Hybrid Integrated Quantum Random Number Generator

Abstract

The present invention relates to a hybrid integrated quantum random number generator (hiQRNG), in particular a photonic QRNG constructed as a hybrid integrated structure consisting of a photon source and a detector for single photons directly coupled to the source in a compact and attack-proof design. The present invention relates to a hybrid integrated quantum random number generator, hiQRNG, (100) comprising a photon source (12) and a single-photon detector (22), wherein the photon source (12) and the single-photon detector (22) are arranged as separate components in a vertical direction one above the other in a common hybrid structure.

Description

[0001] The present invention relates to a hybrid integrated quantum random number generator (hiQRNG), in particular to an entropy source for a photonic QRNG constructed as a hybrid integrated structure consisting of a single photon source (SPS) and a detector for single photons directly coupled to the SPS in a compact and attack-proof design. Technological background

[0002] Random events and the determination of probabilities play a particularly prominent role in many areas of science and technology. For example, Monte Carlo simulations and secure encryption methods rely heavily on the generation of random numbers. A general distinction is made between so-called pseudo-random numbers and true random numbers. While the former are generated using deterministic formulas by pseudo-random number generators (PRNGs), and are therefore not absolutely random, non-deterministic random number generators (TRNGs) for generating true random numbers are generally based on real, unpredictable processes such as thermal or atmospheric noise, rather than on artificially generated patterns by deterministic algorithms.However, even the results of such non-deterministic random number generators based on external parameters can, depending on the underlying random element, still tend slightly towards higher or even numbers due to weak correlations, for example, and thus enable at least a partial predictability of the random numbers generated in this way.

[0003] Quantum random number generators (QRNGs), a special subgroup of TRNGs, are based on fundamental quantum processes for random number generation and are therefore, at least theoretically, not dependent on other external factors and effects that influence statistics. Quantum random number generators thus represent the currently best available source of true random numbers. Current digital QNRGs can deliver entropy rates (i.e., a sequence of bit values ​​with maximum randomness or entropy) of up to several hundred Mbps. The generated random numbers are required in both classical encryption methods and a variety of quantum computing and quantum cryptography methods to ensure secure key exchange (Secure / Quantum Key Distribution, SKD / QKD).Therefore, non-manipulable and fast QRNGs are essential for generating secure keys in cryptography.

[0004] Due to their particularly easy implementation, many QRNGs are realized as photonic QRNGs using the random properties of photons. A simple concept for generating random numbers is the behavior of a photon, which is either reflected or transmitted at a semitransparent beam splitter independently of other photons. Another approach is to utilize the random arrival times of photons at a single-photon detector. This distribution effect, based on intrinsic, fundamentally non-deterministically computable photon statistics of the photons of a corresponding photon source, can also be used to generate truly random numbers.The random numbers can be generated, in particular, via the varying time differences between two consecutive detection events on the single-photon detector, with the arrival times generally exhibiting a distribution characteristic of the type of photon source (i.e., thermal, coherent, or non-classical photon source). The combination of a photon source suitable for random number generation with a correspondingly sensitive single-photon detector is also referred to as the entropy source of the corresponding QRNG, with random number generation being determined by the temporal sequence of the individual detection events in the entropy source.A corresponding QRNG requires at least one entropy source and can include at least one additional component for evaluating the individual detection events and / or for providing a digital random number sequence suitable for further processing based on the respective arrival times of the photons. The terms entropy source and QRNG are therefore largely used synonymously in the present application.

[0005] Typically, a single-photon detector (SPD) initially generates a detector pulse from a single incident photon. This pulse is then converted into a timestamped digital representation of the detection event in a time-to-digital converter (TDC) and can be further processed accordingly. The photon sources in QRNGs are usually laser diodes (LDs) or simple light-emitting diodes (LEDs) that are highly attenuated to the single-photon level. Their emitted photons can then be recorded as SPDs with temporal resolution by one or more particularly sensitive single-photon avalanche diodes (SPADs).Such photon sources that simultaneously emit only a single photon or a few photons are also referred to as single-photon sources (SPS) in this application. However, they do not necessarily have to be true single-photon emitters, for example, based on a single isolated two-level system.

[0006] SPADs are a type of photodetector similar to photodiodes (PDs) and avalanche photodiodes (APDs), but with significantly increased sensitivity. SPADs can be digitally read and evaluated – even within a common integrated circuit. If such an integrated detector circuit is excited by individual photons, only one electron-hole pair is generated per exciting photon in the sensor-active region (absorption region). The excited electrons are drawn to the cathode by electric fields, and the excited holes are drawn to the anode. In a SPAD, the charge carriers drift through a so-called avalanche region, within which a charge avalanche is generated by enhanced impact ionization. These are therefore highly sensitive photon receiver elements that, upon activation, store a high amount of charge (approximately 105 - 10 6 electrons) with high temporal resolution.

[0007] A SPAD is typically operated in Geiger mode above its respective breakdown voltage, whereby a single photon is detected via the generated charge avalanche and subsequently registered as a single event. To reduce the dead time during registration, active or passive suppression or quenching of further charge carrier amplification can occur immediately after the onset of the avalanche formation. In addition to the SPAD, the integrated circuit can also include a so-called single-photon counter (SPC). In this case, instead of directly outputting a single detector pulse, an immediate statistical evaluation of the temporal distribution of the individual detected single-photon events is generally performed.

[0008] Statistical analysis performed in parallel with random number generation can, for example, be used to further secure the random number generation process against potential attacks. Particularly in the case of non-integrated photonic QRNGs constructed from individual components, the required transmission paths within the system offer a wide range of attack possibilities. Therefore, to increase security, such systems are implemented as compactly as possible and isolated from their external environment. In addition to avoiding potential attack scenarios, another advantage of such compact QRNGs is that natural influences from outside the system that may impair random number generation can also be minimized to the greatest extent possible.Accordingly, compact QRNGs based on photon noise are currently provided as hybrid component systems in which a SPS and a SPAD are connected as independent elements, for example via planar waveguide structures.

[0009] From EP 3 529 694 B1, an integrated quantum random number generator (iQRNG) with a PLC and one or more SPDs is also known, in which the PLC and the SPD(s) are completely integrated in CMOS technology in a single semiconductor substrate in such a way that they are arranged directly next to each other (see Fig. 1 with associated figure description). The SPS is provided by a suitably doped pn junction, so that it generates a detectable photon current when the photon source is suitably biased in the forward or reverse direction. The SPDs are intended to be SPADs, which are preferably produced through common manufacturing processes with the SPSs and have the same chemical structure.

[0010] The joint integration ensures that the photon flux generated by the SPS can flow directly to an adjacent SPAD through optical crosstalk within one and the same semiconductor material. Unlike non-integrated photonic QRNGs constructed from individual components, it does not first have to overcome or tunnel through a potentially empty coupling gap that physically separates the two components. The integrated "side-by-side" configuration makes the QRNG presented in the publication more compact and structurally less complex than conventional hybrid QRNGs of the same functional type. Furthermore, thanks to the integration of all components, the random number generator is significantly more robust and immune to external environmental influences and attempts at manipulation by external attackers.

[0011] However, it is still possible, at significantly increased expense, to interfere with, influence, and / or monitor the random number generation process during the QRNG's operation. Since the iQRNG disclosed in the publication essentially has a planar structure, individual photons could certainly be tapped or additionally introduced from above or below the plane of the substrate.

[0012] The horizontal juxtaposition of the structures is also not ideal in terms of efficiency and required space consumption. Efficiency is particularly limited by the required lateral distance between the SPS and the SPAD and the associated high absorption of the photons in the semiconductor material. Furthermore, without special precautions, the photons emitted by the SPS are largely scattered into the material surrounding the SPS, meaning that only a portion of the generated photons can be detected by an associated SPAD. While multiple SPADs can be arranged around a single SPS, increasing efficiency and thus the digital entropy rate through joint evaluation of the connected SPADs, this significantly increases the space consumption of such an iQRNG.On the other hand, even with a single emitter-detector pair, it must be ensured that undetectable photons cannot propagate uncontrollably within the substrate and cause interference elsewhere in the substrate. The associated lateral blocking regions therefore also increase the effective area consumption of the iQRNG.

[0013] An iQRNG, also realized in CMOS technology (HV-CMOS), with a corresponding arrangement of a photon source and a single-photon detector next to each other is also known from Khanmohammadi et al. (Khanmohammadi et al. “A monolithic silicon quantum random number generator based on measurement of photon detection time.” IEEE Photonics Journal 7.5 (2015): 1-13). An n-well located in a circular, near-surface region between a central n ++-region as cathode and several ring-shaped p++ regions as anode as a photon source is surrounded by a SPAD as a single-photon detector (see Fig. 2 with associated figure description). The photons emitted by the SPS are thus detected from all sides of the plane, which allows for increased efficiency while requiring less space compared to the iQRNG known from EP 3 52 694 B1. The SPS is thus directly integrated into the SPAD. However, individual photons can also be emitted into the substrate or extracted from its surface. Likewise, the injection of corresponding photons by an attacker to influence the statistics is also possible in this way.

[0014] The aforementioned disadvantages of previous iQRNGs can be overcome or at least significantly reduced by stacking a suitable SPS and a SPAD within a common semiconductor material. A light-emitting avalanche Zener diode (Zener avLED) operating at an operating point below or close to the breakdown voltage can be used as the SPS. By stacking a Zener avLED and a SPAD in a common semiconductor substrate, a particularly compact and secure integrated QRNG can be provided. An advantageous implementation of the described iQRNG in a modern and particularly widely applicable bipolar CMOS-DMOS technology (BCD technology), particularly on silicon, is also possible.

[0015] However, the integration approaches presented so far all have the disadvantage that, although they are extremely compact and thus enable implementation in a variety of electronic integrated circuits (ICs), the specific circuit design, the material system used, and the associated manufacturing technology allow only limited flexibility for adaptations or modifications to these designs. These can sometimes only be achieved at relatively high cost as independent new developments. For example, some applications with special requirements may require alternative emitter-receiver concepts for the use of other spectral ranges, which, however, cannot be easily implemented with such conventional iQRNGs.Although full integration into a material system can improve the optical coupling and provide better protection against manipulation, the further processing of the raw signals is still solved externally in the state of the art or is implemented in the SPAD technology used and is therefore usually limited in performance.

[0016] Therefore, there is a need for a compact and cost-effective QRNG with increased flexibility for adaptations and modifications compared to the state of the art. The QRNG should be largely protected against external attacks while achieving the highest possible efficiency and minimizing substrate losses. Furthermore, the QRNG should be as technology-open as possible and be based on the most widely applicable technology platform possible. Description of the invention

[0017] The object of the invention is achieved by the subject matter of the independent patent claim. Preferred developments are the subject matter of the dependent claims.

[0018] One aspect of the present invention relates to a hybrid integrated quantum random number generator (hiQRNG) comprising a photon source and a single-photon detector, wherein the photon source and the single-photon detector are arranged as separate (i.e., structurally and mechanically initially separate) components vertically one above the other in a common hybrid structure. A hiQRNG according to the invention can also comprise multiple photon sources coupled to a single single-photon detector (e.g., to increase the effective photon or entropy rate or the reliability) or multiple single-photon detectors coupled to a single photon source. The combination of multiple photon sources and single-photon detectors to provide a single hiQRNG is also possible.

[0019] In contrast to the prior art, there is no planar juxtaposition of the individual optoelectronic components. Rather, the invention provides a compact arrangement of a photon source and a single-photon detector one above the other in a common hybrid structure. Hybrid integration is understood as the assembly of an integrated circuit from two or more different individual components (in contrast to full integration, in which the individual components are formed together in one material). This thus represents a compact 3D arrangement with low space requirements for the hiQRNG. Preferably, a receiver chip with a low-voltage single-photon avalanche diode (SPAD) can be combined with an emitter chip using any technology.

[0020] Preferably, the photon source and the single-photon detector are each elements produced in a separate semiconductor material by microstructuring. The individual (micro)chips can then be aligned with their surfaces to one another using appropriate manufacturing processes (e.g., in a face-to-face arrangement) and arranged and connected to form a common hybrid structure according to the invention. The alignment of the chips to one another can be achieved, for example, using alignment marks, and the accuracy can be in the range of a few micrometers or even less. The hybrid structure forms a microintegrated, non-monolithic unit, which can in particular be a so-called chiplet. The hybrid chiplet structure can additionally be combined with other chiplet modules with the same or different functionality.In a face-to-face arrangement, the optically coupled surfaces of the two chips are positioned opposite each other in such a way that the photons provided by the photon source are generated as close as possible to the single-photon detector. This allows the aperture angle and the irradiation area to be kept as small as possible, further reducing the potential for interference.

[0021] The chips comprising the photon source and the single-photon detector (hereinafter also referred to as emitter and receiver chips) can be designed as "real" chips (i.e., for example, as a microstructure produced using semiconductor technology in or on a corresponding semiconductor substrate). However, the individual chips can also be, for example, hybrid or otherwise combined individual structures. In particular, the chip with the photon source and / or the chip with the single-photon detector can each be formed by substructures consisting of several individual chip layers or chip levels ("fake" multilayer chips or chip-like structures). In particular, the receiver chip can be constructed in a so-called backside-illuminated (BSI) configuration.

[0022] The photon source can, for example, be a color or defect center in or on a substrate or background material suitable for hybrid integration. Color or defect centers can be excited optically or electrically. A color or defect center can be generated intrinsically in the substrate or background material or it can be provided directly by it. Alternatively, color or defect centers can also be added to the substrate or background material as isolated elements (e.g., using known implantation or manipulation methods). A defect center suitable as a photon source is, for example, nitrogen vacancies in diamond (so-calledDiamond NV centers), whereby nanodiamonds with only one or a few defect centers can be introduced into the surface of a corresponding substrate or background material (an additional excitation light source is necessary to excite photon emission at diamond NV defect centers).

[0023] The photon source is preferably a single-photon source (SPS), configured to simultaneously emit only a single photon or a few photons. Such photon sources that simultaneously emit only a single photon or a few photons are also referred to as single-photon emitters in this application. However, they do not necessarily have to be true single-photon emitters, for example, based on a single isolated two-level system; rather, conventional light sources can also be configured as (quasi-)SPSs by attenuating the emission or the supplied current accordingly.

[0024] The photon source is preferably a pn junction, an avalanche diode, or a single-photon avalanche diode (SPAD), each configured as an emitter. The photon source can be formed in or from a direct semiconductor material (e.g., a III / V semiconductor) or, preferably, in or from an indirect semiconductor material (e.g., silicon). Radiating pn junctions are known to those skilled in the art. By supplying them with only a low current and possibly additionally significantly attenuating the intensity of the generated radiation using optical filters and absorbers, these pn junctions can be utilized for QRNG applications. With appropriate attenuation, operation as a PLC is even possible.The formation in or from an indirect semiconductor material offers the particular advantage that photon generation is greatly hampered in such materials for energetic reasons and thus the effective photon generation rate is only low even with easily controllable currents during activation and can already enable operation as a PLC without any additional attenuation measures.

[0025] It is also known that, under certain circumstances, photon generation and thus radiation emission can occur even in non-radiative pn junctions (e.g., pn junctions in indirect semiconductors). However, the electro-optical conversion rate is generally so low that these rather randomly generated photons can usually be neglected in the design of conventional circuits. In combination with a highly sensitive detector, such extremely weakly radiating pn junctions can also be used as photon sources in a QRNG. What has been said for non-radiative pn junctions applies accordingly to avalanche diodes and SPADs, which are also typically assumed to be non-radiative. By selecting the appropriate operating parameters, low photon emission can also be observed and used for QRNG applications.In all the examples mentioned, the main focus is on providing a stable photon flux with only an extremely low intensity (i.e. a low photon rate or only one photon per unit of time).

[0026] For example, the photon source can be a light-emitting avalanche Zener diode (Zener avLED) operating at an operating point below or close to the breakdown voltage. The Zener avLED preferably has a breakdown voltage of <10 V, more preferably a breakdown voltage of <8 V, and even more preferably a breakdown voltage of <7 V. This type of single-photon source allows for a high single-photon rate at a relatively low operating voltage, even below and in the range of the Zener breakdown voltage, and, with the desired design, can exhibit a preferentially directed emission of the generated photons from the substrate toward the single-photon detector. This makes Zener avLEDs particularly suitable for use as a single-photon source in a hiQRNG according to the invention.

[0027] The single-photon detector is preferably a single-photon avalanche diode (SPAD). This refers to detectors that, due to their particularly high sensitivity with high amplification and low (dark) noise, are in principle capable of detecting and proving single photons.

[0028] The photon source preferably extends as an extended region over a plurality of single-photon detectors. In this embodiment, the photons emitted by a single, large-scale photon source (i.e., a strip or area emitter) can thus be detected by a plurality of single-photon detectors. The photon source can be designed such that photons emitted simultaneously at distant regions of the photon source are correlated with one another at most slightly, i.e., the individually emitted photons are generated statistically largely independently of one another. A large-scale photon source has the advantage that it is easier to generate and control, and in particular, the required accuracy for the mutual alignment of the photon source and the single-photon detectors can be significantly reduced.

[0029] Preferably, the photon source is arranged in or on an emitter chip, the single-photon detector is arranged in or on a receiver chip, and the emitter chip and the receiver chip are connected to one another by a chip-to-chip connection via a connection region such that photons emitted by the photon source can be directly detected by the single-photon detector via a transmission path. It has already been stated that the photon source and the single-photon detector can each be elements produced in a separate semiconductor material by microstructuring, and in particular that the photon source can also be a color or defect center in or on a substrate or background material suitable for hybrid integration. The semiconductor materials or the substrate or background material can be chips (microchips orThis can be viewed as organic optoelectronics, with the individual chips generally being formed as rigid bodies (wafers or substrates). However, the chips can also be made of one or more flexible materials suitable for a corresponding chip-to-chip connection ("organic optoelectronics").

[0030] The term "chip-to-chip connection" means that two originally separate chips are firmly connected to one another using a specific process. In addition to the purely structural arrangement, electrical contacts can also be formed between the chips. A chip-to-chip connection can be achieved by mutual surface contact between one surface of the respective chips (so-called "direct bonding"). The resulting contact area then forms a connection region. If the chip-to-chip connection is made via solder points (microbumps) with a distance between the respective opposing surfaces, a spatial connection region is formed. Therefore, the emitter chip and the receiver chip preferably contact one another directly in the connection region, or they are separated from one another by at least one intermediate layer.An intermediate layer can, for example, be a dielectric (e.g., silicon oxide or silicon nitride). However, the intermediate layer can also be formed by an open, evacuated, or free space (cavity) filled with a protective gas or another suitable filler material. The at least one intermediate layer can be produced or provided both as part of the hybrid structure and by at least one of the respective individual chips. In particular, a first intermediate layer, provided together with the emitter chip, and a second intermediate layer, provided together with the receiver chip, can be arranged in the connection region, thus separating the chips from one another at a distance.

[0031] Since, according to the invention, the photon source and the single-photon detector are arranged vertically one above the other as separate components in a common hybrid structure, they are separated from each other by a planar or spatially formed connecting region. The transmission path for photons emitted by the photon source must therefore pass through the connecting region. In other words, the transmission path represents the optical path for the transmission of photons from the photon source to the single-photon detector.

[0032] The chip-to-chip connection preferably comprises a dielectric or metallic bond, an adhesive bond, and / or a soldered bond. Such chip-to-chip connections are well known to those skilled in the art, both in the electronic and optoelectronic fields. For example, a connection technology based on metallic microbumps is presented in Fukushima et al. (Fukushima et al., "Nonconductive film and compression molding technology for self-assembly-based 3D integration." Proceedings - Electronic Components and Technology Conference (2012)). A bonding method based on Cu bumps is known, for example, from Kim et al. (Kim et al., "Wafer level Cu-Cu direct bonding for 3D integration." Microelectron. Eng. 137 (2015)). For further methods for providing chip-to-chip connections, reference is made to the extensive specialist literature on this subject.Examples of this include flip-chip bonding, bump bonding, and optical (adhesive) connection technologies. However, to the inventors' knowledge, such chip-to-chip connections have not yet been used to implement a hiQRNG by arranging a photon source (or a single-photon source) and a single-photon detector opposite one another.

[0033] Preferably, the transmission path is surrounded by a local light shield in the connection area. A local light shield can, in particular, be an area made of a material that is opaque to the photons emitted by the photon source, or can have a corresponding structure. The photons can, for example, be absorbed by the local light shield, so that they cannot penetrate the area. However, it is preferred that the local light shield represents an area that reflects the photons, so that the photons can still reach the single-photon detector and be detected by it. A local light shield can, for example, be designed as a metallic casing of the transmission path (e.g., as a cylindrical structure). However, it can also be an implantation area or another type of casing structure to provide high absorption for the emitted photons.The local light shield is intended to limit the propagation of photons in the connection area to a dedicated transmission path. In particular, the photons should not lead to an optical background within a hybrid structure according to the invention (i.e., outside the immediate vicinity of the photon source and / or the single-photon detector). Furthermore, any coupling of extraneous photons into the transmission path (e.g., in the event of an attempted attack) should be prevented.

[0034] Preferably, the emitter chip and / or the receiver chip are each at least partially surrounded by a light shield. In principle, the light shield has the same function as a local light shield, but the intended protection relates to the entire hybrid structure according to the invention and not just to a specific transmission path. Preferably, both the emitter chip and the receiver chip are surrounded by an opaque potting compound, a housing (packaging) or a metallic frame for shielding purposes, or they are firmly enclosed therein. In order to harden a hiQRNG according to the invention against attacks by reverse engineering, the light shield can also be used as a mechanical protective device. For example, a housing can be designed in such a way that non-destructive exposure of the interior (i.e. the still functional hybrid structure) is not possible or only possible with considerable technical effort.For example, a light shield may be covered with an opaque plastic material.

[0035] The emitter chip and the receiver chip are preferably connected to one another by at least one electrical connection. The provision of electrical connections (e.g., in flip-chip bonding) is well known to those skilled in the art. Electrical connections can be provided, for example, via a bond contact, microbump, or as a through-silicon via (TSV). Although in some embodiments of the invention the emitter chip and the receiver chip, despite hybrid integration as a common hiQRNG, can continue to comprise independent electronic circuits which can also be controlled separately and contacted externally, it is preferred, however, that at least the read-out electronics required for operating the hiQRNG, control electronics, optional evaluation electronics, and any additional electronic circuit blocks are integrated.Integrated Circuit (IC) blocks are located on only one of the two chips. However, an arrangement on the emitter chip is preferred, as the additional components are then not tied to the technology of the receiver chip for providing a single-photon detector. The emitter chip is less demanding and can be implemented in a variety of technologies and material systems.

[0036] On the one hand, this reduces processing effort and thus deployment costs (different technologies and material systems can be combined), and on the other hand, it enables greater compactness and thus less space consumption. This also leads to a significant cost reduction, but also has significant security advantages. By making the hiQRNG components as compact as possible, the volume effectively available for attacks is also limited. The more compact the circuit design, the more secure the random number generation can be considered. Therefore, instead of forming a multitude of electrical connections between the individual components, the single-photon detector, for example, can be coupled to the emitter chip with all the required circuit components using just a few electrical connections.A circuit design that is as compact as possible, offering minimal potential attack surface, is preferred. However, the preferred design depends on the specific design of a hiQRNG and the respective application requirements.

[0037] An optical connection between the photon source of the emitter chip and the single-photon detector of the receiver chip is generally established via unguided simple radiation coupling. The photons can therefore, in principle, propagate freely within the hybrid structure, whereby suitable adaptations (e.g., through shielding or reflectors) can also achieve largely directional coupling. However, the coupling can be improved by further measures, such as the provision of additional waveguide structures or imaging structures (e.g., lens-like optical elements). Preferably, the optical connection technology used also simultaneously provides a mechanical connection between the emitter chip and the receiver chip to form a common hybrid structure. For example, an adhesive suitable for optical applications (e.g.,NOA68 from Norland Products) both a mechanical adhesive connection for a face-to-face arrangement of the chips via flip-chip bonding and the corresponding optical coupling through the adhesive surface or the adhesive region can be realized. An additional intermediate layer can also be arranged within the adhesive region, in which the waveguide or imaging structures described above are integrated at the appropriate locations. However, corresponding additional intermediate regions can also be combined, independently of an adhesive connection, with all other connection technologies known to those skilled in the art for chip-to-chip connection or those specified above.

[0038] Preferably, the photon source and / or the single-photon detector are isolated from the respective chip environment and / or other elements (e.g., control electronics, readout electronics, electronic circuit blocks, bond pads, neighboring entropy sources or QRNG, etc.) by at least one optical shield or at least one light shield. An optical shield can, in particular, be a region made of a material that is opaque to the photons emitted by the photon source, or with a corresponding structure. The photons can, for example, be absorbed by the optical shield, so that they cannot penetrate the region. However, it is preferred that the optical shield represents a region that reflects the photons, so that the photons can still reach the single-photon detector and be detected by it.An optical shield can, for example, be formed as a metallic casing for the photon source and / or the single-photon detector. However, it can also be an implantation region or a casing structure created in another way to provide high absorption for the emitted photons. The photon source and / or the single-photon detector can be isolated from the environment by the optical separation, particularly at the sides and / or at the bottom or top. However, in the direction of the transmission path, the optical shield must have at least a sufficient transmission range for the photons.

[0039] The optical shielding is intended to limit the propagation of photons to a narrow area around the photon source and / or the single-photon detector. In particular, the photons should not lead to an optical background within a hybrid structure according to the invention (i.e., outside the immediate vicinity of the photon source and / or the single-photon detector). Furthermore, it is intended to prevent any possible coupling of extraneous photons (e.g., in the event of an attempted attack) into the immediate vicinity of the photon source and / or the single-photon detector.

[0040] Preferably, the emitter chip and / or the receiver chip further comprises an electronic circuit block and / or at least one bond pad. In particular, the emitter chip and / or the receiver chip can comprise at least one of control electronics, readout electronics, evaluation electronics, and a bond pad. The readout electronics, the control electronics, and / or the evaluation electronics can each be designed as individual components or as a common electronic circuit block. The readout electronics can, for example, comprise a signal amplifier, an A / D converter, and a pulse shaper. A charge pulse generated by the SPAD can thus preferably be converted into a standardized pulse signal for further processing. The associated evaluation electronics can, for example, be a single-photon counter.“Single-Photon Counter, SPC”), whereby a pulse signal provided by the readout electronics can be used as an input signal for the counter.

[0041] The evaluation electronics can, in particular, comprise a time-to-amplitude converter (TAC) or a time-to-digital converter (TDC). With a TAC, an output signal with an amplitude proportional to the time interval between two consecutive input pulses can be generated from two consecutive input pulses. With a TDC, digital time stamps can be assigned to each individual input pulse. Bond pads are typically used for external contacting of a chip and are well known to those skilled in the art. A hiQRNG according to the invention can be connected to other external components via bond pads. The precise arrangement and positioning of the individual elements on the emitter chip and / or the receiver chip depends on the specific circuit design and the respective application requirements.Both the electrical connection between the emitter chip and the receiver chip, as well as the arrangement and positioning of the individual elements on the emitter chip and / or the receiver chip, can thus be adapted accordingly. As already described in the section on electrical connections, a circuit design that is as compact as possible and offers minimal potential for attack is preferred.

[0042] Preferably, a hiQRNG according to the invention comprises an electronic circuit for generating and outputting a digital random number sequence based on the statistical evaluation of the temporal sequence of signals from the single-photon detector.

[0043] Preferably, the emitter chip comprises a plurality of adjacently arranged photon sources, the receiver chip a plurality of adjacently arranged single-photon detectors, and the plurality of photon sources and single-photon detectors are arranged such that the photon sources and the single-photon detectors are positioned opposite each other in pairs. This thus involves a juxtaposition of several photon source-single-photon detector pairs. The pairs can each serve individually as an entropy source for a QRNG, or they can be interconnected at least in groups or as a complete arrangement to form a single QRNG. While in the first case, a plurality of independent random numbers can be provided simultaneously or in parallel, the second case enables an increase in the entropy rate for a common QRNG or several groups of QRNGs.This embodiment of a hiQRNG according to the invention thus enables a high degree of parallelization of random number generation, which can significantly accelerate the provision of random numbers.

[0044] A further aspect of the present invention relates to a manufacturing method for a hybrid integrated quantum random number generator (hiQRNG), comprising providing a photon source and a single-photon detector as separate (i.e., initially structurally and mechanically separate) components and arranging them vertically one above the other in a common hybrid structure. The manufacturing method is derived directly from the associated device features of the hiQRNG according to the invention; therefore, the relevant description sections apply accordingly, both with regard to the individual preferred embodiments and with regard to the resulting technical advantages.A vertical stacked arrangement in a common hybrid structure can therefore preferably be achieved using the electrical, optical, and / or mechanical connection technologies already described above and known to those skilled in the art. A face-to-face arrangement of the respective chips using flip-chip bonding to form an internally electrically and optically connected hybrid chiplet is particularly preferred.

[0045] The advantages of a hiQRNG according to the invention (also referred to as a dual-die QRNG) over known hybrid QRNGs in the prior art are primarily based on the direct stacking of a photon source and at least one associated single-photon detector in a hybrid structure based on interconnected chips, resulting in miniaturization of the entire random number generator structure, as well as the resulting high degree of integration and miniaturization of the generated structure. In contrast to conventional structures with external components (e.g., LEDs), particularly compact structures with extremely small mutual spacings on the order of approximately 5-20 µm can be realized. For this purpose, sufficiently well-known connection techniques for hybrid chip structures can be used by those skilled in the art.Due to the isolation of the photon source and the associated single-photon detector from the environment achieved by the stacked arrangement, the security of random number generation can be significantly increased compared to planar arrangements which are in principle easier to attack. Compared to the known iQRNGs, a hiQRNG according to the invention also represents a particularly technology-open, significantly more adaptable and thus more flexible and cost-effective alternative. Further advantages lie in particular in the short (vertical) distances between the photon source and the single-photon detector, the high coupling efficiency between the structures and the particularly simple segmentation of several QRNGs or entropy sources (i.e., an optical separation of the individual elements). This results in easy scalability, which can greatly increase the resulting number of photon channels and thus also the resulting bandwidth andcan increase the random number generation rate of the entire system.

[0046] A hybrid approach according to the invention enables the realization of photonic QRNGs in almost any technology for optimal signal processing or random number generation. Simple standard processes (not limited to HV-CMOS or BCD processes) can thus be used for both the emitter chip and the receiver chip. This is a significant advantage over conventional iQRNGs in the state of the art, which, due to their direct integration into a common material system, are significantly more limited in their respective feasibility, both in terms of process technology and material specificity. With the hybrid approach according to the invention, however, both the material systems and the process technologies used can be individually and optimally adapted to the intended use for each chip of the hybrid structure. A suitable pn junction, for example, can be used as a photon source.For example, a simple, low-performance version of a SPAD is sufficient as a single-photon detector, which can typically also be implemented in a standard mixed-signal CMOS process. Direct bonding is not required, so an air gap or a suitable material can be inserted between the emitter chip and the receiver chip.

[0047] The vertical arrangement enables easy scalability and thus an increased random number output rate. The emitter chip technology is completely independent of that of the receiver chip. Both technologies can be freely selected according to requirements or starting points. Compared to the state of the art, neither complex bonding technologies (direct bonding, hybrid bonding) nor SOI substrates are required.

[0048] Further aspects of the present invention are disclosed in the dependent claims or in the following description of the drawings. Short description of the characters

[0049] The invention is explained in more detail below using an exemplary embodiment and the accompanying drawings. The figures show: Fig. 1 is a schematic representation of a first embodiment of an iQRNG according to the prior art in plan view; Fig. 2 is a schematic side view of a second embodiment of an iQRNG according to the prior art; Fig. 3 a schematic representation of a method for producing a hiQRNG according to the invention; Fig. 4 a schematic representation of a first embodiment of a hiQRNG according to the invention; Fig. 5 schematic representation of further embodiments of a hiQRNG according to the invention; Fig. 6 a schematic representation of another embodiment of a hiQRNG according to the invention with additional components; Fig. 7 is a schematic representation of another embodiment of a hiQRNG according to the invention with an extended photon source; and Fig. 8 schematic representations of further embodiments of a hiQRNG according to the invention with different chip sizes. Detailed description of the invention

[0050] Detailed embodiments will now be described, which are illustrated by way of example in the accompanying drawings. The effects and features of these embodiments will be described with reference to the accompanying drawings. Throughout the drawings, like reference numerals designate like elements, and redundant descriptions are omitted. The present disclosure may be embodied in various forms and should not be construed as limited only to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present disclosure to those skilled in the art.

[0051] Therefore, methods, elements, and techniques that are not necessary for a person skilled in the art to fully understand the aspects and features of the present disclosure may not be described. In the drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity.

[0052] As used herein, the term "and / or" includes all combinations of one or more of the listed elements. Furthermore, the use of "may" in describing embodiments of the present disclosure refers to "one or more embodiments of the present disclosure." In the following description of embodiments, the singular terms may also include the plural, unless the context clearly indicates otherwise.

[0053] Although the terms "first" and "second" are used to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the present disclosure. Terms such as "at least one of," when preceded by a list of elements, modify the entire list, not just the individual elements of the list.

[0054] Terms such as "substantially," "approximately," and similar terms are used as approximations rather than degrees, and are intended to account for inherent variations in measured or calculated values ​​that will be recognized by those skilled in the art. When the term "substantially" is used in connection with a characteristic that can be expressed by a numerical value, the term "substantially" means a range of at least + / - 5% of the value centered on the value.

[0055] Fig. 1 shows a schematic representation of a first embodiment of an iQRNG 200 according to the prior art in plan view. The representation is based on a corresponding figure in EP 3 529 694 B1 and shows the surface S of an associated substrate 110 into which the QRNG is integrated. A circular photon source 120 with a pn junction configured to provide photons 128 is supplied with current via a corresponding contact and is thereby excited to emit individual photons 128. To detect the emitted photons 128, an associated single-photon detector 130 in the form of a SPAD is arranged next to the photon source 120. However, as in conventional hybrid approaches for photonic QNRGs, the photon source 120 and the single-photon detector 130 are structurally and functionally separate elements that are simply arranged next to one another for integration in a common substrate.

[0056] A charge pulse generated by the single-photon detector 130 upon absorption of a photon 128 can then first be registered and evaluated in an associated electronic sampling means 152, in particular to generate a bit sequence based on the number of photons 128 detected in the single-photon detector 130. Furthermore, an electronic post-processing means 154 is provided, which is to be configured to process the binary sequences of the electronic sampling means 152 in such a way that a so-called "whitening" operation is performed. This whitening operation is to comprise a plurality of compression operations that serve to improve the statistical properties of the generated binary sequences. The post-processing step is to increase the entropy level of the QRNG.However, it must be ensured that the compression operations used do not lead to a fundamental predictability of the generated random numbers by introducing deterministic dependencies in the application.

[0057] To increase the efficiency of random number generation, i.e., the effective entropy rate, the photonic part of the QRNG at the surface S of the substrate 110 is protected by a light-blocking layer 150 ("light inhibitor filter"), which serves to shade it from external light. The light-blocking layer 150 can be provided, in particular, by a metallization layer that can be applied directly during the production process, for example, using CMOS technology, as the last metallization level. This is intended to shield the single-photon detector 130 from external light and make it sensitive only to those photons that pass through the substrate 110 due to crosstalk from the photon source 120.In addition, the metallization layer is also intended to improve the optical coupling of the photons 128 emitted by the photon source 120 by reflecting them inwards and thus preventing them from exiting the surface S of the substrate 110.

[0058] A disadvantage of such a side-by-side arrangement of the optical components is the distance between the components, which reduces the coupling strength due to the low illumination angle and the potential photon absorption in the various materials. Furthermore, despite the partially applied light-blocking layer 150, there is still the potential for optical access and thus an attack from the surface S of the substrate 110 or even from the back of the substrate 110. For example, additional photons can be specifically injected or extracted via these layers, ultimately influencing and compromising the counting statistics and thus the entropy of the generated random numbers.Furthermore, the illustration also shows that the individual photons 128 are emitted isotropically distributed in all spatial directions, so that only a fraction of the photons 128 can be detected by the single-photon detector 130 and thus statistically evaluated. This significantly reduces the efficiency of random number generation and, on the other hand, results in a large number of photons 128 being emitted unused into the substrate 110, where they may also be extracted elsewhere by observers or attackers or cause interference.

[0059] Fig. Figure 2 shows a schematic representation of a second embodiment of an iQRNG 200 (or a “monolithic” entropy source, since in contrast to the representation in Fig. 1 no evaluation electronics are shown) according to the state of the art in a side view. The illustration is based on a corresponding figure from Khanmohammadi et al. (Khanmohammadi et al. "A monolithic silicon quantum random number generator based on measurement of photon detection time." IEEE Photonics Journal 7.5 (2015): 1-13). In this example, too, the basic structure of a side-by-side arrangement of a photon source 120 (Si-LED), which is configured to emit individual photons 128, and a single-photon detector 130 (SPAD) is clearly visible. In contrast to the Fig. 1, the photon source 120 is provided as a circular central element, which is essentially completely surrounded by a correspondingly adapted and circular-ring-shaped single-photon detector 130. The common radial symmetry axis R lies accordingly in the center of the iQRNG formed in this way. The photon source 120 is realized by an n-well formed in a deep n-well ("deep n well"), which is introduced into the surface S of the substrate 110 ("p-substrate") centrally around the radial symmetry axis R. ++ -area as cathode 122 and a p ++ -region is supplied with current as anode 124. Outside the deep n-well, the single-photon detector 130 is also connected to the surface S via an introduced n ++ -region as cathode 132 and a p arranged further away from the radial symmetry axis R ++-region as anode 134. A p-well ("p well") is connected below the cathode 132. Below the anode 134, however, a p-well ("p well") is formed in a deep p-well ("deep p well"). The photon source 120 is provided as an element within the structure of the photon detector 130, so that, in contrast to the Fig. 1 these form a structural and functional unit.

[0060] In this example of an entropy source of an iQRNG 200 according to the prior art, the photons 128 are emitted essentially from all sides into the substrate 110, so that the already mentioned embodiment according to Fig. 1 described disadvantages regarding security against observers or attackers and the reduced efficiency also apply. Due to the specific design as a circular ring arrangement and the structural connection of the single photon detector 130 with the photon source 120, Fig. 1, however, the integration density can be further increased. In addition to a smaller area requirement for forming the iQRNG 200, this also includes increased security against attacks and increased efficiency in random number generation or the entropy rate as advantages. This is particularly related to the fact that the reduction in all distances reduces the loss of photons 128 due to material absorption and unfavorable emission directions. Furthermore, this reduces the area available for potential attacks. Apart from this, however, it is still possible in principle to couple out or inject individual photons 128, particularly at the surface S and at other locations on the substrate 110, in order to influence the counting statistics by attackers.Such a juxtaposition of the two optical components of a QRNG therefore has several disadvantages that impede particularly secure, compact, and reliable random number generation. Further disadvantages of the illustrated embodiment of such an entropy source or an iQRNG 200 include a severely limited process selection and the fact that the functionality of the additionally integrated circuit blocks may be restricted or limited as a result.

[0061] Fig. 3 shows a schematic representation of a method for producing a hiQRNG according to the invention. The method involves providing an emitter chip 10 with a photon source 12 (usually referred to as emitter in the figures) and a receiver chip 20 with a single-photon detector 22 (assumed to be a SPAD in the figures by way of example). In this example, the emitter chip 10 and the receiver chip 20 each have an intermediate layer 14, 24 in the later connection region. The intermediate layers can, for example, be non-conductive films (NCFs) to support the connection process. A surface of the emitter chip 10 and a corresponding surface of the receiver chip 20 are then aligned with one another such that the photon source 12 and the single-photon detector 22 are arranged vertically one above the other as separate components in a common hybrid structure.The photon source 12 is arranged in or on an emitter chip 10, the single-photon detector 22 is arranged in or on a receiver chip 20, and the emitter chip 10 and the receiver chip 20 are connected to one another by a chip-to-chip connection via a connection region such that photons emitted by the photon source 12 can be detected directly by the single-photon detector 22 via a transmission path.

[0062] Fig. Figure 4 shows a schematic representation of a first embodiment of a hiQRNG 100 according to the invention. The embodiment shown essentially gives a final result of the Fig. 3. The reference numerals and their respective assignment to the individual features therefore apply accordingly. The hiQRNG 100 shown comprises a photon source 12 and a single-photon detector 22, wherein the photon source 12 and the single-photon detector 22 are arranged as separate components one above the other in a common hybrid structure in a vertical direction. The photon source 12 forming an emitter can be, for example, a pn junction, an avalanche diode, or a single-photon avalanche diode (SPAD), each of which is configured as an emitter. The single-photon detector 22 is provided by a single-photon avalanche diode (SPAD) in this exemplary embodiment.The photon source 12 is arranged in an emitter chip 10, the single-photon detector 22 is arranged in a receiver chip 20, and the emitter chip 10 and the receiver chip 20 are connected to one another by a chip-to-chip connection via a connection region such that photons emitted by the photon source 12 can be directly detected by the single-photon detector 22 via a transmission path (indicated by the lightning-like arrow). The emitter chip 10 and the receiver chip 20 are separated from one another by a first intermediate layer 14 on the emitter chip 10 and by a second intermediate layer 24 on the receiver chip 20. The intermediate layers can in particular be dielectric layers to support the connection process. However, an intermediate layer can also be an open layer that is evacuated or filled with a protective gas oranother suitable filler material. The chip-to-chip connection can comprise, for example, a bond, adhesive, or solder connection. In the embodiment shown, the emitter chip 10 and the receiver chip 20 are surrounded by a light shield 40 for optical screening. The emitter chip (10) and the receiver chip 20 are connected to one another by at least one electrical connection 30.

[0063] Fig. Figure 5 shows a schematic representation of further embodiments of a hiQRNG 100 according to the invention. In the embodiments shown, the emitter chip 10 comprises a plurality of adjacently arranged photon sources 12, the receiver chip 20 comprises a plurality of adjacently arranged single-photon detectors 22, and the plurality of photon sources 12 and single-photon detectors 22 are arranged such that the photon sources 12 and the single-photon detectors 22 are each arranged opposite one another in pairs. However, the respective pairs of photon sources 12 and single-photon detectors 22 essentially correspond to the Fig. 3. The reference symbols and their respective assignment to the individual features therefore apply accordingly. Fig. 5 thus shows in particular various embodiments of a structural juxtaposition of several pairs of photon sources 12 and single-photon detectors 22 in a hybrid structure according to the invention.

[0064] A simple hybrid structure with several such pairs is shown under a). In the embodiment shown under b), the single-photon detectors 22 are each isolated from their respective chip environment by optical shields 50. However, optical shields 50 can also be present in the emitter chip 10 for the mutual isolation of the individual photon sources 12. The optical shield can, for example, be designed as deep trench isolation (DTI), which is preferably filled with metal. The embodiment shown under c) has a plurality of electrical connections 30 between the emitter chip 10 and the receiver chip 20 and thus corresponds directly to a structural juxtaposition of the Fig. 3. The embodiment under d) exemplifies a combination of the embodiments shown under b) and c). In all embodiments shown, the emitter chip 10 and the receiver chip 20 are surrounded by a common light shield 40.

[0065] Fig. Figure 6 shows a schematic representation of another embodiment of a hiQRNG 100 according to the invention with additional components. The embodiment shown essentially corresponds to the one shown in Fig. 4a. The reference numerals and their respective assignment to the individual features therefore apply accordingly. In contrast, however, the emitter chip 10 further comprises control electronics 19 for controlling the photon sources 12, read-out electronics 16 for reading out the charge pulses provided by the associated single-photon detectors 22, and at least one electronic circuit block (IC block) 17. The electronic circuit block 17 can, for example, be associated evaluation electronics. The detector below the electronic circuit block 17 shown is optional.This detector, which is not directly associated with a photon source 12 (it may also be a single-photon detector), can be used, for example, as an external radiation detector 23 for monitoring for photons radiated from outside, for monitoring a potentially occurring optical background within the hybrid structure according to the invention (i.e., outside the immediate vicinity of the photon source and / or the single-photon detector) or an attempted attack to disrupt the system from outside, or as an additional reference detector. The readout electronics 16 was arranged, by way of example, near the single-photon detectors 22; however, depending on the respective requirements, it can also be arranged elsewhere in the receiver chip 20 and / or the emitter chip 10.

[0066] Fig. Figure 7 shows a schematic representation of another embodiment of a hiQRNG 100 according to the invention with an extended photon source 12. The embodiment shown essentially corresponds to the one shown in Fig. 4a. The reference numerals and their respective assignment to the individual features therefore apply accordingly. In contrast, however, the photon source 12 shown extends as an extended area over a plurality of single-photon detectors 22.

[0067] Fig.8 shows a schematic representation of further embodiments of a hiQRNG 100 according to the invention with different chip sizes. In particular, in the embodiments shown, the emitter chip 10 protrudes laterally beyond the receiver chip 20, although in other embodiments, the receiver chip 20 can also be larger than the emitter chip 10. This provides a freely accessible additional chip area on the protruding part, which can, for example, comprise other electronic circuit blocks (IC blocks) 17. In particular, further circuit blocks 17, bond pads 18, and additional elements and components can be present on both the emitter chip 10 and the receiver chip 20 (or on both simultaneously). This can, for example, achieve better cooling of these IC blocks by exposing them or attaching heat sinks. Furthermore, at least one bond pad 18 (e.g.A metallic bond pad (e.g., a metal bond pad) may be provided for external contacting. An arrangement of at least one bond pad 18 (or, more generally, a contact area suitable for corresponding contacting) in such an exposed area has the advantage that no additional feedthroughs are required on the chip sides of the emitter chip 10 and / or the receiver chip 20 opposite the connection area, thus allowing a greater compactness of the hybrid arrangement to be achieved. The elements arranged on the respective chips may have different sizes and shapes and, depending on the respective requirements, may be arranged on both the receiver chip 20 and the emitter chip 10. It is also possible to distribute certain elements between both chips, wherein at least one electrical connection may be provided for mutual contacting of such distributed components.

[0068] Furthermore, in the embodiments shown, the transmission path in the connection area is surrounded by a plurality of local light shields 52 (e.g., separation structures, shielding). In a), each pair of photon sources 12 and single-photon detectors 22, as well as the outer side, is surrounded by a local light shield 52. In b), the local light shields 52 are only present on the outer sides. However, the integration of local light shields 52 around the transmission path in the connection area is not limited to the embodiments shown and can be carried out in all embodiments of the present invention depending on the respective requirements. Additionally, in both embodiments, the emitter chip 10 and / or the receiver chip 20 can each be at least partially surrounded by a light shield 40. List of reference symbols 10 Emitter chip (e.g. semiconductor substrate with photon source) 12 Photon source (e.g. pn junction configured as emitter, avalanche diode, SPAD, especially as SPS) 14 first intermediate layer (e.g. dielectric silicon oxide or silicon nitride) 16 Read-out electronics 17 electronic circuit block (integrated circuit, IC, block) 18 Bond pad (e.g. metallic bond pad) 19 Control electronics 20 Receiver chip (e.g. semiconductor substrate with single-photon detector) 22 Single photon detector (e.g. SPAD) 23 Extraneous radiation detector (e.g. SPAD) 24 second intermediate layer (e.g. dielectric silicon oxide or silicon nitride) 30 electrical connection (e.g. bond contact, microbump, through silicon via (TSV)) 40 Light shield (e.g. potting, housing, shielding) 50 optical shielding (e.g. deep trench isolation, DTI) 52 local light shield (e.g. separation structures, shielding) 100 hiQRNG (hybrid integrated Quantum Random Number Generator) 110 Substrat 120 photon source (e.g. single photon source, SPS) 122 Cathode (n + , photon source) 124 Anode (p + , photon source) 128 photons 130 Single-photon detector (e.g. single-photon avalanche diode, SPAD) 132 Cathode (n + , single-photon detector) 134 Anode (p + , single-photon detector) 150 light blocking layer 152 means of electronic recording 154 Means of electronic post-processing 200 iQRNG (integrated Quantum Random Number Generator) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 529 694 B1 [0009, 0055] EP 3 52 694 B1

[0013] Cited non-patent literature

[0000] Khanmohammadi et al. “A monolithic silicon quantum random number generator based on measurement of photon detection time.” IEEE Photonics Journal 7.5 (2015): 1-13 [0013, 0059] Fukushima et al. “Nonconductive film and compression molding technology for self-assembly-based 3D integration.” Proceedings - Electronic Components and Technology Conference (2012

[0032] Kim et al. “Wafer level Cu-Cu direct bonding for 3D integration.” Microelectron. Eng. 137 (2015

[0032]

Claims

[1] Hybrid integrated quantum random number generator, hiQRNG, (100) comprising: a photon source (12) and a single-photon detector (22), characterized by , that the photon source (12) and the single-photon detector (22) are arranged as separate components in the vertical direction one above the other in a common hybrid structure. [2] hiQRNG (100) according to claim 1, wherein the photon source (12) is a single photon source, SPS, arranged to provide only single or a few photons (128) at a time. [3] hiQRNG (100) according to claim 1 or 2, wherein the photon source (12) is a pn junction, an avalanche diode or a single photon avalanche diode, SPAD, each configured as an emitter, wherein the photon source (12) is formed in an indirect or in a direct semiconductor material. [4] hiQRNG (100) according to claim 1 or 2, wherein the photon source (12) is a light-emitting avalanche Zener diode, Zener-avLED, operated at an operating point below or near the breakdown voltage, wherein the Zener-avLED preferably has a breakdown voltage of < 10 V. [5] hiQRNG (100) according to one of the preceding claims, wherein the single-photon detector (22) is a single-photon avalanche diode, SPAD. [6] hiQRNG (100) according to one of the preceding claims, wherein the photon source (12) extends as an extended region over a plurality of single photon detectors (22). [7] hiQRNG (100) according to one of the preceding claims, wherein the photon source (12) is arranged in or on an emitter chip (10), the single-photon detector (22) is arranged in or on a receiver chip (20), and the emitter chip (10) and the receiver chip (20) are connected to one another by a chip-to-chip connection via a connection region such that photons emitted by the photon source (12) can be detected directly by the single-photon detector (22) via a transmission path. [8] hiQRNG (100) according to claim 7, wherein the emitter chip (10) and the receiver chip (20) are in direct contact with each other in the connection region or are separated from each other by at least one intermediate layer (14, 24). [9] hiQRNG (100) according to claim 7 or 8, wherein the chip-to-chip connection comprises a dielectric or metallic bond, an adhesive bond and / or a solder bond. [10] hiQRNG (100) according to one of claims 7 to 9, wherein the transmission path in the connection area is surrounded by a local light shield (52). [11] hiQRNG (100) according to one of claims 7 to 10, wherein the emitter chip (10) and / or the receiver chip (20) is / are each at least partially surrounded by a light shield (40). [12] hiQRNG (100) according to one of claims 7 to 11, wherein the emitter chip (10) and the receiver chip (20) are connected to each other by at least one electrical connection (30). [13] hiQRNG (100) according to one of claims 7 to 12, wherein the photon source (12) and / or the single-photon detector (22) is isolated from the respective chip environment and / or other elements by at least one optical shield (50) or at least one light shield (52). [14] hiQRNG (100) according to one of claims 7 to 13, wherein the emitter chip (10) and / or the receiver chip (20) further comprises an electronic circuit block (17) and / or at least one bond pad (18). [15] hiQRNG (100) according to one of claims 7 to 14, wherein the emitter chip (10) comprises a plurality of photon sources (12) arranged side by side, the receiver chip (20) comprises a plurality of single-photon detectors (22) arranged side by side, and the plurality of photon sources (12) and single-photon detectors (22) are arranged such that the photon sources (12) and the single-photon detectors (22) are opposite each other in pairs.

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