Entropy source for an integrated quantum random number generator

Abstract

The invention relates to an entropy source for an integrated quantum random number generator (10), comprising the following: a photon source (40) and a single-photon detector (50), wherein the photon source (40) and the single-photon detector (50) are arranged one above the other in the vertical direction in a common substrate (20) made of a semiconductor material, characterized in that the single-photon detector (50) comprises a doped layer, produced by means of high-energy ion implantation, as part of a p-n junction (54).

Description

[0001] 26714-ELM-PWO (E0020P-WO) 01749EPWQ 1

[0002] Entropy source for an integrated quantum random number generator

[0003] Description

[0004] The invention relates to an entropy source for an integrated quantum random number generator.

[0005] State of the art

[0006] An integrated quantum random number generator with an entropy source is known, for example, from LU 505175 Al.

[0007] Fig. 9 shows a schematic side view of an entropy source of an integrated quantum random number generator according to the prior art. The drawing is taken from LU 505175 Al.

[0008] The entropy source 10' comprises a photon source 40' and a single-photon detector 50', which are arranged in a common substrate. The photon source 40' and the single-photon detector 50' are arranged vertically one above the other in the common substrate.

[0009] The photon source 40' emits single photons, which are detected by the single-photon detector 50'. The photon source 40' has a pn junction. The single-photon detector 50' has two pn junctions 54', namely one from the NBL layer 51' to the upper PBL layer 52' ​​and one from the NBL layer 51' to the lower PBL layer 52".

[0010] The entropy source of the integrated quantum random number generator in LU 505175 A features a large number of doped layers or regions in a partially epitaxially formed substrate. Therefore, the integrated quantum random number generator is technically complex and has high manufacturing costs. 26714-ELM-PWO (E0020P-WO) 01749EPWO 2

[0011] Disclosure of the invention

[0012] The invention is based on the objective of providing an entropy source for an integrated quantum random number generator or an integrated quantum random number generator or an integrated electronic circuit, which is technically simple in design and cost-effective, or a method that is technically simple and cost-effective to implement.

[0013] This problem is solved by an entropy source for an integrated quantum random number generator according to claim 1.

[0014] In particular, the problem is solved by an entropy source for an integrated quantum random number generator, wherein the entropy source comprises: a photon source and a single-photon detector, wherein the photon source and the single-photon detector are arranged vertically one above the other in a common substrate made of a semiconductor material, wherein the single-photon detector comprises a doped layer produced by high-energy ion implantation as part of a pn junction.

[0015] The advantage of this approach is that the entropy source for the integrated quantum random number generator is technically very simple. Furthermore, the entropy source can be manufactured cost-effectively. In particular, the entropy source can have fewer doped layers or regions compared to the prior art, thus greatly simplifying its fabrication.

[0016] The problem can also be solved by an integrated quantum random number generator with such an entropy source. The advantages of the integrated quantum random number generator essentially correspond to the advantages of the entropy source described above.

[0017] The task is also solved by an integrated electronic circuit comprising an integrated quantum random number generator as described above. The advantages of the integrated 26714-ELM-PWO (E0020P-WO) 01749EPWO 3

[0018] The electronic circuits essentially correspond to the advantages of the entropy source or the integrated quantum random number generator described above.

[0019] The problem is also solved by a method for producing an entropy source for an integrated quantum random number generator, in particular an entropy source as described above, wherein the method comprises the following steps: providing a substrate; and generating several doped layers to produce a pn junction of a photon source and a pn junction of a single-photon detector in the substrate, wherein the photon source and the single-photon detector are arranged vertically one above the other in the substrate, and wherein a doped layer of the pn junction of the single-photon detector is produced by high-energy ion implantation.

[0020] The advantages of this method are its technical simplicity and cost-effectiveness. Furthermore, the resulting entropy source can have a very low number of doped layers. Finally, the method can be easily adapted to existing CMOS processes without significantly altering them.

[0021] According to one embodiment of the entropy source, the entropy source comprises at least two photon sources and / or at least two single-photon detectors, wherein the photon sources and / or the single-photon detectors are arranged in the common substrate made of the semiconductor material. An advantage of this is that the entropy source is very compact. Furthermore, the entropy source can provide a particularly high entropy. The entropy source can, for example, be configured for two integrated quantum random number generators. The random numbers generated by the integrated quantum random number generators can, for example, be processed together to generate a single random number. It is particularly conceivable that one (common) photon source and two (or more) single-photon detectors are present, or that two (or more) photon sources and one (common) single-photon detector are present.The single-photon detectors can each comprise a doped layer produced by high-energy ion implantation as part of a pn junction. The photon sources and the single-photon detectors can each be arranged vertically one above the other in a common substrate made of a semiconductor material. 26714-ELM-PWO (E0020P-WO) 01749EPWO 4.

[0022] According to one embodiment of the entropy source, the entropy source is formed in a substrate of an indirect semiconductor, in particular a silicon substrate. The advantage of this is that the substrate is technically simple and inexpensive to produce. This reduces the manufacturing costs of the entropy source.

[0023] According to one embodiment of the entropy source, the entropy source is formed in a BCD substrate using BCD technology. An advantage of this is that the entropy source is particularly cost-effective and easy to manufacture.

[0024] According to one embodiment of the entropy source, a layer of the pn junction in the single-photon detector is identical to a layer of the pn junction in the photon source. Thus, there is one layer that the single-photon detector and the photon source share. This further reduces the number of doped layers or regions required in the entropy source for the integrated quantum random number generator. This simplifies the fabrication process and consequently reduces manufacturing costs.

[0025] According to one embodiment of the entropy source, the portion of the substrate in which the photon source and the single-photon detector are arranged is a non-epitactically generated part of the substrate. The advantage of this is that the substrate in which the entropy source is formed is particularly easy to manufacture. This further reduces the manufacturing costs of the entropy source.

[0026] According to one embodiment of the entropy source, the substrate in which the photon source and the single-photon detector are formed is a CMOS substrate. The advantage of this is that further components can be efficiently arranged within the CMOS substrate. Thus, the integrated quantum random number generator can be easily combined with other components. Furthermore, the entropy source can be fabricated using standard CMOS techniques.

[0027] In particular, it is possible that the entropy source, compared to conventional CMOS, has only one additional module in the form of a retrograde high-energy ion implantation profile for generating the pn junction of the single-photon detector. 26714-ELM-PWO (E0020P-WO) 01749EPWO 5

[0028] According to one embodiment of the entropy source, the doped layer of the single-photon detector, produced by high-energy ion implantation, was created without a masking process.

[0029] The advantage of this is that no complex masking process is necessary. This simplifies the production of the entropy source. It is conceivable that the layer created by high-energy ion implantation extends across the entire width of the substrate or the portion of the substrate treated by high-energy ion implantation.

[0030] According to one embodiment of the entropy source, the doped layer of the single-photon detector, produced by high-energy ion implantation, was created using a masking process. An advantage of this is that the single-photon detector, or its layers, can be fabricated with exceptional precision directly beneath the photon source. Consequently, the single-photon detector has high efficiency, as it can be aligned with or positioned below the photon source in such a way that as many photons as possible reach the single-photon detector via the shortest possible path. This results in particularly good coupling between the photon source and the single-photon detector.

[0031] According to one embodiment of the entropy source, the single-photon detector has a pn junction only on the side facing the photon source. This further reduces the number of layers in the single-photon detector, thus simplifying both the manufacturing process and the electrical application of the component.

[0032] According to one embodiment of the entropy source, the single-photon detector consists of exactly two or exactly three doped layers. The advantage of this is that the entropy source has fewer doped layers and is therefore technically even simpler. The two or three layers mentioned do not include the layers for low-resistance contacting of the substrate surface to provide a supply voltage for the single-photon detector.

[0033] According to one embodiment of the entropy source, the integrated quantum random number generator has deep trench isolation that is essentially parallel to the vertical 26714-ELM-PWO (E0020P-WO) 01749EPWO 6

[0034] The direction is such that the layers or areas of the entropy source are efficiently shielded from neighboring components. This allows the entropy source to be positioned close to other components without reducing its efficiency.

[0035] According to one embodiment of the entropy source, the photon source has a pn junction whose interface is perpendicular to the vertical direction. This further simplifies the manufacturing process.

[0036] According to one embodiment of the entropy source, the photon source has a pn junction whose interface runs parallel to the vertical direction. The advantage of this is that it is particularly easy to manufacture.

[0037] According to one embodiment of the entropy source, the single-photon detector is arranged in a deep-lying high-voltage n-tub (HDNW). An advantage of this is that the pn junctions of the photon source and the single-photon detector are particularly well protected against external influences.

[0038] According to one embodiment of the entropy source, the entropy source consists of five doped layers in a substrate. Thus, the entropy source is technically simple and quick to manufacture.

[0039] According to one embodiment of the entropy source, the pn junction of the single-photon detector is arranged at a distance from the boundary between the substrate carrier itself and the substrate applied to the substrate carrier by epitaxy. An advantage of this is that the entropy source is particularly efficient.

[0040] According to one embodiment of the entropy source, the respective non-common layer of the pn junction of the photon source and the pn junction of the single-photon detector is each more heavily doped than the common layer, which is part of both the pn junction of the photon source and the pn junction of the single-photon detector. An advantage of this is that the breakdown voltage is reduced. 26714-ELM-PWO (E0020P-WO) 01749EPWO 7

[0041] According to one embodiment of the entropy source, the doped layer of the pn junction, produced by high-energy ion implantation, is designed and arranged such that it insulates a portion of the substrate from the remaining portion. The advantage of this is that, in BCD technology, the nMOS sub-transistor is isolated from the substrate, particularly from the p-substrate located below the doped layer of the pn junction produced by high-energy ion implantation, or on the side of the doped layer of the pn junction facing away from the nMOS sub-transistor. This allows for the formation and arrangement of further components within the same substrate. In particular, this facilitates the control and power supply for the operation of both the photon source (e.g.,Zener-avLED) as well as the single-photon detector (e.g. SPAD single-photon detector) on the same substrate.

[0042] According to one embodiment of the entropy source, the entropy source further comprises a doped layer (HPW layer, HVPW layer) arranged between the photon source and the single-photon detector for adjusting the resistance value between the photon source and the single-photon detector. An advantage of this is that the resistance value can be easily adjusted by the width of the doped layer. Furthermore, a so-called quenching resistor for the single-photon detector can be arranged within the volume of the substrate (especially the silicon substrate) or in the epitaxial layer in which the single-photon detector is located. Thus, the entropy source is particularly compact.

[0043] According to one embodiment of the method, no mask is used in high-energy ion implantation. The advantage of this is that the manufacturing process is particularly simple from a technical standpoint.

[0044] According to one embodiment of the method, the doped pn junction layer produced by high-energy ion implantation is generated such that it insulates a portion of the substrate from the rest of the substrate. An advantage of this is that a deep layer (e.g., a DNW layer) can be generated relatively easily, which isolates a portion of the substrate from the rest of the substrate.

[0045] insulated from the rest of the substrate. This allows several independent components to be arranged on the same substrate. In particular, the control and power supply for both the photon source (e.g., Zener-avLED) and the single-photon detector (e.g., SPAD single-photon detector) can be implemented on the same substrate.

[0046] According to one embodiment of the method, the process further comprises the following step: creating a doped layer arranged between the photon source and the single-photon detector for adjusting the resistance value between the photon source and the single-photon detector. An advantage of this is that the resistance value can be adjusted simply and precisely by varying the width of the doped layer. Furthermore, this method allows for the creation of a so-called quenching resistance for the single-photon detector within the same volume of the substrate (especially the silicon substrate) or in the epitaxial layer in which the single-photon detector is located. Consequently, an entropy source requiring very little volume or space can be produced.

[0047] According to one embodiment of the method, the entropy source is fabricated such that a layer of the pn junction of the single-photon detector is identical to a layer of the pn junction of the photon source. This method allows for a particularly simple and rapid fabrication of the entropy source.

[0048] The substrate can be a p-substrate or a p-substrate. However, an n-substrate is also conceivable.

[0049] The photon detector can, in particular, be directly coupled to the photon source.

[0050] The single photon detector can in particular comprise or be a single photon avalanche diode (SPAD).

[0051] The surface of the substrate can be covered with a silicide layer in the region of the entropy source and with a metallization layer above this. This allows photons to be absorbed. 26714-ELM-PWO (E0020P-WO) 01749EPWO 9

[0052] reflected back, thus preventing or hindering the introduction of photons into the entropy source.

[0053] The term "substrate" can be understood, in particular, as the entire semiconductor chip as a body in which, for example, a specific elemental structure is formed using CMOS or other technologies, such as by creating differently doped wells or layers or regions in the semiconductor material. This creation can alternatively or additionally be achieved additively by depositing further layers and structures, or by a sequence of etching and / or deposition steps for such further layers and structures. The substrate can therefore be understood, in particular, as a material support for the semiconductor structures of an entropy source according to the invention, and not merely as a simple support or base substrate for depositing these structures.

[0054] The single-photon detector can comprise or be a single-photon avalanche diode (SPAD). This can be, in particular, a detector with high sensitivity, high gain, and low (dark) noise, capable of detecting single photons. The single-photon detector is typically designed and arranged to receive the photons generated by the photon source.

[0055] BCD technology can refer specifically to bipolar CMOS-DMOS technology. The BCD substrate can consist of a support substrate and epitaxially built layers on the support substrate.

[0056] High-energy ion implantation can, in particular, be ion implantation with energies greater than 700 keV. This means that the ions are accelerated to energies greater than 700 keV. In particular, a doped layer of the pn junction can be created by means of high-energy ion implantation at a depth of more than 1.0 pm, preferably at a depth of more than 1.5 pm in the substrate. In high-energy ion implantation, ions can be injected into the substrate at high velocity. This results in the formation of a deep layer or deep doped region in the substrate. The distribution of the doping created by high-energy ion implantation can typically be retrograde, i.e., the maximum of the typically vertically Gaussian distribution is 26714-ELM-PWO (E0020P-WO) 01749EPWO 10

[0057] The doping concentration is not located at or near the surface of the substrate, but rather at a significant distance from the substrate surface. Specifically, the high-energy ion implantation is performed from the surface where the photon source is located. This can mean, in particular, that the ions are injected into a region that will later lie below the photon source region in order to create the doped layers of the single-photon detector. Typically, the deeper layers, i.e., the doped layers of the single-photon detector, are created or doped first using high-energy ion implantation, and the near-surface layers (including the photon source layers) are created or doped later.

[0058] The terms layer, region, area, and section are used synonymously. A layer, region, area, or section can, in particular, each be a (three-dimensional) part of the respective substrate and / or substrate support.

[0059] The current pulse(s) of the single-photon detector can be recorded and analyzed. A whitening operation can then be performed. This whitening operation (e.g., through compression) can improve the statistical properties. This can involve increasing the entropy.

[0060] The arrival times of the photons and / or the number of photons per unit of time can be used to generate a random number from the current pulses. The current pulse can then be fed into a time-to-digital converter (TDC).

[0061] The entropy source can, in particular, be part of a circuit as shown and described in Fig. 8 of LU 505175 Al.

[0062] The entropy source can be arranged in a pad frame, as described in LU 505175 Al.

[0063] The integrated quantum random number generator (abbreviation: iQRNG) can include an electronic circuit that receives the current pulses from the entropy source as input and generates one or more random numbers from them. The entropy source thus generates the necessary random 26714-ELM-PWO (E0020P-WO) 01749EPWO 11

[0064] Data required for generating randomized numbers. The integrated quantum random number generator therefore includes, in addition to the entropy source, other components that process the signal(s) from the entropy source to generate random numbers.

[0065] Preferred embodiments are described in the dependent claims. The invention is explained in more detail below with reference to a drawing of an exemplary embodiment. Here, the drawing shows...

[0066] Fig. 1 shows a schematic representation of an exemplary first embodiment of an entropy source according to the invention in a side view;

[0067] Fig. 2 shows a schematic representation of an exemplary second embodiment of an entropy source according to the invention in a side view;

[0068] Fig. 3 shows a schematic representation of an exemplary third embodiment of an entropy source according to the invention in a side view;

[0069] Fig. 4 shows a schematic representation of an exemplary fourth embodiment of an entropy source according to the invention in a side view;

[0070] Fig. 5 shows a schematic representation of an exemplary fifth embodiment of an entropy source according to the invention in a side view;

[0071] Fig. 6 shows a schematic representation of a CMOS process without a DNW layer;

[0072] Fig. 7 shows a schematic representation of a CMOS process with a DNW layer;

[0073] Fig. 8 shows a schematic representation of an exemplary sixth embodiment of an entropy source according to the invention in a side view; and

[0074] Fig. 9 shows a schematic representation of an entropy source according to the prior art in a side view.

[0075] In the following description, the same reference numbers are used for identical and equivalently functioning parts. 26714-ELM-PWO (E0020P-WO) 01749EPWQ 12

[0076] Fig. 1 shows a schematic representation of an exemplary first embodiment of an entropy source 10 according to the invention for an integrated quantum random number generator 10 (hereinafter abbreviated as iQRNG) in a side view.

[0077] The density of the lines in the hatched areas and the density of the dots in the dotted areas indicate the respective doping concentration. The denser the lines or dots, the higher the doping concentration. The relative doping concentration of the layers or regions is shown in the lower right of each figure. The arrow indicates the direction of higher doping concentration in the layers. The relative doping concentration is shown separately for n-doped regions or layers and for p-doped regions or layers. An n-layer and a p-layer with essentially the same doping concentration are located at essentially the same height relative to each other. In the lower right of each drawing, omitted or saved layers are intentionally left as gaps to indicate which layers were omitted in the respective embodiment.

[0078] In all drawings, the width of the substrate runs from right to left or vice versa.

[0079] The entropy source 10 can be part of an integrated quantum random number generator; that is, the entropy source can be the core component that generates the random data and thus the "true randomness" of an integrated quantum random number generator. The other components of the integrated quantum random number generator are not shown in the drawings. These are described in more detail in LU 505175, which is fully incorporated herein by reference and to which explicit reference is made again here to avoid repetition. This applies to the first embodiment and to all further embodiments.

[0080] The entropy source 10 comprises a photon source 40 and a single-photon detector 50.

[0081] In particular, the entropy source 10 has exactly one photon source 40 and exactly one single-photon detector 50.

[0082] The photon source 40 and the single-photon detector 50 are arranged vertically, one above the other. In the drawings, the vertical direction runs from top to bottom. The 26714-ELM-PWO (E0020P-WO) 01749EPWO 13

[0083] Photon source 40 is typically located above single-photon detector 50; that is, photon source 40 is closer to the surface of substrate 20 than single-photon detector 50. This means that the distance between photon source 40 and the surface of substrate 20 is smaller than the distance between single-photon detector 50 and the surface of substrate 20. The surface of substrate 20 is shown above in the drawings.

[0084] The photon source 40 and the single-photon detector 50 are arranged in a common substrate 20. The terminals of the photon source 40 and the single-photon detector 50 are located on the surface of the substrate 20.

[0085] The photon source 40 has a pn transition 42, i.e. a transition from a p-doped layer to an n-doped layer or from an n-doped layer to a p-doped layer.

[0086] The substrate 20 in Fig. 1 is a BCD substrate, or a substrate produced using BCD technology. The substrate 20 can, in particular, be a p-substrate or a P-substrate. The substrate 20 is partially produced epitaxially, or by means of epitaxy. In particular, the region in which the photon source 40 is arranged is produced epitaxially.

[0087] The entropy source 10 can be produced as follows, for example. First, a support substrate is provided. A first dopant is introduced into the surface of the support substrate to form a first region 51 (e.g., NBL) of the first conduction type (negative for NBL). Subsequently, an epitaxial layer is grown on the support substrate. Later, a deep layer or a deep second region 52 (e.g., DPW) of the second conduction type (positive for DPW) is created by ion implantation. This second region is directly adjacent to the first layer or region 51. This creates the pn junction 54 of the single-photon detector 50. Furthermore, the introduction of dopants creates additional layers or areas on or near the surface of the epitaxially deposited part of the substrate 20. 26714-ELM-PWO (E0020P-WO) 01749EPWO 14

[0088] The term “deep-lying” can be understood in particular to mean that the respective layer is not located on the surface of the substrate 20 of the entropy source 10.

[0089] It is also conceivable that the respective doping or conduction type is reversed. This means that the first region 51 is positively doped and the second, deep region 52, or the deep layer created by ion implantation, is negatively doped. This also results in a pn junction 54 of the single-photon detector 50.

[0090] The second area 52 (DPW), generated by ion implantation, is completely superimposed on the first area 51 (NBL) when viewed from above. This means, in particular, that at every point in the second area 52, a portion of the first area 51 lies beneath the second area 52 when viewed from above.

[0091] The first embodiment of the entropy source 10 differs from the entropy source 10 according to the prior art (shown in Fig. 9) in the following ways:

[0092] The entropy source 10 does not have a PBL layer or PBL sublayers above and below the NBL layer. Instead, the entropy source 10 has a DPW (deep p-well) layer above the NBL layer as part of the pn junction 54. The single-photon detector 50 is a deep SPAD, also called a deepSPAD. The deepSPAD comprises a pn junction 54 between the first region 51, or first layer (NBL layer), and the second region 52, or second layer (DPW layer). The DPW layer is located immediately adjacent to the NBL layer. The DPW layer is located on the side of the NBL layer associated with the photon source 40. The DPW layer can be produced, for example, at a depth of more than 1.0 pm, preferably more than 1.5 pm. In particular, the DPW layer can be produced by means of boron high-energy ion implantation.

[0093] Entropy source 10 thus has the following n-doped layers or regions: N+, NBL, NW, and HVNW / NEPI, with the doping strength of the layers or regions decreasing in the order mentioned. Furthermore, entropy source 10 has the following p-doped layers or regions: P+, PBL, HVPB, SH_P, HVPW, and P-, with the doping strength of the layers or regions decreasing in the 26714-ELM-PWO (E0020P-WO) 01749EPWO 15

[0094] The sequence mentioned decreases, and P- is the substrate. The PBODY layer in the prior art has been replaced by the HVPB layer. The PW layer (p-well) in the prior art has been replaced by a shallow p-doped layer, SH_P. Instead of the HPW layers in the prior art (see Fig. 9), this embodiment uses HVPW layers (high-voltage p-well).

[0095] The NW layer is not used in the entropy source according to the invention shown in Fig. 1; however, it is generally present in CMOS substrates. Therefore, this NW layer is shown in brackets in the overview of doping levels.

[0096] The PBL layers below the P+ layers arranged under METL, or more precisely, below the HPW layers, which in turn are located below the respective PW layer, which in turn are located below the respective P+ layer, have been omitted at both edges of Fig. 1. The p-substrate is located at this point, transitioning directly from the original substrate into the similarly weakly doped epitaxial layer.

[0097] The SH_P layer is formed in Fig. 1 in the interior of the two HVNW areas or HVNW layers, spaced apart from them.

[0098] The HPW layer or HVPW layer connects the shallow p-layers (PW layer or SH_P layer) located closer to the substrate surface with the very deep p-layers (PBL layer or DPW layer), or is situated between them. By varying the width of the HPW layer or HVPW layer, the resistance or resistance value to the pn junction of the single-photon detector (50) can be specifically varied. This makes it possible, in principle, to place part or even all of the so-called quenching resistance for operating the single-photon detector 50 within the volume of the substrate (especially the silicon substrate) or within the epitaxial layer.

[0099] Furthermore, in Fig. 1 there is no NEPI layer between the SH_P layer and the DPW layer or the NBL layer, whereas in the prior art (see Fig. 9) there is a NEPI layer between the PW layer and 26714-ELM-PWO (E0020P-WO) 01749EPWO 16

[0100] The upper PBL layer or NBL layer contained an HVNW / NEPI layer in which the HPW layer was embedded.

[0101] In particular, the single-photon detector 50 has exactly two layers, namely the NBL layer and the DPW layer. Thus, the single-photon detector 50 has exactly one pn junction 54. No further doped layer is arranged or present on the side of the NBL layer facing away from the photon source 40. This means that no further pn junction is formed on the side of the single-photon detector 50 facing away from the photon source 40.

[0102] The photon source 40 comprises or is a Zener diode avalanche LED (Zener-avLED). The Zener-avLED comprises or is a light-emitting avalanche Zener diode operated at an operating point below or near the breakdown voltage.

[0103] The Zener-avLED generates single photons, which are detected by the single-photon detector 50. The single photons 49 are preferably emitted in the direction of the single-photon detector 50. The photons 49 are detected by the pn junction 54 of the single-photon detector 50, i.e., the junction from the DPW layer to the NBL layer.

[0104] The photon source 40 comprises an N+ layer and, instead of a PBODY layer, an HVPB layer (high-voltage p-body). The HVPB layer is directly adjacent to the SH_P layer. The pn junction 42 of the Zener avLED is the junction between the HVPB layer and the N+ layer. The HVPB layer is trough-shaped, and the N+ layer is embedded within it. An SH_P layer is arranged between the HVPB layer and the HVPW layer. More precisely, the SH_P layer is trough-shaped, and the HVPW layer is embedded within this trough. Both the SH_P layer and the HVPW layer extend substantially to the (top in Fig. 1) surface of the substrate 20. The N+ layer is located partially or completely on the surface of the substrate 20, or, apart from a metallization, is located partially or completely on the surface of the substrate 20. 26714-ELM-PWO (E0020P-WO) 01749EPWO 17

[0105] Instead of the PW layer and having an HPW layer below the PW layer, the entropy source 10 according to this embodiment has an SH_P layer and an HVPW layer below each of these. This means that the SH_P layer has replaced the PW layer and the HVPW layer has replaced the HPW layer compared to the prior art (see Fig. 96).

[0106] To achieve a high breakdown voltage (usually above 15 V), which is necessary for the operation of the single-photon detector, the DPW layer can be spaced laterally from the respective HVNW layers, i.e., a part of the p-substrate 20 is arranged between the DPW layer and the respective HVNW layer.

[0107] The same applies to the distance between the shallow SH_P layer and the HVNW layers, both within and outside the NBL layer 51. The same applies to the distance between the medium-depth HVPW layer and the HVNW layers, both within and outside the NBL layer 51.

[0108] The respective distances between the p-layers (SH_P, HVPW, DPW) and the HVNW layers can be either identical or different. Thus, it is possible that a portion of the p-substrate 20 is also located between the DPW layer and the SH_P layer at the points where the HVPW layer is not present.

[0109] The inner and outer distances of the shallow and medium-depth p-layers (here SH_P and HVPW) to the HVNW regions in the boundary area of ​​the entropy source 10 can be either identical or different. Corresponding distances of the p-layers (SH_P, HVPW, DPW) to an NW layer must also be provided if (within the HVNW layer) the cathode region is additionally provided with a more highly doped n-layer (NW). This is not present in Fig. 1, but is shown in Figures 2-5 and Figure 8 of the further embodiments.

[0110] The deep DPW layer was created using high-energy ion implantation. This process doped a portion of the p-substrate, thereby creating the DPW layer.

[0111] The anode 46 of the photon source 40 and the anode 56 of the single-photon detector 50 are combined. The anodes 46 and 56 can be connected via a common second metallization MET2 an26714-ELM-PWO (E0020P-WO) 01749EPWO 18

[0112] The surface of the substrate 20 is electrically contacted. A second or higher metallization extending over the entire area of ​​the single-photon detector 54 (and preferably also beyond) can also serve as shielding for the entropy source 10 against external influences (light, EMC). This also applies if this continuous metallization is not connected to the common anode; in particular, it can be connected to one of the two cathodes (of the avLED or the single-photon detector) or be floating. The respective cathodes 44, 55 can be electrically contacted via a first metallization MET1. It is also conceivable to implement all connections (common anode and respective cathodes) in a single metallization.

[0113] Entropy source 10 therefore has only a few layers to be introduced and is technically simple in structure.

[0114] Fig. 2 shows a schematic representation of an exemplary second embodiment of an entropy source 10 according to the invention in a side view.

[0115] The second embodiment in Fig. 2 differs from the first embodiment in Fig. 1 in the following ways:

[0116] In the side view, deep trench isolation (DTI) is present on the left and right sides. The isolation extends over the height of all doped layers. Compared to the first embodiment, a P+ layer and the associated layers below the P+ layer for substrate contact have been omitted on both sides of the DTI isolation. These may be present outside the illustration.

[0117] The second embodiment has fewer doped layers than the first embodiment.

[0118] The photon source 40 comprises an N+ layer or a portion of the N+ layer and a portion of a PBODY layer. The pn junction 42 of the photon source 40 is formed between the N+ layer and the PBODY layer. The single-photon detector 50, or the pn junction 54 of the single-photon detector 50, comprises a portion of the PBODY layer and a DNW layer or a portion of the DNW layer and / or a portion of the PW layer and the DNW layer or a portion of the DNW layer. This means that a portion of the PBODY layer is both a layer or a portion of the 26714-ELM-PWO (E0020P-WO) 01749EPWO 19

[0119] The pn junction 42 of the photon source 40 forms both a layer or part of the pn junction 54 of the single-photon detector 50. The same layer PBODY is thus part of the photon source 40 and part of the single-photon detector 50. The single-photon detector 50 comprises exactly two layers, namely the PBODY layer or part of the PBODY layer and the DNW layer or part of the DNW layer.

[0120] The DNW layer was created using high-energy ion implantation. In particular, it is possible to create the DNW layer at a depth greater than 1 pm. The DNW layer can be created, for example, by phosphorus doping.

[0121] Substrate 20 (p-substrate) contains an NBL layer at the bottom, extending from one insulation layer to the other, i.e., from left to right. Above and immediately adjacent to the NBL layer is a so-called C-HDNW layer.

[0122] The DNW layer is embedded within the pot-shaped C-HDNW layer. The C-HDNW layer extends further upwards, partially enclosing the PBODY layer.

[0123] Alternatively, the DNW layer can extend into the cathode region of the NW layers or to the DTI insulation. Conversely, the C-HDNW layer may then be absent.

[0124] Laterally to the PBODY layer, in the upper region of the PBODY layer, a PW layer is present between the PBODY layer and the C-HDNW layer. The PW layer is formed to the left and right of the PBODY layer, and directly adjacent to it. Between the PW layer and the DTI, a portion of the C-HDNW layer and an NW layer within the C-HDNW layer are arranged.

[0125] As can be seen in Fig. 2 (bottom right), the second embodiment omits two p-doped layers compared to the first embodiment, namely the PBL layer and the HVPW layer. An additional n-doped layer, the DNW layer, has been added between the NBL layer and the N+ layer. 26714-ELM-PWO (E0020P-WO) 01749EPWO 20

[0126] The NBL layer was implanted into the surface of the original substrate. The other areas of the substrate, located approximately above the NBL layer, were deposited by epitaxy, as shown in Fig. 2. The DNW layer was created by high-energy ion implantation.

[0127] It is conceivable, of course, that the doping of the layers and the substrate is reversed. This means that an n-substrate is conceivable in which a positive DPW layer is created by ion implantation. The other layers can also be reversed with respect to the doping type (positive vs. negative). This applies to all embodiments.

[0128] Between the lateral N+ layer or the lateral NW layer and the upper P+ layer, there is a further layer of insulation or an isolation area (STI, shallow trench isolation).

[0129] The HVPB layer of the first embodiment was replaced by the PBODY layer. The SH_P layer of the first embodiment was replaced by the PW layer.

[0130] The entropy source 10 is particularly compact. Furthermore, due to its insulation to the left and right, the entropy source 10 can be positioned very close to other components without negatively affecting each other. The SBL layer (Silicide Blocking Layer) prevents the formation of a silicide layer.

[0131] In the second embodiment, the entropy source 10 has the following n-doped layers, in descending order of doping strength: N+, NBL, DNW, NW, HDNW. In the second embodiment, the entropy source 10 has the following p-doped layers, in descending order of doping strength: P+, PBODY, PW, P-, where P- is the substrate.

[0132] The pn junction 54 of the single-photon detector 50 is not located near the boundary or interface between the substrate support and the epitaxially or epitaxially deposited portion of the substrate, but rather the pn junction 54 lies within the epitaxially grown layer. A typical range for the depth of the pn junction 54 is defined in 26714-ELM-PWO (E0020P-WO) 01749EPWO 21

[0133] Range 1.0 pm to max. 4 pm, this is usually in the range of 15% to 70% in relation to the total epitaxial thickness.

[0134] The DNW layer has a similarly high doping strength to the NBL layer.

[0135] This allows the breakdown voltage to be low (e.g., 17 volts). The operating voltage of the single-photon detector (breakdown voltage plus a small overvoltage of a few volts) can therefore also be correspondingly low.

[0136] Fig. 3 shows a schematic representation of an exemplary third embodiment of an entropy source 10 according to the invention in a side view.

[0137] In the third embodiment of the entropy source 10, no part of the substrate was applied by epitaxy. The entropy source 10 is entirely contained within a substrate carrier. In particular, no alignment step was required during manufacturing after epitaxy. Furthermore, in contrast to the second embodiment, the entropy source 10 of the third embodiment lacks an NBL layer, a PBL layer, a C-HDWN layer, and lateral insulation (DTI).

[0138] Substrate 20 was produced using BCD technology.

[0139] At the very bottom of the entropy source 10, the DNW layer is located in the P-substrate. The DNW layer was created by high-energy ion implantation. Above the DNW layer and immediately adjacent to it, the PBODY layer is formed. As in the second embodiment, the single-photon detector 50 in the third embodiment comprises the DNW layer and the PBODY layer, or a portion thereof. As in the second embodiment, the PBODY layer in the third embodiment is also one of the two doped layers of the photon source 40, or forms part of the pn junction 42 of both the photon source 40 and the single-photon detector 50. The photon source 40 comprises the PBODY layer and the N+ layer, or a portion thereof. 26714-ELM-PWO (E0020P-WO) 01749EPWO 22

[0140] As in the second embodiment, in the third embodiment a shallow trench isolation (STI) is arranged between the lateral N+ layer and the lateral NW layer and the upper P+ layer.

[0141] As shown below right, the entropy source 10 has only three n-doped layers (N+, DNW, and NW) and four p-doped layers (P+, PBODY, PW, P-), where P- is the substrate. The NBL and HDNW layers of the n-doped layers have been omitted compared to the second embodiment. The p-doped layers of the third embodiment remain the same as those of the second embodiment.

[0142] Thus, the entropy source 10 of the third embodiment has even fewer layers and is therefore technically simpler in structure. Furthermore, the entropy source 10 is arranged in a non-epi-substrate, i.e., a substrate on which no parts have been deposited by epitaxy.

[0143] The common anode 46, 56 of the photon source 40 and the single-photon detector 50 is not connected to the P substrate. There are essentially no SPAD properties between the DNW layer and the P substrate.

[0144] Fig. 4 shows a schematic representation of an exemplary fourth embodiment of an entropy source 10 according to the invention in a side view.

[0145] The fourth embodiment differs from the third embodiment as follows: The PBODY layer has been omitted. In place of the previous PBODY layer, there is now a more extensive PW layer, which is more heavily doped than the PBODY layer (which was still present in the third embodiment). The photon source 40 thus comprises the N+ layer and the PW layer, or a portion thereof. The single-photon detector 50 comprises the PW layer and the DNW layer, or a portion thereof. The PW layer is therefore partly part of the photon source 40 and simultaneously partly part of the single-photon detector 50. 26714-ELM-PWO (E0020P-WO) 01749EPWO 23

[0146] The photon source 40 comprises, or in this embodiment is, a Zener diode-like avalanche LED. The breakdown voltage of this Zener avalanche LED is therefore different from the breakdown voltage of the first three embodiments.

[0147] The DNW layer is produced using ion implantation. A mask or mask process can be used for this.

[0148] The breakdown voltage of the single-photon detector 50 can be optimized for the application by the process parameters (ion implantation energy and dose) of the DNW layer, in particular reduced to a value significantly less than 40 V, preferably less than 20 V or even less than 15 V.

[0149] As shown below right in Fig. 4, the entropy source 10 has exactly three n-doped layers (N+, DNW, NW) and exactly three p-doped layers (P+, PW, P-), where P- is the substrate 20.

[0150] In the fourth embodiment, no layer was produced or applied by epitaxy. No alignment step was required in the fabrication of the entropy source 10 of the fourth embodiment. Furthermore, the entropy source 10 of the fourth embodiment has no NBL layer, no PBL layer, and no insulation (DTI). The substrate 20 was not fabricated using BCD technology.

[0151] Substrate 20 can be a CMOS substrate.

[0152] The laterally arranged NW layers are spaced apart from the PW layer by the P substrate. This means that P substrate is present between the left NW layer and the PW layer, and P substrate is present between the right NW layer and the PW layer. This is emphasized by two double arrows in Fig. 4.

[0153] Fig. 5 shows a schematic representation of an exemplary fifth embodiment of an entropy source 10 according to the invention in a side view. 26714-ELM-PWO (E0020P-WO) 01749EPWO 24

[0154] The fifth embodiment shown in Fig. 5 differs from the fourth embodiment only in that an additional deep p-well (DPW) is introduced above and laterally within the DNW layer. The DPW layer is fabricated by ion implantation. The introduced p-well modifies the pn junction of the single-photon detector such that the breakdown voltage lies within a manageable range (typically less than or equal to 40 V), which is determined in particular by the use of an insulating CMOS process (DNW below CMOS).

[0155] Fig. 6 shows a schematic representation for a CMOS process without a DNW layer.

[0156] Figure 6 shows the two typical components of a CMOS process: an nMOS transistor on the left and a pMOS transistor on the right. The relevant technical terminals—source (S), drain (D), gate (G), and bulk (B)—of each transistor are indicated above or at the top edge. A DNW layer is then added below the transistor regions, formed or created by high-energy ion implantation, as shown in Figure 7. This creates a so-called isolated CMOS process, or isolating CMOS process. "Isolated" in this case means that the bulk of the nMOS transistor or nMOS sub-transistor is now also isolated from the p-substrate. Thus, components isolated from the entropy source 10 can be formed or arranged on or in the same substrate 20 alongside the entropy source 10.The technical terminal ISO can be added to this nMOS sub-transistor, as shown in Fig. 7.

[0157] In both configurations (Fig. 6 and Fig. 7), the PW tub and the NW tub are usually arranged without any distance between them.

[0158] By using BCD techniques, as well as in the case of the isolated CMOS process, circuit components with significantly increased absolute voltage relative to the substrate potential, i.e., high high-side voltage, can be realized or fabricated. This is not usually possible with a simple CMOS process. This allows, in particular, the control and power supply for the operation of both the photon source (e.g., Zener avalanche LED) and the single-photon detector (e.g., single-photon avalanche diode; SPAD single-photon detector) to be implemented on the same substrate. 26714-ELM-PWO (E0020P-WO) 01749EPWO 25

[0159] Fig. 8 shows a schematic representation of an exemplary sixth embodiment of an entropy source 10 according to the invention in a side view.

[0160] The fifth embodiment differs from the fourth embodiment only in that an alternative or additional lateral pn junction 54 is present. This alternative or additional pn junction 54 is formed between the N+ layer and the PW layer. The additional pn junction 54 is located below the SBL layer. The alternative or additional pn junction 54 runs in a perpendicular direction or parallel to the perpendicular direction. However, the generated photons 49 mostly reach the single-photon detector 50, i.e., downwards.

[0161] Reference symbol list

[0162] 10, 10' Integrated Quantum Random Number Generator

[0163] 20 substrate

[0164] 40, 40' Photon source

[0165] 42 First pn transition (photon source)

[0166] 44, 44' Cathode of the photon source

[0167] 46, 46' Anode of the photon source

[0168] 49, 49' photons

[0169] 50, 50' single photon detector

[0170] 51, 51' first region of the pn transition of the single-photon detector (e.g. NBL)

[0171] 52, 52' second region of the pn junction of the single-photon detector (e.g. DPW)

[0172] 54, 54' second pn junction (single photon detector)

[0173] 55, 55' Cathode of the single-photon detector

[0174] 56, 56' Anode of the single-photon detector

[0175] NBL deep n-layer (engl. “n-type buried layer”)

[0176] DNW deep n-type well

[0177] HDNW low-lying high-voltage deep n-well

[0178] PBL deep p-layer (English: "p-type buried layer")

[0179] HVPW high-voltage p-type well

[0180] HVPB High-voltage p-doped region (English: "p-type body")

[0181] HVNW high-voltage n-type well 26714-ELM-PWO (E0020P-WO) 01749EPWO

[0182] 26

[0183] PW p-well

[0184] NW n-type well

[0185] PBODY p-type body

[0186] NEPI weakly n-doped or (approximately) intrinsic epitaxial region MET1 Metallization 1

[0187] MET2 Metallization 2

[0188] CONT Contact

[0189] STI isolation area (“shallow trench isolation”)

[0190] DTI deep trench isolation

[0191] P + p + -Area

[0192] N + N + -Area

[0193] polysilicon layer

[0194] SH_P shallow p-type layer

[0195] SBL silicide blocking layer

Claims

26714-ELM-PWO (E0020P-WO) 01749EPWO TI Claims 1. Entropy source for an integrated quantum random number generator (10) comprising: a photon source (40) and a single photon detector (50), where the photon source (40) and the single-photon detector (50) are arranged vertically one above the other in a common substrate (20) made of a semiconductor material, characterized by the fact that the single photon detector (50) comprises a doped layer produced by high-energy ion implantation as part of a pn junction (54).

2. Entropy source according to claim 1, wherein the entropy source has at least two photon sources (40) and / or at least two single-photon detectors (50), wherein the photon sources (40) and / or the single photon detectors (50) are arranged in the common substrate (20) made of semiconductor material.

3. Entropy source according to claim 1 or 2, wherein the entropy source is formed in a substrate of an indirect semiconductor, in particular in a silicon substrate.

4. Entropy source according to one of the preceding claims, wherein the entropy source is formed in a BCD substrate using BCD technology.

5. Entropy source according to one of the preceding claims, wherein a layer of the pn junction (54) of the single-photon detector (50) is identical to a layer of the pn junction (54) of the photon source (40).

6. Entropy source according to one of the preceding claims, wherein The part of the substrate (20) in which the photon source (40) and the single-photon detector (50) are arranged is a non-epitactically generated part of the substrate (20). 26714-ELM-PWO (E0020P-WO) 01749EPWQ 28 7. Entropy source according to one of the preceding claims, wherein the photon source (40) has a pn junction (54) whose interface is perpendicular to the vertical direction.

8. Entropy source according to one of the preceding claims, wherein the photon source (40) has a pn junction (54) whose interface runs parallel to the vertical direction.

9. Entropy source according to one of the preceding claims, wherein the pn junction (54) of the single-photon detector (50) is arranged at a distance from the boundary between the substrate carrier itself and the substrate applied to the substrate carrier by means of epitaxy.

10. Entropy source according to one of claims 5-9, wherein the respective non-common layer of the pn junction (42) of the photon source (40) and of the pn junction (54) of the single-photon detector (50) is each more heavily doped than the common layer, which is part of both the pn junction (42) of the photon source (40) and the pn junction (54) of the single-photon detector (50).

11. Integrated quantum random number generator comprising an entropy source according to any of the preceding claims.

12. Integrated electronic circuit comprising an integrated quantum random number generator (10) according to claim 11.

13. Method for producing an entropy source for an integrated quantum random number generator (10), in particular an entropy source according to any one of claims 1-10, wherein the method comprises the following steps: Providing a substrate; and Generating multiple doped layers to generate a pn junction of a photon source (40) and a pn junction (54) of a single-photon detector (50) in the substrate, wherein the photon source (40) and the single-photon detector (50) are in a vertical direction 26714-ELM-PWO (E0020P-WO) 01749EPWO 29 are arranged one above the other in the substrate (20), and wherein a doped layer of the pn junction (54) of the single photon detector (50) is generated by high-energy ion implantation.

14. Method according to claim 13, wherein the entropy source is constructed such that a layer of the pn junction (54) of the single-photon detector (50) is identical to a layer of the pn junction (54) of the photon source (40).

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