Semiconductor dies and corresponding method

Abstract

The disclosure relates to a semiconductor die comprising: a first diode array with a number n1 of series-connected diode junctions, wherein n1 ≥ 1; a second diode array with a number n2 of series-connected diode junctions, wherein n2 ≥ 1, wherein the first diode array and the second diode array are biased with the same current as a temperature sensor, wherein the first diode array and the second diode array differ in their respective number n1, n2 of junctions and / or in a doping concentration of at least one of the junctions.

Description

TECHNICAL FIELD

[0001] The present invention relates to a semiconductor die and a method for measuring a temperature in the semiconductor die. BACKGROUND

[0002] Measuring the temperature in a semiconductor die can be of interest for development and testing purposes, for example, to investigate a new device design or layout. Furthermore, temperature monitoring can also be implemented in the application to ensure high reliability and safety features, for example, in automotive and industrial applications. Overtemperature protection can be used, for example, to protect against overloads and slow (highly inductive) short circuits.

[0003] From DE 10 2018 115 326 B3 a semiconductor arrangement is known in which a diode chain is provided for temperature measurement.

[0004] On-chip diodes for temperature measurement are known from US 5 639 163 A.

[0005] From DE 10 2014 222 214 A1 a semiconductor circuit for temperature measurement with a diode chain is known.

[0006] A semiconductor component with a sensor element is known from EP 4 170 729 A1. SUMMARY

[0007] Examples of the present application relate to a semiconductor die for temperature sensing.

[0008] In one embodiment, a semiconductor die comprises a first diode chain with a number n1, n1 ≥ 1, of series-connected diode junctions and a second diode chain with a number n2, n2 ≥ 1, of series-connected diode junctions. The diode chains differ in at least one of: their respective number n1, n2 of junctions or in a doping concentration of at least one of the junctions. Providing two diode chains to be biased in parallel can enable a differential readout, wherein the different number and / or doping of the junctions results in a different forward voltage. The voltage difference between the diode chains depends on the temperature and can conversely be used to measure a temperature value, see below in detail.

[0009] In this description, in the figures and in the dependent claims, particular embodiments and features are provided. The individual features are intended to be disclosed therein independently of a specific claim category; the disclosure relates to device and apparatus aspects, but also to method and use aspects. For example, if a particular manner of temperature detection is described, this may relate to a respective method for temperature measurement and also to a semiconductor die or system configured for such a measurement. Generally speaking, one approach of this application is to provide a semiconductor die with a first and a second diode chain, wherein these diode chains are configured such that a different forward voltage results for the same current through the chains.

[0010] A respective "diode chain" comprises at least one diode junction or several diode junctions connected in series. If the first and second diode chains differ in the number of junctions, the number in the second chain may, by definition (in the sense of a uniform formulation), be fewer. The second diode chain may comprise at least one junction, for example, exactly one junction, while the first diode chain may comprise at least two junctions, where n1 ≠ n2.

[0011] For example, using the first and second diode strings connected in parallel, for example, in the die or the measurement system, can reduce or even eliminate the effect of parasitic resistance elements. Due to the intrinsic properties of the junctions, even a single diode string can exhibit a temperature-dependent voltage drop and could be used for temperature sensing. Because this measurement is based on the intrinsic properties of the junction, it can be comparatively stable in the face of process variations. However, parasitic resistance elements in the circuit can affect the accuracy of a sensor with a single diode string, because the resistance elements themselves can exhibit a temperature dependence (increasing the diode area could increase the relative contribution to the IV characteristic, but would come at the expense of area).

[0012] Compared to the use of a bipolar transistor located in the bulk material, diode chains for temperature sensing can facilitate integration into the die. Depending on the detailed design, they may require less or even no active device area, for example, compared to a bipolar transistor fabricated in the semiconductor body of the die. Furthermore, a bipolar device may not be available in every technology, especially in high-voltage or discrete power switching applications. In this respect, the current approach can enable the combination of the simplicity of a diode with a differential readout capability or system.

[0013] Assuming a first and second diode chain, one of which contains an additional diode D2, the voltage difference can be calculated as follows VDiff=VD2=Vf,0−kT(T−T0)

[0014] When the diode strings are biased with the same current, the voltage difference between both strings is determined by the additional diode D2, since the terms or contributions resulting from the same elements in both strings are canceled. More generally, the forward voltage resulting from the difference between the strings, for example, the forward voltage of the junction(s) in which the strings differ (e.g., in doping and / or number), can be measured directly. In other words, any resistance contribution due to the relative or differential approach can be essentially canceled, while only the remaining difference based on the number of junctions and / or doping is measured. The present sensor system or method can, for example, improve accuracy, e.g.,compared to a single chain, while reducing material or integration costs, for example, compared to an integrated bipolar device.

[0015] In one embodiment, a first resistor R1 of the first diode chain and a second resistor R2 of the second diode chain are essentially the same, for example, differing by no more than 10%, 5%, or 3%. In particular, the resistors R1 and R2 may be equal to within the limits of conventional engineering accuracy. If both chains have essentially the same series resistance, the effects caused by the series resistance can be canceled out, so that the voltage difference is determined solely by the properties of the diode(s). For illustration, assuming that n1=3 and n2=1, the voltage difference can be calculated as follows: VDiff=2∗VD=2∗Vf,0−2∗kT(T−T0)

[0016] The second diode chain may, for example, comprise one or more n- and p-type strips in addition to the junction to mimic the series resistance and possibly even the contact resistance of the first diode chain (see below in detail). Alternatively, or in addition to the matching of the first and second resistors, a corresponding conductor resistance R M be adjusted so that the conductor tracks intended for contacting the first and second diode chain have basically the same resistance (deviation of no more than 10%, 5% or 3%).

[0017] In one embodiment, a first semiconductor region with the first chain and a second semiconductor region with the second diode chain have the same length L. In particular, this can also apply if the first and second diode chains have a different number of junctions (n1 ≠ n2), whereby, for example, the same resistance is possible with the same length. The length L can be taken in a longitudinal direction, e.g., the current flow direction, in which the junctions of the respective diode chains are connected in series.

[0018] In one embodiment, the first diode chain has a plurality of first zones, and the second diode chain has at least one first zone, wherein the number of first zones in the diode chain is different. A summed length L 11 of the plurality of first zones of the first diode chain is, however, equal to a summed length L 21the at least one first zone of the second diode chain. A substantially equal combined length of the first zones in each diode chain can lead to a substantially equal resistance of the respective first zones in the two diode chains. Generally, in this disclosure, the first doping type can be, in particular, an n-type.

[0019] In one embodiment, the first diode chain has a plurality of second zones, and the second diode chain has at least one second zone, wherein the number of second zones in the diode chain is different. A summed length L 12 of the plurality of second zones of the first diode chain is, however, equal to a summed length L 22the at least one second zone of the second diode chain. A substantially equal combined length of the second zones in each diode chain can result in a substantially equal resistance of the second zones in the two diode chains. Generally, in this disclosure, the second doping type can be, for example, a p-type.

[0020] A diode chain with at least two series-connected junctions may comprise a plurality of first and second zones arranged alternately, e.g., along the longitudinal direction. For the series connection, e.g., to obtain diodes with the same orientation, every second junction may be bridged by a conductive bridge, e.g., in a metallization layer above it. In one embodiment, the first and second diode chains differ in their number of junctions but have the same number of conductive bridges between the first and second zones. The same number of conductive bridges may make it possible to set the same resistance in the chains, even when taking into account a junction resistance, e.g., a metal-semiconductor contact resistance.

[0021] To illustrate, assuming that the number n1 of junctions in the first diode chain is greater than the number n2 of junctions in the second diode chain, n1 > n2, the first diode chain can have (n1 - 1) conductive bridges connecting the junctions in series. Then, the second diode chain can be provided with the same number (n1 - 1) of metal bridges to adjust the contact resistance, although a smaller number (n2 - 1) of metal bridges would be sufficient for the series connection of the smaller number n2 of junctions.

[0022] In one embodiment, the semiconductor die additionally comprises a semiconductor device. The semiconductor device may have a load terminal, for example a source region, on a first side of a semiconductor body. On the first side, which may also be considered the front side, a contact structure of the device may be arranged, for example a contact plate (for example a source plate). The contact structure may have at least one metallization layer, for example on an insulating layer arranged on the first side of the semiconductor body. The semiconductor body may comprise a semiconductor substrate and, for example, at least one epitaxial layer. In general, the diode chain(s) may be integrated into the semiconductor body, for example in an epitaxial layer, in particular in an uppermost epitaxial layer that forms the first side of the semiconductor body.

[0023] However, in a particular embodiment, the diode chain or chains is / are arranged on the first side of the semiconductor body, in particular on an insulating layer arranged on the first side of the semiconductor body. Placing the diode chain above the semiconductor body may allow the sensor to be placed in the active region of the device without significantly impairing its function or reducing the semiconductor area available for the device. In other words, the device does not need to be interrupted to place the diode chains laterally into the active region, which may also be relevant for temperature measurement per se (a disruption of the device could distort the temperature profile).

[0024] In addition to the (first) load terminal on the first side of the semiconductor body, the device may have a second load terminal, for example, a drain region. Depending on the device type, the second load terminal may also be arranged on the first side of the semiconductor body, e.g., in a lateral device. Alternatively, it may be arranged on a second side of the semiconductor body perpendicular to the first side. In addition to the load terminals, the device may comprise a control terminal, for example, a gate region for controlling a current flow between the load terminals. In general, the device may be a bipolar or IGBT device (having, for example, an emitter and a collector), a JFET, and / or a transistor device having a source and a drain region.

[0025] In one embodiment, the first and second diode chains are each formed in a polysilicon layer arranged on the first side of the semiconductor body. Specifically, the polysilicon layer can be applied, for example, to the insulating layer arranged on the first side of the semiconductor body. A first and second zone, for example, an n-type and p-type zone, can be formed in the polysilicon layer by doping, which are arranged alternately in a respective diode chain, see above. The conductive bridges in each diode chain and / or conductive tracks for connecting to each diode chain can be formed in a conductive layer above the polysilicon layer, in particular a metallization layer.

[0026] In one embodiment, the diode chains are arranged together with the semiconductor device in an active region of the semiconductor die. Viewed in a vertical plan view, the active region may be surrounded by an edge termination structure. In a respective vertical cross-section perpendicular to a respective lateral edge of the die, the edge termination structure is arranged laterally between the active region and the respective lateral edge of the die. The active region may be filled with a plurality of device cells connected in parallel, for example, depending on the required current carrying capacity.

[0027] In one embodiment, the first and second diode chains may be arranged closer to a center than to an edge of the active region. This refers to a vertical plan view, wherein the center is the geometric center of the active region. If the first and / or second diode chains have / have a non-negligible lateral extension with respect to the active region, a center of the respective semiconductor region (first region in the case of the first diode chain and second region in the case of the second diode chain) may be considered for comparing the position of the respective diode chain with the center of the active region.

[0028] Regardless of a specific position relative to the center of the active region, the diode chains may be placed relatively close to each other. For example, with reference to an average lateral width of the active region, which may be taken as the mean of its smallest and largest extensions along a line crossing the center of the active region, the first and second diode chains may be placed, for example, at a lateral distance of at most 50%, 40%, 30%, or 20% of this lateral width. Specifically, the distance between the first and second diode chains may be taken as the lateral distance between their centers (of the first and second semiconductor regions, respectively, see above).

[0029] In one embodiment, the first and second diode strings may be arranged on a common isotherm. Regardless of a specific spacing between the diode strings, the temperature on the isotherm may be the same. Specific temperature values ​​may depend on the device characteristics and its operation during use. However, the temperature distribution, e.g., the relative temperature profile across the device, may be defined by the device geometry, for example, by the size and shape of the active region.

[0030] The contact structure of the semiconductor device may, in particular, comprise a contact pad (load pad), for example, a source plate, in a topmost metallization layer. In one embodiment, the first and second diode chains are each connected via conductive traces arranged in a wiring layer below the topmost metallization layer. In particular, these conductive traces may extend below the contact pad (source plate), namely, be covered by the contact pad. In other words, the topmost metallization layer must not be interrupted to contact the diode chains, because, for example, the differential approach that cancels out resistance elements allows for smaller / thinner conductive traces with a higher resistance.

[0031] In general, the topmost metallization layer can be the only metallization layer of the contact structure. Alternatively, the contact structure can comprise one or more metallization layers below the topmost metallization layer, for example, for wiring the control terminal of the device. The conductive traces connected to the diode strings can be formed in such a metallization layer or, alternatively, for example, in a polysilicon layer.

[0032] In one embodiment, a system for measuring a temperature value comprises the semiconductor die, a control circuit, and a readout circuit. As described below, the control and / or readout circuit may be integrated into the die or provided externally, for example, as a laboratory measurement setup or as another component of a module. Regardless of these details, the control circuit is configured to apply a current to the first diode chain and to the second diode chain, for example, to apply the same current to both chains. The readout circuit may be configured to measure a voltage difference between the first diode chain and the second diode chain, which may be the forward voltage of the junction(s) in which the diode chains differ, see above in detail.

[0033] In one embodiment, the control circuit and / or the readout circuit are integrated into the semiconductor die. This can enable integrated temperature sensing, in particular overtemperature protection, for example, to protect against overload or short circuits.

[0034] In one embodiment, the control circuit and / or the readout circuit is provided in a separate die, wherein the semiconductor die with the diode chains and the separate die are combined in one module. In the module, the die with the diode chains and the separate die can be mounted, for example, on a common circuit board and / or enclosed in a common housing. The dies can be electrically connected to each other via bond wires, clips, or other connection techniques. The control and readout circuitry can also be distributed between the dies, for example, the control circuit can be integrated in the die with the diode chains and the readout circuit can be provided in the separate die, or vice versa.

[0035] In one embodiment, a method for measuring a temperature with a semiconductor die, in particular with a semiconductor system, may comprise: - applying a current, in particular the same current, to the first diode chain and to the second diode chain; - Measuring a voltage difference between the diode chains.

[0036] To apply the current, a first current source can be provided for the first diode chain and a second current source for the second diode chain, with each diode chain having its own current source. Alternatively, a common current source can be provided, for example, with a multiplexer that repeatedly switches between the first and second diode chains. The diode chains can be at a common reference potential, and the resulting voltage values ​​can be subtracted from each other to determine the V Diff to obtain.

[0037] In one embodiment, a method of manufacturing the semiconductor die may include forming the first and second diode chains. Forming the first and second diode chains may, in particular, include: - providing a polysilicon layer doped with a first doping type, - Providing a patterned mask on the doped polysilicon layer, - Implanting the second dopant type through openings defined by the mask. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention and other embodiments are discussed in more detail below using exemplary embodiments. The individual features may also be relevant in other combinations. Fig. 1 shows a die with an active area and diode chains in a vertical plan view; Fig. Figure 2 shows a first and a second diode chain in a more detailed view; Fig. Figure 3 shows a circuit diagram and represents a system for measuring a temperature with the diode chains of Fig. 2; Fig. Figure 4 shows a possible device that can be used in the active area of ​​the die of Fig. 1 is arranged in a vertical cross-section; Fig. 5 shows a first and second diode chain in a slightly different construction than in Fig. 2; Fig. 6 shows possibilities for a lateral arrangement of the diode chains in the active region; Fig. 7a, b summarize some procedural steps. SPECIAL EMBODIMENTS

[0039] Fig. 1 shows a semiconductor die 1 in a vertical plan view. In an active region 1a of the die 1, a semiconductor device 200 is arranged, see Fig. 4 for further details of a possible construction. A contact pad 255 is arranged in a topmost metallization layer 250, which is electrically connected to the underlying device structure, for example, a source metallization plate. A control pad 256, which is connected to a control terminal of the device 200, and temperature sensing pads 251, 252 are arranged adjacent to the contact pad. The first temperature sensing pad 251 is connected to a first diode chain 10, and the second temperature sensing pad 252 is connected to a second diode chain 20.

[0040] The diode chains 10, 20 are formed in a polysilicon layer beneath the contact pad 255 and connected via conductor tracks 261, 262 in a wiring layer 260 beneath the uppermost metallization layer 250. Although in this embodiment the diode chains 10, 20 are arranged in the active region 1a, the contact pad 255 can remain uninterrupted. The active region 1a is surrounded by an edge termination structure 1b, which is shown only schematically here and will not be discussed further here.

[0041] Fig. 2 illustrates the first diode chain 10 and the second diode chain 20 in more detail. The first diode chain 10 comprises a number n1 of diode junctions 15, where n1 = 3 in the illustrated embodiment. The second diode chain 20 comprises a number n2 of diode junctions 25, where n2 = 1 in this example. Thus, the diode chains 10, 20 differ in their respective number n1, n2 of junctions 15, 25. In the illustrated embodiment, the junctions 15, 25 are provided with the same doping concentration; alternatively, the diode chains 10, 20 could differ in the doping concentration of at least one junction (alternatively or in combination with the different numbers n1, n2).

[0042] The diode chains 10, 20 are formed in a polysilicon layer 270, in which the first diode chain 10 is arranged in a first semiconductor region 31 and the second diode chain 20 is arranged in a second semiconductor region 32. Although the diode chains 10, 20 differ in their respective number n1, n2 of junctions 15, 25, the first and second semiconductor regions 31, 32 have the same length L. This can essentially enable the same sheet resistance in the diode chains 10, 20, which can subsequently cancel each other out, see Fig. 3 in detail.

[0043] The first diode chain 10 comprises a plurality of first zones 11 made of a first doping type and a plurality of second zones 12 made of a second doping type, wherein the first and second zones 11, 12 are arranged alternately one behind the other. In the example shown, the first type is n-type and the second type is p-type. Every second junction, e.g., np-junction in this example, is bridged by a conductive bridge 14 formed above the polysilicon layer 270. In the example shown, the conductive bridges 14 are formed in the wiring layer 260 of the conductive tracks 261, 262.

[0044] Although in this example it has only one diode junction 25, the second diode chain 20 comprises a plurality of first zones 21 made of the first doping type and second zones 22 made of the second doping type. In addition to bridging the np junction, the metal bridges 24 of the second diode chain 20 also bridge a pn junction to provide the desired number n2=1 of junctions 25.

[0045] A summed length L 11 of the first zones 11 of the first diode chain 10, which is obtained by adding the partial lengths of each first zone 11, is equal to a summed length L 21 of the first zones 21 of the second diode chain 20. Likewise, a summed length L 12 of the second zones 12 of the first diode chain 10 is equal to a summed length L 22the second zones 22 of the second diode chain 20. Furthermore, in this example, the first and second diode chains 10, 20 are provided with the same number of conductive bridges 14, 24, which can enable the same resistance even taking into account the metal-semiconductor contact resistance.

[0046] The conductive traces 261, 262 connect the diode chains to a respective pad 265, 266. The pads 265, 266 are formed in the wiring layer 260 and can be connected to the temperature sensing pads 251, 252 in the uppermost metallization layer via vertical connections, which are not shown here. In general, additional conductive traces can be provided to connect the diode chains at their opposite ends. In the example shown, the opposite ends of the diode chains 10, 20 are connected to the contact pad 255 (see Fig. 1). During operation, contact pad 255 may be at ground potential.

[0047] The circuit diagram in Fig. 3 shows a system 300 for measuring a temperature with the first and second diode chains 10, 20 as in Fig. 2. In this example, the first diode chain 10 comprises three junctions 15, namely diodes, and the second diode chain 20 comprises one junction 25, namely a diode. As explained above, the same sheet resistances 301, 302 are set for the diode chains 10, 20, so that these resistance elements cancel each other out in a differential measurement. The same applies to resistor 303 of conductor track 261 and resistor 304 of conductor track 262.

[0048] The diode chains 10, 20 can be biased with a current via a control circuit 310, with the same current being applied to both diode chains 10, 20. In the embodiment shown, the control circuit 310 comprises two current sources 311, 312; alternatively, a single current source with a multiplexer could be used. The system 300 further comprises a readout circuit 320, for example, a voltmeter 321, to measure a voltage difference between the two chains 10, 20 or branches. The voltage drop can be calculated as follows: VDiff=VD1+2∗VD2+lf∗(RS1+RS2+RM+Rext)−VD1− lf∗(RS1+RS2+RM+Rext)=2∗VD2

[0049] Since the film resistances 301, 302 and the resistances 303, 304 of the conductor tracks are equal and cancel each other out, the voltage difference is calculated as follows VDiff=2∗VD=2∗Vf,0−2∗kT(T−T0)

[0050] At their opposite ends, the diode chains 10, 20 are connected to the ground region 309 via contact pad 255. In this example, the device 200 is connected as a low-pressure switch, with its first load terminal 201 (source region, see below) connected to ground and its second load contact 205 (drain region, see below) connected to the load. The control terminal 207 is connected to the control pad 256.

[0051] Fig. 4 illustrates a possible device 200 in a vertical cross-section. In this example, the device 200 is a transistor, wherein the first load terminal 201 is a source region 202 and the second load terminal 205 is a drain region 206. In this illustrated vertical configuration, the source region 202 and the drain region 206 are arranged on opposite sides 210.1, 210.2 of a semiconductor body 210, with a body region 203 and a drift region 204 arranged vertically therebetween. The source region 202, the drift region 204, and the drain region 206 are made of a first doping type, the drift region 204 with a lower concentration than the drain region 206, and the body region 203 is made of a second doping type. In the example shown, the first type is n-type and the second type is p-type.

[0052] In the transistor device, the control terminal 207 may be a gate electrode 208. In this illustrated embodiment, it is arranged in a gate trench 215 etched into the semiconductor body 210 from the first side 210.1. The gate electrode 208 is capacitively coupled to the body region 203 via a gate dielectric 209. Optionally, a field electrode 218 may be provided, which is capacitively coupled to the drift region 204. In the example shown, the field electrode 218 is provided in the same gate trench 215 below the gate electrode 208.

[0053] The contact structure 220, which is arranged on the first side 210.1 of the semiconductor body 210, is coupled to the first load terminal 201, in this example, e.g., source region 202. In addition to the contact pad 255, it comprises a vertical connection 256 that extends through the insulating layer 215.

[0054] As schematically illustrated by the dashed lines, the polysilicon layer 270 may be integrated below the top metallization layer 250. In the schematic drawing of Fig. 4, only the topmost metallization layer 250 is shown, but an additional wiring layer may be provided, for example, above the polysilicon layer 270 and below the topmost metallization layer 250. In a region of the device 200 in which a corresponding diode chain is integrated, the vertical connection 265 may be interrupted (source and body regions 202, 203 connected in front of or behind the drawing plane).

[0055] Fig. Figure 5 shows a further plan view of a first diode chain 10 and a second diode chain 20. As in the example of Fig. 2, the diode chains 10, 20 differ in their respective number n1, n2 of junctions 15, 25. Nevertheless, the semiconductor regions 31, 32 are designed to have the same length L, with the first zones 11, 21 and the second zones 12, 22 each having the same summed length, see above in detail. In contrast to the embodiment of Fig. 2 are the diode chains 10, 20 of Fig. 4 are not designed to have the same number of conductive bridges.

[0056] The top view of Fig. 6 again shows the complete die 1, see the notes above. During operation, the device 210 heats up, which can lead to a temperature distribution across the die 1 or, in particular, the active region 1a. Typically, it heats up more in the center than in edge sections, with the temperature profile having, for example, a bell shape. In order to measure a sufficiently large or even the maximum temperature value, the diode chains 10, 20 can be placed closer to a center 150 of the active region 1a than to a corresponding edge 155, 152, 153, 154 of the active region 1a. In particular, the diode chains 10, 20 can be placed on a common isotherm 165 so that they are at the same temperature during operation.

[0057] In the Fig.7a, b summarize some method steps. A method 450 for measuring a temperature may, in particular, include applying 455 a current to the diode chains and measuring 460 a voltage difference between the diode chains. Forming 500 the first and second diode chains may include providing 505 a doped polysilicon layer, providing 510 a patterned mask on the polysilicon layer, and implanting 515 an opposite doping type through the mask.

Claims

[1] Semiconductor die (1) comprising: a first diode chain (10) with a number n1 of series-connected diode junctions (15), where n1 ≥ 1; a second diode chain (20) with a number n2 of series-connected diode junctions (25), where n2 ≥ 1; wherein the first diode chain (10) and the second diode chain (20) are connected in parallel and are intended to be biased with the same current as a temperature sensor (100), wherein the first diode chain (10) and the second diode chain (20) differ in their respective number n1, n2 of junctions (15, 25) and / or in a doping concentration of at least one of the junctions (15, 25). [2] The semiconductor die (1) of claim 1, wherein the first diode chain (10) comprises a first resistor R1 and the second diode chain (20) comprises a second resistor R2, the first resistor R1 and the second resistor R2 being substantially equal. [3] Semiconductor die (1) according to claim 1 or 2, wherein the first diode chain (10) is formed in a first semiconductor region (31) and the second diode chain (20) is formed in a second semiconductor region (32), wherein the first diode chain (10) and the second diode chain (20) differ in their respective number n1, n2 of junctions (15, 25) and the first semiconductor region (31) and the second semiconductor region (32) nevertheless have the same length L. [4] Semiconductor die (1) according to one of the preceding claims, wherein the first diode chain (10) comprises a plurality of first zones (11) and the second diode chain (20) comprises at least one first zone (21), wherein the first zones (11, 21) are each made of a first doping type, wherein the number of first zones (11, 21) in the first diode chain (10) and in the second diode chain (20) is different, but a summed length L 11 of the plurality of first zones (11) of the first diode chain (10) is equal to a summed length L 21 which is at least one first zone (21) of the second diode chain (20). [5] Semiconductor die (1) according to one of the preceding claims, wherein the first diode chain (10) comprises a plurality of second zones (12) and the second diode chain (20) comprises at least one second zone (22), wherein the second zones (12, 22) are each made of a second doping type, wherein the number of second zones (12, 22) in the first diode chain (10) and in the second diode chain (20) is different, but a summed length L 12 of the plurality of second zones (12) of the first diode chain (10) is equal to a summed length L 22 which is at least one second zone (22) of the second diode chain (20). [6] Semiconductor die (1) according to one of the preceding claims, wherein the first diode chain (10) and the second diode chain (20) are different in their respective number n1, n2 of junctions (15, 25), wherein the first diode chain (10) and the second diode chain (20) nevertheless have an equal number of conductive bridges (14, 24), in particular metal bridges, between the first zones (11, 21) made of a first doping type and the second zones (12, 22) made of a second doping type. [7] Semiconductor die (1) according to one of the preceding claims, comprising: a semiconductor device (200); wherein the semiconductor device (200) has a load terminal (201) on a first side (210.1) of a semiconductor body (210) and a contact structure (220) on the first side (210.1) of the semiconductor body (210), in particular on an insulating layer (215) arranged on the first side (210.1) of the semiconductor body (210); wherein the first diode chain (10) and the second diode chain (20) are arranged on the first side (210.1) of the semiconductor body (210). [8] Semiconductor die (1) according to claim 7, wherein the first diode chain (10) and the second diode chain (20) are each formed in a polysilicon layer arranged on the first side (210.1) of the semiconductor body (210). [9] Semiconductor die (1) according to claim 7 or 8, wherein the semiconductor device (200) is arranged in an active region (1a) of the semiconductor die (1) and the first diode chain (10) and the second diode chain (20) are also arranged in the active region (1a). [10] Semiconductor die (1) according to claim 9, wherein, relative to a center (150) of the active region (1a), the first diode chain (10) and the second diode chain (20) are arranged closer to a center (150) than to an edge (151-154) of the active region (1a). [11] Semiconductor die (1) according to claim 9 or 10, wherein, with respect to a temperature profile (160) of the semiconductor device (200), the first diode chain (10) and the second diode chain (20) are arranged on a common isotherm (165). [12] Semiconductor die (1) according to one of claims 7 to 11, wherein the contact structure (220) comprises a contact pad in an uppermost metallization layer, wherein the first diode chain (10) and the second diode chain (20) are connected via conductor tracks in a wiring layer below the uppermost metallization layer, wherein the conductor tracks are in particular covered by the contact pad. [13] System (300) for measuring a temperature value in a semiconductor die (1), comprising: a semiconductor die (1) comprising: a first diode chain (10) with a number n1 of series-connected diode junctions (15), where n1 ≥ 1; a second diode chain (20) with a number n2 of series-connected diode junctions (25), where n2 ≥ 1; wherein the first diode chain (10) and the second diode chain (20) are intended to be biased with the same current as a temperature sensor (100), wherein the first diode chain (10) and the second diode chain (20) differ in their respective number n1, n2 of junctions (15, 25) and / or in a doping concentration of at least one of the junctions (15, 25), a control circuit (310) for applying a current to the first diode chain (10) and to the second diode chain (20); a readout circuit (320) for measuring a voltage difference between the first diode chain (10) and the second diode chain (20), wherein the first diode chain (10) and the second diode chain (20) are connected in parallel in the system (300). [14] System (300) according to claim 13, comprising a semiconductor die (1) according to any one of claims 2 to 12. [15] The system (300) of claim 13 or 14, wherein at least one of the control circuit (310) or the readout circuit (320) is integrated into the semiconductor die (1). [16] The system (300) of any one of claims 13 to 15, wherein at least one of the control circuit (310) or the readout circuit (320) is provided in a separate die, wherein the semiconductor die (1) and the separate die are combined in one module. [17] A method for measuring (450) a temperature with a semiconductor die (1) according to any one of claims 1 to 12 or with a system (300) according to any one of claims 13 to 16, comprising the following steps: - applying (455) a current to the first diode chain (10) and to the second diode chain (20); - measuring (460) a voltage difference between the first diode chain (10) and the second diode chain (20). [18] A method for producing the semiconductor die (1) according to any one of claims 1 to 12, comprising the following steps: - Forming (500) the first diode chain (10) and the second diode chain (20). [19] The method of claim 18, wherein forming the first diode chain (10) and the second diode chain (20) comprises: - providing (505) a polysilicon layer doped with a first doping type, - providing (510) a structured mask on the doped polysilicon layer, - implanting (515) the second doping type through openings defined by the mask.

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