Resistor and method for determining the temperature of a resistor - Patents.com

Abstract

The present invention relates to a resistor (2) having at least one connection element (3, 3') and at least one resistive element (4), wherein at least a portion (411) of the surface (41) of the resistive element (4) as a substrate or at least a portion (311) of the surface (31) of the connection element (3, 3') as a substrate is coated with a coating (5) having at least one layer (50, 51, 52, 53). According to the present invention, the coating (5) is implemented in such a way that at an interface (61) between the substrate and the coating (5) there is direct metal-semiconductor contact, thereby forming a pn junction at the interface (61), and / or at least at an interface (62) between a first layer (50, 51) and a second layer (52) of the coating (5) there is direct metal-semiconductor contact or a first semiconductor-second semiconductor contact, thereby forming a pn junction at the interface (62). The resistor 2 is configured such that either one layer (50, 51, 52, 53) of the coating (5) on the one hand, or the uncoated portion (412, 412') of the surface (41) of the resistive element (4) on the other hand or the uncoated portion (312) of the surface (31) of the connecting element (3, 3') on the other hand, or either the first layer (50, 51) of the coating (5) on the one hand, or the further layer (52, 53) on the other hand, is contactable to detect a measurement signal for determining the temperature of the resistor (2).

Description

Technical Field

[0001] The present invention relates to a resistor provided with a coating for measuring the temperature of the resistor, as well as a method for determining the temperature of the resistor.

Background Art

[0002] For current measurement in electronic circuits, a measuring resistor connected in series with the component to be monitored is used. In that case, the current value is determined from the voltage drop across the measuring resistor, referred to as a shunt resistor, according to Ohm's law. In this case, it is assumed that the resistance value is known. Accurate and reliable measurement of current values is particularly important, for example, in battery management systems for electric vehicles or hybrid vehicles. Such low-ohmic measuring resistors of approximately 10 to 50 μOhm, as well as resistors comprising connection elements for connecting the resistor to a current circuit, can be manufactured from a longitudinally welded composite material. This is known, for example, from Patent Document 1. This composite material is produced from three metal strips, and the individual metal strips are connected to one another by respective longitudinal seams by an electron beam method or a laser welding method. At this time, the central metal strip is made of a metal having a very low temperature coefficient of resistance. The actual resistive element of the measuring resistor is formed from this material. The two outer strips are usually made of a highly conductive material such as copper. Such materials often have a higher temperature coefficient of resistance than the material of the resistive element. Connection elements are formed from these two outer strips, via which the measuring resistor can be connected to the current circuit.

[0003] Accurate knowledge of the resistance value is necessary to determine the current value from the voltage drop across the measured resistance. Here, the effect of temperature on the intrinsic resistivity of the material used plays a crucial role. Therefore, in order to perform corrections for temperature-dependent resistance behavior, the temperature of the resistor, which can take values ​​from -40 to +170°C during operation, must be known. The temperature of the resistor can be measured by a temperature sensor, and this information can be used to correct the resistance value. This is well known, for example, from Patent Documents 2 and 3. Determining the temperature of a resistor is usually done by either a passive analog sensor, such as an NTC, PT100 temperature probe, or thermocouple, or an active sensor (IC) with sensor data evaluation and a communication interface. This temperature sensor is an additional component that increases cost and design complexity. Furthermore, because temperature sensors react to temperature changes with a time delay, this can negatively impact accuracy. This is particularly important when detecting heat generation in short-duration peak currents that occur, such as during extreme acceleration in electric vehicles. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] European Patent Application Publication No. 0605800 [Patent Document 2] German Patent Application Publication No. 19906276 [Patent Document 3] European Patent No. 2793034 [Overview of the project] [Problems that the invention aims to solve]

[0005] This invention is based on the objective of providing a resistor that overcomes the aforementioned drawbacks. In particular, temperature measurement must respond quickly to changes in the resistor's temperature. Furthermore, this invention is also based on the objective of providing a method for measuring the temperature of a resistor. [Means for solving the problem]

[0006] The present invention relates to A resistor having at least one connecting element and at least one resistive element for connecting a resistor to an electric circuit, wherein the resistive element is electrically connected to the connecting element via a contact surface, and at least one of the resistive elements and at least one of the connecting elements are made of different conductive materials, and at least a portion of the surface of the resistive element as a substrate or at least a portion of the surface of the connecting element as a substrate is coated with a coating having at least one layer, wherein the coating is designed such that a metal and a semiconductor are in direct contact at a first interface between the substrate and the coating, thereby forming a pn junction at the first interface. The coating is applied and / or is applied such that at least at a second interface between the first layer of the coating and the second layer of the coating, the metal and the semiconductor are in direct contact, or the first semiconductor and the second semiconductor are in direct contact, thereby forming a pn junction at the second interface, and at least one layer of one of the coatings, the uncoated portion of the surface of the other resistive element or the uncoated portion of the surface of the connecting element, or the first layer of one of the coatings, or at least one further layer of the other, is accessible to detect a measurement signal for determining the temperature of the resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] [Figure 1] This is a diagram of a resistor comprising a coating on a resistive element. [Figure 2] This is a diagram of a resistor comprising a coating in a recess of a resistive element. [Figure 3] This is a diagram of a resistor comprising a coating on a raised region of a resistive element. [Figure 4] This is a diagram of a resistor comprising a coating on a connection element. [Figure 5] This is a diagram of a resistive element comprising a coating having a first layer structure. [Figure 6] This is a diagram of a resistive element comprising a coating having a second layer structure. [Figure 7] This is a diagram of a resistive element comprising a coating having a third layer structure. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0008] The present invention relates to a resistor having at least one connecting element and at least one resistive element for connecting the resistor to an electric circuit. The resistive element is electrically connected to the connecting element via a contact surface. The range of the resistive element perpendicular to the contact surface is called the length. One at least one resistive element and the other at least one connecting element are made of different conductive materials, preferably metallic materials. In this case, the intrinsic electrical resistance of the material of the resistive element can be at least 10 times greater than the intrinsic electrical resistance of the material of the connecting element. On the other hand, the value of the temperature coefficient of resistance of the material of the connecting element is much larger than the value of the temperature coefficient of resistance of the material of the resistive element, and is usually at least 80 times greater. In particular, the value of the temperature coefficient of resistance of the material of the resistive element is 5.10 -5 It can be less than 1 / K, and the temperature coefficient of resistance of the connecting element material is approximately 4.10 -3 The ratio can be 1 / K. The connecting elements of the resistor may be made of copper, preferably a low-alloy copper alloy, or aluminum, preferably a low-alloy aluminum alloy, or may include at least one of these materials. The resistive element may be made of a copper alloy commonly used as a resistive alloy. At least one connecting element may have means for connecting the resistor to an external current circuit, such as a hole. The resistor may preferably have two connecting elements, with the resistive element positioned between them.

[0009] At least a portion of the surface of the resistive element as a substrate or at least a portion of the surface of the connecting element as a substrate is coated with a coating having at least one layer. This coating may have one or more layers. Here, the term "layer" refers to a uniform spatial arrangement of material, where the area of ​​material perpendicular to the surface of the substrate in the spatial direction, i.e., the thickness of the layer, is significantly smaller than the area of ​​material parallel to the surface of the substrate in the spatial direction.

[0010] According to a first aspect of the present invention, the coating is implemented such that a metal and a semiconductor are in direct contact at the interface between the substrate and the coating, thereby forming a pn junction at this interface. Preferably, the substrate material is a metal, and the coating layer in direct contact with the substrate is made of a semiconductor. Both one coating layer and the uncoated portion of the other substrate, i.e., the surface of the resistive element or connecting element, are accessible to detect a measurement signal for determining the temperature of the resistor. When the coating is applied to a resistive element, both at least one layer of one coating and the uncoated portion of the surface of the other resistive element are accessible to detect a measurement signal for determining the temperature of the resistor. When the coating is applied to a connecting element, both at least one layer of one coating and the uncoated portion of the surface of the other connecting element are accessible to detect a measurement signal for determining the temperature of the resistor. Preferably, the coating layer in direct contact with the substrate is accessible.

[0011] According to a second aspect of the present invention, at least at the interface between a first layer of coating and a second layer of coating, the metal and the semiconductor are in direct contact, or the first semiconductor and the second semiconductor are in direct contact, thereby forming a pn junction at this interface. Both the first layer of one coating and the other at least one further layer of coating, particularly the second layer of coating in direct contact with the first layer, can be directly or indirectly contacted to detect a measurement signal for determining the temperature of the resistor.

[0012] This invention is based on the idea of ​​directly determining temperature using the temperature behavior of the current-voltage characteristic curve of a pn junction. The current-voltage characteristic curve of a pn junction can be expressed using the Shockley equation, similar to the diode characteristic curve. The Shockley equation includes temperature-dependent values, namely temperature voltage and reverse current. Therefore, the current-voltage characteristic curve of a pn junction varies with temperature. If the current flowing through the pn junction and the voltage dropping through the pn junction are known, the dominant temperature at the pn junction can be calculated based on the temperature dependence, assuming the current-voltage characteristic curve is known. Meterimetric detection of such a pn junction as a temperature sensor can be performed using discrete components such as a constant current source, operational amplifier, or analog-to-digital converter (ADC), or alternatively, in an integrated circuit (IC).

[0013] According to the present invention, such a pn junction is realized by a coating on the resistor. This coating is thin compared to the substrate and has only a small amount of thermal mass. On the other hand, thermal bonding between the coating and the substrate occurs over a large area. Therefore, the temperature of the pn junction is always very close to the temperature of the substrate. Rapid temperature changes can also be detected without a significant time delay. The coating may be applied to either the resistive element or the connecting element. This makes it possible to determine the temperature of the resistive element or the connecting element.

[0014] The pn junction may be realized directly at the interface between the substrate and the coating. In this case, the conductive substrate, preferably a metallic substrate, functions as the n-part of the pn junction due to its free electrons. The coating layer in direct contact with the substrate must be selected so that it functions like a semiconductor in combination with the substrate, i.e., it has fewer free electrons than the substrate. This layer then forms the p-part of the pn junction. A resistor having such a pn junction can be manufactured by depositing or stacking layers of, for example, a copper-based material, preferably an oxide, on the surface of the resistor. The selected material pair forms a pn junction with a unique current-voltage characteristic curve.

[0015] Alternatively, a pn junction can be realized at the interface between the first and second layers of the coating, i.e., by a suitable layer structure of the coating. At this interface, either the metal and the semiconductor, or the first and second semiconductors, are in direct contact with each other.

[0016] Given the well-known semiconductor properties described, suitable material combinations using copper as a starting material include, for example, Cu / Cu(I)O and p-Cu 2 O / n-ZnO, SnF 2 :SnO 2 / CuAlO 2 or p-Cu 2 O / n-Cu 2 The oxides mentioned as examples possess semiconductor properties. These can be called "oxidizing semiconductors." In such oxides, the energy difference (band gap) between the valence band and the conduction band is on the same scale as semiconductors, i.e., in the range of a few electron volts (eV). Thermal excitation lifts electrons from the valence band to the conduction band. Therefore, the electrical conductivity of oxides increases with temperature. The material pairs mentioned form material transitions with current-voltage characteristic curves that can be expressed by the Shockley equation, as in the case of semiconductor diodes. Starting from the examples mentioned, further material pairs with similar properties can be found. In such material pairs, oxides function like semiconductors and can therefore be referred to as "semiconductors" in this invention.

[0017] A special advantage of the present invention is that the temperature sensor formed by the coating is mounted on the resistor over a wide area, rather than at a single point. Therefore, a good thermal coupling exists between the sensor and the object whose temperature is to be measured. Furthermore, because the coating has only a very small amount of its own heat capacity, the temperature sensor responds very quickly to temperature changes in the substrate. In other words, due to its very small thermal mass, the coating has very little thermal inertia and can therefore detect temperature changes in the substrate very quickly.

[0018] In one embodiment of the present invention, the coating may have at least one layer, which is formed from or contains a doped semiconductor. Doping makes it possible to appropriately adjust the properties of the semiconductor. In particular, doping can affect the current-voltage characteristic curve of a pn junction. In this way, the accuracy of temperature measurements, for example, can be improved. For example, p-Cu 2 O / n-Cu 2 As in the case of O, both p-doping and n-doping of the same base material can be considered. Doping can be performed during the coating process.

[0019] In a further embodiment of the present invention, the coating may have at least two layers, which are selected such that the pn junction is part of an npn junction or a pnp junction. In this way, a bipolar layer array is realized. The third material of the layer array may be a third layer of the coating, or a substrate, i.e., a substrate of one of the conductive materials of the resistor. Measurement accuracy can be clearly improved by such an arrangement, since npn junctions or pnp junctions have clearly higher temperature consistency than pn junctions. In a particularly preferred configuration of this embodiment, all three materials of the bipolar layer array, in particular all three layers of the bipolar layer array, may be contactable to detect a measurement signal for determining the temperature of the resistor. This makes it possible to realize a circuit equivalent to a bipolar transistor connected as a diode.

[0020] In a further embodiment of the present invention, the coating may be applied only to a portion of the surface of the resistive element. In this way, it becomes possible to detect the temperature of critical areas of the resistive element, such as particularly high-temperature areas.

[0021] In particular, in this embodiment, the resistive element may have a length perpendicular to the contact surface between the resistive element and the connecting element, and the coating may be applied to the center of the surface of the resistive element relative to its length. Thus, the coating is positioned in the region of the resistive element furthest from the contact surface with respect to the connecting element. The highest temperature occurs in this region. The average temperature of the resistor can be estimated from the highest temperature.

[0022] Preferably, the coating area can be at least 1 mm, particularly preferably at least 1.5 mm, and at most 4 mm, particularly preferably at most 2.5 mm, in the direction perpendicular to the contact surface. By selecting the dimensions of the coating in this area, the amount of electricity to be measured is set to an advantageous range.

[0023] Furthermore, in the special configuration of the aforementioned embodiments of the present invention, the coating may be applied over the entire width of the resistive element. The width of the resistive element is understood to be the range of the resistive element in the longitudinal direction with respect to the contact surface, i.e., lateral direction with respect to the direction of the current. In this special configuration of the present invention, the averaged temperature over the entire width of the resistive element is measured.

[0024] In a further special configuration of the above-described embodiment of the present invention, the first measuring tap may be in contact with the coating, i.e., the layer of the coating, and the second measuring tap may be in contact with the uncoated portion of the surface of the resistive element, i.e., mounted on the uncoated portion of the surface of the resistive element. This arrangement of the measuring taps makes it possible to detect the voltage drop occurring at the pn junction at the interface between the resistive element as a substrate and the coating.

[0025] In an alternative embodiment of the present invention, the coating may be applied only to a portion of the surface of the connecting element, directly adjacent to the contact surface with respect to the resistive element. In this positioning of the coating, the temperature of the connecting element is measured in close proximity to the resistive element. From this measured temperature, the temperature of the resistive element can then be detected with sufficient accuracy. Depending on the choice of material, it may be simpler to apply the coating to the connecting element than to the resistive element.

[0026] In a special configuration of this embodiment of the present invention, the first measuring tap can contact the coating, i.e., the layer of the coating, and the second measuring tap can contact the uncoated portion of the surface of the connecting element, i.e., it may be attached to the uncoated portion of the surface of the connecting element. This arrangement of the measuring taps makes it possible to detect the voltage drop occurring at the pn junction at the interface between the connecting element as a substrate and the coating.

[0027] In further embodiments of the present invention, the coating may have a layer in direct contact with the substrate that contains or is an oxide of the substrate material. The material affinity between the substrate and the coating material in direct contact with the substrate creates particularly favorable conditions for the formation of a pn junction. For example, when a coating is applied to a copper connector, the layer in direct contact with the connector may be Cu(I)O or contain Cu(I)O. Similarly, when a coating made of a copper-manganese alloy is applied to a resistive element, the layer in direct contact with the resistive element may be CuMnO. 2 is or CuMnO 2 It can include...

[0028] In an alternative embodiment of the present invention, a barrier layer may be present between the substrate and the coating. In this case, the first measuring tap contacts a first layer of the coating, and the second measuring tap contacts another layer of the coating. The barrier layer causes material separation between the substrate and the coating, but not thermal separation. Therefore, the substrate does not materially affect the coating process. In other words, the coating can be selected from a wide range of materials, independent of the substrate material. This allows the coating to be optimized with respect to its function as a temperature sensor. For example, the barrier layer can be made of nickel.

[0029] In a further embodiment of the present invention, the coating may further have a layer used for passivation of the coating and for electrical contact of the non-metallic layer of the coating. Preferably, this passivation layer is a metallic layer. Such a layer may be the layer of the coating furthest from the substrate.

[0030] In further embodiments of the present invention, the coating may have at least one layer having a thickness of at least 50 nm, preferably at least 70 nm, and at most 100 μm, preferably at most 10 μm. In particular, each layer of the coating may have a thickness in the region described in detail above and in a particularly preferred sub-region. A coating including one or more layers in the region described in detail is particularly well suited for realizing a temperature sensor based on a pn junction.

[0031] In further embodiments of the present invention, the coating may be applied by CVD or PVD. CVD and PVD are well suited for applying the types of coatings described above. In particular, these methods enable doping of the semiconductor layer applied using these methods.

[0032] In further embodiments of the present invention, the coating may be applied to recesses on the surface of the substrate or to raised areas on the surface of the substrate. In some applications, it may be advantageous to apply the coating to recesses on the surface of the substrate to protect the surface from environmental impacts, such as mechanical damage. Conversely, in some applications, it may be advantageous to apply the coating to raised areas on the surface of the substrate, which may, for example, allow for advantageous contact with a measuring tap.

[0033] In a further embodiment of the present invention, the resistor can be made into contact using a plug, printed circuit board, or cable to detect the measurement signal. These components allow for the reading of the measurement signal that needs to be detected to determine the temperature in a simple and low-cost manner.

[0034] Further technical features and advantages of resistors according to the present invention will be explicitly described here with reference to the description relating to the method according to the present invention for determining the temperature of a resistor, as well as to the drawings, descriptions of the drawings, and examples.

[0035] A further aspect of the present invention relates to a method for determining the temperature of a resistor. The resistor has a coating as described above. The coating is selected such that a pn junction is formed at the contact surface between the substrate and the coating, or at the contact surface between two layers of the coating. According to the present invention, the current flowing through the pn junction and the voltage dropping through the pn junction are detected. From these two measurements, the temperature of the resistor is determined using the temperature-dependent current-voltage characteristic curve of the pn junction. According to a further aspect of the present invention, the aforementioned coating is used to determine the temperature of the resistor.

[0036] Further technical features and advantages of the method according to the present invention for determining the temperature of a resistor, and the use of the coating according to the present invention for determining the temperature of a resistor, will be explicitly described here with reference to the description of the resistor according to the present invention, as well as the drawings, the description of the drawings, and the examples.

[0037] Embodiments of the present invention will be described in more detail based on schematic diagrams that are not to scale.

[0038] In all the diagrams, corresponding parts are given the same reference numeral.

[0039] Figure 1 shows a resistor 2 comprising two connecting elements 3,3' and a resistive element 4 positioned between the two connecting elements 3,3'. The resistive element 4 is electrically connected to the two connecting elements 3,3' via contact surfaces 34,34'. The extent of the resistive element 4 between the two contact surfaces 34,34' is called the length L. In the illustrated embodiment, for the sake of simplification, the resistive element 4 is depicted such that its width B, i.e., its longitudinal extent relative to the contact surfaces 34,34', is the same as the extent of the connecting elements 3,3' in that direction. Typically, the longitudinal extent of the resistive element 4 relative to the contact surfaces 34,34' is slightly smaller than the extent of the connecting elements 3,3' in that direction. Means for connecting the resistor 2 to an external current circuit, such as holes in the connecting elements 3,3', are not shown for the sake of simplification.

[0040] The resistive element 4 has a freely accessible surface 41. A thin strip-shaped coating 5 is applied to a portion 411 of the surface 41 of the resistive element 4. Since this coating 5 is applied in the center between the two contact surfaces 34, 34', there is one uncoated portion 412, 412' of the surface 41 of the resistive element 4 between the coating 5 and each of the connecting elements 3, 3'. The coating extends across the entire width B of the resistive element 4. Alternatively, the coating 5 may extend only to a portion of the width B of the resistive element 4. A pn ​​junction, not shown in detail, is formed at the interface 61 between the coating 5 and the resistive element 4.

[0041] The first measuring tap 71 is mounted so as to make direct contact with the coating 5. The second measuring tap 72 is mounted so as to make contact with the uncoated portion 412 of the surface 41 of the resistive element 4. Using these two measuring taps 71 and 72, the voltage dropping across the pn junction can be detected.

[0042] In a case not shown in Figure 1, where the coating 5 extends only to a portion of the width B of the resistive element 4, the uncoated portions 412,412' of the surface 41 of the resistive element 4 also include regions that are as far away from the connecting elements 3,3' as the coating 5. Therefore, when current flows through the resistive element 4, this region becomes at the same potential as the coating 5. In this case, the second measuring tap 72 may, advantageously, be mounted on this region of the uncoated portions 412,412' of the surface 41 of the resistive element 4. Particularly preferably, the second measuring tap 72 can be positioned such that it is at the same distance from the two connecting elements 3,3' as the first measuring tap 71 that is in contact with the coating 5. Thus, measurement errors are reduced.

[0043] Figure 2 shows a preferred embodiment of the resistor 2. The embodiment shown in Figure 2 differs from the embodiment shown in Figure 1 in that the coating 5 is located within the recess 8 of the resistive element 4. All other features of the resistor 2 shown in Figure 2 are consistent with those of the resistor 2 shown in Figure 1. Furthermore, as described in relation to Figure 1, it is also possible that the coating 5 and the recess 8 extend only to a portion of the width B of the resistive element 4, or that only the coating 5 extends only to a portion of the width B of the resistive element 4, while the recess 8 extends across the entire width B of the resistive element 4. In these cases, the second measuring tap 72 may be advantageously positioned as described in relation to Figure 1.

[0044] Figure 3 shows a further preferred embodiment of the resistor 2, in which the coating 5 is applied to the raised region 9 of the resistive element 4. All other features of the resistor 2 shown in Figure 3 are consistent with those of the resistor 2 shown in Figure 1. Furthermore, as described in relation to Figure 1, it is also possible that the coating 5 and the raised region 9 extend only to a portion of the width B of the resistive element 4, or that only the coating 5 extends only to a portion of the width B of the resistive element 4, while the raised region 9 extends across the entire width B of the resistive element 4. In these cases, the second measuring tap 72 may be advantageously positioned as described in relation to Figure 1.

[0045] Figure 4 shows an alternative embodiment of resistor 2. The basic structure of this resistor 2 with respect to the connecting elements 3, 3' and the resistive element 4 is consistent with the embodiment shown in Figure 1. The connecting element 3 has a freely accessible surface 31. A thin strip-like coating 5 is applied directly to the transition portion 311 of the surface 31 of the connecting element 3 at the transition to the resistive element 4. Thus, the surface 31 of the connecting element 3 has an uncoated portion 312. This coating extends over the entire extent of the connecting element 3 in the longitudinal direction of the contact surfaces 34, 34'. Alternatively, the coating 5 may extend only over a portion of the connecting element 3 in the longitudinal direction of the contact surfaces 34, 34'. A pn ​​junction, not shown in detail, is formed at the interface 61 between the coating 5 and the connecting element 3. A first measuring tap 71 is mounted so as to directly contact the coating 5. A second measuring tap 72 is mounted so as to contact the uncoated portion 312 of the surface 31 of the connecting element 3. These two measurement taps 71 and 72 can be used to detect the voltage drop across the pn junction.

[0046] In a case not shown in Figure 4, where the coating 5 extends only to a portion of the width B of the connecting element 3, the uncoated portion 312 of the surface 31 of the connecting element 3 also includes a region that is as far away from the resistive element 4 as the coating 5. Therefore, when current flows through the resistor 2, this region is at the same potential as the coating 5. In this case, the second measuring tap 72 may, advantageously, be mounted on this region of the uncoated portion 312 of the surface 31 of the connecting element 3. Particularly preferably, the second measuring tap 72 can be positioned such that it is at the same distance from the resistive element 4 as the first measuring tap 71 that is in contact with the coating 5.

[0047] The embodiment of resistor 2 shown in Figure 4 can be modified by directly applying a thin strip-shaped coating 5 to the respective transition points on the two connecting elements 3,3' to the resistive element 4. Thus, the temperature of each of the two connecting elements 3,3' can be measured in close proximity to their respective contact surfaces 34,34'. Based on these temperatures, the thermal voltage generated at each transition point between the resistive element 4 and the connecting elements 3,3' can be estimated.

[0048] Figure 5 shows a resistive element 4 having a coating 5 with a first layer structure. The illustrated resistive element 4 can be part of a resistor 2 according to Figures 1 to 3. For reasons of simplification, the connecting elements 3, 3' that contact both sides of the resistive element 4 are not shown. The coating 5 consists of a first layer 50 that is in direct contact with the resistive element 4 and a further layer 59 used for passivation of the coating 5 and for electrical contact of the first layer 50. The first layer 50 is preferably made from or contains an oxide of the material of the resistive element 4. The further layer 59 is made of metal and is the top layer 59 of the coating 5, i.e., the layer furthest from the substrate. A pn ​​junction, not shown, is formed at the interface 61 between the first layer 50 of the coating 5 and the resistive element 4. A first measuring tap 71 contacts the coating 5 by contacting the top layer 59 of the coating 5. In this way, the first layer 50 of the coating 5 is electrically contacted. The second measuring tap 72 contacts the resistive element 4 in an uncoated area 412 of the surface 41. Using these two measuring taps 71, 72, the voltage dropping across the pn junction can be detected.

[0049] Figure 6 shows a resistive element 4 having a coating 5 with a second layer structure. The resistive element 4 shown can be part of the resistor 2 shown in Figures 1 to 4. For the sake of simplification, the connecting elements 3 and 3' that contact both sides of the resistive element 4 are not shown. The coating 5 consists of a barrier layer 58 directly applied to the resistive element 4, an uppermost layer 59 used for passivation and contact of the coating 5, and two further layers 51 and 52 positioned between the barrier layer 58 and the uppermost layer 59. The first of these two layers, layer 51, is applied on top of the barrier layer 58. The second of these two layers, layer 52, is in direct contact with the uppermost layer 59. The first layer 51 can be a p-doped semiconductor. In this case, the second layer 52 is an n-doped semiconductor. However, it is also possible to have the first layer 51 as an n-doped semiconductor and the second layer 52 as a p-doped semiconductor. In both cases, a pn junction (not shown) is formed at the interface 62 between the first layer 51 and the second layer 52 of the two further layers. The first measuring tap 71 is in contact with the first layer 51 of the two further layers. The second measuring tap 72 is in contact with the coating 5 by contacting the top layer 59 of the coating 5. In this way, the second layer 52 of the further layers of the coating 5 is electrically in contact. Using these two measuring taps 71, 72, the voltage dropping across the pn junction can be detected.

[0050] Figure 7 shows a resistive element 4 having a coating 5 with a third layer structure. The resistive element 4 shown can be part of the resistor 2 shown in Figures 1 to 4. For reasons of simplification, the connecting elements 3, 3' that contact both sides of the resistive element 4 are not shown. The coating 5 consists of a barrier layer 58 directly applied to the resistive element 4, an uppermost layer 59 used for passivation and contact of the coating 5, and three further layers 51, 52, 53 positioned between the barrier layer 58 and the uppermost layer 59. The first layer 51 of these three layers is applied on top of the barrier layer 58. The third layer 53 of these three layers is in direct contact with the uppermost layer 59. The second layer 52 of these three layers is positioned between the first layer 51 and the third layer 53. The first layer 51 can be a p-doped semiconductor. In this case, the second layer can be an n-doped semiconductor, and the third layer 53 can be a p-doped semiconductor. However, it is also possible to make the first layer 51 an n-doped semiconductor, the second layer 52 a p-doped semiconductor, and the third layer 53 an n-doped semiconductor. A pn ​​junction (not shown) is formed at the interface 62 between the first layer 51 and the second layer 52 of the three further layers. Similarly, a pn junction (not shown) is formed at the interface 62' between the second layer 52 and the third layer 53 of the three further layers, so that the three further layers 51, 52, and 53 become an npn-type or pnp-type bipolar layer array. The first measurement tap 71 is in contact with the first layer 51 of the three further layers. The second measurement tap 72 is in contact with the coating 5 by contacting the top layer 59 of the coating 5. In this way, the third layer 53 of the further layers of the coating 5 is electrically in contact. Furthermore, an optional third measurement tap 73 is in contact with the second layer 52. The combination of the three measurement taps 71, 72, and 73 creates a circuit that can detect temperature using two pn junctions. Such a circuit is equivalent to a diode-connected bipolar transistor.

[0051] The coating 5 shown in Figures 5, 6, and 7 can be applied not only to the resistive element 4, but also to the connecting element 3 shown in Figure 4, or to the two connecting elements 3 and 3', as described in relation to Figure 4, in a similar manner. [Explanation of symbols]

[0052] 2 resistor 3,3' connecting element 31 Surface 311 Coated portion 312 Uncoated parts 34,34' contact surface 4 Resistor elements 41 Surface 411 Coated portion 412,412' Uncoated portion 5 Coating 50,51,52,53 layers 58 Barrier layer 59 layers 61,62,62' boundary surface 71, 72, 73 Measuring taps 8 recesses 9. Elevated areas L Length B Width

Claims

1. A resistor having at least one connecting element and at least one resistive element for connecting a resistor to an electric circuit, wherein the resistive element is electrically connected to the connecting element via a contact surface, and at least one of the resistive elements and the other at least one connecting element are made of different conductive materials, and at least a portion of the surface of the resistive element as a substrate or at least a portion of the surface of the connecting element as a substrate is coated with a coating having at least one layer, The coating is implemented such that a metal and a semiconductor are in direct contact at a first interface between the substrate and the coating, thereby forming a pn junction at the first interface, and / or at least at a second interface between a first layer of the coating and a second layer of the coating, the metal and a semiconductor are in direct contact, or the first semiconductor and the second semiconductor are in direct contact, thereby forming a pn junction at the second interface, and at least one layer of one of the coatings, the uncoated portion of the surface of the other resistive element or the uncoated portion of the surface of the connecting element, or the first layer of one of the coatings, or at least one further layer of the other, are accessible to detect a measurement signal for determining the temperature of the resistor. A resistor characterized by the following features.

2. The resistor according to claim 1, characterized in that at least one of the coating layers is formed from or includes a doped semiconductor.

3. The resistor according to claim 1, characterized in that at least two of the coating layers are selected such that the pn junction is part of an npn junction or a pnp junction.

4. The resistor according to any one of claims 1 to 3, characterized in that the coating is applied only to a portion of the surface of the resistive element.

5. The resistor according to claim 4, characterized in that the resistive element has a length perpendicular to the contact surface, and the coating is applied to the center of the surface of the resistive element with respect to the length of the resistive element.

6. The resistor according to claim 4, characterized in that the resistive element has a width in the longitudinal direction of the contact surface, and the coating is applied over the width of the resistive element.

7. The resistor according to claim 4, characterized in that the first measuring tap is in contact with the coating, and the second measuring tap is in contact with the uncoated portion of the surface of the resistive element.

8. The resistor according to any one of claims 1 to 3, characterized in that the coating is applied to a part of the surface of the connecting element, directly adjacent to the contact surface with respect to the resistive element.

9. The resistor according to claim 8, characterized in that the first measuring tap is in contact with the coating, and the second measuring tap is in contact with the uncoated portion of the surface of the connecting element.

10. The resistor according to any one of claims 1 to 3, characterized in that the coating is in direct contact with the substrate and has a layer containing an oxide of the substrate material, or a layer that is an oxide.

11. A resistor according to any one of claims 1 to 3, characterized in that there is a barrier layer between the substrate and the coating, the first measuring tap is in contact with the first layer of the coating, and the second measuring tap is in contact with the further layer of the coating.

12. The resistor according to any one of claims 1 to 3, characterized in that the coating has a layer used for passivating the coating and for electrical contact of the non-metallic layer of the coating.

13. The resistor according to any one of claims 1 to 3, characterized in that the coating has at least one layer having a thickness of 50 nm or more and 100 μm or less.

14. The resistor according to any one of claims 1 to 3, characterized in that the coating is applied by CVD or PVD.

15. The resistor according to any one of claims 1 to 3, characterized in that the coating is applied to recesses on the surface of the substrate or to raised areas on the surface of the substrate.

16. The resistor according to any one of claims 1 to 3, characterized in that the resistor is configured to be contactable using a plug, a printed circuit board, or a cable in order to detect the measurement signal.

17. A method for determining the temperature of a resistor according to any one of claims 1 to 3, characterized in that a current flowing through the pn junction and a voltage dropping through the pn junction are detected, and the temperature of the resistor is determined from the detected current and voltage.

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