beam within the sensor area.

[0005] "Preparation of Lead Sulfide Thin Films by the Atomic Layer Epitaxy Process" by M Leskelae, L Niinistoe, P Niemela, E Nykaenen, P Soininen, M Tiitta, and J Vaehaekangas studied the preparation of lead sulfide thin films on different substrates by atomic layer deposition (ALD). The sulfur source used in all experiments was H2S, while the following compounds were tested as lead sources: bromide, iodide, acetate, and a chelate of thorium dioxide (2,2,6,6-tetramethyl-3,5-heptanedione) with diethyldithiocarbamate. The final composite showed the highest growth rate. Growth experiments were performed at 300-350°C, and film thicknesses varied between 0.1 and 1 μm. Results showed that the films were polycrystalline and randomly oriented. The conductivity was p-type, and the carrier concentrations and mobilities were comparable to those found in films deposited by conventional chemical methods.

[0006] "Fabrication and Characterization of Lead Sulfide Thin Films by Atomic Layer Deposition," ECS Transactions 16(4), pp. 29-36, 2008, by NPDasgupta, SP Walch, and FB Prinz, presents a study on the deposition of lead sulfide (PbS) films by ALD. PbS films were deposited from Pb(tmhd)2 and H2S precursors at precursor sublimation temperatures of 165-175°C. Film growth rates of 0.13-0.18 nm / cycle were obtained, which are higher than previously published values. The linear growth rate characteristic of ALD was observed without chemical contamination. AFM images show that the films are polycrystalline, with grain size increasing with film thickness.

[0007] "Design of an Atomic Layer Deposition Reactor for Hydrogen Sulfide Compatibility," Rev. Sc. Instr. 81, 044102, 2010, by NPDasgupta, JF Mack, MCLangston, Al Bousetta, and FBPrinz, describes a customized ALD reactor designed with components compatible with hydrogen sulfide (HS) chemistry. HS is used as a reactant in the ALD of metal sulfides. The use of HS in an ALD reactor requires special attention to safety issues due to the highly toxic, flammable, and corrosive nature of HS. The reactor was designed with consideration for material compatibility with HS for all wetted parts. A customized safety interlock system was developed to shut down the system in the event of a toxic gas leak, power outage, loss of building ventilation, or loss of compressed air pressure. ALD of lead sulfide (PbS) and zinc sulfide (ZnS) was demonstrated without any chemical contamination or detectable release of HS.

[0008] J. Xu, B.R. Sutherland, S. Hoogland, F. Fan, S. Kinge, and E.H. Sargent, "Atomic Layer Deposition of Thin Absorbing Films on Nanostructured Electrodes for Short-Wavelength Infrared Light Detection," Appl. Phys. Lett. 107, 153105, 2015, reports that ALD has become the industry standard for large-area deposition of a wide array of oxide materials, owing to its ability to form high-quality thin films without high temperatures or high vacuum. Recently, it has shown promise for the formation of nanocrystalline sulfide films. Here, they demonstrate the feasibility of ALD lead sulfide for optical detection. Due to the conformal capabilities of ALD, they utilize ZnO nanowire electrodes to enhance the absorptance without compromising the extraction efficiency of the absorbing layer. The nanowires are first coated with a thin anti-shunt TiO layer, followed by an infrared-active ALD PbS layer for optical sensing.

[0009] In particular, to prevent degradation of the photoconductive material due to external influences, such as humidity and / or oxygen, an optical sensor including a photoconductive material may be at least partially covered by an encapsulation layer. For this purpose, the encapsulation layer is typically provided by using an encapsulation adhesive, usually an epoxy adhesive, and / or an encapsulation glass. Additionally or alternatively, the optical sensor may be encapsulated in a hermetic package. However, the encapsulation glass and encapsulation adhesive are preferably selected for their absorption characteristics over the wavelength range that may be relevant for sensing with the photoconductive material. Here, borosilicate glass and quartz glass are known to absorb at wavelengths above approximately 2500 nm, which can significantly limit the spectral response of photoconductive materials, particularly PbS and PbSe. Other encapsulation glasses, such as sapphire, may offer more suitable absorption characteristics, but they typically tend to be very expensive. Furthermore, hermetic packages are generally bulky and difficult and expensive to integrate into printed circuit boards.

[0010] "Photoconductive Properties of Chemically Deposited PbS with Dielectric Overcoatings," J. Appl. Phys. 46, p. 3489, 1975, by G. H. Blount, K. Preis, R.T. Yamada, and R.H. Bube, describes vacuum-deposited overcoatings of Al2O3, As2S3, CdTe, MgF2, SiO2, and SiO2 on thin-film PbS photodetectors. The overcoating thicknesses were approximately the thicknesses required to optimize antireflection properties. Although the overcoatings produced low yields for Al2O3, MgF2, and CdTe, none of them significantly degraded the detector's performance. This low yield is apparently due to the physical incompatibility of the overcoatings with the PbS film. Improved detector performance was obtained with As2S3 via reduction of 1 / f noise and passivation against adverse environments.

[0011] "Low-Temperature Al2O3 Atomic Layer Deposition," Chem. Mater. 16, pp. 639-645, 2004, by MD Groner, FH Fabreguette, JW E Lam, and SM George, reports Al2O3 films deposited by ALD at temperatures as low as 33°C in a viscous fluid reactor using alternating exposures of Al(CH3)3 (trimethylaluminum, TMA) and H2O. Low-temperature Al2O3 ALD films have the potential to coat thermally fragile substrates such as organic, polymeric, and biomaterials. The density of the Al2O3 films decreased with decreasing deposition temperature. The density of the Al2O3 ALD film was 3.0 g / cm3 at 177°C. 3 , 2.5 g / cm at 33°C 3 AFM images showed that the Al2O3 ALD films grown at low temperatures were very smooth, with a root-mean-square (RMS) roughness of only 0.4 ± 0.1 nm. Elemental analysis of the films using forward recoil spectroscopy revealed increasing hydrogen concentrations with decreasing growth temperature. Except for the parent aluminum and oxygen concentrations, no other elements were observed by Rutherford backscattering spectroscopy. Low-temperature Al2O3 ALD at 58 °C was demonstrated for the first time on polyethylene terephthalate (PET) polymer substrates.

[0012] US 5,291,066A discloses a moisture-proof integrated circuit module including at least one integrated circuit component of a high density interconnect (HDI) structure, fabricated by applying to a substrate a continuous multi-layer sequence having a plurality of via holes therein. The sequence covers the component and the module substrate, each sequence including a dielectric film and a plurality of lands including metal that extend into the vias of the sequence to provide electrical interconnection. The module includes at least one moisture barrier film to prevent ingress of moisture through the module to the circuit component.

[0013] US 7,939,932 B2 discloses low-temperature inorganic dielectric ALD films (e.g., Al2O3 and TiO2) deposited on packaged or unpackaged chip devices to coat the device, including exposed electrical contacts. Such low-temperature ALD films can generally be deposited without damaging the packaged chip device. The ALD films are generally deposited to a thickness sufficient to provide desired qualities (e.g., hermeticity of the entire packaged chip device, passivation of electrical contacts, biocompatibility, etc.), while allowing electrical connections (e.g., by soldering) to be made directly through the ALD film to the electrical contacts without exposing the electrical contacts.

[0014] W. Yoon, A.R. Smith, E.E.F.oos, J.E.B. Boercker, W.B. Heuer, and J.G.Tischler, "Electrical Measurements of PbSe Nanocrystal Thin Films Passivated by Remote Plasma Atomic Layer Deposition of Al2O3 Under Ambient Conditions," IEEE Transactions on Nanotech. 12(2), pp. 146-151, 2013, reported that PbSe nanocrystal thin-film transistors (TFTs) were passivated using remote plasma ALD of approximately 10 nm thick Al2O3 films at 150 °C. By using a highly reactive remote oxygen plasma source, one complete ALD cycle took approximately 15 seconds with a growth rate of approximately 0.11 nm / cycle. The effective mobility measured under ambient conditions for the Al2O3-passivated PbSe nanocrystal TFTs was comparable to previously reported values ​​for air-free PbSe nanocrystal TFTs, indicating that the ALD Al2O3 layer prevents oxidation and degradation of the nanocrystal film upon atmospheric exposure. The effective mobility of the passivated devices was also found to vary negligibly over 30 days under ambient conditions. The results demonstrate that remote plasma ALD processing of Al2O3 can form an effective passivation layer on air-sensitive nanocrystals at low temperatures and high deposition rates.

[0015] C. Hu, A. Gassenq, Y. Justo, K. Devloo-Casier, H. Chen, C. Detavernier, Z. Hens, and G. Roelkens, "Air-stable shortwave infrared PbS colloidal quantum dot photoconductors passivated by Al2O3 atomic layer deposition," Appl. Phys. Lett. 105, 171110, 2014, presents PbS colloidal quantum dot photoconductors with Al2O3 ALD passivation for air-stable operation. Two different inorganic ligands for the quantum dots, S 2- and OH - PbS / S with a cutoff wavelength of up to 2.4 lm has been investigated. 2- Photoconductors have been obtained with reported responsivities up to 50 A / W at 1550 nm.

[0016] Y. Liu, M. Gibbs, C.L. Perkins, J. Tolentino, M.H. Zarghami, J. Bustamante Jr., and M. Law, Robust, "Functional Nanocrystalline Solids by Loading with Atomic Layer Deposition," Nano Letters, Vol. 11, No. 12, October 24, 2011, pp. 5349-535, describes optoelectronic devices based on films of lead chalcogenide, specifically PbSe, nanocrystals, in which low-temperature ALD is used to load PbSe nanocrystals with metal oxides, specifically amorphous alumina, to produce inorganic nanocomposites in which the nanocrystals are locked in place and protected against oxidative and photothermal damage.

[0017] “7cm 2 V -1 s -1"PbSe Quantum Dot Field-Effect Transistors with Air-Stable Electron Mobility Exceeding 1000 kJ / s," Nano Letters, Vol. 13, No. 4, March 1, 2013, pp. 1578-87, describes films of lead chalcogenide, specifically PbSe, colloidal quantum dots filled with metal oxide, specifically amorphous alumina, by low-temperature ALD to achieve high charge carrier mobility in FETs, with simultaneous passivation of surface states by ALD coating.

[0018] Japanese Patent Application Laid-Open No. 2002-219267A discloses a photoelectric converter having improved moisture resistance by having the side edges of a protective member protrude from the side edges of a sensor substrate, while simultaneously positioning the side edges of the contact surface between the binder layer and the protective member outside the side edges of the substrate. Specifically, the width of the thin glass plate that functions as the protective member is formed such that the upper portion is wider than the width of the sensor substrate, and the side edges of the glass plate protrude outward from the side edges of the substrate. The binder layer has both side edges that protrude outward toward the top, with the contact surface between the layer and the glass plate extending to the side edges of the glass plate and the other contact surface with the substrate extending to the side edges of the substrate. Therefore, the boundary between the layer and the glass plate expands in the width direction, and the boundary between the layer and the substrate similarly expands, simultaneously expanding the width of the layer 29 itself.

[0019] US2013 / 313604A1 discloses a method for manufacturing a light-emitting semiconductor component, in which a light-emitting semiconductor chip is placed on a mounting area of ​​a carrier and electrically connected to electrical contact areas on the mounting area. An encapsulation layer is applied to the chip using ALD. After mounting, all open surfaces and electrical connections of the chip are covered by the encapsulation layer.

[0020] WO 2015 / 044529 A1 discloses a component formed by a substrate, a semiconductor chip, e.g., an optoelectronic component, such as a light-emitting diode, electrical contact wires, an electrical contact layer, conductive tracks, and a protective layer, where the protective layer is optically transparent, preferably has a thickness of 100 nm or less, and is made by ALD.

[0021] WO2018 / 193045A1 discloses a detector for optical detection, comprising: a circuit carrier designed to carry at least one layer, the circuit carrier being or including a printed circuit board; a reflective layer arranged on a partition wall of the circuit carrier and designed to reflect an incident light beam, thereby generating at least one reflected light beam; a substrate layer directly or indirectly adjacent to the reflective layer and at least partially transparent to the incident light beam; a sensor layer arranged on the substrate layer and designed to generate at least one sensor signal in a manner dependent on irradiation of the sensor layer by the incident light beam and the reflected light beam; and an evaluation device designed to generate at least one piece of information by evaluating the sensor signal.

[0022] WO 2018 / 019921 A1 discloses an optical sensor including at least one photoconductive material layer, at least two individual electrical contacts in contact with the photoconductive material layer, and a cover layer deposited on the photoconductive material layer, the cover layer being an amorphous layer containing at least one metal-containing compound. The optical sensor can be supplied in a compact, airtight package that still provides a high degree of protection against possible degradation due to humidity and / or oxygen. Furthermore, the cover layer can activate the photoconductive material, thereby improving the performance of the optical sensor. Furthermore, the optical sensor can be easily manufactured and integrated into a circuit carrier device.

[0023] Despite the advantages contained in the above-mentioned devices, there remains a need for improved optical sensors and spatial detectors that are simple, cost-effective, and yet reliable. [Prior art documents] [Patent documents]

[0024] [Patent Document 1] WO2012 / 110924A1 [Patent Document 2] WO2014 / 097181A1 [Patent Document 3] WO2016 / 120392A1 [Patent Document 4] US5,291,066A [Patent Document 5] US7,939,932B2 [Patent Document 6] Japanese Patent Application Publication No. 02-219267A [Patent Document 7] US2013 / 313604A1 [Patent Document 8] WO2015 / 044529A1 [Patent Document 9] WO2018 / 193045A1 [Patent Document 10] WO2018 / 019921A1 [Non-patent literature]

[0025] [Non-Patent Document 1] "Preparation of lead sulfide thin films by atomic layer epitaxy process" by M Leskelae, L Niinistoe, P Niemela, E Nykaenen, P Soininen, M Tiitta, and J Vaehaekangas [Non-patent document 2] "Fabrication and Characterization of Lead Sulfide Thin Films by Atomic Layer Deposition," by NPDasgupta, SP Walch, and FB Prinz, ECS Transactions 16(4), pp. 29-36, 2008 [Non-patent document 3] "Design of an Atomic Layer Deposition Reactor for Hydrogen Sulfide Compatibility," by N.P. Dasgupta, J.F. McLangston, A. Bousetta, and F.B. Prinz, Rev. Sc. Instr. 81, 044102, 2010 [Non-patent document 4] J. Xu, B.R. Sutherland, S. Hoogland, F. Fan, S. Kinge, and E.H. Sargent, "Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared light detection," Appl. Phys. Lett. 107, 153105, 2015 [Non-Patent Document 5] G.H. Blount, K. Preis, R.T. Yamada, and R.H. Bube, "Photoconductive Properties of Chemically Deposited PbS with a Dielectric Overcoating," J. Appl. Phys. 46, p. 3489, 1975 [Non-patent document 6] MD Groner, FH Fabreguette, JW E Lam, and SM George, "Low-Temperature Al2O3 Atomic Layer Deposition," Chem. Mater. 16, pp. 639-645, 2004 [Non-Patent Document 7] W. Yoon, A.R. Smith, E.E.F. Oos, J.E.B. Boercker, W.B. Heuer, and J.G.T. Tischler, "Electrical Measurements under Ambient Conditions of PbSe Nanocrystalline Thin Films Passivated by Remote Plasma Atomic Layer Deposition of Al2O3," IEEE Transaction Nanotech. 12(2), pp. 146-151, 2013 [Non-patent document 8] C. Hu, A. Gassenq, Y. Justo, K. Devloo-Casier, H. Chen, C. Detavernier, Z. Hens, and G. Roelkens, "Air-stable shortwave infrared PbS colloidal quantum dot photoconductors passivated by Al2O3 atomic layer deposition," Appl. Phys. Lett. 105, 171110, 2014 [Non-Patent Document 9] Y. Liu, M. Gibbs, C.L. Perkins, J. Tolentino, M.H. Zarghami, J. Bustamante Jr., and M. Law, Robust, "Functional Nanocrystalline Solids via Atomic Layer Deposition Packing," Nano Letters, Vol. 11, No. 12, October 24, 2011, pp. 5349-55. [Non-Patent Document 10] Y. Liu, J. Tolentino, M. Gibbs, R. Ihly, C.L. Perkins, Y. Liu, N. Crawford, J.C. Emminger, and M. Law, "PbSe quantum dot field-effect transistors with air-stable electron mobilities exceeding 7 cm2V-1s-1," Nano Letters, Vol. 13, No. 4, March 1, 2013, pp. 1578-87. Summary of the Invention [Problem to be solved by the invention]

[0026] The problem addressed by the present invention is therefore to identify an apparatus and method for optical detection that at least substantially avoids the drawbacks of known apparatus and methods of this type.

[0027] It is desirable to provide improved, simple, cost-effective and reliable optical sensors and detectors for detecting optical radiation, particularly in the infrared spectral range, particularly with respect to sensing at least one of transmission, absorption, emission and reflection.

[0028] It is further desirable to provide improved, simple, cost-effective and reliable optical sensors and detectors for determining the position of objects in space, particularly with respect to the depth or both the depth and width of at least one object, and more particularly that can cover at least one region of the infrared spectral range.

[0029] More specifically, it would be desirable to be able to provide the optical sensor with an encapsulation layer that can be particularly improved to avoid degradation over time due to external influences, such as due to humidity and / or oxygen. [Means for solving the problem]

[0030] This problem is solved by the present invention with the features of the independent patent claims. Advantageous developments of the invention, which can be realized individually or in combination, are set out in the dependent claims and / or in the following description and detailed embodiments.

[0031] As used herein, the terms "having," "comprising," and "including," as well as grammatical variations thereof, are used in a non-exclusive manner. Thus, the phrase "A has B," as well as the phrases "A comprises B," or "A includes B," can refer to both the fact that A includes one or more additional components and / or ingredients in addition to B, and the case where no other components and / or ingredients are present in A in addition to B.

[0032] In a first aspect of the present invention, an optical sensor is disclosed, wherein the optical sensor according to the present invention comprises: - a substrate mounted on a circuit carrier device; - at least one layer of photoconductive material applied directly or indirectly to said substrate; - at least two discrete electrical contacts in contact with said layer of photoconductive material; a cover overlying the layer of photoconductive material and an accessible surface of the substrate, the cover being an amorphous cover comprising at least one metal-containing compound; and wherein at least one of the substrate and the cover is optically transparent within a wavelength range.

[0033] As used herein, an "optical sensor" generally refers to a device designed to generate at least one sensor signal in a manner dependent on illumination of a sensor area by a light beam. The sensor signal may generally be any signal indicative of at least one of transmission, absorption, emission, and reflection of an incident light beam illuminating the sensor area, which may be provided by an object. By way of example, the sensor signal may be or include a digital signal and / or an analog signal. By way of example, the sensor signal may be or include a voltage signal and / or a current signal. Additionally or alternatively, the sensor signal may be or include digital data. The sensor signal may include a single signal value and / or a series of signal values. The sensor signal may also include any signal derived by combining two or more individual signals, such as by averaging two or more signals and / or forming a quotient of two or more signals.

[0034] An "object" may generally be any object selected from living and non-living things. Thus, by way of example, at least one object may include one or more articles and / or one or more parts of articles. Additionally or alternatively, the object may be or include one or more living organisms and / or one or more parts thereof, e.g., a human being, e.g., a user, and / or one or more body parts of an animal.

[0035] As used herein, "position" generally refers to any item of information relating to the position and / or orientation of an object in space. For this purpose, by way of example, one or more coordinate systems may be used, and the position of an object may be determined using one, two, or more coordinates. In this specification, a first coordinate refers to the depth of the object, which refers to the distance between the optical sensor and the object, while two other coordinates, which may be perpendicular to the first coordinate, may refer to the width of the object. By way of example, one or more Cartesian and / or other types of coordinate systems may be used. By way of example, the coordinate system may be a detector coordinate system, in which the detector has a predetermined position and / or orientation.

[0036] According to the present invention, the optical sensor includes at least one layer of photoconductive material, which layer of photoconductive material can function as a sensor area. As used herein, a "sensor area" is considered to be a section of the optical sensor designed to receive illumination of the optical sensor by a light beam, which illumination causes the generation of at least one sensor signal in the manner in which the illumination is received by the sensor area, and the generation of the sensor signal can be governed by a defined relationship between the sensor signal and the manner of illumination of the sensor area.

[0037] As used herein, the term "photoconductive material" refers to a material that can support an electric current and thus exhibits a specific electrical conductivity, which depends, inter alia, on the material's irradiation. Since electrical resistivity is defined as the reciprocal of electrical conductivity, the term "photoresistive material" can alternatively be used to refer to the same type of material. In this type of material, electric current is conducted through at least one first electrical contact, through the material, and to at least one second electrical contact, the first electrical contact being insulated from the second electrical contact, while both the first and second electrical contacts are directly connected to the material. For this purpose, the direct connection can be provided by any known means known from the state of the art, such as plating, welding, soldering, wire bonding, thermosonic bonding, stitch bonding, ball bonding, wedge bonding, compliant bonding, thermocompression bonding, anodic bonding, direct bonding, plasma activated bonding, eutectic bonding, glass frit bonding, adhesive bonding, transient liquid phase diffusion bonding, surface activated bonding, tape automated bonding, or by depositing a highly conductive material, in particular a metal such as gold, beryllium-doped gold, copper, aluminum, silver, platinum, or palladium, as well as alloys comprising at least one of the above-mentioned metals, in the contact area.

[0038] For purposes of the present invention, the photoconductive material used in the sensor region of the optical sensor may preferably comprise an inorganic photoconductive material, and / or a solid solution thereof, and / or a doped variant thereof. As used herein, the term "solid solution" refers to a state of a photoconductive material in which at least one solute is contained in a solvent, thereby forming a homogeneous phase, in which the crystalline structure of the solvent may generally be unchanged by the presence of the solute. As an example, binary lead selenide (PbSe) may be dissolved in lead sulfide (PbS), resulting in a PbS 1-x Se x where the value of x can range from 0 to 1. As used further herein, the term "doped modification" may refer to a state of a photoconductive material in which a single atom, separate from the constituents of the material itself, is introduced into a site within the crystal that would be occupied by an intrinsic atom in the undoped state.

[0039] In this regard, inorganic photoconductive materials are or contain, in particular, one or more of selenium, tellurium, selenium-tellurium alloys, metal oxides, Group 4 elements or compounds, i.e., elements belonging to Group 4 or compounds containing at least one Group 4 element, Group 3-Group 5 compounds, i.e., compounds containing at least one Group 3 element and at least one Group 5 element, Group 2-Group 6 compounds, i.e., compounds containing, on the one hand, at least one Group 2 element or at least one Group 12 element and, on the other hand, at least one Group 6 element, and / or chalcogenides, preferably those selected from the group consisting of sulfide chalcogenides, selenide chalcogenides, ternary chalcogenides, quaternary chalcogenides, and higher chalcogenides. As commonly used, the term "chalcogenide" refers to oxides, i.e., compounds that may contain elements from Group 16 of the periodic table other than sulfides, selenides, and tellurides. Additionally, the term "chalcogenide" may refer to mixed chalcogenides, such as sulfoxides, sulfoselenides, selenide tellurides, etc. However, other inorganic photoconductive materials may be suitable as well.

[0040] In a particularly preferred embodiment of the present invention, the optical sensor may be provided in the form of at least one layer of a photoconductive material, which may include a sulfide chalcogenide, preferably lead sulfide (PbS), a selenide chalcogenide, preferably lead selenide (PbSe), a ternary chalcogenide, preferably lead sulfoselenide (PbSSe), or other suitable material. Since at least the preferred photoconductive materials described above are generally known to exhibit characteristic absorption characteristics in the infrared spectral range, an optical sensor having a layer containing the preferred photoconductive material described above may preferably be used as an infrared sensor. However, other embodiments and / or other photoconductive materials are also possible, particularly those disclosed in WO 2018 / 019921 A1.

[0041] The aforementioned photoconductive material may include a layer of material that may contain at least some crystals exhibiting a size greater than 15 nm. Here, the layer of photoconductive material may be produced by applying at least one deposition method selected from the group consisting of vacuum deposition, sputtering, atomic layer deposition, chemical vapor deposition, spray pyrolysis, electrodeposition, anodic oxidation, electroconversion, electroless immersion growth, sequential ion adsorption and reaction, chemical bath deposition, and solution-gas interface techniques. As a result, the layer of photoconductive material may exhibit a thickness of 10 nm to 100 μm, preferably 100 nm to 10 μm, and more preferably 300 nm to 5 μm. However, other photoconductive materials described above and / or below may also be used for this purpose and may be processed in the same or similar manner.

[0042] Preferably, the photoconductive material can be fabricated by depositing the respective material on an insulating substrate, preferably a substrate as described in more detail below, particularly to provide mechanical stability to the photoconductive material layer. In this manner, a photosensor according to the present invention can be obtained by depositing selected layers on a suitable substrate and providing at least two separate electrical contacts. Here, irradiation of the photoconductive material in the sensor area by an incident light beam results in a change in electrical conductivity in the irradiated layer of photoconductive material. In certain embodiments, the substrate may be or include a conductive substrate, and an additional insulating intermediate layer may be present between the conductive substrate and at least one layer of photoconductive material.

[0043] In a particularly preferred embodiment, the substrate can be applied directly or indirectly to a circuit carrier device, such as a printed circuit board (PCB). In this specification, the term "printed circuit board," commonly abbreviated as "PCB," refers to an electrically non-conductive planar board onto which at least one layer of conductive material, particularly a copper layer, is applied, specifically laminated, on the board. Other terms referring to this type of circuit carrier, which further includes one or more electronic, electrical, and / or optical components, include printed circuit assembly, abbreviated as "PCA," printed circuit board assembly, abbreviated as "PCB assembly" or "PCBA," circuit card assembly, abbreviated as "CCA," or simply "card." In PCBs, the board can contain glass epoxy, where cotton paper (typically tan or brown) impregnated with phenolic resin can also be used as the board material. Depending on the number of sheets, the printed circuit board can be a single-sided PCB, a two-layer or double-sided PCB, or a multi-layer PCB, where different sheets are connected to each other using so-called "vias." For the purposes of this invention, the application of a single-sided PCB may be sufficient; however, other types of printed circuit boards may also be applicable. Double-sided PCBs can have metal on both sides, while multi-layer PCBs can be designed by sandwiching additional metal layers between further layers of insulating material. In multi-layer PCBs, layers can be stacked alternately, each metal layer individually etched, and internal vias can be plated before the layers are stacked together. Furthermore, the vias can be or include copper-plated holes, which can preferably be designed as conductive paths through the insulating board.

[0044] The substrate carrying the layer of photoconductive material, corresponding electrical contacts, and, if applicable, further layers can be disposed on a circuit carrier device such as a PCB by, for example, gluing, soldering, welding, or other methods, or directly or indirectly deposited on an adjacent surface of the circuit carrier device. For example, the substrate can be attached to a circuit carrier device such as a PCB by a thin film of adhesive disposed between the substrate and an adjacent surface of the circuit carrier device such as a PCB. For further embodiments of printed circuit boards, see https: / / en.wikipedia.org / wiki / Printed_circuit_board. However, alternatively, other types of circuit carriers can also be applied.

[0045] As a result, when a light beam impinges on the sensor area, the at least two electrical contacts can provide a sensor signal that depends on the electrical conductivity of the photoconductive material. The term "light beam" generally refers to an amount of light emitted in a specific direction. Thus, a light beam can be a bundle of light rays having a predetermined extent in a direction perpendicular to the propagation direction of the light beam. Preferably, the light beam can be or include one or more Gaussian light beams, which can be characterized by one or more Gaussian beam parameters, such as one or more of the beam waist, Rayleigh length, or any other beam parameter or combination of beam parameters suitable for characterizing the beam diameter extent and / or beam propagation in space. Here, the light beam can be emitted by the object itself, i.e., originate from the object. Additionally or alternatively, other sources of light beams are also possible. Thus, as outlined in more detail below, one or more illumination sources can be provided that illuminate the object using one or more primary light rays or beams, such as one or more primary light rays or beams having predetermined characteristics. In the latter case, the light beam propagating from the object to the detector may be a light beam reflected by the object and / or a reflecting device connected to the object.

[0046] The at least two individual electrical contacts may be applied to different locations of the photoconductive material layer, particularly in such a way that the at least two individual electrical contacts are electrically insulated from each other. Herein, the electrical contacts may comprise vapor-deposited metal layers, which may be readily provided by known vapor deposition techniques. In particular, the vapor-deposited metal layers may comprise one or more of gold, silver, aluminum, platinum, magnesium, chromium, or titanium. Alternatively, the electrical contacts may comprise graphene layers.

[0047] According to the present invention, the photosensor further comprises a cover covering the accessible surfaces of both the photoconductive material and the substrate. As commonly used, the term "accessible surfaces" refers to the portions of the body, particularly the photoconductive material layer and the substrate, that are accessible by the atmosphere surrounding the photosensor. Preferably, the cover is applied in such a way that it can directly contact the top and side surfaces of the photoconductive material layer and at least the side surfaces of the substrate. As already indicated above, the substrate carries the photoconductive material layer, and therefore the top surface of the photoconductive material layer refers to the broad surface of the photoconductive material layer that is not directly or indirectly applied to the substrate. As commonly used, the term "layer" refers to an elongated body having two broad surfaces with a side surface disposed between them. Because both the photoconductive material and the substrate are provided as layers, each includes a side surface. For details regarding the top and side surfaces of the photoconductive material layer and the side surfaces of the substrate, please refer to the following figures.

[0048] In a preferred embodiment, the cover may completely cover the accessible surfaces of both the photoconductive material layer and the substrate side, particularly in a preferred arrangement where the substrate is attached to a circuit carrier device, such as a PCB, in the manner described above. In this preferred embodiment, the cover may be a continuous coating that continuously covers both the photoconductive material layer and the substrate side. As a result, the cover can cover all accessible surfaces of both the photoconductive material and the substrate, thus preventing direct contact between the photoconductive layer material or the substrate and the ambient atmosphere, thereby avoiding degradation of the photoconductive material due to external influences such as humidity and / or oxygen. Compared to covers such as those disclosed in WO 2018 / 019921 A1, which are deposited only on a layer of photoconductive material separate from the area where the cover layer and the substrate meet (where the preferred conformal cover layer necessarily contacts even a small portion of the substrate surface), the cover according to the present invention significantly improves the long-term stability of the optical sensor. As a result, the cover according to the present invention improves the reduction or elimination of external influences by further minimizing or reducing the effects of humidity and / or oxygen on the layer of photoconductive material, in particular by blocking and / or impeding pathways through or along the surface of the substrate that can transmit humidity and / or oxygen to the layer of photoconductive material.

[0049] Thus, the cover according to the present invention can be adapted to provide improved encapsulation for the photoconductive material. As used herein, the term "encapsulation" may refer to a package, preferably an airtight package, for preventing partial or complete deterioration of the light sensor or its sections, particularly the sections of photoconductive material in the sensor region of the light sensor, as much as possible, due to external influences such as humidity and / or oxygen contained in the ambient atmosphere. Here, it may be considered that the package is preferably adapted to cover all accessible surfaces of the photoconductive material, and that the layer of photoconductive material may be deposited on a substrate already adapted to protect the surface sections of the photoconductive material. In other words, the substrate and the cover layer may be adapted to cooperate to complete improved packaging, preferably improved airtight packaging, of the photoconductive material.

[0050] Preferably, at least one deposition method can be used to deposit the cover. For this purpose, the at least one deposition method can be selected from atomic layer deposition, chemical vapor deposition, sputtering processes, or a combination thereof. Consequently, in a particularly preferred embodiment, the cover can be or include an atomic deposition coating, a chemical vapor deposition coating, a sputtering coating, or a coating produced by using at least two of the above-mentioned deposition methods, with atomic deposition coatings or coatings produced using a combination of atomic deposition coating and sputtering being particularly preferred. In other words, in this particularly preferred embodiment, the cover can be obtained by an ALD process, a CVD process, a sputtering process, or a combination thereof, with an ALD process or a combination of ALD and sputtering being particularly preferred. In this specification, the term "atomic layer deposition," the equivalent terms "atomic layer epitaxy" or "molecular layer deposition," and their respective abbreviations "ALD," "ALE," or "MLD" are generally used to refer to a deposition process that may include a self-limiting processing step and a subsequent self-limiting reaction step. Therefore, the process applied in accordance with the present invention may also be referred to as an "ALD process." For further details regarding the ALD process, reference can be made to "Chem." Rev. 110, pp. 111-131, 2010, by George. Furthermore, the term "chemical vapor deposition," usually abbreviated as "CVD," refers to a method in which a surface of a substrate or a layer located on a substrate is exposed to at least one volatile precursor, which can react and / or decompose on the surface to produce a desired deposit. Often, possible by-products can be removed by applying a gas flow over the surface. Furthermore, the term "sputtering" refers to a process in which a solid target material is used to release particles as a result of high-energy particles impacting the target.Furthermore, the combination of an ALD process and a sputtering process allows for first sputtering a coarse phase containing coarse grains on the surface of the photoconductive material, followed by the generation of a fine phase by using ALD that can be specifically adapted to fill the spaces, gaps, and / or pores between the coarse grains, ultimately providing a thicker cover in a shorter time. On the other hand, first performing an ALD process followed by a sputtering process allows for first filling a conformal coating, particularly a porous photoconductive layer, particularly by a slow ALD process, to protect the photoconductive layer from the sputtering process, which may be more damaging to the material surface, and then providing a thick layer within a short processing time. For further details regarding preferred manufacturing processes for providing the cover, reference can be made to the method descriptions elsewhere in this document.

[0051] Further according to the present invention, the cover includes at least one metal-containing compound. The metal-containing compound preferably includes a metal, which may be selected from the group consisting of Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, and Bi. In certain embodiments, the metal-containing compound may include a metalloid, alternatively referred to as a "metalloid," which may be selected from the group consisting of B, Si, Ge, As, Sb, and Te. Preferably, the at least one metal-containing compound may be selected from the group consisting of Al, Ti, Ta, Mn, Mo, Zr, Hf, and W.

[0052] As used herein, the at least one metal-containing compound may preferably be selected from the group consisting of oxides, hydroxides, chalcogenides, pnictides, carbides, or combinations thereof. As already defined above, the term "chalcogenide" refers to compounds that may contain elements from Group 16 of the periodic table other than oxides, i.e., sulfides, selenides, and tellurides. Similarly, the term "pnictide" refers to binary compounds that may preferably contain elements from Group 15 of the periodic table, i.e., nitrides, phosphides, arsenides, and antimonides. As described in more detail below, the metal-containing compound may preferably contain at least one oxide, at least one hydroxide, or a combination thereof, preferably at least one oxide, at least one hydroxide, or a combination thereof of Al, Ti, Zr, or Hf, or equally preferably, a nitride of Si. In a particularly preferred embodiment of the present invention, the metal-containing compound included in the cover may be a composition containing aluminum oxide and / or aluminum hydroxide, which is also commonly referred to as Al2O3 for convenience.

[0053] In certain embodiments, the cover may include at least two portions that differ in composition such that adjacent portions have different metal-containing compounds, each providing an amorphous structure. For example, the cover may include alternating adjacent portions of an aluminum-containing compound and a zirconium- or hafnium-containing compound. However, other combinations of metal-containing compounds are also possible. Furthermore, the laminate may further include an additional portion that may be or include at least one of a metal compound, a polymer compound, a silicone compound, or a glass compound. Other types of materials are also possible. Furthermore, the laminate may include an additional portion that may alternatively be crystalline or nanocrystalline.

[0054] In a particularly preferred embodiment of the present invention, the cover may exhibit a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm, which may reflect, in particular, the amount of metal-containing compound in the cover, which may be advantageous for achieving the above-mentioned function of providing encapsulation of the photoconductive material.

[0055] In a further particularly preferred embodiment of the present invention, the cover may be conformal with respect to the adjacent surface of the photoconductive material or substrate. As defined above, the thickness of the conformal cover may therefore follow the corresponding surface of the photoconductive material or substrate within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm, which deviation occurs over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover, thereby excluding any contamination or imperfections that may be present on the cover surface.

[0056] As mentioned above, the layer of photoconductive material can be applied directly or indirectly to at least one substrate. As commonly used, the term "substrate" refers to an elongated body adapted to support a layer of material, particularly a layer of photoconductive material as used herein, and in particular to provide mechanical stability to the layer of photoconductive material. Furthermore, the term "directly" refers to direct attachment of the layer of photoconductive material to the substrate, while the term "indirectly" refers to attachment of the layer of photoconductive material to the substrate via at least one intermediate layer, such as an adhesive layer. Preferably, the substrate is provided as a layer having a lateral extension at least 5 times, preferably at least 25 times, and more preferably at least 100 times, the thickness of the layer. In particular, the thickness of the substrate may be from 10 μm to 2000 μm, preferably from 50 μm to 1000 μm, and more preferably from 100 μm to 500 μm.

[0057] At least one of the substrate and the cover layer is preferably optically transparent within a selected wavelength range. Therefore, it is particularly advantageous to select the metal-containing compound used in the cover layer so that it is optically transparent within the desired wavelength range, preferably by exhibiting suitable absorption properties. Alternatively or additionally, the material applied to the substrate may exhibit optically transparent properties within the desired wavelength range. In particular, this feature may allow for a wider range of material choices for metal-containing compounds that may not be optically transparent within the desired wavelength range, since the substrate may exhibit sufficient transparency. To this end, the substrate may particularly comprise at least one insulating material that is at least partially transparent, preferably selected at least partially from the group including glass, metal oxide, ceramic material, or doped variants thereof. In this specification, the insulating material may particularly be selected from at least one transparent glass, weakly doped semiconductor, metal oxide, or ceramic material, and may in particular be selected from sapphire (Al2O3), glass, quartz, fused silica, silicon, germanium, zinc sulfide (ZnS), or zinc selenide (ZnSe). Alternatively, the substrate may comprise a material having at least partially optically transparent properties. The insulating material may be selected in particular, or in addition, so that the cover also exhibits at least partially optically transparent properties. On the other hand, if the substrate may already be at least partially transparent, a wider variety of different materials may be employed for the cover layer, including optically opaque materials.

[0058] As described above, the photoconductive material layer can be applied directly or indirectly to at least one substrate, with at least one of the substrate and cover preferably being optically transparent within a selected wavelength range. Therefore, it may be advantageous to select the metal-containing compound used in the cover so that it is optically transparent within the desired wavelength range, particularly by exhibiting suitable absorption characteristics. Alternatively or additionally, the material applied to the substrate may exhibit optically transparent properties within the desired wavelength range. In particular, this feature allows for a wider range of material choices for metal-containing compounds that may not be optically transparent within the desired wavelength range, as long as the substrate exhibits sufficient transparency. Here, the substrate material may be selected from at least one of transparent glass, silicon, germanium, metal oxides, metals, or semiconductor materials, particularly aluminum-doped tin oxide (AZO), indium-doped tin oxide (ITO), zinc sulfide (ZnS), or zinc selenide (ZnSe), with glass or silicon being particularly preferred. For semiconductor or conductive layers that may exhibit too high conductivity to function as a good insulating substrate, an insulating interlayer that is optically transparent within the desired wavelength range may be employed.

[0059] Furthermore, in addition to the aforementioned function of providing encapsulation of the photoconductive material, the cover may simultaneously exhibit additional functions for the photoconductive material. In this regard, the metal-containing compound may be specifically selected so as to simultaneously perform the desired additional functions. In particular, the metal-containing compound used for the cover may exhibit a high refractive index, preferably at least 1.2, more preferably at least 1.5, to qualify as an appropriate anti-reflection material. As described above, the cover may be deposited in a conformal manner, particularly using ALD or a combination of ALD and sputtering, so that the cover closely conforms to the surface of the photoconductive material. In particular, a PbS or PbSe layer used as a photoconductive layer typically exhibits a fairly rough surface with protrusions and recesses rather than a smooth surface. It has been found that Al2O3 can be deposited as a cover that can closely conform to the surface of the PbS or PbSe layer. As a result, reflection of incident light can be minimized. This observation contrasts with known deposition methods, in which the deposited material typically grows via coalescence, which only minimizes protrusions and recesses that may be present on the surface of the photoconductive material layer. Furthermore, the cover may exhibit additional functionality selected from scratch resistance, hydrophilicity, hydrophobicity, self-cleaning, anti-fogging, and electrical conductivity. Other types of functionality, particularly high dielectric constants, may also be possible, preferably by using Al2O3 or ZrO2, which may be employed to generate high dielectric strength, particularly by using a high electric field, such as by applying a high voltage across the optical sensor. For the purpose of a particular selected functionality, the cover may further include one or more additives, such as one or more stabilizers, added to achieve the desired additional functionality of the cover. In particular, the cover may include glass or glass particles as stabilizers. However, other types of additives are also feasible.

[0060] In certain embodiments, particularly when it is not appropriate to provide the cover with the desired additional functionality, or when the degree of the additional functionality provided by the selected cover is insufficient, the cover may be at least partially covered by at least one additional layer at least partially disposed on the cover. Alternatively or additionally, the at least one additional layer may be at least partially disposed between the photoconductive material layer and the cover. Preferably, the additional layer may be or exhibit the additional functionality, and thus may include at least one of an anti-reflection layer, a light filter layer, a scratch-resistant layer, a hydrophilic layer, a hydrophobic layer, a self-cleaning layer, an anti-fogging layer, a high-dielectric-constant layer, or a conductive layer. Those skilled in the art can easily select and provide at least one additional layer. However, other embodiments may also be possible.

[0061] In a preferred embodiment, the cover may partially or completely cover electrical contacts, which may be specifically configured to be bondable, such as to one or more leads to an external circuit. Here, the electrical contacts may be bondable using wires, such as gold or aluminum wires, where the electrical contacts may preferably be bondable through the cover. In certain embodiments, an adhesive layer may be provided on the electrical contacts, in which case the adhesive layer may be specifically adapted for bonding. To this end, the adhesive layer may include at least one of Ni, Cr, Ti, or Pd.

[0062] In a further aspect of the invention, a detector for optical detection, in particular for the detection of optical radiation in the infrared spectral range, in particular for sensing at least one of transmission, absorption, emission and reflection provided by at least one light beam, or a detector for determining the position of at least one object, in particular for determining the position of at least one object with respect to the depth or both the depth and width of the at least one object, is disclosed. According to the invention, a detector for optical detection of at least one object comprises: - at least one optical sensor as described elsewhere herein, the optical sensor including at least one sensor area, the optical sensor being designed to generate at least one sensor signal in a manner dependent on illumination of the sensor area by a light beam; and at least one evaluation device, which is designed to generate at least one item of information relating to the optical radiation provided by the light beam by evaluating the sensor signal of the optical sensor, Includes.

[0063] In this specification, the listed components may be separate components. Alternatively, two or more components may be integrated into one component. Furthermore, the at least one evaluation device may be formed as a separate evaluation device independent of the transfer device, which may preferably be selected from at least one of an optical lens, a mirror, a beam splitter, an optical filter, and an optical sensor, but may preferably be connected to the optical sensor to receive the sensor signal. Alternatively, the at least one evaluation device may be fully or partially integrated into the optical sensor.

[0064] According to the invention, the detector includes at least one of the optical sensors described elsewhere in this document. The detector may therefore be designed to detect electromagnetic radiation in a fairly wide spectral range, preferably in the infrared (IR) spectral range, whereby the following may be particularly selected for the photoconductive layer in the sensor area of ​​the optical sensor: indium gallium arsenide (InGaAs) for wavelengths up to 2.6 μm, indium arsenide (InAs) for wavelengths up to 3.1 μm, lead sulfide (PbS) for wavelengths up to 3.5 μm, lead selenide (PbSe) for wavelengths up to 5 μm, indium antimonide (InSb) for wavelengths up to 5.5 μm, and mercury cadmium telluride (MCT, HgCdTe) for wavelengths up to 16 μm.

[0065] The term "evaluation device" as used herein generally refers to any device designed to generate at least one item of information, i.e., information relating to at least one of transmission, absorption, emission, and reflection, or of at least one object, or for determining the position of at least one object, in particular the depth or both the depth and width of the at least one object. By way of example, the evaluation device may be or comprise one or more integrated circuits, such as one or more application-specific integrated circuits (ASICs), and / or one or more digital signal processors (DSPs), and / or one or more field-programmable gate arrays (FPGAs), and / or one or more data processing devices, such as one or more computers, preferably one or more microcomputers and / or microcontrollers. Additional components may be constituted by one or more preprocessing devices, such as one or more devices for receiving and / or preprocessing sensor signals, e.g., one or more analog-to-digital converters and / or one or more filters, and / or data acquisition devices. As used herein, a sensor signal may generally refer to one of the longitudinal sensor signals and, if applicable, the lateral sensor signals. Additionally, the evaluation device may include one or more data storage devices. Additionally, as outlined above, the evaluation device may include one or more interfaces, such as one or more wireless interfaces and / or one or more wired interfaces.

[0066] For further information regarding detectors for optical detection or any components thereof, in particular evaluation devices, reference can be made to WO2014 / 097181A1 and WO2018 / 019921A1.

[0067] In a further aspect of the present invention, a method for manufacturing an optical sensor is disclosed, which may preferably be used to produce or manufacture at least one optical sensor according to the present invention, such as at least one optical sensor according to one or more embodiments disclosed in further detail below in other parts of this document. Accordingly, for any embodiment of the method, reference may be made to the description of the various embodiments of the optical sensor.

[0068] The method includes the following steps, which may be performed in the given order or in a different order. Furthermore, additional method steps not listed may be provided. Unless otherwise specified, two or more, or even all, of the method steps may be performed at least partially simultaneously. Furthermore, two or more, or even all, of the method steps may be performed repeatedly two or more times.

[0069] The method according to the invention comprises the following steps: a) providing a substrate mounted on a circuit carrier device, at least one layer of photoconductive material applied directly or indirectly to the substrate, and at least two discrete electrical contacts contacting the layer of photoconductive material; and b) thereafter depositing an amorphous cover over the layer of photoconductive material and accessible surfaces of the substrate, the cover including at least one metal-containing compound; wherein at least one of the substrate and the cover is optically transparent within a wavelength range.

[0070] Step a) provides a substrate, at least one layer of photoconductive material, and respective electrical contacts. In particular, the materials of each of the substrate, the photoconductive layer, and the electrical contacts can be selected from the corresponding material list presented above.

[0071] Step b) can be performed by using at least one of the methods described above to generate a cover. Step b) can be repeated at least once, preferably at least 10 times, and more preferably at least 100 times. In a particular embodiment, at least two adjacent cover portions can be deposited in the form of a stack. Here, the term "stack" can refer to a deposition pattern in which adjacent portions can differ in their respective compositions. Thus, adjacent portions can differ in that they contain different metal-containing compounds. Alternatively, at least one of other types of compounds, particularly metal compounds, polymeric compounds, silicone compounds, and glass compounds, can be used in some but not all of the adjacent portions, such as alternating with layers containing metal-containing compounds. Preferably, the at least one metal-containing compound, and, if applicable, other types of compounds, are deposited until a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 100 nm, and most preferably 50 nm to 95 nm is achieved. Here, the at least one metal-containing compound, and if applicable, other types of compounds, are deposited in such a manner that the cover is preferably conformal to the adjacent surface of the photoconductive material or substrate, and thus the thickness of the conformal cover may follow the corresponding surface of the photoconductive material or substrate within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the conformal cover.

[0072] In a particularly preferred embodiment of the present invention, at least one deposition method is used to deposit a metal-containing compound. Preferably, the deposition method can be selected from at least one of an atomic layer deposition (ALD) process, a chemical vapor deposition (CVD) process, a sputtering process, or a combination thereof. For further details regarding the ALD process or the CVD process, please refer to the above description. To provide a metal-containing compound, two different types of precursors can be preferably used, where the first precursor is or includes an organometallic precursor, and the second precursor is or includes a fluid. As commonly used, the term "fluid" can refer to the non-solid state of the second precursor. For example, to provide an aluminum (Al)-containing compound, the first precursor can be or include TMA, i.e., trimethylaluminum Al(CH3)3, while the second precursor can be or include H2O, oxygen, air, or a solution thereof, or ozone. Alternatively or additionally, to provide a zirconium (Zr)-containing compound, the first precursor may be or include TDMA-Zr, i.e., tetrakis(dimethylamido)zirconium(IV), and the second precursor may be or include HO, a solution thereof, or ozone. Herein, at least one precursor may be mixed with an inert gas, in particular nitrogen (N) or argon (Ar), to provide a particularly stable fluid flow.

[0073] As already mentioned above, at least one additional layer can be further deposited on the cover or a section thereof. Alternatively or additionally, at least one additional layer can be at least partially deposited on the layer of photoconductive material and then coated with the cover. In this specification, the additional layer can be selected to be or include at least one of an anti-reflection layer, an optical filter layer, an encapsulation layer, a scratch-resistant layer, a hydrophilic layer, a hydrophobic layer, a self-cleaning layer, an anti-fogging layer, a high-dielectric layer, or a conductive layer.

[0074] As described above, the desired optical sensor is generally designed to generate at least one sensor signal in response to illumination of a sensor area included in the optical sensor by an incident light beam. For this purpose, at least two electrical contacts adapted to electrically contact the photoconductive material included in the sensor area are further provided. Generally, the electrical contacts can be provided before or during either method step a) or b). In a particularly preferred embodiment, the electrical contacts can be provided before step b), such as by providing a vapor-deposited metal layer by known vapor deposition techniques, where the metal layer can include one or more of silver, aluminum, platinum, magnesium, chromium, titanium, gold, or graphene. Alternatively, the electrical contacts can be provided by a galvanic or chemical deposition process, such as electroless Ni, electroless Au, galvanic Ni, or galvanic Au. Here, a cover can be deposited in a manner that also completely or partially covers the electrical contacts. In this particular embodiment, the electrical contacts are at least partially, preferably completely, covered by the cover and can therefore be bonded to at least one external connection by using a conductive lead, preferably in the form of a wire, in particular a gold (Au), aluminum (Al) or copper (Cu) wire, which can in particular be bonded to the electrical contacts through the cover layer. As an example, gold (Au) contacts covered by the cover layer can subsequently be connected by wire bonding.

[0075] In a particularly preferred embodiment, the layer of photoconductive material comprises at least two distinct sensor areas: Preferably, it may comprise an array of individual sensor areas, which are applied directly or indirectly to the same substrate, also called a "common substrate," which may therefore present a fairly large surface area. In this embodiment, the individual sensor areas are first applied directly or indirectly to the common substrate in step a), and at least two individual electrical contacts are provided as contacts for each of the individual sensor areas in the layer of photoconductive material. The individual sensor areas are then separated from one another in such a way that each individual sensor area is carried by a respective portion of the substrate. Finally, a cover is deposited on each of the individual sensor areas and on the accessible surface of each portion of the substrate in step b).

[0076] Additionally, details regarding the fabrication process for the optical sensor are provided elsewhere in this document.

[0077] Devices according to the present invention can be used in combination with surface mount technology packages such as bump chip carriers, ceramic leadless chip carriers, leadless chip carriers, leaded chip carriers, leaded ceramic chip carriers, dual leadless chip carriers, plastic leaded chip carriers, package-on-package chip carriers, etc. Furthermore, the device according to the invention can be mounted on semiconductor packages with standard through-hole or source mount technology, such as DO-204, DO-213, metal electrode leafless surface, DO-214, SMA, SMB, SMC, GF1, SOD, SOT, TSOT, TO-3, TO-5, TO-8, TO-18, TO-39, TO-46, TO-66, TO-92, TO-99, TO-100, TO-126, TO-220, TO-226, TO-247, TO252, TO-263, THIN, SIP, SIPP, DFN, DIP, DIL, Flat Pack, SO, SOIC, SOP, SSOP, TSOP, TSSOP, ZIP, LCC, PLCC, QFN, QFP, QUIP, QUIL, BGA, eWLB, LGA, PGA, COB, COF, COG, CSP, Flip The device according to the present invention can be used in combination with chips, PoPs, QPs, UICCs, WL-CSPs, WLPs, MDIPs, PDIPs, SDIPs, CCGAs, CGAs, CERPACKs, CQGPs, LLPs, LGAs, LTCCs, MCMs, MICRO SMDXTs, etc. Furthermore, the device according to the present invention can be used in combination with pin grid arrays (PGAs) such as OPGAs, FCPGAs, PACs, PGAs, and CPGAs. Furthermore, the device according to the present invention can be used in combination with flat packages such as CFPs, CQFPs, BQFPs, DFNs, ETQFPs, PQFNs, PQFPs, LQFPs, QFNs, QFPs, MQFPs, HVQFPs, SIDEBRAZEs, TQFPs, TQFNs, VQFPs, and ODFNs. Furthermore, devices according to the present invention can be used in combination with small outline packages such as SOP, CSOP MSOP, PSOP, PSON, PSON, QSOP, SOIC, SSOP, TSOP, TSSOP, TVSOP, μMAX, WSON, etc.Furthermore, the device according to the present invention can be used in combination with chip scale packages such as CSP, TCSP, TDSP, micro SMD, COB, COF, and COG. Furthermore, the device according to the present invention can be used in combination with ball grid arrays such as FBGA, LBGA, TEPBGA, CBGA, OBGA, TFBGA, PBGA, MAP-BGA, UCSP, μBGA, LFBGA, TBGA, SBGA, and UFBGA. Furthermore, the device according to the present invention can be used in combination with further electronic devices such as chip-in-multi-chip packages such as SiP, PoP, 3D-SiC, WSI, and near-field communications. For more information on integrated circuit packaging, the following sources can be referenced:

[0078] - https: / / en.wikipedia.org / wiki / List_of_integrated_circuit_packaging_types or - https: / / en.wikipedia.org / wiki / List_of_integrated_circuit_package_dimensions

[0079] In a further aspect of the present invention, the use of the detector according to the present invention is disclosed. The detector is used for a purpose selected from the group consisting of gas detection, fire detection, flame detection, heat detection, smoke detection, combustion monitoring, spectroscopy, temperature sensing, motion sensing, industrial monitoring, chemical sensing, exhaust gas monitoring, and security. In particular, the detector can be used for infrared detection, heat detection, thermometer, heat-seeking, flame detection, fire detection, smoke detection, temperature sensing, spectroscopy, and the like. Furthermore, the detector can be used for exhaust gas monitoring, combustion process monitoring, industrial process monitoring, chemical process monitoring, food processing process monitoring, and the like. Furthermore, the detector can be used for temperature control, motion control, exhaust control, gas sensing, gas analysis, motion sensing, chemical sensing, and the like. For further applications of the optical sensors and detectors disclosed herein, reference can be made to WO2016 / 120392A1 and WO2018 / 019921A1. However, further application fields may still be envisioned.

[0080] The above-described optical sensors and detectors, methods, and proposed uses offer significant advantages over the prior art. Thus, the optical sensor according to the present invention is particularly sensitive across at least a portion of the infrared spectral range, thereby providing an efficient and reliable large-area position sensing device for the infrared spectral range. Compared to known devices in the art, the optical sensor proposed herein, which can be preferably supplied in a compact, airtight package, offers improved protection over time against degradation due to external influences such as humidity and / or oxygen, even at high temperatures and humidity levels. The materials used in the optical sensor can be selected to ensure that the sensor exhibits suitable absorption characteristics across a wide spectral range. For example, a cover comprising the material Al2O3 may be transparent to light beams with wavelengths up to 5 μm. Other materials can be used for other desired absorption characteristics across other spectral ranges. Furthermore, since various materials exhibit refractive indices greater than 1.3, such as Al2O3, which exhibits a refractive index of approximately 1.75, each selected cover can simultaneously exhibit anti-reflection functionality. As discussed above, this type of cover material can form a smooth cover that can conformally and tightly follow the surface of the photoconductive material and the surface of the substrate.

[0081] Furthermore, the optical sensor is easy to manufacture and can be easily integrated into the package.

[0082] Here, by manufacturing the cover according to the present invention, particularly by using atomic layer deposition (ALD) or a combination of ALD and sputtering, leak-tight encapsulation can be provided, particularly by filling pinholes and porous structures in the layer of photoconductive material, as well as by blocking and / or obstructing pathways that can transmit moisture and / or oxygen through or along the surface of the substrate to the layer of photoconductive material. In this regard, it may be noted that the ALD process or a combination of ALD and sputtering is generally a batch process that can be applied to multiple samples in a single batch. Furthermore, the electrical contactability possible even through the cover and the non-bulky hermetic package of the optical sensor allows for easy integration into a circuit carrier device, such as a printed circuit board (PCB). In an alternative embodiment, the encapsulated photoconductive layer can be contacted using through-glass vias, which can enable a direct hermetic connection from the top to the bottom of the substrate. In a particularly preferred embodiment, the substrate can be directly glued or soldered onto a circuit carrier device, such as a PCB.

[0083] In summary, in the context of the present invention, the following embodiments are considered preferred:

[0084] Embodiment 1: An optical sensor comprising a substrate, at least one layer of photoconductive material applied directly or indirectly to the substrate, at least two discrete electrical contacts contacting the layer of photoconductive material, and a cover covering the photoconductive material and an accessible surface of the substrate, wherein the cover is an amorphous cover comprising at least one metal-containing compound.

[0085] Embodiment 2: The optical sensor according to the preceding embodiment, wherein the at least one metal-containing compound comprises a metal or a metalloid, wherein the metal is selected from the group consisting of Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, and Bi, and the metalloid is selected from the group consisting of B, Si, Ge, As, Sb, and Te.

[0086] Embodiment 3: The optical sensor according to the preceding embodiment, wherein the at least one metal-containing compound is selected from the group consisting of Al, Ti, Ta, Mn, Mo, Zr, Hf, and W.

[0087] Embodiment 4: An optical sensor according to any one of the preceding embodiments, wherein the at least one metal-containing compound is selected from the group comprising an oxide, a hydroxide, a chalcogenide, a pnictide, a carbide, or a combination thereof.

[0088] Embodiment 5: The optical sensor according to the preceding embodiment, wherein the at least one metal-containing compound comprises at least one oxide, at least one hydroxide, or a combination thereof, of Al, Ti, Zr, or Hf; or a nitride of Si.

[0089] Embodiment 6: A photosensor according to any one of the preceding embodiments, wherein the cover is in direct contact with the top and side surfaces of the layer of photoconductive material and at least a side surface of the substrate.

[0090] Embodiment 7: An optical sensor according to any one of the preceding embodiments, wherein the cover completely covers accessible surfaces of both the layer of photoconductive material and the side of the substrate.

[0091] Embodiment 8: The optical sensor according to the preceding embodiment, wherein the cover is a continuous coating that continuously covers both the layer of photoconductive material and the side of the substrate.

[0092] Embodiment 9: The optical sensor according to the preceding embodiment, wherein the cover is further adapted to function as an anti-reflective layer.

[0093] Embodiment 10: An optical sensor according to any one of the preceding embodiments, wherein the cover is or includes a laminate having at least two adjacent portions, the adjacent portions differing by their respective compositions, and at least one of the adjacent portions includes the at least one metal-containing compound.

[0094] Embodiment 11: The optical sensor according to the preceding embodiment, wherein at least one of the adjacent portions comprises at least one of a metal compound, a polymer compound, a silicone compound, and a glass compound.

[0095] Embodiment 12: An optical sensor according to any one of the preceding embodiments, wherein the cover has a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm.

[0096] Embodiment 13: A light sensor according to any one of the preceding embodiments, wherein the cover is conformal with respect to the layer of photoconductive material or an adjacent surface of the substrate.

[0097] Embodiment 14: An optical sensor according to the preceding embodiment, wherein the thickness of the conformal cover follows the corresponding surfaces of the photoconductive material and the substrate with a deviation of ±50 nm, preferably ±20 nm, most preferably ±10 nm over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover.

[0098] Embodiment 15: An optical sensor according to any one of the preceding embodiments, wherein the cover is or includes an atomic deposition coating or a chemical vapor deposition coating.

[0099] Embodiment 16: An optical sensor according to any one of the preceding embodiments, wherein the cover further exhibits a further function selected from at least one of scratch resistance, hydrophilicity, hydrophobicity, self-cleaning, anti-fogging, and electrical conductivity.

[0100] Embodiment 17: An optical sensor according to any one of the preceding embodiments, wherein the cover is further at least partially coated with at least one additional layer, and / or the at least one additional layer is at least partially deposited between the layer of photoconductive material and the cover.

[0101] Embodiment 18: An optical sensor according to the preceding embodiment, wherein the additional layer is or includes at least one of an anti-reflection layer, an optical filter layer, an encapsulation layer, a scratch-resistant layer, a hydrophilic layer, a hydrophobic layer, a self-cleaning layer, an anti-fogging layer, a high-dielectric-constant layer, or a conductive layer.

[0102] Embodiment 19: The optical sensor according to any one of the preceding embodiments, wherein the photoconductive material comprises an inorganic photoconductive material.

[0103] Embodiment 20: A photosensor according to the preceding embodiments, wherein the inorganic photoconductive material comprises one or more of selenium, tellurium, selenium-tellurium alloys, photoconductive metal oxides, Group 4 elements or compounds, Group 3-Group 5 compounds, Group 2-Group 6 compounds, chalcogenides, pnictogenides, halides, and solid solutions and / or doped variants thereof.

[0104] Embodiment 21: An optical sensor according to the preceding embodiment, wherein the chalcogenide is selected from the group including sulfide chalcogenides, selenide chalcogenides, telluride chalcogenides, ternary chalcogenides, quaternary chalcogenides, and higher chalcogenides.

[0105] Embodiment 22: The sulfide chalcogenide is lead sulfide (PbS), cadmium sulfide (CdS), zinc sulfide (ZnS), mercury sulfide (HgS), silver sulfide (AgS), manganese sulfide (MnS), bismuth trisulfide (BiS), antimony trisulfide (SbS), arsenic trisulfide (AsS), tin(II) sulfide (SnS), tin(IV) disulfide (SnS), indium sulfide (InS). , copper sulfide (CuS), cobalt sulfide (CoS), nickel sulfide (NiS), molybdenum disulfide (MoS2), iron disulfide (FeS2), chromium trisulfide (CrS3), copper indium sulfide (CIS), copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), and solid solutions and / or doped variants thereof.

[0106] Embodiment 23: An optical sensor according to any one of the preceding two embodiments, wherein the selenide chalcogenide is selected from the group comprising lead selenide (PbSe), cadmium selenide (CdSe), zinc selenide (ZnSe), bismuth triselenide (BiSe), mercury selenide (HgSe), antimony triselenide (SbSe), arsenic triselenide (AsSe), nickel selenide (NiSe), thallium selenide (TlSe), copper selenide (CuSe), molybdenum diselenide (MoSe), tin selenide (SnSe), cobalt selenide (CoSe), indium selenide (InSe), copper zinc tin selenide (CZTSe), and solid solutions and / or doped variants thereof.

[0107] Embodiment 24: An optical sensor according to any one of the preceding three embodiments, wherein the telluride chalcogenide is selected from the group comprising lead telluride (PbTe), cadmium telluride (CdTe), zinc telluride (ZnTe), mercury telluride (HgTe), bismuth tritelluride (BiTe), arsenic tritelluride (AsTe), antimony tritelluride (SbTe), nickel telluride (NiTe), thallium telluride (TlTe), copper telluride (CuTe), molybdenum ditelluride (MoTe), tin telluride (SnTe), and cobalt telluride (CoTe), silver telluride (AgTe), indium telluride (InTe), and solid solutions and / or doped variants thereof.

[0108] Embodiment 25: The ternary chalcogenide is selected from the group consisting of mercury cadmium telluride (HgCdTe), mercury zinc telluride (HgZnTe), mercury cadmium sulfide (HgCdS), lead cadmium sulfide (PbCdS), lead mercury sulfide (PbHgS), copper indium disulfide (CuInS), cadmium sulfoselenide (CdSSe), zinc sulfoselenide (ZnSSe), thallium sulfoselenide (TlSSe), cadmium zinc sulfide (CdZnS), cadmium chromium sulfide (CdCrS), mercury chromium sulfide (HgCrS), copper chromium sulfide (CuCrS), cadmium lead selenide (CdPbSe), copper indium diselenide (CuInSe), indium arsenide 3. The optical sensor according to any one of the preceding four embodiments, wherein the metal oxide is selected from the group comprising indium gallium monoxide (InGaAs), lead monoxide sulfide (PbOS), lead monoxide selenide (PbOSe), lead sulfoselenide (PbSSe), arsenic selenide telluride (AsSeTe), indium gallium phosphide (InGaP), gallium arsenide phosphide (GaAsP), aluminum gallium phosphide (AlGaP), cadmium selenite (CdSeO), cadmium zinc telluride (CdZnTe), cadmium zinc selenide (CdZnSe), copper-zinc-tin-sulfide-selenium chalcogenide (CZTSSe), and solid solutions and / or doped variants thereof.

[0109] Embodiment 26: An optical sensor according to any one of the preceding five embodiments, wherein the photoconductive metal oxide is selected from the group comprising copper (II) oxide (CuO), copper (I) oxide (CuO), nickel oxide (NiO), zinc oxide (ZnO), silver oxide (AgO), manganese oxide (MnO), titanium dioxide (TiO), barium oxide (BaO), lead oxide (PbO), cerium oxide (CeO), bismuth oxide (BiO), cadmium oxide (CdO), and solid solutions and / or doped variants thereof.

[0110] Embodiment 27: An optical sensor according to any one of the preceding six embodiments, wherein the Group 2-6 compound is selected from the group comprising cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), cadmium zinc telluride (CdZnTe), mercury cadmium telluride (HgCdTe), mercury zinc telluride (HgZnTe), and mercury zinc selenide (CdZnSe), and solid solutions and / or doped variants thereof.

[0111] Embodiment 28: An optical sensor according to any one of the preceding seven embodiments, wherein the Group III-V compound is selected from the group comprising indium antimonide (InSb), boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs) and gallium antimonide (GaSb), and solid solutions and / or doped variants thereof.

[0112] Embodiment 29: An optical sensor according to any one of the preceding eight embodiments, wherein the Group 4 element or compound is selected from the group comprising doped diamond (C), doped silicon (Si), silicon carbide (SiC) and silicon germanium (SiGe), and solid solutions and / or doped variants thereof.

[0113] Embodiment 30: An optical sensor according to any one of the preceding embodiments, wherein the cover at least partially covers the electrical contacts.

[0114] Embodiment 31: An optical sensor according to the preceding embodiments, wherein the electrical contacts are preferably bondable by using wires, in particular gold (Au), aluminum (Al), or copper (Cu) wires.

[0115] Embodiment 32: An optical sensor according to any one of the preceding embodiments, wherein the electrical contacts are joinable through the cover.

[0116] Embodiment 33: An optical sensor according to any one of the preceding embodiments, wherein the at least two electrical contacts are applied to different locations on the layer of photoconductive material.

[0117] Embodiment 34: An optical sensor according to any one of the preceding embodiments, wherein the electrical contacts comprise at least one electrode material selected from the group consisting of silver (Ag), platinum (Pt), molybdenum (Mo), aluminum (Al), gold (Au), and graphene.

[0118] Embodiment 35: An optical sensor according to the preceding embodiment, wherein an adhesive layer is provided on the electrical contacts, the adhesive layer being particularly suitable for adhesion.

[0119] Embodiment 36: The optical sensor according to the preceding embodiment, wherein the adhesion layer includes at least one of nickel (Ni), chromium (Cr), titanium (Ti), or palladium (Pd).

[0120] Embodiment 37: An optical sensor according to any one of the preceding embodiments, wherein the substrate has a thickness of 10 μm to 1000 μm, preferably 50 μm to 500 μm, more preferably 100 μm to 250 μm.

[0121] Embodiment 38: An optical sensor according to any one of the preceding embodiments, wherein at least one of the substrate and the cover is optically transparent within a wavelength range.

[0122] Embodiment 39: An optical sensor according to any one of the preceding two embodiments, wherein the substrate is an electrically insulating substrate.

[0123] Embodiment 40: An optical sensor according to any one of the preceding three embodiments, wherein the substrate comprises one of glass, silicon (Si), a transparent conductive oxide (TCO), or a transparent organic polymer, and the transparent conductive oxide preferably comprises indium tin oxide (ITO), fluorine-doped tin oxide (SnO2:F;FTO), aluminum-doped zinc oxide (AZO), magnesium oxide (MgO), or a perovskite transparent conductive oxide.

[0124] Embodiment 41: An optical sensor according to any one of the preceding four embodiments, wherein the substrate is or comprises a conductive substrate, and an additional insulating intermediate layer is present between the conductive substrate and the at least one layer of photoconductive material.

[0125] Embodiment 42: An optical sensor according to any one of the preceding embodiments, wherein the substrate is applied directly or indirectly to a circuit carrier device.

[0126] Embodiment 43: An optical sensor according to the preceding embodiment, wherein the substrate is adhered to the circuit carrier device.

[0127] Embodiment 44: An optical sensor according to any one of the preceding two embodiments, wherein the substrate is attached to the circuit carrier device via a thin film of adhesive disposed between the substrate and an adjacent surface of the circuit carrier device.

[0128] Embodiment 45: An optical sensor according to any one of the preceding three embodiments, wherein the circuit carrier device is a printed circuit board.

[0129] Embodiment 46: A detector for optically detecting at least one object, comprising: - at least one optical sensor according to any one of the preceding embodiments, the optical sensor including at least one sensor area and designed to generate at least one sensor signal in a manner dependent on illumination of said sensor area by a light beam; and at least one evaluation device, which is designed to generate at least one item of information relating to the optical radiation provided by the light beam by evaluating the sensor signal of the optical sensor; a detector.

[0130] Embodiment 47: A detector according to the preceding embodiment, wherein the detector is adapted to generate the sensor signal by one or more of measuring the electrical resistance or conductivity of at least a portion of the sensor area.

[0131] Embodiment 48: A detector according to the preceding embodiment, wherein the detector is adapted to generate the sensor signal by performing at least one current-voltage measurement and / or at least one voltage-current measurement.

[0132] Embodiment 49: A detector according to any one of the preceding embodiments relating to the detector, further comprising at least one illumination source.

[0133] Embodiment 50: A detector according to the preceding embodiment, wherein the illumination source is selected from: an illumination source that is at least partially connected to the object and / or at least partially identical to the object; an illumination source that is designed to at least partially illuminate the object with primary radiation.

[0134] Embodiment 51: A detector according to the preceding embodiment, wherein the light beam is generated by reflection of primary radiation on the object and / or by emission by the object itself stimulated by the primary radiation.

[0135] Embodiment 52: A detector according to the preceding embodiment, wherein the spectral sensitivity of the optical sensor is covered by the spectral range of the illumination source.

[0136] Embodiment 53: A detector according to any one of the preceding embodiments relating to a detector, wherein the detector further comprises at least one transfer device, the transfer device being adapted to direct the light beam to the light sensor.

[0137] Embodiment 54: A method for manufacturing an optical sensor, comprising the steps of: a) providing a substrate, at least one layer of photoconductive material applied directly or indirectly to the substrate, and at least two discrete electrical contacts contacting the layer of photoconductive material; and b) thereafter depositing an amorphous cover over said layer of photoconductive material and accessible surfaces of said substrate, said cover comprising at least one metal-containing compound.

[0138] Embodiment 55: The method according to the preceding embodiment, wherein the layer of photoconductive material comprises at least two individual sensor areas applied directly or indirectly to the same substrate, and the individual sensor areas are separated from each other during steps a) and b).

[0139] Embodiment 56: The method according to the preceding embodiment, wherein the individual sensor areas are separated from one another during step a) and step b) in such a way that each of the individual sensor areas is carried by a respective portion of the substrate.

[0140] Embodiment 57: The metal inclusion comprises a metal or metalloid, the metal being lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), cesium (Cs), barium (Ba), lanthanum (La), cerium (Cs), or the like. Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), and bismuth (Bi), and said metalloid is selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te).

[0141] Embodiment 58: The method according to the preceding embodiment, wherein the metal of the metal-containing compound is selected from the group consisting of aluminum (Al), titanium (Ti), tantalum (Ta), manganese (Mn), molybdenum (Mo), zirconium (Zr), hafnium (Hf), and tungsten (W).

[0142] Embodiment 59: The method according to any one of the preceding embodiments referring to a method, wherein the at least one metal-containing compound is selected from the group comprising an oxide, a hydroxide, a chalcogenide, a pnictide, a carbide, or a combination thereof.

[0143] Embodiment 60: The method according to the preceding embodiment, wherein the at least one metal-containing compound is selected from at least one oxide, at least one hydroxide, or combinations thereof of aluminum (Al), titanium (Ti), zirconium (Zr), or hafnium (Hf); or a nitride of silicon (Si).

[0144] Embodiment 61: A method according to any one of the preceding embodiments referring to a method, wherein step b) is repeated at least once.

[0145] Embodiment 62: The method according to the preceding embodiment, wherein at least two adjacent portions are deposited as a stack, said adjacent portions being selected to be different with respect to their respective compositions, and at least one of said adjacent portions comprising said at least one metal-containing compound.

[0146] Embodiment 63: The method according to the preceding embodiment, wherein at least one of the adjacent portions is selected to include at least one of a metal compound, a polymer compound, a silicone compound, and a glass compound.

[0147] Embodiment 64: A method according to any one of the preceding embodiments referring to a method, wherein the cover is deposited until it achieves a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 nm to 95 nm.

[0148] Embodiment 65: A method according to any one of the preceding embodiments referring to a method, wherein the cover is deposited on the top and side surfaces of the layer of photoconductive material and on at least the side surfaces of the substrate so as to be a conformal cover to the photoconductive material or adjacent surfaces of the substrate.

[0149] Embodiment 66: The method according to the preceding embodiment, wherein the thickness of the conformal cover follows the corresponding surfaces of the photoconductive material and the substrate within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover.

[0150] Embodiment 67: The method according to any one of the preceding embodiments referring to a method, wherein at least one deposition method is used to deposit the metal-containing compound, and the at least one deposition method is preferably selected from an atomic layer deposition process, a chemical vapor deposition process, a sputtering process, or a combination thereof, preferably an atomic layer deposition process, and a combination of an atomic layer deposition process and a sputtering process.

[0151] Embodiment 68: A method according to any one of the preceding embodiments, wherein at least one additional layer is deposited on the cover or a section thereof, and / or the at least one additional layer is at least partially deposited on the layer of photoconductive material and subsequently covered by the cover.

[0152] Embodiment 69: The method according to the preceding embodiment, wherein the additional layer is or is selected to include at least one of an anti-reflective layer, a light filter layer, an encapsulation layer, a scratch-resistant layer, a hydrophilic layer, a hydrophobic layer, a self-cleaning layer, an anti-fogging layer, a high dielectric constant layer, or a conductive layer.

[0153] Embodiment 70: A method according to any one of the preceding embodiments referring to methods, wherein step b) is performed in a vacuum chamber.

[0154] Embodiment 71: The method according to the preceding embodiment, wherein the electrical contacts are provided before step b) and the cover is further partially deposited on the electrical contacts.

[0155] Embodiment 72: A method according to the preceding embodiment, wherein the electrical contacts are joined to at least one external connection by using a conductive lead, preferably in the form of a wire, in particular a gold (Au), aluminum (Al) or copper (Cu) wire.

[0156] Embodiment 73: The method according to the preceding embodiment, wherein the conductive leads are joined to the electrical contacts through the cover.

[0157] Embodiment 74: Use of a detector according to any one of the preceding embodiments referring to a detector, wherein the detector is used for a purpose selected from the group consisting of: gas detection, fire detection, flame detection, heat detection, smoke detection, combustion monitoring, spectroscopy, temperature sensing, motion sensing, industrial monitoring, chemical sensing, exhaust gas monitoring, security applications. [Brief explanation of the drawings]

[0158] Further optional details and features of the invention are apparent from the following description of preferred exemplary embodiments in conjunction with the dependent claims. In this context, certain features may be implemented alone or in combination with other features. The invention is not limited to the exemplary embodiments. The exemplary embodiments are shown diagrammatically in the figures. The same reference numerals in the individual figures refer to identical elements or elements with the same function or elements that correspond to each other in terms of their function.

[0159] Specifically, in the diagram below: [Figure 1] 1A and 1B are diagrams illustrating a preferred exemplary embodiment of an optical sensor according to the present invention. [Figure 2] 1 illustrates a preferred exemplary embodiment of a photodetector according to the present invention; [Figure 3] 3A-3C illustrate an exemplary embodiment of a method for manufacturing an optical sensor according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0160] Illustrative Embodiments 1A and 1B each highly diagrammatically illustrate an exemplary embodiment of an optical sensor 110 according to the present invention in a side view. The optical sensor 110 thus includes at least one layer 112 of photoconductive material 114. In particular, the layer 112 of photoconductive material 114 may exhibit a thickness of 10 nm to 100 μm, preferably 100 nm to 10 μm, and more preferably 300 nm to 5 μm. In a preferred embodiment, the layer 112 of photoconductive material 114 may include an essentially flat surface; however, other embodiments are possible that may exhibit variations in the surface of the layer 112, such as gradients or steps. Here, the layer 112 of photoconductive material 114 may preferably be manufactured as described below with respect to FIG. 3. However, other manufacturing methods are also possible.

[0161] In the exemplary embodiment of FIG. 1 , the photoconductive material 114 may be or include at least one chalcogenide, which may preferably be selected from the group including sulfide chalcogenides, selenide chalcogenides, telluride chalcogenides, and ternary chalcogenides. Specifically, the photoconductive material 114 may be or include a sulfide, preferably lead sulfide (PbS), a selenide, preferably lead selenide (PbSe), or a ternary chalcogenide, preferably lead sulfoselenide (PbSSe). Many of the preferred photoconductive materials 114 are generally known to exhibit unique absorption characteristics in the infrared spectral range, and therefore the photosensor 110 may preferably be used as an infrared sensor. However, other embodiments and / or other photoconductive materials for this purpose are also feasible, particularly the photoconductive materials described elsewhere in this document for this purpose.

[0162] Furthermore, the optical sensor 110 according to the present invention comprises a cover 116, which preferably completely covers the accessible surface 118 of the photoconductive material 114. As already mentioned above, the cover 116 may be adapted to provide encapsulation for the photoconductive material 114, in particular as an airtight package, to avoid degradation of the optical sensor 110 or its compartments, in particular the photoconductive material 114, due to external influences such as humidity and / or oxygen. As mentioned above, the cover 116 is an amorphous cover comprising at least one metal-containing compound 120. In a particularly preferred embodiment as described herein, the metal-containing compound 120 may comprise a metal selected from the group consisting of Al, Zr, Hf, Ti, Ta, Mn, Mo, and W, with the metals Al, Ti, Zr, and Hf being particularly preferred. However, other types of metals are also feasible, in particular those metals indicated elsewhere in this document for this purpose. Furthermore, the metal-containing compound 120 may be selected from the group consisting of an oxide, a hydroxide, a chalcogenide, a pnictide, a carbide, or a combination thereof.

[0163] In this particular embodiment, the metal-containing compound 120 may preferably include at least one oxide of Al, at least one hydroxide of Al, or a combination thereof, which has the formula AlO x (OH) y , 0≦x≦1.5 and 0≦y≦1.5, where x+y=1.5. In this particular embodiment, the cover 116 can exhibit a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm. This thickness range reflects, among other things, the amount of metal-containing compound 120 within the cover 116, which can be advantageous in achieving the aforementioned function of providing encapsulation of the photoconductive material 114.

[0164] Further, in this particular embodiment, the cover 116 can be a conformal cover relative to the adjacent surface 118 of the photoconductive material 114. Thus, as defined above, the thickness of the conformal cover can follow the corresponding surface 118 of the photoconductive material 114 within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm, and this deviation occurs over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface 122 of the cover 116, thereby excluding any contamination or imperfections that may be present on the surface 122 of the cover 116.

[0165] Alternatively, the metal-containing compound 120 can include at least one oxide of Zr, at least one hydroxide of Zr, or a combination thereof, which has the formula Z r O x (OH) y , 0≦x≦2 and 0≦y≦2, where x+y=2. However, other types of metal-containing compounds 120 may also be feasible, particularly Hf. In all cases, there may still be a residue of unreacted organic ligands.

[0166] 1A and 1B, at least one layer of photoconductive material 114 is preferably applied directly to at least one substrate 124, which may preferably be or include an insulating substrate. Here, the thickness of substrate 124 may be 10 μm to 2000 μm, preferably 50 μm to 1000 μm, and more preferably 100 μm to 500 μm. At least one of cover 116 and substrate 124 is optically transparent in a desired wavelength range, such as in or near the infrared spectral range, to allow an incident light beam 126 to reach photoconductive material 114 to optically modify the conductivity within layer 112 of photoconductive material 114.

[0167] As shown schematically in FIG. 1A , a beam path 128 of an incident light beam 126 can be configured to pass through the cover 116 to generate a light spot having a diameter 130 within the layer 112 of photoconductive material 114. Therefore, it may be particularly advantageous to select the metal-containing compound 120 so that the cover 116 exhibits suitable absorption properties, preferably optically transparent within the desired wavelength range. Alternatively (although not shown here), it may be preferable to select the metal-containing compound 120 so that the cover 116 is not optically transparent within the desired wavelength range. This type of selection may be particularly advantageous when a particular metal-containing compound 120 exhibits particularly favorable properties for the optical sensor 110 apart from providing optical transparency within the desired wavelength range. Furthermore, it may be preferable that one or both of the metal-containing compound 120 used in the cover 116 and the material applied to the substrate 124 can exhibit optically transparent properties within the desired wavelength range, such as to enable the optical sensor 110 to sense the light beam 126 from both directions. Here, the substrate 124 can include an optically transparent material 132, particularly glass. However, other materials that may be at least partially optically transparent in the infrared spectral range may also be feasible.

[0168] In contrast to optical sensors known from the prior art, in particular WO 2018 / 019921 A1, which also contact the accessible surface 134 of the substrate 124, the cover 116 not only covers the accessible surface 118 of the photoconductive material 114 apart from the area where the cover 116 contacts the substrate 124, preferably where the shared cover 116 necessarily contacts even a small portion of its surface with the substrate 124, but also the accessible surface 134 of the substrate 124. Preferably, the cover 116 can be applied in such a way that it completely contacts all accessible surfaces 118, 134 of the photoconductive material 114 and the substrate 124, respectively. In particular, the cover 116 can be applied so that it is in direct contact with the top and side surfaces of the layer 112 of photoconductive material 114 and at least the side surfaces of the substrate 124. However, other types of encapsulation of the photoconductive material 114 are also possible, in particular as an airtight package. As a result, the cover 116 thus prevents direct contact between the layer 112 of the photoconductive material 114 or the substrate 124 and the ambient atmosphere, thereby avoiding degradation of the photoconductive material 114 due to external influences such as humidity and / or oxygen.

[0169] Compared to a cover layer deposited only on the layer of photoconductive material, as disclosed in WO 2018 / 019921 A1, the cover 116 according to the present invention significantly improves the long-term stability of the optical sensor 110. This effect can be experimentally verified, as can be derived from the comparison of Tables 1 and 2 below. For this purpose, dark resistance values ​​in MΩ were measured and shown to vary with increasing exposure time of various samples of the optical sensor 110 to ambient atmosphere (standard pressure) at 26°C. The dark resistance values ​​were measured using a voltage divider circuit of 10 V / mm, linearly extrapolated to 50 V / mm. Here, the layer 112 of photoconductive material 114 of each sample was 2 x 2 mm 2 The chip contained PbS with an active area of ​​1000 nm.

[0170] As shown in Table 1, samples A1 to A7 comprised a cover layer according to the state of the art, in particular as disclosed in WO2018 / 019921A1.

[0171] [Table 1]

[0172] In contrast, samples B1-B7 shown in Table 2 included a cover 116 according to the present invention.

[0173] [Table 2]

[0174] While samples A1-A7 made according to the state of the art began to show decreasing values ​​of dark current after 1000-1500 hours of exposure, samples B1-B7 made according to the present invention did not show any decrease in dark current within the same exposure times. As a result, cover 116 according to the present invention improves the reduction or elimination of external influences by further minimizing or reducing the effects of humidity and / or oxygen on layer 112 of photoconductive material 114, particularly by blocking and / or impeding pathways by which humidity and / or oxygen can be transmitted through or along the surface of substrate 124 to layer 112 of photoconductive material 114.

[0175] 1A and 1B, the optical sensor 110 according to the present invention comprises at least two individual electrical contacts 136, 136′, i.e., at least one first electrical contact 136 and at least one second electrical contact 136′, which are adapted to contact the layer 112 of photoconductive material 114. To this end, the electrical contacts 136, 136′ may be constructed and arranged such that an electric current can be conducted from the first electrical contact 136 through the layer 112 of photoconductive material 114 to the second electrical contact 136′, or vice versa, or such that a voltage can be applied to the layer 112 of photoconductive material 114 using the first electrical contact 136 and the second electrical contact 136′. For both purposes, the first electrical contact 136 can be electrically insulated from the second electrical contact 136', while both the first electrical contact 136 and the second electrical contact 136' are in direct contact with the layer 112 of photoconductive material 114. As further illustrated herein, the cover 116 can at least partially cover the electrical contacts 136, 136' such that the electrical contacts 136, 136' are configured to be coupleable to one or more leads 138, 138', or the like, which may lead to an external circuit, as particularly shown in FIG.

[0176] A direct connection between any one of the electrical contacts 136, 136′ and the layer 112 of photoconductive material 114 can be provided by any known process capable of providing an electrical contact, such as plating, welding, soldering, wire bonding, thermosonic bonding, stitch bonding, ball bonding, wedge bonding, compliant bonding, thermocompression bonding, anodic bonding, direct bonding, plasma activated bonding, eutectic bonding, glass frit bonding, adhesive bonding, transient liquid phase diffusion bonding, surface activated bonding, tape automated bonding, or depositing a highly conductive material in the contact area. To allow sufficient electrical conductivity through the electrical contacts 136, 136′ while at the same time providing sufficient mechanical stability of the electrical contacts 136, 136′, the electrical contacts 136, 136′ preferably comprise at least one electrode material selected from the group consisting of metals silver (Ag), copper (Cu), platinum (Pt), aluminum (Al), molybdenum (Mo), or gold (Au), alloys containing at least one of the foregoing metals, and graphene. However, other types of electrode materials are also feasible.

[0177] As shown schematically in FIG. 1B, the substrate 124 may be attached to a circuit carrier device 142, particularly a printed circuit board (PCB) 144, preferably via a thin film of adhesive 140. For this purpose, wires such as gold wire, beryllium-doped wire, aluminum wire, platinum wire, palladium wire, silver wire, or copper wire may be used as leads 138, 138′ for coupling to electrical contacts 136, 136′, such as contact pads (not shown here) on the circuit carrier device 142. In a particularly preferred embodiment as shown in FIG. 1B, the electrical contacts 136, 136′ may be coupleable through the cover 116. This feature may, in particular, improve the encapsulating function of the cover 116 while at the same time providing stability to the electrical contacts 136, 136′.

[0178] FIG. 2 shows, in a highly schematic manner, an exemplary embodiment of a light detector 150 according to the present invention, which may preferably be adapted for use as an infrared detector. However, other embodiments are also possible. The light detector 150 includes at least one light sensor 100, as described in more detail above, which may be arranged along the optical axis of the detector 150. In particular, the optical axis may be the axis of symmetry and / or the axis of rotation of the configuration of the light sensor 100. The light sensor 100 may be arranged in a housing of the detector 150. Furthermore, at least one transfer device may be included, preferably a refractive lens. An opening in the housing, which may in particular be arranged concentrically with respect to the optical axis, may preferably define the field of view of the detector 150.

[0179] Furthermore, the optical sensor 100 is designed to generate at least one sensor signal in a manner dependent on the illumination of the sensor area 152 by the light beam 126. Here, the detector 150 may have a straight beam path or an inclined beam path, an angled beam path, a diverging beam path, a deflected or split beam path, or other type of beam path. Furthermore, the light beam 126 may propagate once or repeatedly along each beam path or partial beam path, unidirectionally or bidirectionally.

[0180] The FiP effect allows the optical sensor 100 to provide a sensor signal that depends on the beam cross-sectional area 130 of the light beam 126 in the sensor region, given the same total illumination power. However, other types of signals are possible. As indicated above, the sensor region 152 includes at least one layer 112 of a photoconductive material 114, preferably a chalcogenide, particularly lead sulfide (PbS), lead selenide (PbSe), or lead sulfoselenide (PbSSe). However, other photoconductive materials 114, particularly other chalcogenides, may also be used. As a result of the use of the photoconductive material 114 in the sensor region 152, the electrical conductivity of the sensor region 152 depends on the beam cross-sectional area 130 of the light beam 126 in the sensor region 152, given the same total illumination power. As a result, the resulting sensor signal provided by the optical sensor 110 upon impact by the light beam 126 may depend on the electrical conductivity of the photoconductive material 114 in the sensor region 152, thus allowing the beam cross-sectional area 130 of the light beam 126 in the sensor region 152 to be determined.

[0181] Via further electrical leads 154, 154′ to which the leads 138, 138′ are joined, the sensor signal may be transmitted to an evaluation device 156, which is generally designed to generate at least one item of information by evaluating the sensor signal of the optical sensor 110. For this purpose, the evaluation device 156 may comprise one or more electronic devices and / or one or more software components for evaluating the sensor signal. Generally, the evaluation device 156 may be part of and / or include one or more data processing devices 158. The evaluation device 156 may be fully or partially integrated into the housing and / or may be fully or partially embodied as a separate device electrically connected to the optical sensor 100 in a wireless or wired manner. The evaluation device 156 may further comprise one or more additional components, such as one or more electronic hardware components and / or one or more software components, such as one or more measurement units and / or one or more evaluation units and / or one or more control units (not shown here).

[0182] 3A-3C show, in a very schematic manner, an exemplary embodiment of a method for manufacturing an optical sensor 110 according to the invention.

[0183] 3A , prior to providing the layer 112 of photoconductive material 114, which preferably comprises glass as the optically transparent material 132, electrical contacts 136, 136′ may be created on the substrate 124 in the form of a vapor-deposited metal layer, which may be provided by known vapor deposition techniques. In particular, the vapor-deposited metal layer may comprise one or more of Ag, Al, Pt, Mg, Cr, Ti, or Au. Alternatively, the electrical contacts 136, 136′ may comprise a layer of graphene. However, as described in more detail above, other methods of creating the electrical contacts 136, 136′ are also feasible.

[0184] 3A, a layer 112 of a photoconductive material 114 is subsequently provided. For this purpose, the photoconductive material 114 can be synthesized according to the following procedure: 0.015 mol / L of thiourea or its substitution products, 0.015 mol / L of lead acetate, lead nitrate or its substitution products, and 0.15 mol / L of sodium hydroxide or its substitution products are dissolved in a reaction volume, thereby obtaining a clear solution at room temperature. As is known from the prior art, when the above-mentioned solutions are mixed in any order, lead sulfide (PbS) precipitates from the solution at temperatures above 30°C in such a way that a uniform and relatively smooth layer can usually be formed on the side walls and bottom of the liquid-containing reactor or on the walls of any object located therein.

[0185] However, just before lead sulfide (PbS) actually precipitates from the mixed precipitation solution, an additive capable of degassing a relatively large amount of nascent oxygen, preferably an aqueous solution of potassium persulfate, hydrogen peroxide, or sodium perborate, is added thereto, and lead sulfide (PbS) is precipitated therefrom in the usual manner, but in an activated form that can be further sensitized by direct use in the cell or by aging or low-temperature baking. The precipitation solution and activator are mixed, preferably at a temperature above 35°C, and stirred for 1 to 3 hours, during which time deposition occurs. Here, the amount of nascent oxygen from persulfate ions, perborate ions, or hydrogen peroxide added to the solution to precipitate PbS, expressed in moles, is preferably 0.01 to 0.5 stoichiometric amount of PbS in the bath, expressed in moles, where the stoichiometric amount of PbS is the amount that would be formed if there was total conversion of the lead and sulfur precipitation compounds to lead sulfide.

[0186] After the formation of the lead sulfide (PbS) layer, an aging step can optionally be carried out in a climate chamber, preferably at a temperature of about 50°C and a humidity of greater than 70%, which has been found to be beneficial for photoconductive performance. Improved photoconductivity can be obtained if the deposited and aged film is further treated by annealing, i.e., by heating in vacuum or air at a temperature of about 100°C to 150°C for 1 to 100 hours.

[0187] However, other types of methods for providing the layer 112 of photoconductive material 114 may also be feasible.

[0188] 3B shows the deposition of a metal-containing compound 120 as an amorphous covering 116 on the accessible surfaces 118, 134 of the layer 112 of the photoconductive material PbS 114 and the substrate 124, particularly to function as an encapsulation layer. For this purpose, at least one precursor adapted to react with the metal-containing compound 120 can be used. In this preferred embodiment, an atomic layer deposition (ALD) process, or a combination of ALD and sputtering, is used as the deposition method. Alternatively, other deposition processes, such as a chemical vapor deposition (CVD) process, can also be applied.

[0189] In a preferred embodiment of the present invention, the cover 116 comprises Al2O3 produced by an ALD process or a combination of an ALD process and a sputtering process. Alternatively, stacks such as Al2O3 / TiO2 / Al2O3 / ... or Al2O3 / ZrO2 / Al2O3 / ... can also be produced. In this particular embodiment, the ALD process was carried out applying the following process parameters:

[0190] - First precursor: H2O; - second precursor: Al(CH3)3 (trimethylaluminum, TMA); - Temperature about 60℃; - Approximately 700 cycles.

[0191] As further shown in FIG. 3B, an Al2O3-containing cover 116 may be applied in accordance with the present invention in such a manner as to simultaneously cover the accessible surface 118 of the photoconductive PbS layer 112, the electrical contacts 136, 136' that may contact the photoconductive PbS layer 112, and the accessible surface 134 of the substrate 124.

[0192] 3C, two electrical contacts 136, 136' making electrical contact with the layer 112 of photoconductive material 114 can be preferably ultimately joined to at least one external connection by conductive leads 138, 138', such as gold wires, which can be provided here through the cover layer 116. However, as mentioned above, other ways of providing the electrical contacts 136, 136' to the photoconductive PbS layer 112 are also feasible, such as by providing the leads 138, 138' already before depositing the amorphous cover 116, i.e., by providing the leads 138, 138' in an intermediate process step between process steps as shown in FIGS. 3A and 3B.

[0193] In a particularly preferred embodiment, the layer 112 of photoconductive material 114 can include at least two individual sensor areas (not shown here), which are preferably an array of individual sensor areas, and the individual sensor areas are preferably applied directly or indirectly to the same substrate 124, which is also called a "common substrate" and which can therefore exhibit a fairly large area. In this particular embodiment, the individual sensor areas are first applied directly or indirectly to the common substrate 124, and at least two electrical contacts 136, 136' are provided to the individual sensor areas in the layer 112 of photoconductive material 114. The individual sensor areas are then separated from one another in a manner carried by the respective portions of the substrate 124. Finally, a cover 116 is deposited on the individual sensor areas and on each accessible surface 118, 134 of the respective portions of the substrate 124. [Explanation of symbols]

[0194] List of Reference Numbers 110 Sensors 112 Layer of photoconductive material 114 Photoconductive materials 116 Cover 118 accessible surface of layer of photoconductive material 120 Metal-containing compounds 122 Cover surface 124 board 126 Light Beam 128 Beam Path 130 Diameter of light beam; beam cross-sectional area 132 Optically transparent materials 134 accessible surface of substrate 136, 136' electrical contacts 138, 138' Electrical connection leads 140 Thin Film of Adhesive 142 Circuit Carrier Device 144 Printed Circuit Board 150 photodetectors 152 Sensor Area 154,154' Further electrical leads 156 Evaluation Device 158 Processing equipment

Claims

1. 1. An optical sensor (110) comprising: a substrate (124) mounted on a circuit carrier device (142); at least one layer (112) of photoconductive material (114) applied directly or indirectly to the substrate (124); at least two discrete electrical contacts (136, 136') contacting the layer (112) of photoconductive material (114); and a cover (116) covering accessible surfaces of the photoconductive material (114) and the substrate (124), wherein the cover (116) is an amorphous cover comprising at least one metal-containing compound (120), and at least one of the substrate (124) and the cover (116) is optically transparent within a wavelength range.

2. 10. The optical sensor of claim 1, wherein the at least one metal-containing compound comprises a metal selected from the group consisting of aluminum (Al), titanium (Ti), tantalum (Ta), manganese (Mn), molybdenum (Mo), zirconium (Zr), hafnium (Hf), and tungsten (W).

3. The optical sensor (110) of claim 1 or 2, wherein the at least one metal-containing compound (120) is selected from the group comprising oxides, hydroxides, chalcogenides, pnictides, carbides, or combinations thereof.

4. The optical sensor (110) of any one of claims 1 to 3, wherein the cover (116) has a thickness of 10 nm to 600 nm.

5. The optical sensor (110) of any one of claims 1 to 4, wherein the cover (116) is a conformal layer with respect to the layer (112) of photoconductive material (114) and adjacent surfaces of the substrate (124).

6. The optical sensor (110) of any one of claims 1 to 5, wherein the cover (116) completely covers accessible surfaces of both the layer (112) of photoconductive material (114) and the side surfaces of the substrate (124), and the cover (116) is a continuous coating that continuously covers both the layer (112) of photoconductive material (114) and the side surfaces of the substrate (124).

7. The optical sensor (110) of any one of claims 1 to 6, wherein the cover (116) is or includes an atomic deposition coating.

8. The optical sensor (110) of any one of claims 1 to 7, wherein the cover (116) further at least partially covers the electrical contacts (136, 136').

9. The optical sensor (110) of any one of claims 1 to 8, wherein the electrical contacts (136, 136') are joinable through the cover (116).

10. 10. The optical sensor of claim 9, wherein the photoconductive material comprises at least one chalcogenide selected from the group consisting of sulfide chalcogenides, selenide chalcogenides, telluride chalcogenides, ternary chalcogenides, quaternary chalcogenides, higher order chalcogenides, and solid solutions and / or doped variations thereof.

11. 11. The optical sensor (110) of claim 10, wherein the chalcogenide is selected from the group consisting of lead sulfide (PbS), lead selenide (PbSe), and solid solutions and / or doped variants thereof.

12. A detector (150) for optical detection, an optical sensor (110) according to any one of claims 1 to 11, comprising at least one sensor area (152), the optical sensor (110) being designed to generate at least one sensor signal in a manner dependent on illumination of said sensor area (152) by a light beam (126); and at least one evaluation device (156) designed to generate at least one item of information relating to the optical radiation provided by the light beam (126) by evaluating the sensor signal of the optical sensor (110); a detector (150) including:

13. 13. Use of the detector (150) of claim 12, wherein the intended use is selected from the group consisting of gas detection, fire detection, flame detection, heat detection, smoke detection, combustion monitoring, spectroscopy, temperature sensing, motion sensing, industrial monitoring, chemical sensing, exhaust gas monitoring, and security applications.

14. A method of manufacturing an optical sensor (100) comprising the steps of: a) providing a substrate (124) mounted on a circuit carrier device (142), at least one layer (112) of photoconductive material (114) applied directly or indirectly to said substrate (124), and at least two discrete electrical contacts (136, 136') contacting said layer (112) of photoconductive material (114); and b) thereafter depositing an amorphous cover (116) on the accessible surfaces of the layer (112) of the photoconductive material (114) and the substrate (124), the cover (116) comprising at least one metal-containing compound (120); The method, wherein at least one of the substrate (124) and the cover (116) is optically transparent within a wavelength range.

15. 15. The method of claim 14, wherein the layer (112) of the photoconductive material (114) has at least two individual sensor areas applied directly or indirectly to the same substrate (124), and the individual sensor areas are separated from each other during steps a) and b) in such a way that each of the individual sensor areas is carried by a respective portion of the substrate (124).

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