Sensor device and corresponding method

Abstract

To provide a sensor concept having improved trade-off among detection accuracy, applicability to different measurement tasks, and adaptability to different measurement conditions.SOLUTION: A sensor device (20, 20 ', 20 ") for determining a property of a fluid, gas or liquid, comprises a control gate (2), a sensing layer (6) and at least one insulating layer between the sensing layer (6) and the control gate (2), the at least one insulating layer comprising a floating gate (4).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention refer to sensor devices, methods for manufacturing the sensor devices, and methods for performing measurements using the sensor devices. Preferred embodiments refer to sensor devices for determining properties of fluids, gases, or liquids, in particular capacitance or charge. [Background technology]

[0002] In the prior art, there are several patent documents that discuss sensors in the same application field. For example, WO2005103667A1 refers to a FET-based sensor for determining gases. DE4333875 discloses a capacitance-controlled field-effect transistor that forms the basis for a semiconductor gas sensor device. US Patent Application Publication No. 2013 / 0126947 refers to another semiconductor gas sensor. A fluid sensor and a method for testing fluids are disclosed in US Patent No. 9,716,140 (B2). WO2019 / 063650 refers to a fluid sensor. Here, a capacitively controlled field-effect transistor CCFET is also used. SGFET (Suspended Gate Field Effect Transistor) and FGFET (Floating Gate Field Effect Transistor) are particular variants. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2005 / 103667 [Patent Document 2] West German Patent Application Publication No. 4333875 [Patent Document 3] US Patent Application Publication No. 2013 / 0126947 [Patent Document 4] U.S. Patent No. 9,716,140 [Patent Document 5] International Publication No. 2019 / 063650 Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a sensor concept with an improved trade-off between detection accuracy and applicability to different measurement tasks and adaptability to different measurement conditions. [Means for solving the problem]

[0005] That object is solved by the subject matter of the independent claims.

[0006] An embodiment of the present invention provides a sensor device for determining a property of a fluid, gas, or liquid, the sensor device comprising: a control gate, a sensing layer, and at least one insulating layer between the control gate and the sensing layer, wherein the at least one insulating layer comprises a floating gate.

[0007] According to embodiments, the sensor device comprises a substrate, such as a semiconductor substrate. For example, the control gate may be integrated into said substrate. According to further embodiments, the control gate may be made of a conductive material, such as a doped semiconductor or a metal.

[0008] According to an embodiment, the sensor device further comprises one or more transistors, in particular MOSFET transistors, which may be integrated or arranged in said substrate.

[0009] An embodiment of the present invention refers to a sensor device formed by a kind of layer stack, for example arranged on a substrate comprising an insulating layer and a sensing layer, on which a floating gate may be arranged.

[0010] The embodiment is based on the principle that a control gate can be arranged in addition to the floating gate below the insulating layer. The floating gate, which is typically used for measurements, is elevated by the control gate, which allows the potential at the floating gate to be kept constant, for example by changing the potential at the control gate. This can improve the measurement accuracy. Furthermore, the entire sensor device can be adapted to different measurement conditions and applications.

[0011] According to an embodiment, the sensor device comprises a first transistor, in particular a MOSFET transistor, with the floating gate connected to the first transistor. Alternatively, the sensor device may comprise a second transistor, in particular a MOSFET transistor, with the floating gate connected to the gate of the second transistor. For example, the first transistor may be a p-channel transistor. According to an embodiment, the second transistor may be an n-channel transistor. Both transistors may be implemented using CMOS. According to another embodiment, the sensor device comprises first and second transistors, in particular MOSFET transistors, with the floating gate connected to the gate of the first transistor and the gate of the second transistor.

[0012] Regarding the floating gate, it should be noted that the floating gate can be positioned inside at least one insulating layer. For example, the at least one insulating layer can comprise a combination of different insulating layers depending on the embodiment. Here, the floating gate can be integrated into one layer. According to the embodiment, the control gate, the sensing layer, and / or the floating gate can be arranged at the same lateral position of the sensor device. In other words, the control gate and the sensing layer are arranged to form a common lateral projection or a common lateral overlap. The aforementioned transistors are arranged laterally adjacent to the control gate and the sensing layer. The floating gate can be arranged to cover the control gate and / or the sensing layer, or preferably, to extend laterally across the projection of the control gate and / or the projection of the sensing layer. Due to the lateral extension, the floating gate can be connected to a transistor arranged on the side of the control gate. For example, the control gate can be made of a conductive material, such as a metal layer in the at least one insulating layer.

[0013] According to other embodiments, the sensor device further comprises one or more counter electrodes arranged on the at least one insulating layer. For example, the counter electrodes may comprise a conductive material, with an insulating material separating the one or more counter electrodes from the sensing layer. According to embodiments, multiple counter electrodes are used, which differ in terms of their topology. Advantageously, the counter electrodes (together with the control gate) can maintain a constant potential of the floating gate by varying the potential of the control gate and / or the potential of the counter electrode. Preferably, the counter electrodes are arranged laterally adjacent to the sensing layer such that the projections of the counter electrodes and the sensing layer do not overlap (i.e. are adjacent to each other).

[0014] According to embodiments, one or more counter electrodes may be beneficially configured to act as a reference electrode for guiding the liquid and / or to act as an electrical shield for insulating the fluid and / or to define an electrical potential for insulating the fluid.

[0015] According to embodiments, the fluid, gas or liquid is analyzed for a property by use of a sensing layer. The property may be, for example, a charge or the nature of the fluid, gas or liquid. The sensing device may then be configured to respond to such a charge or to change its capacitance depending on the fluid, gas or liquid.

[0016] With regard to the sensing device, it should be noted that the sensing device may comprise a metal, a semiconductor material, an insulating material, a biological (reactive) material, or a chemically reactive material. The sensing layer may be configured to detect charges present on the front or rear surface of the sensing layer, or alternatively, to detect physical or chemical modifications in the capacitance of the sensing layer. For this purpose, the sensing layer may be configured to change its capacitance depending on the fluid, gas, or liquid in its surroundings, or may be reactive to the charge of the fluid, gas, or liquid in its surroundings.

[0017] According to a further embodiment, the sensing layer may be configured to detect a combination of (changed) charge and (changed) capacitance. According to an embodiment, the insulating layer comprises a kind of sink in which the sensing layer is placed.

[0018] According to a further embodiment, the sensor device may comprise a ring guard, in particular a ring guard arranged on at least one insulating layer and / or arranged around the sensing layer. Preferably, the ring guard may be arranged around the sensing layer on the insulating layer. The ring guard advantageously has the task of avoiding potential perturbations that may lead to parasitic signals.

[0019] According to further embodiments, the sensor device may comprise a temperature sensing element, for example a temperature sensing element implemented as a diode. For example, the temperature sensing element may be arranged in the substrate. According to further embodiments, the sensor device further comprises a heating element, for example a heating element integrated around the sensing layer. Both elements, either in combination or separately, help to control the temperature for the sensing layer.

[0020] Another embodiment refers to a method for manufacturing a sensor device, the method comprising: providing a substrate comprising a control gate; providing at least one insulating layer on the substrate, the at least one insulating layer comprising a floating gate; providing a sensing layer on at least one insulating layer; Includes:

[0021] Another embodiment refers to a method for determining charge and / or capacitance using a sensing device, the method comprising the main step of determining a change in voltage on a floating gate.

[0022] In the following, embodiments of the present invention will be discussed in succession with reference to the accompanying figures. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic block diagram of a sensor device according to a basic embodiment; [Figure 2A] 1 is a schematic block diagram of a sensor device with a control gate and an additional MOSFET according to an embodiment. [Figure 2B] 2B is a schematic block diagram of a sensor device compatible with the sensor device of FIG. 2A, but with optional features according to a further embodiment; [Figure 3] FIG. 1 is a schematic block diagram of a sensor device according to an improved embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0024] In the following, embodiments of the present invention will be discussed in succession with reference to the accompanying figures, in which the same reference numerals are provided for objects having the same or similar functions so that the descriptions are interchangeable and applicable.

[0025] 1 shows a sensor device 20, which may be based on silicon or any other semiconductor material. The sensor device 20 comprises at least a sensing layer 6, which is arranged on an insulator, for example as an upper layer. The insulator is marked with the reference numeral 3. According to the embodiment, the insulator may be a single insulating layer or a combination of different insulating layers. The insulating layer comprises a floating gate 4, for example made from a conductive material. Here, the floating gate 4 is positioned in the insulating layer 3.

[0026] Furthermore, the sensor device 20 comprises a control gate 2 made from a conductive material such as a doped semiconductor or a metal. The control gate 2 may be located in or on a semiconductor substrate 1. It should be noted that the semiconductor substrate 1 is an optional feature, as the control gate 2 may be located in other layers, for example a semiconductor layer, or in other types of substrates.

[0027] Regarding the lateral arrangement, it should be noted that the insulating layer 3 comprising the floating gate 4 can be arranged above the control gate 2. As a result, all elements 6, 3, 4 and 2 can be arranged according to the preferred embodiment in the same lateral region, i.e. have a common lateral projection.

[0028] According to an embodiment, the floating gate 4 is positioned inside the insulating layer 3, for example positioned between different insulating layers of the insulator 3. The insulator 3 comprises one or more insulating layers and is referred to below as an element also marked with the reference numeral 3. According to an embodiment, the area of ​​the floating gate 4 is greater than, equal to or smaller than the control gate. Preferably, the area of ​​the floating gate 4 extends laterally over the area of ​​the elements 2 and / or 6, since the floating gate 4 may be connected to the gate of a MOSFET or generally to the gate of a transistor that may be arranged next to the area of ​​the elements 2 and / or 6. It should be noted that the floating gate 4 has a c sens and the potential determined by C with respect to the control gate 2 CG An optional transistor, which may also be arranged in the substrate / semiconductor substrate 1, is marked by the reference numeral 12.

[0029] Now that the structure of the sensor device 20 has been discussed, its functionality will be discussed. The sensor device 20 is configured to detect physical or chemical modifications of the capacitance of the sensing layer 6. The capacitance can be changed due to a fluid, gas, or liquid 19 in the surroundings of the sensing layer 6. For example, the change in capacitance or capacitance can result from charges in the fluid 19. This means, in other words, that according to further embodiments, the sensor device 20 is configured to detect charges (physisorbed species, chemisorbed species, dipoles, and / or ions) present on the surface or in the bulk of the sensing layer 6 and that can arise from the fluid, gas, and / or liquid 19. According to further embodiments, the sensor device 20 can be configured to detect physical or chemical modifications of the capacitance of the sensing layer 6. Furthermore, a combination of charges and / or capacitances can be detected in one device 20. As a result, the sensor 20 can detect changes in charge and capacitance in the fluid / gas or liquid 19.

[0030] It should be noted that, according to an embodiment, the sensor device 20 can be used for any type of fluid.

[0031] The directional charge in the sensing layer 6 can be detected as follows: The charge or capacitance in the sensing layer 6 results in a change in the potential of the floating gate 4. The change in the potential of the floating gate affects the source-drain current of the MOSFET or transistor 12. The change in the source-drain current can be measured directly, for example by a measurement circuit (not shown). With the sensing circuit, the source-drain current can be kept constant and the change in the potential of the floating gate is measured. For example, by changing the potential on the control gate 2, the potential of the floating gate can be kept constant. This increases the accuracy.

[0032] It can be determined that the sensor layer 6 can increase the amount of the determined property due to capacitance, capacitance change, charge resulting in capacitance, or charge change resulting in capacitance change. According to an embodiment, changes in film thickness or electrical film parameters can also be detected, as they result in changes in capacitance.

[0033] A sensor device 20' with optional elements is discussed in connection with Figure 2A. A structure such as that shown by Figure 2A is called a CCSFET, i.e., a floating gate CHEM-FET with a control gate and a counter electrode.

[0034] The device 20' comprises a substrate 1 in which a control gate 2 is disposed. In the substrate, an insulator 3 is disposed together with a sensing layer 6. As can be seen, the sensing layer 6 is disposed in a sink 3S of the insulator 3.

[0035] Instead of transistor 12, substrate 1 comprises a MOSFET transistor 5 which is also arranged laterally adjacent to the region of control gate 2. Floating gate 4 is connected to MOSFET 5, or more specifically to the gate of MOSFET 5.

[0036] According to an embodiment, the sensor device 20′ may comprise one or more reference electrodes (electrolytes) marked with the symbols 9a and 9b. A Faraday cup 8 for gas detection may also be present. The Faraday cup may be arranged on the reference / counter electrode 9 and extend vertically from the surface of the sensor 20′ around the sensing layer 6. For example, the counter electrode (reference electrode 9) may have different topologies, such as a planar, cylindrical, or any three-dimensional structure such as a Faraday cup 8. According to an embodiment, the counter electrode 7 may act as a reference electrode 9 for guiding the liquid. According to another embodiment, the counter electrode 7 may act as an electrical shield for insulating the fluid. According to a further embodiment, the counter electrode 7 may define a potential for insulating the fluid. In other words, the counter electrode here may act as a Faraday cup 7 (e.g., for gas detection) or as a reference electrode (e.g., for electrolyte measurement).

[0037] It should be noted that all electrodes 9a and 9b, as well as the contacts of transistor 5 and control gate 2, may have through wires so that the respective elements can be electrically connected from the rear side of substrate 1 or from a redirection layer within substrate 1. CE , V CG , V S , and V D The potential V of the counter electrode 7 is CE can be varied to keep the potential of the floating gate constant. CE and / or the control gate potential V CG can be varied together. For example, equal or different potentials can be applied to the control gate 2 and the counter electrode 7.

[0038] When gas is being detected, a Faraday cup 8 is positioned to surround the sensing layer 6. A counter electrode 7 is electrically connected to the Faraday cup 8 for electrical shielding and to maintain a constant potential around the sensing layer 6. When charge in a liquid is being detected, the counter electrode 7 acts as a reference electrode 9.

[0039] When the sensing layer 6 is exposed to a fluid, charges accumulate on the surface and in the sensing layer 6. The charges induce a change in the potential of the floating gate 4. The change in the potential of the floating gate 4 changes the source-drain current of the MOSFETs 5, 12, which is measured directly. This makes it possible to determine the concentration of charges in the fluid.

[0040] For completeness, the abbreviations for voltages are as follows: V CE : Voltage counter electrode V GR : Voltage guard ring V CG : Voltage controlled gate V S : Source voltage V D : Drain voltage

[0041] 2B shows another variant of a sensor device 20′ in which a reference electrode (electrolyte) 9 is combined with the counter electrode 7. In addition to the counter electrode 7 and the reference electrode 9, a so-called ring guard 10 may be arranged. The ring guard 10 is arranged between the counter electrode 7 / reference electrode 9 and the sensing layer 6. It should be noted that the counter electrode 7, the reference electrode 9 and / or the guard ring 10 may be arranged around the sensing layer 6 according to the embodiment.

[0042] A structure such as that shown by Figure 2B can be called a CCSFET, i.e., a floating gate CHEM-FET with a control gate and a counter electrode. Again, the counter electrode 7 can act as a Faraday cup (gas detection) or as a reference electrode (electrolyte measurement).

[0043] An additional guard ring 10 may be arranged according to an embodiment between the sensing layer 6 and the counter electrode and may have the purpose of performing a kind of shielding. In particular, the guard ring 10 may avoid potential perturbations that may lead to parasitic signals.

[0044] Note that one or more counter electrodes, reference electrodes, and / or guard rings may be made from conductive materials and are disposed on the insulator 3 but (optionally but preferably) separated from the sensing layer 6.

[0045] It should be noted that, according to embodiments, the elements 11, 10, 8, 7 and / or 9 may extend around the sensing layer 6 as a ring or in different shapes.

[0046] FIG. 3 shows a sensor device 20″ comprising as basic elements a substrate 1, an insulator 3 and a sensing layer 6. A structure such as that shown by FIG. 3 can be called a CCSFET, i.e. a floating gate CHEM-FET with a control gate and a counter electrode.

[0047] An insulator 3 covers an area of ​​the substrate 1, and a sensing layer 6 covers an area above the floating gate 2. The sensing layer 6 is disposed on the insulator 3 at a sink 3S. Electrodes 7, 9 and a guard ring 10 are also disposed. Two transistors 5 and 12 are formed in the substrate 1. Transistor 5 may be an n-MOSFET transistor, and transistor 12 may be a p-MOSFET transistor. The floating gate 4 is electrically connected to both gates of both transistors 5 and 12, i.e., extends to both sides outside the area defined by the lateral projections of the sensing layer 6 and the control gate 2. Depending on the embodiment, the floating gate may be connected to transistor 5, such as a MOSFET, or to transistor 12, such as a MOSFET, or to both transistors 5 and 12. The transistors may be MOSFETs, such as having a p-channel like transistor 12, or an n-channel like transistor 5. Both transistors 5 and 12 may be CMOS transistors and may comprise the inputs of an amplifying device.

[0048] It should be noted that with respect to the sensing layer 6 and / or the control gate 2, both layers are laterally limited in terms of their dimensions. As discussed above, the sensing layer 6 is laterally limited by the sink or by the walls of the sink 3S.

[0049] According to a further embodiment, the device 20" may comprise a temperature sensing element 13, which may for example be integrated into the substrate 1 and formed as a kind of diode. The device 20" also comprises a heating element 11, which may have a topology. For example, the heating element may be implemented to heat the sensing layer 6 to a desired temperature. Here, the heating element 11 is arranged on the insulator 3 and extends, for example, around the sensing layer. Both the heating element 11 and the temperature sensing element 13 have the purpose of maintaining the sensing layer 6 at a desired temperature or of controlling the desired temperature. It should be noted that the heating element 11 can be used without the temperature sensing element 13, and that the temperature sensing element 13 can be used without the heating element 11.

[0050] 2A, 2B, and 3, the floating gate 4 can be larger, equal to, or smaller than the control gate 2. Regarding the counter electrode 7, the counter electrode 7 acts as a Faraday cup (gas detection) or as a reference electrode (electrolyte measurement).

[0051] Starting from the structure of the three embodiments of Figures 2A, 2B and 3, which have different transistor configurations and different floating gates, functionality is considered.

[0052] Also, in the above embodiment, the transistors 12 and 5 have been considered as n-type or p-type transistors. It should be noted that both transistors 5 and 12 can be of the same type or of different types, i.e., the MOSFETs 5 and 12 can be n-type, p-type, or a combination of both (CMOS). In a variant, the floating gate 4 is connected to the gate of the n-channel MOSFET 5 and to the gate of the p-channel MOSFET 12. This makes it possible to detect floating charges of any potential.

[0053] Possible applications of devices 20, 20', and 20" are gas measurements, electrolyte measurements, biological measurements, detection of surface film buildup or removal, clean-in-place (CIP) measurements (charge and capacitance), and / or phase change measurements.

[0054] As discussed above, further embodiments refer to a method for manufacturing a device. Here, the method defines the fabrication of a single layer, namely providing a substrate 1 with a control gate 2 and optionally with transistors 5 and 12, providing an insulator 3 including a floating gate 4, and providing a sensing layer 6. Optionally, a step of providing a sink 3S in the insulator 3 may be applied before providing the sensing layer 6 on the surface of the insulator 3. Also, optional method steps for providing electrodes 7, 9, 10, and 8 may be applied.

[0055] Another embodiment refers to a method for performing the measurement, which includes the central step of determining the change in voltage on the floating gate 4 so as to determine the charge or capacitance. The change in voltage can be detected by using detection of the source-drain current of the respective transistors 5, 12, or 5 and 12.

[0056] According to a further embodiment, the floating gate is laterally arranged such that it laterally covers the control gate and the sensing layer and is between the control gate and the sensing layer. According to a further embodiment, the floating gate is between the control gate and the sensing layer.

[0057] Although some aspects have been described in the context of an apparatus (sensor device), it is clear that these aspects also represent a description of the corresponding method, in which a block or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method step also represent a description of the corresponding block, item, or feature of the corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the most important method steps may be performed by such an apparatus.

[0058] The foregoing embodiments are merely illustrative for the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. It is therefore intended to be limited only by the scope of the appended claims, and not by the specific details presented using the description and explanation of the embodiments herein. [Explanation of symbols]

[0059] 3 Insulators, insulating layers 3S Sink 4 Floating Gate 5. MOSFET Transistors 6 Sensing layer, sensing layer, sensor layer 7 Counter electrode, Faraday cup 8 Faraday cup, electrodes 9, 9a, 9b Reference electrode (electrolyte), counter electrode 10 Ring guard, guard ring, electrode 11 Heating element 12 MOSFET transistors 13 Temperature sensing element 19 Fluids, Gases, and Liquids 20, 20', 20" sensor devices c sens potential of the sensing layer 6 C CG Control gate 2 potential V CE Potential of counter electrode 7 V CG Control gate potential V S Source Voltage V D Drain Voltage

Claims

1. A sensor device (20, 20', 20") for determining properties of a fluid, gas or liquid, comprising: a control gate (2); a sensing layer (6); at least one insulating layer between said sensing layer (6) and said control gate (2), said at least one insulating layer comprising a floating gate (4); Equipped with A sensor device (20, 20', 20"), wherein said control gate (2), said sensing layer (6) and said floating gate (4) are at least partially arranged in the same lateral position of said sensor device.

2. the at least one insulating layer comprises a combination of different insulating layers; and / or 2. The sensor device (20, 20', 20") according to claim 1, wherein the floating gate (4) is positioned inside the at least one insulating layer or inside a combination of different insulating layers formed by the at least one insulating layer.

3. said sensor device (20, 20', 20") further comprises one or more transistors (5, 12), in particular MOSFET transistors; and / or the sensor device (20, 20', 20") further comprises a first transistor (5, 12) and / or a second transistor (5, 12), in particular a MOSFET transistor, and the floating gate (4) is connected to the gate of the first transistor (5, 12) or to the gate of the second transistor (5, 12), or 2. The sensor device (20, 20', 20") according to claim 1, further comprising a first transistor (5, 12) and a second transistor (5, 12), in particular MOSFET transistors, and the floating gate (4) is connected to the gate of the first transistor (5, 12) and to the gate of the second transistor (5, 12).

4. 2. The sensor device (20, 20', 20") according to claim 1, wherein the floating gate (4) is configured to maintain a constant potential by varying the potential at the control gate (2) or at a counter electrode (7, 9, 8).

5. further comprising one or more counter electrodes (7, 9, 8) disposed on said at least one insulating layer, or further comprising one or more counter electrodes (7, 9, 8) comprising a conductive material and an insulating material separating said one or more counter electrodes (7, 9, 8) from said sensing layer, or The sensor device (20, 20', 20") according to claim 1, further comprising a plurality of counter electrodes (7, 9, 8) having different topologies, disposed on said at least one insulating layer.

6. 6. The sensor device (20, 20', 20") according to claim 5, wherein the one or more counter electrodes (7, 9, 8) are configured to act as a reference electrode (7, 9, 8) for guiding the liquid and / or to act as an electrical shield for insulating the fluid and / or to define a potential for insulating the fluid.

7. The sensor device (20, 20', 20'') according to claim 1, wherein the at least one insulating layer comprises a sink in which the sensing layer (6) is disposed.

8. said sensing layer (6) comprises a metal, a semiconducting material, an insulating material, a biological (reactive) material and / or a chemical (reactive) material; and / or 2. The sensor device (20, 20', 20") of claim 1, wherein the sensing layer (6) is configured to detect charges present on the surface or in the bulk of the sensing layer (6), or to detect physical or chemical modifications in the capacitance of the sensing layer (6), or to detect a combination of charges and capacitance.

9. the sensor device (20, 20', 20") comprises a substrate, in particular a semiconductor substrate, or 2. The sensor device (20, 20', 20") according to claim 1, wherein the sensor device (20, 20', 20") comprises a substrate, in particular a semiconductor substrate (1), and the control gate (2) and / or one or more transistors (5, 12) are arranged in the substrate.

10. the control gate (2) and the sensing layer (6) are arranged to form a common lateral projection or a common lateral overlap; and / or one or more transistors (5, 12) and / or one or more counter electrodes (7, 9, 8) are arranged laterally adjacent to said control gate (2) and / or said sensing layer (6); and / or the floating gate (4) laterally covers the control gate (2) and / or the sensing layer (6), or the floating gate (4) extends laterally over the projection of the control gate (2) and / or the projection of the sensing layer (6), and / or the floating gate (4) is laterally positioned so as to laterally cover and be between the control gate (2) and the sensing layer (6); and / or The sensor device (20, 20', 20") according to claim 1, wherein the floating gate (4) is between the control gate (2) and the sensing layer (6).

11. said control gate (2) comprises a conductive material, in particular a doped semiconductor or a metal; and / or The sensor device (20, 20', 20") according to claim 1, wherein the floating gate (4) comprises a conductive material.

12. the layer of the sensor device (20, 20', 20") comprises a ring guard (10), in particular a ring guard (10) arranged on the at least one insulating layer, or 2. The sensor device (20, 20', 20") according to claim 1, wherein a layer of the sensor device (20, 20', 20") comprises a ring guard (10), in particular a ring guard (10) arranged on the at least one insulating layer, the ring guard (10) being arranged around the sensing layer (6).

13. further comprising a temperature sensing element, in particular a temperature sensing element implemented as a diode; and / or The sensor device (20, 20', 20") according to claim 1, further comprising a heating element, in particular a heating element integrated around the sensing layer (6).

14. Providing a substrate (1) comprising a control gate (2); providing said substrate with at least one insulating layer, said insulating layer comprising a floating gate (4); providing a sensing layer (6) on said at least one insulating layer; 2. A method for manufacturing a sensor device (20, 20', 20") according to claim 1, comprising:

15. A method for determining charge and / or capacitance using a sensor device (20, 20', 20") according to claim 1, comprising determining the change in voltage on the floating gate (4).

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