DE10154498A1 - Hall probe system has Hall voltage controlled by control voltage applied between electrode region and conductive Hall region by influencing charge carriers available for Hall current - Google Patents

Abstract

The system has a conductive Hall region (10) through which a Hall current can flow and at which a Hall voltage can be tapped, a device for producing a control voltage depending on an influencing parameter and an electrode region (22) electrically isolated from the Hall region. The Hall voltage is controlled by a control applied between the electrode and conductive Hall regions that influencing the charge carriers available for a Hall current. AN Independent claim is also included for the following: a method of manufacturing an inventive system.

Description

The present invention relates to the field of Hall probe systems and in particular in the field of sensitive Hall probe systems with control devices for Controlling a Hall voltage.

Hall probes, which together with evaluation electronics (ASICs, ASIC = application specific integrated circuit = application-specific integrated circuit) in semiconductor chips are integrated in large numbers at many nowadays Applications, for example in automobiles, electricity meters, Fan motors etc. used.

With these integrated Hall sensors it is possible to get accurate Magnetic field sensors with extensive additional functions that for example a programmability and intelligent Include sensors or smart sensors to manufacture. It can the well-known CMOS or BiCMOS silicon technology for Manufacture of reliable and inexpensive integrated Hall probes can be used in large quantities. Because of these advantages, the former are preferred used discrete Hall probes made from a direct semiconductor exist, increasingly rarely used, whereby a direct Semiconductor is defined such that the energy maximum of Valence band and the energy minimum of the conduction band same crystal impulses. Examples of direct Semiconductors are GaAs and InSb.

Accordingly, an indirect semiconductor is defined by that the energy maximum of the valence band and the energy minimum of the conduction band are not at the same crystal impulses. Examples of indirect semiconductors are silicon and Germanium.

As is known, Hall probe systems and in particular in Hall sensor systems integrated on one chip by many Parameters affected. For example, the magnetic Sensitivity S by temperature and mechanical Voltage state of the substrate is affected. It is also known that with high magnetic fields, d. H. over 200 mT, the magnetic sensitivity depends on the applied magnetic field, so the Hall voltage is not a linear function of that applied magnetic field is. Typically the magnetic one Hall sensor sensitivity of all of the above Influencing parameters, d. H. from the magnetic field B, which Temperature T and the mechanical stress σ, depending.

With regard to a mechanical stress state of the Substrate on which the Hall probe is applied in particular the mechanical interaction of the substrate and in particular a local environment on the substrate with the Sensor housing and its elements, such as a chip, an adhesive, a guide frame or the potting compound, for influencing responsible. Add to that the mechanical environment in the application, for example a May include glue or other fasteners. by virtue of of the different coefficients of thermal expansion the materials used also change Stress state σ versus temperature, however, the Dependence of the mechanical stress state on the Temperature is very poorly defined, unstable and poor is reproducible. Therefore, it is desirable that magnetic sensitivity of a Hall probe in a targeted manner influence.

Before further on known methods for influencing the Magnetic sensitivity is considered to be the basics of a Hall probe are explained here.

For the sake of simplicity, a Hall probe is to be abstracted below in such a way that it has an active region or Hall region, which can be understood as a square plate with a constant thickness. Contacts are attached in the corners of this square, two diagonally opposed contacts to the primary side and to the secondary side being combined. The probe is supplied with electrical energy on the primary side by either feeding a current I _{H into} a current source or applying a voltage U _{H on the} primary side to a voltage source. In the first case, a voltage U _H arises as a reaction to the current flow I _H , in the second case the voltage drop U _H generates a current I _H. Ohm's law U _H = R _H × I _H applies to both cases, whereby R _{H is} referred to as the primary-side resistance of the Hall probe.

In the absence of an external magnetic field, the two remaining contacts of the Hall probe are ideally at the same potential. However, as soon as an external, ie a magnetic field B _Z not caused by the current I _{H is} perpendicular to the Hall plate, a small voltage U _h can be measured between the two remaining contacts, ie on the secondary side. If the magnetic induction B _{z is} not too great, ie for Hall probes in silicon not greater than about 200 mT, the Hall voltage U _{h is} proportional to the magnetic induction B _z . The proportionality factor is referred to as sensitivity or magnetic sensitivity S. U _h = S × B _z . Since the sensitivity in a first approximation depends linearly on the current I _H , the current-related sensitivity S _I = S / I _{H is} independent of the primary current. The following applies


where r _{n is} the scattering factor of the majority charge carriers in the material of the Hall probe, n is the density of the free charge carriers in the material of the Hall probe, t is the thickness of the Hall plate, G is a geometry factor and q is the elementary charge.

Hall probes in which the majority charge carriers are free electrons are preferably used in practice, which is why the term n was used in the above equation for the density of the free charge carriers. According to the above equation, it can be seen that the current-related sensitivity S _{I is defined} exclusively by physical and geometric parameters of the probe, which makes this variable very suitable as a parameter of the probe. Alternatively, a voltage-related sensitivity S _U = S / U _H can also be defined, which results in the following relationship:

In the above equation µ * | n is a Hall mobility, which results as the product of an electron mobility µ _n and the scattering factor r _n , so that:

The ratio of the length of the current carrying cross section to its width, d. H. l / w, is identical to the number of Squares (squares), being common in microelectronics is common to any resistance as the product of Square resistance times the number of squares. The Square resistance as a tenth of the resistance value of a Resistance defined, its length 10 times its width equivalent.

The current-related sensitivity S _I has the favorable property for many applications that it only depends slightly on the temperature. This is because the number of free charge carriers in a sufficiently highly doped semiconductor material is essentially constant for usual temperatures of more than -40 ° C. and for usual dopant concentrations, ie it is equal to the dopant concentration. Furthermore, the scattering factor also changes only slightly with temperature, ie by a few percent in the range from -40 ° C to 150 ° C. The other influencing variables of the current-related sensitivity are either natural constants or constant geometric variables.

The Hall probe can be used for low requirements Accuracy in temperature therefore with a constant Primary current are operated. The sensitivity the Hall probe mainly due to a change in the scattering factor changed.

For applications where high accuracy of typically 1% or less for a temperature range of -40 ° C to 150 ° C is required, however, this is not sufficient. Especially with integrated Hall probes in Magnetic field ASIC devices result in another Problem that it is difficult to run a stream with a perfect temperature constant on the integrated circuit too produce. Typically, one is used in known Hall sensors electrical voltage in a given Temperature range is very constant, using a bandgap principle generated, the electrical voltage then using a Control loop circuit on a resistor to drop brought. The electrical resulting from the drop Current through this resistor can then be coupled out are used and as the primary current through the Hall probe become.

However, the above method has the disadvantage that electrical resistors themselves always have a temperature response have so that by applying a temperature constant Voltage across a resistor is not a temperature constant Primary electricity can be generated. Minor improvements can be connected in parallel and / or Series connection of resistors of different technologies, for example high-resistance polysilicon, low-resistance polysilicon or diffusion resistors, but the electricity generated in this way is always a function of temperature has negative curvature, d. H. that the curve current open towards the bottom or viewed from below is concave.

The effect of this decrease in the current generated with increasing temperature on the sensitivity is further increased by the fact that the temperature response of the current-related sensitivity S _I (T) also decreases with increasing temperature. Furthermore, at high temperatures there is a drop in sensitivity due to leakage currents from the integrated probe into the substrate.

It is therefore necessary for accurate Hall probes Primary current through the Hall probe at low and high Temperatures slightly, d. H. in a range of about 2%, to raise. This represents a non-linear temperature compensation because it is also fed into the Hall probe Correction current over the temperature a parabolic course with a positive curvature, i.e. H. a curve that is open at the top or concave when viewed from above, should have. Circuits that generate such a current are known and are referred to as parabolic generators.

The principle of raising the primary current described above by using a parabola generator Temperature adjustment of Hall probes has the disadvantage that a Ratiometry is very difficult to achieve.

Ratiometry means that the output signal is exactly proportional to the operating voltage. It is with relatively little chip area and Power consumption possible, the primary current through the Hall probe exactly proportional to the operating voltage to make the Compliance with ratiometry for a Hall probe.

However, it is much more complex and with a big one Chip area connected, a correction current for Compensate for example the one described above To design temperature influences ratiometrically. To achieve one ratiometric correction current would need a circuit be used that multiplies two voltages together, more specifically a ratiometric and at the same time Temperature constant voltage with a voltage of a desired one Temperature response, which is independent of the operating voltage have to be. The usual analog multiplier circuits are not sufficiently precise.

As a result, known parabola generators generate Correction currents, their proportionality to the supply voltage for many Applications is not sufficiently precise ratiometric.

Another way to make corrections regarding, for example, a temperature response, mechanical Tensions or non-linear magnetic field dependency, consists of the output signal, for example by a Analog / digital converter, digitize and then the Make corrections in a digital way. A yourself possibly subsequent digital / analog converter can generate an analog output voltage again and this make essentially ratiometric at the same time. This principle however, has an increased chip area consumption, so that the same only for applications such as an integrated pressure sensor, which is used due to the complexity of the ASIC devices such chip area consumption increased chip area can be tolerated.

However, typical for simple magnetic field sensors the allowed chip areas are very small, and furthermore by a very small housing limited, so that Circuit design is usually not acceptable.

It is also known, see for example Ch. Schott, H. Blanchard, R. S. Popovic, R. Racz, and J. Hrejsa, "High- Accuracy Analog Hall Probe "in IEEE Trans. Instrum. Meas., Vol. 46, No. 2, April 1997, to compensate for a decrease in Hall probe sensitivity to strong magnetic Induction and to compensate for temperature effects Compensation circuit to be used in the case of compensation by a feedback adjustment of the primary Hall current is carried out.

Further in Ch. Schott and R. S. Popovic, "Linearizing integrated Hall devices, Transducers '97, 1997 International Conference on Solid-State Sensors and Actuators, Chicago, June 16-19, 1997 describe a Hall device that a Shielding has. Electrical voltages are also on Scanning areas of a Hall device can be tapped and subjected to an averaging process. The averaged electrical voltage is then applied to the shield.

As is known, compensation from Hall probe systems with regard to the effect of mechanical tension performed the offset of the Hall voltage. Under a The offset of the Hall voltage is that electrical voltage understand that despite a switched off magnetic field at the Taps of the Hall voltages can be measured. The Hall voltage offset is therefore an additive component that is added to the measurement signal, the majority of the Offset of integrated Hall probes by the piezoresistive effect can be explained.

For example, US 5,614,754 describes a reduction of Piezo influences on the offset of the Hall voltage one Hall probe arranged by a substrate by an active Area of the Hall probe in certain directions of the substrate is arranged.

Furthermore, US 4,037,150 discloses a concept for elimination the effect of a non-equipotential voltage on the Hall voltage, in which a Hall generator two pairs has opposite electrodes that alternate with energy be supplied. The value of the electrical voltage of the Hall The generator is the signal of the first and the Signal of the second pair of electrodes obtained by a arithmetic mean is formed.

Furthermore, US 3,886,446 describes the use of a digital device for eliminating an influence of the Non-equipotential voltage on the results of a measurement the electromotive force of a Hall device.

US 5,260,614 describes a Hall sensor with a automatic compensation. Changes in the Sensitivity of the Hall element caused by a temperature or at a production can be introduced by a defined Control of the supply current and the offset current compensated.

The object of the present invention is a improved concept for sensitive measurement of Create magnetic fields with Hall probe systems.

This object is achieved by a Hall probe system according to claim 1 and a method according to claim 27 or 28 solved.

The present invention is based on the knowledge that a current-related sensitivity of a Hall probe system in Dependency of an external influencing parameter of the conductive Hall range can be controlled by connecting to a Electrode area that is electrically isolated from the Hall area and located near the Hall area, one Control voltage is applied by the influence parameter of the conductive hall range. By creating the Control voltage at the electrode area becomes the current-related Sensitivity and therefore the Hall voltage by a Influencing those available for the Hall current Charge carriers controlled by the applied control voltage.

An advantage of the present invention is that through the concept according to the invention in a ratiometric Hall probe system while maintaining the ratiometry one Compensation or reduction of external influences on the Hall probe can be performed.

In one embodiment of the present invention as an electrode area for applying the control voltage conductive cover or cover used, by an insulation layer between the Hall region and the conductive cover layer is arranged, of which Hall area is electrically isolated.

In another embodiment, the Electrode region by a doped region, for example a Top layer, a doped trough or the substrate itself can be formed, wherein the doped region to the Hall region abuts and has a doping type that is opposite to the doping type of the Hall region. This forms with appropriate applied voltages on one formed between the Hall region and the doped region pn junction an electrically insulating space charge zone between the Hall region and the doped region, where in this embodiment, the control of the Hall voltage by changing the width of the space charge zone in the Hall area of the Hall probe system takes place.

The concept according to the invention is used in a Embodiment used to reduce or compensate for a Influence of a mechanical strain on the substrate to reach the hall area. With others A reduction of temperature-related effects is exemplary embodiments and a reduction of non-linear Magnetic field dependencies of the Hall voltage are carried out at high magnetic fields.

Preferred embodiments of the present invention are described below with reference to the accompanying Drawings explained in more detail. Show it:

Figure 1a is a diagram showing a dependence of the current-related sensitivity S _I as a function of a voltage between a conductive layer and a common-mode potential of a Hall range.

Fig. 1b is a block diagram of a measuring circuit for determining the curve of Fig. 1a;

Fig. 2 is a block diagram of an embodiment of the present invention, in which is carried an influence of the Hall sensor by adjusting a potential of a conductive cover, and by setting the common-mode potential;

FIG. 3a shows a block diagram of one embodiment for linearizing a response of a temperature sensitivity of a ratiometric Hall probe system;

FIG. 3b is a diagram for explaining the operation of the circuitry of Figure 3b to the temperature history of sensitivity.

Fig. 4 is a block diagram of a circuit structure for linearization of the sensitivity of a Hall probe ratiometric system;

Figure 5a is a block diagram of an embodiment of the present invention for reducing influences of mechanical tension.

Figure 5b is a block diagram of another embodiment of the present invention for reducing mechanical influences of tension.

6a is a first embodiment of a strain sensor device for detecting mechanical tension.

Figure 6b is a second embodiment of a strain sensor device for detecting mechanical tension.

FIG. 7a is a circuit diagram of a current control of a Hall probe;

FIG. 7b is a circuit diagram of a voltage control of a Hall probe;

Fig. 8 is a known embodiment of a voltage source for generating a voltage having a predetermined temperature coefficient; and

Figure 9 is an embodiment of the present invention may be used in which a plurality of strain sensors for detecting mechanical tension, and the two ways shows., As the sensitivity of the Hall probe can be influenced by an electric signal (A1, A2).

FIG. 1a is a graph showing a current-related sensitivity S _I as a function of an electrical voltage applied to the Hall range between a region of the Hall insulated cover and the common-mode point.

Common mode point or common mode point understood the point in the reverberation area at which the electrical potential the arithmetic mean of electrical potentials on the secondary Hall connections equivalent.

FIG. 1b shows a block diagram for the determination of the curve shown in Fig. 1a. Referring to FIG. 1b 10 comprises a Hall field on the primary side to a first terminal 12 and second terminal 14. The first connection 12 is connected to an output of a differential amplifier 15 . The Hall region 10 also has a first and a second Hall connection 18 and 20 , each of which is connected to an input of an addition device 21 . An output of the adder 21 is connected to the negative input of the differential amplifier 15 . The positive input of the differential amplifier 15 is connected to a voltage source 23 . An insulated cover 22 is arranged above the Hall area 10 and is connected to a first pole of a voltage source 25 . The second pole of the voltage source 25 is connected to ground.

Through the first connection 12 , the Hall region is connected to a regulated primary potential U _SUP , which results in a constant primary current I _H between the first connection 12 and the second connection 14 . On the secondary side, the Hall voltage U _h results as a differential voltage between the voltages U ₂ and U ₃ . The Hall voltage U _h indicates the vertical magnetic field component of a magnetic field 27 . The voltage U _SUP applied to the first connection 12 is regulated by a control circuit which is formed by the differential amplifier 15 and the addition device 21 in connection with the first connection 12 and the Hall connections 18 and 20 , so that the potential of the common Mode point has a constant voltage to ground. The value of the common mode potential is defined in accordance with the formula U _CM = 0.5. (U ₂ + U ₃ ), the common mode potential being unaffected by the magnetic field. The cover over the probe is now made to a related against U _CM potential U _D-CM = U _D - set U _CM.

In order to determine the sole influence of the cover potential on the current-related sensitivity, the potential of the substrate must be constant compared to the common mode potential. For this purpose, the control circuit comprising the two input variables U ₂ , U ₃ , the addition device 21 , the differential amplifier 15 and the reference voltage 2 U _CM , which is applied to the positive input of the differential amplifier 15, is used. This circuit regulates U _SUP so that U _{CM is} always the arithmetic mean of the two potentials U ₂ and U ₃ .

If the control circuit for keeping the common mode potential constant were not used by setting the electrical voltage U _SUP at the first stop 12 to a constant value, the primary side resistance of the Hall probe is changed by a change in the voltage U _D , so that the voltage on the primary side of the Hall probe changes, as a result of which the common mode potential on the secondary side changes by approximately half the voltage change. This would change the reverse voltage between the Hall region 10 and a substrate by this amount, so that instead of measuring a pure influence of the lid potential, a small influence of the substrate potential is also measured, which is, however, a factor of 10 stronger.

The cover layer or the cover is typically at known Hall probe systems available and from the Hall area through an insulating layer, such as a dielectric layer, electrically insulated.

As is known, a constant electrical voltage is applied to the cover layer in order to keep the influence of the current-related sensitivity, as shown in FIG. 1 a, small by a changing electrical potential of the cover layer in relation to the common mode potential of the Hall region , Consequently, the dependence of the current-related sensitivity shown in FIG. 1a is undesirable in known Hall probe systems and is suppressed by the application of the constant voltage.

According to the invention, however, the dependency shown in FIG. 1a can be used in order to specifically influence and control the magnetic sensitivity by applying a control voltage.

The curve shown in FIG. 1a relates to an n-doped Hall region, in which the majority charge carriers in the Hall region are electrons, as a result of which the current-related sensitivity S _I drops with increasing voltage between the cover layer and the common mode potential U _{D -CM} results.

The physical reason for this arises from the fact that charge carriers are attracted or repelled between the cover layer and the active layer, depending on the sign of the voltage and the type of charge carriers, so that an effective layer thickness t of the Hall region changes. The change in the effective layer thickness t causes the change in the current-related sensitivity S _{I of} the Hall probe system.

Consequently, it is understandable that with a p-doped Hall range an incline of the curve with opposite Sign, but the provision of a p- doped Hall range in known applications rather is unusual.

The changes in sensitivity achieved are in a range of approximately -1.5% / V when the electrode area is formed by a cover layer, which by a Insulating layer of a field oxide is isolated from the Hall area.

Consequently, it is possible to fine tune the Perform sensitivity to an extent of about 2% by following the Cover suitable voltages in a range below 3V be created.

In a further embodiment, instead of conductive cover of the probe to apply the electrode area the control voltage consist of a doped region which has a doping with a doping type that differs from that Doping type of the Hall region differs. With preferred In exemplary embodiments, the doped region comprises a trough, in which the Hall area is arranged, a doped Cover layer or the substrate itself.

Since the doped area lies directly on the Hall area and a doping type opposite to the Hall region has between the doped region and the Hall area a pn junction with an electrically isolated Space charge zone formed. In contrast to the one Insulation layer insulated cover layer must be in this Embodiment can be ensured during operation of the probe, that between the deck area and the reverb area formed pn junction is always switched in the reverse direction. consequently with a Hall probe system in which the Hall area n- is doped, the p-doped cover area always on one voltage is more negative than the Hall range.

In the embodiments with a pn- Transition takes place influencing the current-related Sensitivity by changing the width of the space charge zone in the reverb area and consequently by changing the effective layer thickness t of the Hall area instead.

In the case of an n-doped Hall region and a p-doped covering region, the same functional dependency is shown, ie that the current-related sensitivity decreases with increasing U _D-CM and consequently with a decreasing blocking voltage.

In contrast to the embodiment with an educated pn transition can in the embodiment with a insulated conductive cover the entire Operating voltage range as a control range of the lid potential be used. In addition, this one Embodiment prevented by the electrical insulation layer at high temperatures leakage currents from the conductive Coverage in the Hall area of the Hall probe system or vice versa occur.

As explained in more detail below, the Control of current-related sensitivity according to the invention used be, for example, a temperature response of the to slightly change the magnetic sensitivity of the probe, the dependence of the magnetic sensitivity of the Hall probe system from mechanical tensioning of the To reduce or compensate for the substrate or Control sensitivity so that non-linear Magnetic field dependencies can be reduced.

The insulated cover has a large design Variety of possibilities. Regarding the material can the insulated cover, for example made of a metal, such as for example an aluminum metallization, or one conductive semiconductor layer, such as one Layer of polysilicon can be formed. typically, covers the insulated cover large parts of the probe, whereby a variety of training courses are available. For example, the insulated cover can be covered by a Solid material can be formed to withstand the penetration of mechanical forces a housing that is applied to the Hall probe system, derived on the substrate. Furthermore, the insulated cover be formed as a slotted lid to mechanical Tensions exerted by the lid material on the probe to build up on not too large areas.

Furthermore, in a further embodiment insulated conductive cover to be formed as a grid Reduce eddy current effects. Preferably you can the vertical and horizontal bars in be arranged at different levels, whereby the current paths of induced eddy currents, analogous to a laminated Transformer plate, are interrupted.

As another possible education, the isolated one Covered by a variety of vertical or horizontal parallel lines can be formed.

Furthermore, the cover can be formed from several parts be, the same with each other by means of external lines can be interconnected, which is preferably star-shaped is done to prevent loops and thereby the Reduce eddy current effects. You can also do this even individual parts of the cover to a fixed constant Potential. For example, the cover in four parts can be divided, with two parts connected to ground while the two remaining parts are used to create the electrical control voltage that affects the sensitivity of the Hall probe influenced in the manner described above, be used. Alternatively, two parts can be used the common mode potential of the reverb area is set, while the two remaining parts for creating the Control voltage can be used.

In a further embodiment, the Electrode area for applying a control voltage to the substrate itself represents, in this example, the substrate doping with a doping type opposite to that Is the doping type of the Hall region. Corresponding to that Embodiment in which a doped covering area with opposite doping type was used, also forms with this embodiment, a space charge zone, which in in this case between the Hall region and the doped Substrate is formed. Again, it must be taken into account that the control voltage is only in such a range is applied that between the substrate and Hall area formed pn junction is always switched in the reverse direction, so that the space charge zone formed as electrical insulation acts.

Fig. 2 is a block diagram showing a first embodiment of the present invention. In this embodiment, control of the current-related sensitivity by the cover 22 as well as by changing the voltage between the common mode point of the Hall region 10 and a doped region which is doped with a doping type opposite to the Hall region. As already mentioned, the doped region can comprise, for example, a doped well or the substrate itself.

The circuit configuration of FIG. 2 essentially corresponds to the circuit configuration shown in FIG. 1b, which was used in FIG. 1b for measuring the curve shape of FIG. 1a. In contrast to the circuit structure according to FIG. 1b, the circuit structure has a first control device 27 for applying a first control voltage instead of the voltage source 23 and a second control device 29 for applying a second control voltage instead of the voltage source 25 . The first control device 27 generates a first control voltage U _St1 , which is applied to the positive input of the differential amplifier, as a function of one or more influencing parameters that describe an influence on the Hall area and can be, for example, a temperature, a mechanical tension state of the substrate or an applied magnetic field 15 is created. By means of the first control voltage U _St1 , the differential _amplifier 15 _applies such a potential U _SUP to the first connection 12 of the Hall region 10 that the common mode point of the Hall region 10 is set to an electrical potential which is half of the first control voltage U _St1 corresponds. Hence:

U _St1 = 2.U _CM .

As already mentioned above, this changes the extent of the space charge zone formed at the boundary region of the Hall region 10 and of the substrate, so that the current-related sensitivity changes. This results in a sensitivity to the change in the current-related sensitivity of + 10% / V based on the potential between the common mode point and the substrate. Depending on one or more influencing parameters, the control device applies such a control voltage that the external influences on the Hall area described by influencing parameters are reduced or compensated for.

The second influence on the current-related sensitivity is in this embodiment, the application of an electrical control voltage to the cover 22 by the second control device 29. The second control means 29 generates in dependence on one or more effect parameters, for example, a temperature of the Hall region, a mechanical Tension state of the substrate or a magnetic field penetrating the Hall region 10 , a second control voltage U _St2 , which is applied to the cover 22 in order to reduce or compensate for external influences on the Hall region. In contrast to the influence by changing the common mode potential compared to the substrate potential or well potential, the change in the potential of the cover 22 results in a smaller change in the current-related sensitivity per voltage present between the cover 22 and the common mode potential reached, the change being about -1.5% / V.

In the present exemplary embodiment, the Hall region 10 can be influenced either by both control devices 27 , 29 or only by one of the control devices, ie the control device 27 or the control device 29 . In the latter case, the control device, which is not used for control, applies a constant potential to the electrode region which is connected to it, ie either to the cover 22 or the doped substrate or the doped well. For example, by generating a constant control voltage U _St2 by the second control _device 29, the potential of the cover 22 can be set to a constant value, while the first control device 27 for controlling the current-related sensitivity of the Hall region 10, the first control voltage U _St1 depending on one or more Influence parameters of the Hall area 10 generated. The electrical potential of the cover 22 can also be constantly set to the common mode potential by the second control device 29 .

As has already been explained with reference to FIG. 1b, the control _circuit formed by the addition _device 21 , the differential _amplifier 15 and the first control voltage U _{St1 causes} the common mode point to be independent of a voltage applied to the cover 22 the first control voltage predetermined value is maintained. If this control _{circuit is omitted} by keeping U _SUP constant, the primary side resistance of the Hall probe changes due to the second control voltage U _St2 applied to the cover, so that the primary side voltage at Hall region 10 also changes and the common mode potential changes , which represents the arithmetic mean of the voltages tapped at the first Hall connection 18 and the second Hall connection 20 , changes on the secondary side by approximately half of this voltage change.

As a result, the reverse voltage between the Hall region 10 and the substrate at the common mode point also changes by this amount, so that this change adds a small influence of the substrate potential or well potential to the influence of the cover potential, but an influence, which is caused by the substrate potential is about a factor of 10 stronger.

In this case, by applying the second control voltage U _St2 to the cover 22 as the sole control voltage, the current-related sensitivity of the Hall region 10 can be influenced with a greater sensitivity to a fixed common mode potential, so that the control 22 by means of a applied control voltage can be influenced by a few percent.

The influence on the current-related sensitivity of the Hall region 10 is independent of controlling the sensitivity by changing the Hall current I _H. In one embodiment, this can be used, for example, such that first the Hall current I _{H is} roughly controlled, for example to achieve compensation for temperature-related influences on the sensitivity, whereas the above-described influencing _{according to the} invention via the first control voltage U _St1 and / or the second control voltage U _{St2 is} fine- _tuned . Furthermore, there is also the possibility of influencing a parameter on the Hall region, which has a linear and non-linear component, such as a temperature coefficient, which describes temperature-related effects on the Hall region 10 , in such a way that the linear component is adjusted of the Hall current I _{H is} carried out while the compensation of a non-linear influence is carried out by applying the first and / or second control voltage according to the invention to the cover 22 or to the common mode potential.

An advantage of the concept according to the invention is that the sensitivity due to the control voltages applied to the cover 22 and / or to the doped region has a multiplicative nature, that is to say that the ratiometry of the output signal is not significantly impaired by the change in the current-related sensitivity if the primary current of the probe is ratiometric. It is consequently possible with the concept according to the invention to create a ratiometric Hall probe system in a simple manner, in which a control of the Hall probe to reduce external influences is also carried out ratiometrically and consequently does not impair the ratiometry of the Hall probe system.

In a particularly preferred embodiment, in which the Hall probe system is a ratiometric Hall probe system, this can be achieved in that the potential of the cover 22 or the potential of the common mode point are independent of the operating voltage, but the control circuit for determining the common Mode point must be active. A largely perfect ratiometry of the sensor signal of the Hall probe is thereby achieved.

A circuit structure for linearizing a temperature response of the sensitivity of a Hall probe, in which the Hall probe is designed as a ratiometric Hall probe, will now be explained with reference to FIG. 3a.

The circuit configuration of FIG. 3a substantially corresponds to the circuit configuration of FIG. 2, where a well-known circuit construction is shown in Fig. 3a, in addition, to achieve a ratiometric Hall current I _H. For this purpose, the second connection 14 is connected to a drain connection of an N-MOS transistor 31 . The source terminal of the N-MOS transistor 31 is connected to ground via a resistor 33 . Furthermore, the source terminal of the N-MOS transistor 31 is connected to a negative input of a differential amplifier 33 . The positive input of the differential amplifier 33 is connected to a voltage divider, which consists of a first resistor 35 a and a second resistor 35 b. The output of the differential amplifier 33 is connected to a gate connection of the N-MOS transistor 31 .

An operating voltage V _{DD is} applied to the voltage divider, a fraction k of the operating voltage V _{DD being} present between the resistors 35 a and 35 b. The voltage divided by the voltage divider to a value of kV _DD is input to the positive input of the differential amplifier 33 and applies the divided voltage to a resistor 37 through the control loop, which is formed from the differential amplifier 33 and the N-MOS transistor 31 on. The current I _H = kV _DD / Rs flowing through the resistor 37 , which has a resistance value R _S , to the ground is consequently proportional to the operating voltage V _DD and is therefore ratiometric.

In order to obtain a Hall voltage U _h which is linearly proportional to the operating voltage V _DD , the common mode potential of the Hall probe, which is defined by the arithmetic mean of the potentials U ₂ and U ₃ , is determined by means of the control loop the addition device 21 and the differential amplifier 15 are formed, and the control voltage which is constant in this exemplary embodiment and which is set to a value U _const is kept constant with respect to the operating voltage.

In the embodiment, the controller 25 is adapted to be applied to the cover 22, a control voltage U _st2, the control voltage is used to provide a temperature response of the sensitivity to linearize a Hall probe. As is shown schematically in FIG. 3a, a control voltage with a parabolic shape open at the bottom is used for this, which is explained below.

Since the resistor 37 , which defines the Hall current I _H , does not change its resistance value R _S linearly as a function of the temperature, the current is also not linear with respect to the temperature. In other words, the Hall voltage U _h tapped at the Hall connections 18 and 20 does not change linearly with respect to the temperature, even if the current-related sensitivity of the Hall probe system is constant with respect to the temperature.

The appropriate control voltage is applied by detecting the temperature of the Hall region and / or the substrate by a temperature detection device (not shown) and selecting the assigned voltage. The assigned voltage is obtained from the parabolic curve, which defines the control voltage required for the linearization of the temperature curve against the temperature. By applying the voltage U _St2 , which was obtained from the parabolic curve, to the cover 22 , the current-related sensitivity of the Hall probe system can be controlled such that the same is raised by a few percent at low and high temperatures, so that the Hall voltage U _h a has much greater linearity, ie that non-linear terms are greatly reduced in terms of temperature. It is important that the control voltage U _St2 is substantially independent of the operating voltage V _DD , which can be achieved, for example, by using a known parabola generator to generate the control voltage U _St2 , which is provided by an on-chip constant voltage _source with a Voltage U _{b is} supplied, which is constant with respect to the operating voltage V _{DD of} the Hall probe.

FIG. 3b shows a graph in which the effect of the linearization above-described is shown of the temperature response of the current-related sensitivity.

According to FIG. 3b, the sensitivity S = U _h / B of the Hall probe system based on the operating voltage V _{DD is} plotted as a function of the temperature. A dashed curve line represents the course of the sensitivity that results when a constant potential is applied to the cover 22 . In comparison, a curve of sensitivity is shown as a solid line, which results from a control of the potential of the cover 22 by a parabola generator. As can be seen, the solid curve obtained by means of the control shows a course which, at low and high temperatures, has a substantially greater linearity compared to the uncontrolled course of the curve, which is represented by a dashed line. Accordingly, the Hall probe system described in FIG. 3a is suitable for linearizing the sensitivity, the ratiometry of the Hall voltage output signal U _h being retained, since the influence on reducing the non-linear temperature contributions is achieved by modulating the current-related sensitivity S _I , as described above was explained.

Another embodiment of the present invention will now be explained with reference to FIG . In this exemplary embodiment, a non-linear influence of the magnetic field on the Hall probe is reduced.

The circuit configuration of Fig. 4 corresponds to generate in Fig. Circuit structure shown 3a with the exception that is formed in this embodiment, the control device 29 to the control voltage U _St2 in dependence of the magnetic field passes through the Hall region 10.

According to FIG. 4, a magnetic field detecting device 39 with the first Hall terminal 18 and the second Hall terminal 20 is connected. The output of the magnetic field detection device 39 is connected via a resistor to a negative input of a differential amplifier 41 . A voltage source 43 is connected to ground with a first pole, while a second pole of the voltage source 43 is connected to the positive input of the differential amplifier 41 . The output of the differential amplifier 41 is connected in terms of feedback via a resistor 45 to the negative input of the differential amplifier 41 . Furthermore, the output of the differential amplifier 41 is connected to the cover 22 .

In the circuit construction of FIG. 4 is a signal to the controller 25, ie more specifically to the negative input of the differential amplifier 41, is applied by the magnetic field detecting device 39. The magnetic field is detected by the magnetic field detection device 39 by tapping the voltage at the first Hall connection 18 and tapping the voltage at the second Hall connection 20 , the output signal of the magnetic field detection device 39 being subtracted U3-U2 with subsequent magnification and inversion in an inverting manner Amplifier is generated. The output signal, which is consequently proportional to the amount of the vertical component of the magnetic induction, is applied via the resistor to the negative input of the differential amplifier 41 . The differential amplifier 41 subtracts the voltage applied to the negative input from a reference voltage U _ref , which is generated by the voltage source 43 , so that the control voltage U _{St2 is} generated at the output of the differential _amplifier 41 , which is from the amount of the vertical component of the magnetic induction depends. In the case of a strong magnetic field, a low voltage is applied to the cover 22 , which increases the sensitivity of the Hall probe in order to reduce or compensate for the non-linear influence of the magnetic field on the Hall area.

Furthermore, in the exemplary embodiment according to FIG. 4, an electrical voltage U _{SUP is applied} to the second connection of the Hall region 10 via the control loop, which is formed from the differential amplifier 15 , the adding device 21 , the connection 12 and the Hall connections 18 , 20 causes the common mode potential to be set to the control voltage U _St1 generated by the control _device 27 , as was explained with reference to FIGS . 2 and 3a. The control voltage U _St1 can either depend on an external parameter or can preferably be set to a constant value, so that the sensitivity of the Hall probe can only be controlled by the control device 29 , that is to say via the control voltage U _St2 applied to the conductive cover 22 , that of the Value of the magnetic field depends.

As in the embodiment according to FIG. 3a, the Hall probe in this embodiment is ratiometric, since the Hall current I _{H is} generated as a ratiometric Hall current and the common mode potential via the control circuit formed by the addition device 21 and the differential amplifier 15 and by the constant voltage, which is present at the positive input of the differential amplifier 15, is kept at a fixed potential.

In the embodiment according to FIG. 4, it should be noted that the control loop formed by the differential amplifier 41 and the resistor 45 can develop a tendency to oscillate, which can be avoided by suitable stabilization measures, as are well known in the prior art in theory of feedback can.

Another advantage of the concept according to the invention is that when compensating for temperature effects on the current-related sensitivity, the curvature of the curve in the range from -40 ° C to 150 ° C is usually of the order of 2%, so that the by the application of Control voltage to the cover 22 changes are very well adapted to this problem. The changes achieved by the application of the control voltage are sufficiently large to adequately cover the range mentioned, but on the other hand they are not too large to carry out an adjustment of the control voltage with a complex and undesired accuracy. The dependence of the current-related sensitivity S _{I can} be increased within certain limits by making the insulation layer as thin as possible in the case of an insulated cover. This can be done, for example, by using a gate oxide instead of a field oxide. In the exemplary embodiments in which the control takes place through a space charge zone formed at a pn junction, the sensitivity of the control can be increased in that the doping of the electrode region, ie the doping of a cover layer or the doping of the substrate or a trough of the Substrate, larger than the doping concentration of the Hall region 10 is selected. This causes the space charge zone to spread predominantly in the Hall region with a lower doping, so that when the reverse voltage at the pn junction formed increases, the effective depth of the Hall region is modulated with a larger stroke, as a result of which the magnetic sensitivity changes more.

The control of the potentials of the invention Electrode areas can also be used to control the influences caused by mechanical tension of the substrate be reduced or compensated.

With reference to FIGS. 5 to 9, further exemplary embodiments of the present invention will now be explained, in which the control concept according to the invention is used in order to reduce or compensate for an influence of a mechanical tension on the Hall area.

Before going into the individual embodiments a brief explanation of the Basics of mechanical tension and its effects on the reverb area.

Indirect semiconductors show, in contrast to direct ones Semiconductors, strong piezo effects, what the use of Hall probes, for example on silicon substrates, are more difficult. There integrated Hall probes nowadays mainly in Silicon substrates are manufactured, it is desirable to such Reduce influences.

Under piezo effect is a change in electrical parameters of the semiconductor material under the influence of a mechanical Understood tension. More specifically, a piezoresistive effect and a piezo Hall effect can be distinguished.

Both effects are based on a change in the band structure under the mechanical tension and a consequent Realization of the energy minima of the conduction band or Energy maxima of the valence band through the charge carriers.

More specifically, the application of pressure leads to one Removal of the degeneracy of the energy minima of the conduction band and the energy maxima of the valence band and a subsequent one Splitting them up.

The piezoresistive effect indicates how the specific ohmic resistance changes under the influence of a mechanical tension sensor. The following applies:

ρ = ρ ₀ (1 + Σπ _{i, j} σ _{i, j} ) [1]

In Eq. 1 σ _{i, j is} a mechanical tension sensor and π _{i, j is} a piezoresistive coefficient, the summation over i = 1. , , 3, j = 1. , , 3 extends.

Regarding the piezoresistive effect and the piezoresistive coefficients, as well as the directional dependencies of the piezoresistive effect in n- and p-doped silicon, extensive investigations are known, see for example Yozo Kanda: "A graphical representation of the piezoresistive coefficients in silicon ", by Y. Kanda, IEEE Trans. Electron Devices, vol. ED-29, pp. 64-70, Jan. 1982.

Furthermore, the piezo-Hall effect describes the change in the Hall constant depending on the mechanical stress state. The following applies:

R _h = R _h0 (1 + ΣP _{i, j} σ _{i, j} ) [2]

In Eq. 2 are σ _{i, j} a mechanical tension sensor and P _{i, j} piezo Hall coefficients, the summation in turn over i = 1. , , 3, j = 1. , , 3 extends.

Investigations of the Piezo Hall effect and the Piezo Hall Coefficients are, for example, in the scientific B. Hälg, "Piezo-Hall coefficients of n-type silicon ", J. Appl. Phys., 64 (1), pp. 276-282, July 1, 1988 described, it being known from the same that a Temperature coefficient of the piezo Hall effect clearly from a temperature coefficient of the piezoresistive effect different.

As mentioned above, is due in particular to the very well known CMOS or BiCMOS silicon technology, nevertheless the disadvantages of the occurring piezo effects in purchase taken to produce a reliable and inexpensive of integrated Hall probes in large numbers to reach.

Therefore, nowadays mainly integrated Hall probes made of silicon, using the same in particular through the principle of the spinning current Hall probe was made possible by a time-discrete Signal processing can be achieved that a disruptive offset or Offset of the Hall voltages of an integrated Hall probe from a useful signal is separated.

The following is the impact of the piezoresistive effect and the Piezo Hall effect on the operation of an integrated Hall probe and evaluation electronics explained in more detail.

The piezo Hall effect causes a change in the current-related sensitivity S _{I of} the Hall probe, depending on how the tensions of a substrate of the Hall probe change, for example due to changes in the mechanical properties of a sensor housing. The current-related sensitivity S _I is defined as follows:

In Eq. 3 is U _h the Hall voltage of the Hall probe, I _H the current through the Hall probe, B the magnetic flux density, t the effective thickness of the active layer of the Hall probe and G a geometry factor which describes the influence of the contact electrodes on the Hall voltage. R _H is the Hall constant, which is inversely proportional to a charge carrier density in the Hall probe.

In addition to the piezo Hall effect, the Hall probe is affected by the piezoresistive effect, which causes a current through the Hall probe to change when, as is customary in integrated circuits, it is defined by a resistor, to which one, possibly using a control loop, an electrical voltage drops. Since the sensitivity S results from the product of the current-related sensitivity S _I times the Hall current I _H , the change in the current due to the piezoresistive effect has a multiplicative effect on the change in the sensitivity S of the Hall probe. The following applies:

S = S _i I _H = U _h / B [4]

Due to the fact that the semiconductor chips are typically be provided with a housing made of a potting compound which has a different coefficient of thermal expansion than the silicon chip has, Chip due to the bracing of the two components similar a bimetal strip very high at different temperatures mechanical tension. The occurring pressure and Shear stress components can easily be in one Order of magnitude of 100 MPa and even mechanical Damage to the chip can result, for example Cracks in the surface of the chip or a break in the chip shows.

A well-defined application of this mechanical Tensions over the entire service life and the entire So far, the temperature range of an integrated Hall probe system has been not yet successful for commercial applications. thats why it is necessary to compensate for the mechanical To carry out voltages at which the compensation changed Conditions is adjusted.

In addition, magnetic field sensors have an aggravating effect typically cast in particularly thin housing types so that they are narrow when used Air gaps can be installed. Providing in a narrow Air gap is carried out to create a high magnetic field obtained, the size of the magnetic field from the measurement depends on the gap. The requirement of a very thin Housing includes due to the lack of space Applying a gel to the integrated circuit chip from how it is used in other arrangements to Pouring integrated circuits with low stress.

Preferred exemplary embodiments of the present invention are explained below with reference to FIGS. 5-9, in which compensation or reduction of influences which are brought about by mechanical tensioning of the substrate is carried out.

FIG. 5a is a block diagram showing an embodiment of the present invention (not shown) in which on a substrate, which is preferably a (100) silicon substrate is an active region or conductive Hall area 10 is formed. The conductive Hall region 10 is preferably integrated as a well in the substrate, the well being formed by doping with dopant atoms in accordance with known techniques for integrated circuits.

Preferably, the substrate is lightly doped with a first charge carrier type, for example a p-type, while the conductive Hall region 10 is doped with the opposite charge carrier type, so that an electrical charge occurs through a space charge zone which occurs in a boundary region of the Hall region with the substrate Isolation of the Hall area from the substrate results.

The conductive Hall region 10 has a first connection 12 and a second connection 14 in order to conduct a predetermined Hall current I _H through the Hall region 10 . The Hall current I _H can be generated by either a current controller or a voltage controller, as explained below.

A common mode point or common mode point is defined in the Hall region 10 by the electrical potentials present at the first connection 12 and the second connection 14 such that the electrical potential of the common mode point is equal to the arithmetic one for each magnetic field Is the mean of the electrical potential present at the first connection 18 and the electrical potential present at the second connection 20 .

Consequently, for the common mode potential U _CM , if U3 is the potential of the first connection 18 and U2 is the potential of the second connection 20 :

U _CM = 0.5 × (U2 + U3) [5].

The Hall region 10 also has Hall connections 18 and 20 arranged perpendicular to the current profile of the Hall current I _{H in} order to tap a Hall voltage U _h at the same.

The Hall voltage U _h arises when a magnetic field passes through the conductive Hall region 10 , so that the charge carriers injected by the Hall current I _H are deflected by the Lorentz force perpendicular to the Hall current direction. The first and second Hall connections 18 and 20 are preferably arranged in the direction of the Hall current I _H in the middle between the first connection 12 and the second connection 14 in order to tap the Hall voltage in a defined manner. Typically, ie in a Hall region 10 with a homogeneous specific resistance, the common mode point is also approximately in the middle between the first connection 12 and the second connection 14 , so that the first Hall connection 18 and the second are for the magnetic field-free fall Hall connection 20 are approximately at the potential of the common mode point.

A conductive cover 22 is also provided on the conductive Hall region 10 . In this exemplary embodiment, the cover 22 is electrically insulated from the conductive Hall region 10 by an insulating layer made of silicon oxide. The conductive cover 22 serves as electrical protection for the Hall region 10 in order to reduce electrical interference thereon, and is applied using known methods.

In alternative exemplary embodiments, the cover 22 is arranged as a doped layer directly on the Hall region, electrical insulation being achieved in that the doping of the cover 22 is selected opposite to the doping of the Hall region 10 , so that a space charge zone is formed in a border region. that has an isolating effect.

A tension sensor device 24 for detecting mechanical tension of the substrate is also provided on the substrate. The configuration and arrangement of the tension sensor device 24 is explained in more detail below. An output of the tension sensor device 24 is connected to an input of a compensation device 26 . The compensation device 26 also has two outputs 26 a, 26 b, and two inputs 26 c, 26 d, the output 26 a with the supply connection 12 , the second output 26 b with the cover 22 , the first input 26 c with the Hall connection 18 and the second input 26 d is connected to the Hall connection 20 .

The following is a compensation for the Hall voltage in the embodiment regarding mechanical stresses of the substrate explained.

The tension sensor device 24 detects the mechanical tension and generates a tension sensor signal A, which is received by a compensation device 26 . The tension sensor signal A, which depends on the mechanical tensioning of the substrate, is applied to the input of the compensation device 26 and used by the same, in order to output a compensation signal to compensate or reduce influences of the mechanical tensioning of the substrate on the sensitivity S of the Hall probe to generate.

In the exemplary embodiment described, the compensation signal is an electrical voltage which is generated by the compensation device 26 between the common mode point and the cover 22 .

The following is the performing the compensation under Use of the tension sensor signal A explained in more detail. How An influencing can already be mentioned before the charge carrier in the Hall area and consequently one Influencing the Hall voltage by applying a electrical voltage between a cover and the common mode Point of the reverberation area.

The electrical voltage applied between the common mode point and the cover 22 has the effect that charge carriers accumulate or are drawn off in a surface region of the Hall region 10 which is opposite the cover 22 , depending on the polarity of the electrical voltage applied. This allows the sensitivity S of a Hall probe to be influenced within certain limits, as will be explained below.

The sensitivity of a Hall probe can be expressed by the following equation:

Equation 6 can be found in the introduction to the description Equations 1-4 are derived, in which the Definition for the piezo Hall effect and the piezoresistive Effect and definition of sensitivity of the Hall probe is given.

In equation 6, S _{0 represents} a factor that includes those terms that are not affected by mechanical stress. Equation 6 describes the influence on the sensitivity, which is composed of the piezo Hall effect on the Hall probe and the piezoresistive effect on a resistor, which defines the Hall current. Location-dependent variables are identified by a superscript. The superscript H refers to the Hall range, whereas R refers to the resistance that generates the Hall current.

The current of the probe also goes into the sensitivity, wherein the current through a current control of the Hall probe, at which uses another circuit which is replaced by a Resistance generates a current, or through a Voltage circuit are generated. In the case of current control, the Resistance spatially separated from the Hall area, while in Case of voltage control of the Hall probe Internal resistance of the Hall probe determines the current, so that in this case the superscript R through the superscript H must be replaced.

Equation 6 suggests that the Piezo Hall effect is opposite to the piezoresistive effect in terms of an effect on the sensitivity of a Hall probe. In fact, however, it depends on the sign of the coefficients P _{i, j} and π _{i, j} whether there is a reducing effect of the two effects or, if the signs are opposite, a reinforcing effect.

Consequently, under the auspicious case of a reducing This may result in compensation be carried out so that with a suitable choice of the piezo Hall effect and the piezoresistive effect in Equation 6 cancel each other out.

This method is disadvantageous, however, since the compensation can only be achieved at one temperature, since the piezo-Hall coefficients P _{i, j} and the piezoresistive coefficients, _{i, j change} with the temperature, the temperature coefficients being significantly different.

With the implementation of the compensation according to the invention influencing the charge carriers in the Hall area and thus the sensitivity of the Hall probe will be the above mentioned disadvantages avoided.

Instead of influencing the charge carriers by means of a cover arranged above the Hall area, as described above, in an alternative exemplary embodiment which is described below, the charge carriers can be influenced by changing the extent of space charge zones at border areas of the Hall area 10 .

In an exemplary embodiment in which the cover 22 is a conductive region implanted on the substrate with an opposite doping to the Hall region 10 , this can be done by regulating the electrical voltage between the common mode point and the cover 22 . As a result, the space charge zone that forms in the boundary region of the Hall region / cover and thus the sensitivity of the Hall probe can be controlled within certain limits.

Furthermore, the influencing of a space charge zone in a Embodiment by regulating an electrical Voltage between the common mode point of the reverb area and the Be performed when the substrate and the substrate Hall region has doping of opposite charge carriers.

Alternatively, in the embodiment explained with reference to FIG. 5b, the Hall region is itself formed in a well of the substrate, in which case the influencing of the space charge zone in the Hall region by regulating an electrical voltage between the well in which the Hall area or the integrated Hall probe is arranged, and the common mode point is carried out.

Fig. 5b shows an embodiment in which the Hall region is arranged in a tub 58 10. The tub 58 is doped with a dopant that is opposite to the doping of the Hall region 10 . Thereby, a space charge region 10 is formed at the border areas of the Hall region to the tub 58 from whose extent is dependent in the Hall region 10 by the potential difference between the tub 58 and the Hall area 10th Since the first 12 and second 14 connections are at different potentials, the expansion of the space charge zone in the Hall region 10 is not constant, but changes in the direction of the course of the Hall current. For example, if the well 58 is p-doped and is grounded, and if the first connection 12 of the n-doped Hall probe 10 is connected to positive potential and the second connection 14 is connected to ground, then the potential difference between the Hall region 10 and the well 58 in the lowest value in the area of the second connection 14 and the greatest voltage difference in the area of the first connection 12 . Consequently, the thickness of the space charge zone is maximum in the area of the first connection 12 and minimal in the area of the second connection 14 .

In contrast to the exemplary embodiment according to FIG. 5 a, in this exemplary embodiment the compensation device 26 is connected to the trough 58 instead of the cover 22 . In this embodiment, the compensation device 26 carries out a compensation in such a way that an electrical voltage is generated between the common mode point and the well 58 using the tension sensor signal A, which voltage influences the space charge zone at the boundary region between the Hall probe 10 and the well 58 , which in turn influences the sensitivity of the Hall probe and consequently the Hall voltage U _h tapped at the first Hall connection 18 and the second Hall connection 20 .

Adjustment of the electrical voltage between the common mode point and the well 58 is preferably achieved in that the value of the common mode potential by detecting the potentials at the first Hall connection 18 and the second Hall connection 20 and performing an arithmetic Averaging these potentials is detected. The detected common-mode potential is compared in a subsequent circuit with the value of an electrical voltage between the common-mode point and the substrate or cover given by the compensation signal, and the potential at the connection 12 is then set so that the compensation required electrical voltage is present between the common mode point and substrate or cover 22 . As will be explained below in one exemplary embodiment, a known control loop can be used for this purpose, which is constructed from an average value image and a differential amplifier.

The change in the sensitivity of the Hall probe caused by the influencing of the charge carriers in the Hall region 10 can be represented mathematically as follows. The following applies to the influencing by applying an electrical voltage between the cover and the common mode point:

S ₀ ∼ S ₀₀ (1 + c _DB U _D-CM ) [7]

where c _{DB is} a cover bias coefficient and U _{D-CM is} the electrical voltage between the cover and the common mode potential of the Hall probe. The cover bias coefficient describes the effect of the electrical voltage U _D-CM between the cover and the common mode potential of the Hall probe on the charge carriers and consequently on the current-related sensitivity S ₀ .

In the event that compensation is carried out by applying an electrical voltage between the substrate and the common mode point, the following relationship applies:

S ₀ ∼ S ₀₀ (1 + C _BB U _CM-B ) [8]

C _{BB is} a back bias coefficient and U _{CM-B is} the voltage difference between the common mode potential and the substrate potential. Corresponding to the lid bias coefficient, the back bias coefficient describes the sensitivity of the influence of the current-related sensitivity S ₀ by the electrical voltage U _D-CM between the substrate and the common mode potential. Typically, the substrate is at ground, so that the potential of the substrate is 0 V.

Taking into account the formulas in Eq. 6, Eq. 7 and Eq. 8, the following relationship results for the sensitivity of the Hall probe:

The electrical voltage U _D-CM or U _CM-B applied by the compensation device 26 is determined using the tension sensor signal A in such a way that the terms dependent on the tension are eliminated, as a result of which the sensitivity S of the Hall probe or the tapped Hall voltage U _h largely independent of mechanical stresses on the substrate.

The suitable choice of the electrical voltages U _D-CM or U _CM-B is carried out by the compensation device 26 using the tension sensor signal A. Certain components of the voltage tensor can be emphasized in the tension sensor signal, as will be explained below with reference to FIGS. 6a and 2b.

FIG. 6a shows an embodiment of the strain sensor device 26. A first 28 and a second 30 piezoresistive resistor of a first type and a first 32 and a second 34 piezoresistive resistor of a second type are arranged in an H circuit.

As it is explained in more detail below, differs the piezoresistive resistance of a first type of a piezoresistive resistor of a second type, that the same on the substrate in different directions are arranged, whereby certain components of the Stress tensors are emphasized.

In the H circuit, the first piezoresistive resistor of a first type 28 and the second piezoresistive resistor of a second type 34 are connected in series in a first branch, while in a second branch the first piezoresistive resistor of a second type 32 is connected to the second piezoresistive resistor one first type are connected in series. The first branch and the second branch are also connected in parallel. Starting from a first node at which the first and second branches branch, in the first branch the first piezoresistive resistor of a first type 28 is connected to the first node 36 , while in the second branch the first piezoresistive resistor of a second type 32 is connected to the first node 36 is connected.

Consequently, in a second node 38 of the H circuit in the first branch, the second piezoresistive resistor of a second type 34 and the second piezoresistive resistor of a first type 30 are connected to the second node 38 . The first node 36 and the second node 38 are also connected to a voltage source 40 .

By applying an electrical voltage between the first node 36 and the second node 38 through the voltage source 40 , a first tap 42 can be connected between the first piezoresistive resistor of a first type 28 and the second piezoresistive resistor 34 of a second type in the first Branch is arranged and a second tap 44 , which is arranged between the first piezoresistive resistor of a second type 32 and the second piezoresistive resistor of a first type 30 , a differential voltage U _{Δ can be} tapped.

As will be explained further below, the tapped differential voltage U _{Δ is} proportional to certain components of the mechanical stress tensor which acts on the piezoresistive resistors 28-34 .

An alternative exemplary embodiment of a circuit structure of the tension sensor device, in which a current mirror device is used, is shown in FIG. 6b.

Referring to FIG. 6b, a piezo-resistive resistance is of a first type 46, connected via a first terminal connected to a first pole of a voltage source 50 which is grounded. A second connection of the piezoresistive resistor of a first type 46 is connected to a negative input of a differential amplifier 52 . A positive input of the differential amplifier 52 is connected to a second pole of the voltage source 50 . The output of the differential amplifier 52 is connected to a gate connection of an nMOS transistor 54 . A source terminal of the nMOS transistor 54 is in turn connected to the second terminal of the piezoresistive resistor of a first type. A drain terminal of the nMOS transistor 54 is connected to an input of a current mirror device 56 . The output of the current mirror circuit 56 is in turn connected to a second connection of a piezoresistive resistor of a second type 48 . A first connection of the piezoresistive resistor of a second type 48 is in turn connected to the first pole of the voltage source 50 , which is connected to ground.

The connection of the differential amplifier 52 and the transistor 54 according to FIG. 6b with the second connection of the piezoresistive resistor of a first type 64 represents a subsequent circuit which detects the potential present at the second pole of the voltage source 50 , which is generated by a reference voltage U _{0 of} the voltage source 50 is defined, is applied to the second connection of the piezoresistive resistor of a first type 64 . According to Ohm's law, this results in a current flow

I _φ = U ₀ / R _φ

The current I _φ is transmitted via the drain-source connection of the field effect transistor 54 into the current mirror device 56 , which transfers a current with the value of the current I _φ to the piezoresistive resistor of a second type 48 . As a result, the same current flows through the piezoresistive resistor of a first type 46 and the piezoresistive resistor of a second type 48 .

In order to use the circuit according to FIG. 6b for detecting a mechanical tension of the substrate, the potential is detected at the second connection of the piezoresistive resistor of a first type 46 and the second connection of the piezoresistive resistor of a second type 48 , and the voltage difference U _Δ of Potentials are output as tension sensor signal A.

The exemplary embodiments of the tension sensor device 24 shown in FIGS. 6a and 2b both use the same principle, namely that an equal current flows through a resistor of a first type and a resistor of a second type.

Since the piezoresistive resistor of a second type is rotated by an angle α with respect to the piezoresistive resistor of a first type, the two resistors differ with respect to the piezoresistive effect if the same mechanical stresses act on both resistors. As a result, different voltages drop in the resistors of a first type and the resistors of a second type when an equal current flows through them. The tapped difference U _{Δ of} the electrical voltages is consequently proportional to a linear combination of certain components of the voltage sensor and to the electrical voltage U ₀ , which generates the electrical current through the resistors. The following applies:

U _Δ = U ₀ Σπ _{i, j} σ _{i, j}

It depends on which terms of the stress tensor are emphasized on the choice of the directions of the reference resistors and the Doping, d. H. whether there is an n or a p type, depending on how it is detailed below for a (100) silicon substrate is explained. Thereby other terms of the stress tensor designed practically negligible small. The difference in electrical voltages at the piezoresistive resistors of a first and second type are therefore a direct measure for certain terms of the voltage sensor.

The embodiment according to FIG. 6a has the advantage that it is easy to implement, since no active components such as transistors or differential amplifiers are required for implementation.

The embodiment according to FIG. 6a, however, has the disadvantage that the two types of resistance are not at the same electrical potential, since they are connected in series. If the piezoresistive resistors are designed as diffusion resistors in the substrate, this can have a disruptive effect, since they sometimes have pronounced non-linearities. This means that the resistance value is dependent on the common-mode potential of the resistor with respect to the substrate or with respect to the well in which the resistor is arranged.

Strictly speaking, it is not possible to have exactly the same voltage tensor act on two different resistors. For the functionality of the principle described above, which is implemented in the circuits according to FIGS. 6a and 2b, it is only necessary that the two voltage tensor, which act on the two piezoresistive, different resistances, can be assigned to one another in a determined sense. More precisely, the difference between the relevant components of the voltage tensor must be determined on the piezoresistive resistors, since the difference of the electrical voltages across the piezoresistive resistors, and consequently the strain sensor signal A, is described by the following expression:

Here σ denotes  (1) | i, j a stress tensor at the location of the piezoresistive resistance of a first type and σ  (2) | i, j one Voltage tensor at the location of the piezoresistive resistor of a second type.

In a further exemplary embodiment, which represents an extension of the principle mentioned above, different technological implementations are also possible for the piezoresistive resistors. This results in different values for the piezoresistive coefficients, so that the differential _output voltage U _{Δ takes the} following form:

Here denotes π  (1) | i, j the piezoresistive coefficient of Resistance of a first type and π  (2) | i, j the piezoresistive Coefficients of resistance of a second type.

The resistors can vary in technology can be realized, whereby a greater flexibility or greater choice of resistors is achieved.

The disadvantage, however, is that the tolerance in pairs (Matching) of the two resistors is much worse, especially if the two resistors are technologically compatible different manufacturing processes were produced. For example, a manufacturing process include different masks and / or implantation steps.

The different piezoresistive coefficients therefore require that the process-related tolerances are trimmed by subsequent adjustment. In the case of the tension sensor device according to FIG. 6b, this can be achieved in the simplest case by designing the current mirror device in order to enable an adjustment by setting different currents. Such a comparison is preferably carried out when testing the wafer, since in this state the integrated circuit has a state with the least mechanical stresses, and in subsequent processing steps, which include sawing the wafer and attaching a housing, large mechanical stresses on the Wafers or the substrate are exercised.

It may also be necessary to carry out a comparison even then perform when the piezoresistive resistors were technologically the same. Such a comparison is for example, required if the different current directions of the piezoresistive resistors Lithography-related differences result that are too big Differences in the output voltages.

A determination of absolute sizes of individual components of the voltage tensor is achieved by measuring the differential _output voltage U _Δ . This requires that the exact size of the piezoresistive coefficients be known. Since the piezoresistive coefficients are largely independent of an exact dopant concentration for dopings below 10 ¹⁸ cm ^-3 , low-doped piezoresistive resistors are preferably suitable for implementation as stress sensor elements for detecting mechanical stresses. With these weak dopings, the piezoresistive coefficient is hardly influenced by fluctuations in the doping concentration, which are part of the manufacturing processes.

Now that the circuit structure of the Tension sensor device has been explained, the training and arrangement the piezoresistive resistors on the substrate and the related highlighting of certain components of the mechanical tension tensor explained in more detail during the detection.

The following is a (100) silicon substrate assumed that typically for CMOS and BiCMOS processes and partly also used for pure bipolar processes.

The piezoresistive resistors can be either p- or n- be endowed. In the case of a (100) silicon substrate, this offers itself a p-type as diffusion or implantation resistance, d. i.e. the majority carrier density through holes is determined.

The following is a preferred arrangement for the p-type of piezoresistive resistors explained. The arrangement of the piezoresistive resistors is called an angle φ in Referred to the [110] direction in crystal. φ is the Angle between the direction of current flow through the piezoresistive resistance and the [110] direction of the wafer, the Angle against a top view of the top of the wafer is counted positive clockwise. The [110] direction is normal to a primary flat of the wafer, causing the Direction is clearly defined.

The piezoresistive resistors are preferred as elongated ones integrated resistors are formed in the substrate so that the current flow direction of the resistors parallel to the longer side of the resistors.

The dependence of a diffusion or implantation resistance on the mechanical stress state can now be given by the following equation:

A normal stress component of the mechanical stress is defined by σ _'11 , which lies in the wafer plane and points in the [110] direction. This direction corresponds to an angle of φ = 0 °.

Furthermore, σ _'22 indicates a normal stress component, which lies in the wafer plane and into which [ 1 , 1,0] shows, which corresponds to an angle of φ = 90 °. Furthermore, σ _'33 corresponds to a normal stress component that points normally to the wafer plane in the [001] direction. σ _{'12 also} indicates a shear stress lying in the wafer plane.

A change in the resistance due to mechanical tensioning of the substrate is completely described according to equation 11 by the three piezoresistive coefficients π ₁₁ , π ₁₂ , π ₁₄ .

The individual chips on the wafer are usually such arranged that the directions φ = 0 ° and φ = 90 ° Vertical or horizontal direction of the integrated circuit correspond. These directions can be interchanged, depending on whether the integrated circuit is upright or lying down is present.

The advantage of arranging the resistors in the directions φ = 0 ° and φ = 90 ° for p-doped resistors and the Effects on the strain sensor signal will now be explained.

For this purpose, the known piezoresistive constants for p-doped resistors are considered first. The following numerical values apply to the piezoresistive constants in lightly doped p-silicon:

TPa means Tera-Pascal, ie 10 ¹² N / m ² .

If you compare the values of the piezoresistive coefficients, you will notice that π p | 44 has a value that is about 20 times higher than the next larger coefficient. It is therefore advantageous to use this coefficient for a sensitive measurement of the mechanical tension of the substrate. In order to achieve a separation of the terms with π p | 44 from all other terms in equation 11, two identical resistances are considered below, which differ only in an orientation with respect to the current flow direction. Consequently, the following equation applies to a first resistor which has an orientation with φ = 0 °, ie whose current direction points in the [110] direction:

Furthermore, for a resistor which is rotated by α = 90 ° with respect to the [110] direction, ie which is a current flow direction in the [ 1 , 1,0] direction shows the following equation for resistance:

If one looks at equations 12 and 13, it can be seen that a π p | 44 dependency occurs in both, the respective terms differing in terms of the sign. It can also be seen that all other terms in both equations 12 and 13 occur with the same sign. Consequently, by subtracting equation 12 from equation 13, the π p | 44 term can be isolated, where:

The realization of a circuit structure which carries out such a subtraction is achieved by the circuit structure according to FIG. 6a or the circuit structure according to FIG. 6b.

Now that it has been explained that the differential output voltage is directly proportional dependent on the difference between the normal voltage components in the horizontal and vertical directions of the integrated circuit, the proportionality constant being the product of π p | 44 and the reference voltage U ₀ , it is for detecting the mechanical stress necessary that the difference of the normal stress component does not disappear. In other words:

σ _^'11 - ^σ' ₂₂ ≠ 0

If the difference between the normal stress components becomes zero or if it is close to zero, it disappears Differential output voltage or takes a small value, although the individual normal voltage components are large can. This is the case where the Circuit arrangement of the resistors a measurement of the tension of the Substrate is no longer possible or inaccurate.

To wipe out the difference of To prevent normal voltage components, it is necessary to certain unfavorable Recognize symmetries at which the Remove normal voltage components. Such symmetry is the case that on a square substrate a square Housing with a square guide frame centric is appropriate. Such symmetry can be prevented by the substrate or the chip on which the Hall probe is appropriate with a large aspect ratio is used in which a width significantly larger than one Height or height is significantly greater than a width.

There is also a possibility that the To prevent difference in the normal voltage components in that the resistors are not in the middle of the chip but in the Be placed near the edge. In contrast to the middle of the chip, the main axis components differ on Edge of the chip even if the one described above quadratic symmetry is present. Preferably the Piezoresistive resistors not directly on the edge but with a distance from the edge which corresponds to a thickness of the Corresponds to chips because of the mechanical tension in the Near the edge extremely different to the tension in the middle are what is known as the Principle de Saint Venant and further the mechanical tension on the edge after going through thermal cycles during a Life can change significantly, making a deterministic Connection no longer exists.

Now that for p-doped integrated resistors advantageous alignment for sensitive detection of a mechanical strain of the substrate was derived now alignments for n-doped integrated resistors considered.

The piezoresistive coefficients for n-doped silicon are summarized in the following table:

From the table above it can be seen that the largest term is π n | 11 - π n | 12, so that the arrangement of the n-doped piezoresistive resistors with an angle of φ = ± 45 ° with respect to the [110 ] - direction of the (100) silicon wafer. The following relationship results for the resistance with φ = -45 °:

The following relationship also results for the arrangement of the resistor with φ = + 45 °:

The above equations now show that by subtracting R _φ - R _{φ + α} the term can be isolated with π n | 11 - π n | 12, so that:

By providing the same current for the resistor R and the resistor R _{φ + α} , for example through the H-bridge circuit according to FIG. 6a or the current mirror circuit according to FIG. 6b, a signal U _Δ can be tapped as a differential voltage which is proportional to the shear stress component σ _'12 . Hence:

From the above equation reveals that n-doped resistors preferably for detecting the shear stress component σ 'are used _12, where again it must be guaranteed that this component at the location of the chip on which the resistor is mounted for detecting the mechanical stress , does not disappear. As with the arrangement of the p-doped resistors, it must also be required for the arrangement of the n-doped resistors that the n-doped resistor is not arranged in the middle of a chip if the chip itself has a square shape and in particular one on the Chip-attached housing with a square shape is mounted centrally on the chip.

Advantageously, there are again the possibilities to choose a chip with a large aspect ratio or the Resistances near the edge with the appropriate distance to be arranged towards the edge.

Now that the advantageous orientations of p-doped Resistors and n-doped resistors for detection mechanical tension has been explained, is now said to Question are asked which resistor arrangement, i. H. p- doped resistors with φ = 0 ° and 90 ° or n-doped Resistors with an alignment of φ of + 45 ° and -45 ° am most advantageous is used.

The selection depends on which of the stress tensor, σ _'11 and σ' ₂₂ or σ _'12 is relevant for the particular application, that is the greatest influence on the Hall voltage has. Since this can change greatly for the different applications and embodiments of the chip, no generally applicable rules can be specified for this. A determination is preferably carried out by finite element simulations and / or experimental measurements in order to analyze the voltage tensor on the chip for the respective chip and the respective housing.

From a manufacturing perspective, the same is recommended Doping the resistors to detect the mechanical Tension and the reverberation area. With a current control doping of the resistor, the defined the Hall current to choose immediately. That means that at n-doped resistors are preferred when the Hall region and / or the resistor is n-doped. It's the same way manufacturing technology advantageous for a Compensation of a p-doped Hall current resistor and / or a p- doped Hall area p-doped resistors as Tension sensor elements for detecting the mechanical To use bracing.

The advantage of this approach is that manufacturing-related scattering of the piezoresistive effect both on the as a tension sensor element for detection mechanical tension serving resistors as well as on the Hall current resistance and the Hall area and impact largely compensate. For example, due to a excessive implantation dose a piezoresistive coefficient that is smaller than the nominal, desired, whereby the output signal A of the tension sensor element becomes smaller than the desired one. The opposite is true however due to the excessive implant dose Hall current resistance and / or the Hall area less than expected to respond to the piezo effect, causing to Compensation also requires a smaller strain sensor signal becomes.

Now that the generation of the tension sensor signal has been explained by an arrangement of piezoresistive resistors, the generation of the Hall current will now be discussed with reference to FIGS. 7a and 7b. Either a current control or a voltage control can be used.

Fig. 7a shows a current control in which the Hall current is independent of the resistance of the Hall probe. A first pole of a voltage source 60 , which is grounded, is connected to a first terminal of a reference resistor 62 . A second connection of the reference resistor 62 is connected to a negative input of a differential amplifier 64 . The positive input of the differential amplifier is connected to a second pole of the voltage source 60 . The second connection of the reference resistor 62 is also connected to a drain connection of a field effect transistor 66 . The gate of transistor 66 is connected to the output of differential amplifier 64 , while the drain of the transistor is connected to an input of a current mirror device 68 . An output of the current mirror device 68 is connected to the first connection of the Hall region 10 , whereas the second connection of the Hall region 10 is connected to the first pole of the voltage source 60 . The Hall region 10 also has the first Hall connection 18 and the second Hall connection 20 for tapping the Hall voltage.

As can be seen, the circuit configuration corresponds to the circuit configuration of an embodiment of the tension sensor device 24 , in which a current mirror device is used to generate an identical current. In contrast to this, the piezoresistive resistors are replaced by the reference resistor 62 and the resistance of the Hall region 10 in this circuit construction.

The control loop, which consists of the voltage source 60 , the differential amplifier 64 , the transistor 66 and the reference resistor 62 , generates a voltage defined by the voltage source 60 at the second connection of the reference resistor 62 , which according to Ohm's law flows a current through the reference resistor 62 generated. This current is copied to the Hall region 10 by the current mirror device 68 , so that a current having the same value as the current through the reference resistor 62 is generated by the Hall region 10 . The circuit structure represents a current control, since the output resistance of the current mirror device is substantially higher impedance than the resistance of the Hall region 10 , so that the current through the Hall region 10 is independent of the resistance thereof.

As is known to those skilled in the art, other circuits can be used to generate a constant current that is independent of the resistance of the Hall region. In general, however, the current source accommodated on the substrate has resistors and / or MOS transistors which are subject to a piezoresistive influence. In FIG. 7 a, this is represented by the voltage tensor σ R | i, j, which acts on the reference resistor 62 , and the voltage tensor σ H | i, j, which acts on the Hall region 10 .

As has already been explained above, the piezo Hall effect also acts on the Hall region, so that the overall influence on the sensitivity is the sum of the piezoresistive effect at the location of the current-defining resistor 62 and from the Piezo Hall effect on the Hall region 10 results. Hence:

Since the mechanical tension tensor is generally not homogeneously distributed over the chip surface, the tension tensor differs at the location of the reference resistor 62 and the Hall region 10 .

An exemplary embodiment for voltage control of an integrated Hall probe will now be explained with reference to FIG. 7b. A voltage source 70 is connected to the second connection of the Hall region 10 via a first pole, which is grounded. Furthermore, the second pole of the voltage source 70 is connected to the positive input of a differential amplifier 72 . The negative input of the differential amplifier 72 is connected in terms of feedback to an output of the differential amplifier 72 . The output of the differential amplifier 72 is also connected to the first connection 12 of the Hall region 10 . The Hall region 10 also has the first Hall connection 18 and the second Hall connection 20 for tapping the Hall voltage. By the feedback moderate interconnection of the differential amplifier 72, the voltage source acting in conjunction with the differential amplifier 72 as a voltage follower, so that the Hall region 10 defined by the voltage source 70, electric voltage U _H is present at the first terminal of the fourteenth According to Ohm's law, the Hall region 10 results in a Hall current I _H which is influenced by a piezoresistive influence on the Hall region 10 . In addition, the Hall region 10 is subject to the influence of the Piezo Hall effect, so that the overall sensitivity is as follows:

In contrast to the current control, the sensitivity in the voltage control is therefore dependent only on a mechanical voltage tensor at the location of the Hall region 10 , the sensitivity being influenced by the Piezo Hall effect and the piezoresistive effect of the Hall region 10 .

The generation of the signal for compensation by the compensation device 26 will be explained in more detail below with reference to the exemplary embodiments according to FIG. 5 (cover common mode potential) and according to FIG. 5b (trough common mode potential).

In both exemplary embodiments, the compensation device 26 amplifies the tension sensor signal A with an amplification factor V _A. Consequently, for the first exemplary embodiment according to FIG. 5 there is a dependency of the sensitivity according to the following formulas:

The first equation describes the case where Detection of the mechanical stress p-doped piezoresistive Resistors used in a 0 ° or 90 ° arrangement become. The equation below describes the case that is n-doped Piezoresistive resistors as strain sensor elements be used in an arrangement with + 45 ° and -45 ° are arranged.

Furthermore, for the exemplary embodiment according to FIG. 5b, the following results for the Hall sensitivity:

The first equation describes the case of p-doped piezoresistive resistors in an arrangement of 0 ° or 90 °, while the equation below describes the case that as tension sensor elements n-doped piezoresistive Resistors with an arrangement of + 45 ° or -45 ° used become.

As already mentioned, the superscript describes a place on the substrate. Through the equations above consequently, the components in the three different places, d. H. the location of the reverb area, the location of the current defining Resistance and the location of the mechanical Linked piezoresistive resistance. Since these are generally not identical, they result complicated functional dependencies.

In order to carry out a compensation, the gain V _A is determined in such a way that the sensitivity S becomes independent of mechanical tension on the substrate. In this case, S = S ₀₀ applies, whereby the following dependencies result for the variable V _A U ₀ :

The first equation of the above equations describes the case of p-doped piezoresistive tension sensor resistors with an influence on the lid / common mode potential by the compensation device 26 , the second equation describes the case of n-doped piezoresistive tension sensor resistors with an influence on the lid / Common-mode potential, the third equation describes the case of p-doped piezoresistive strain sensor resistors with an influence on the well / common-mode potential and the fourth equation describes the case of n-doped piezoresistive strain sensor resistors with an influence on the well / common Mode potential by the compensation device 26 .

The suitable gain V _A required for compensation must be determined from numerical calculations for tensioning the housing, which can be very extensive, and / or from experimentally determined data.

The above derivations were based on the assumption performed that on the substrate a constant temperature is present. However, it is known that the piezoresistive Coefficients, the Hall piezo coefficients as well Change the tension of the substrate depending on the substrate temperature. It is therefore advantageous to make the compensation dependent on perform the substrate temperature, as in a The embodiment described below is explained.

In order to achieve a temperature-dependent compensation of mechanical voltage states, the electrical voltage output by the compensation device 26 must have a temperature response that compensates for these temperature-related influences, such that the Hall voltage at least in a certain temperature range is independent of the stress influences of the substrate and independent of the temperature of the substrate.

The temperature dependence of the substrate tension arises from the fact that the parties involved Materials typically the silicon semiconductor material the sealing compound, the guide frame and an adhesive include different thermal expansion coefficients exhibit. This can also lead to a lifting of the Tension on the substrate come when the potting compound have high temperature above their Glass activation temperature is.

With regard to the temperature dependencies of the piezoresistive coefficients π _{i, j} and the piezo-Hall coefficients P _{i, j} , it should be noted that they have pronounced temperature coefficients, but for low-doped resistors and Hall ranges, these temperature coefficients are robust to process-related fluctuations in the dopant concentrations are in the usual measure. Furthermore, the temperature coefficients of the piezoresistive coefficients π _{i, j} and the piezo Hall coefficients P _{i, j} differ significantly.

This raises the term


only for a certain temperature, whereas the same for other temperatures affects the sensitivity of the Hall probe in the presence of mechanical tension.

In one embodiment of the present invention, the influence determined by the temperature is compensated for by applying an electrical voltage U ₀ to the tension sensor element, which has a temperature response U ₀ (T), so that the equations 14 apply to all temperatures. . 6b, this may take place in that the voltage source 40 or voltage source 50 is connected to a temperature controller that controls the voltage source 40 or voltage source 50 so that it has a preset temperature response with reference to Fig. 6a and Fig. The temperature control device has a temperature sensor that detects a temperature of the substrate.

Using the detected temperature value of the substrate, the control device then delivers a signal which controls the voltage source 40 or 50 , so that the electrical voltage applied by the voltage source 40 or 50 is temperature-dependent and has a temperature response, so that that output by the tension sensor element Tension sensor signal A also has a temperature response. Since the tension sensor signal A is received by the compensation device 26 and the compensation device 26 performs a compensation using the tension sensor signal A, the compensation performed is also temperature-dependent, the temperature influence on the piezo sensitivity of the Hall sensor system being compensated for by the suitably chosen temperature response of the voltage source.

The appropriate choice of the temperature response must be from the known temperature coefficients of the piezoresistive Coefficients and the Piezo Hall coefficient can be determined.

The setting of a defined temperature response can also done by known circuits that the Take advantage of the temperature dependence of the band gap of semiconductors.

Fig. 8 shows such a known circuit which includes a temperature dependent electrical voltage U (t) due to a so-called produced bandgap principle. A first transistor 74 with an emitter area F1 and a second transistor 76 with an emitter area F2 are each connected to a diode by connecting a collector and base, the collector or base being connected to ground. As a result, transistor 74 and transistor 76 are connected to form a diode and are connected to one another on the ground side. A first terminal of a resistor 78 is connected to the emitter of transistor 76 . The second terminal of resistor 78 is connected to a negative input of a differential amplifier 80 . The positive input of differential amplifier 80 is also connected to the emitter of transistor 74 . Furthermore, the emitter of transistor 74 is connected to a first input of a controllable current source 82 . The output of the differential amplifier 80 is connected to a control input of the adjustable current source 82 . Furthermore, the second connection of the resistor 78 is connected to a first connection of a resistor 84 , the second connection of the resistor 84 being connected to a second input of the controllable current source 82 . The mode of operation of the circuit construction is based on the fact that a lower electrical voltage drops in transistor 76 when the current between emitter and collector is the same, since transistor 76 has an emitter area F2 which is larger than emitter area F1 of transistor 74 . Differential amplifier 80 compares the potential of the emitter of transistor 74 and the second terminal of resistor 78 , the controllable current source 82 being equal to a current flowing from the second input of the controllable current source 82 to the ground through the emitter of transistor 74 sets a current that flows from the second input of controllable current source 82 to transistor 84 via transistor 84 , transistor 78 and transistor 76 . The control loop adjusts the current value I, which flows through the resistor 74 or through the resistors 84 , 78 and the transistor 76 , such that the voltage drop across the transistor 76 and across the resistor 78 is equal to the voltage drop across the transistor 74 , Since the diffusion voltages of the transistor 74 and the transistor 76 now have a temperature response due to the temperature dependence of the semiconductor bandgaps, the temperature response of the current I can be adjusted by adjusting the ratio of the emitter areas F1 and F2 and by a suitable choice of the resistance values of the resistors 78 and 84 can be set to a desired temperature response.

By tapping an electrical voltage between ground and the second connection of the resistor 84 , a temperature response of an electrical voltage U (T) can be set via the temperature response of the current I. This electrical voltage U (T) is now buffered by a voltage follower and applied as a temperature-dependent electrical voltage instead of the electrical voltage U ₀ to the tension sensor elements, as shown in FIGS . 6a and 2b.

The generation of the electrical tension sensor element voltages by the known bandgap principles, such as, for example, the circuit according to FIG. 8, also has the advantage that such a circuit is easy to produce in integrated circuit technology, yet being insensitive to mechanical stresses of the Substrate is largely achieved. Consequently, both the absolute value of the tension sensor voltage U ₀ and the temperature response of U _{0 can} be reproduced with a sufficiently good accuracy.

The temperature dependency of U ₀ represents an advantage in that it is only through this temperature dependency that it is possible to generate a temperature-compensated signal on the chip which is proportional to the tension of the chip. In contrast to known tension sensors, in which resistance rosettes are used, but which are measured individually and therefore have to be provided with connections in order to connect them to further processing devices, the solution described provides a tension sensor voltage that is generated from a supply voltage of the chip and subsequently a tension _sensor signal U _Δ , which is applied as an input signal to the compensation device 26 , represents a completely self-sufficient principle.

The concept according to the invention offers great flexibility, because both for the selection of the tension sensor device (n- Type, p-type, arrangement and location on the substrate) as well as for performing compensation (coverage / common mode Voltage, trough / common mode voltage) several options exist. The individual options can also can be combined, resulting in a large amount of Realization possibilities of the present invention offers.

An embodiment in which tension sensor elements of different types and different compensation options are used is explained in more detail below with reference to FIG. 9.

According to FIG. 9, the tension sensor device has a plurality of tension sensor elements 85 arranged on a substrate. The tension sensor elements can differ in terms of doping (n-doping, p-doping) and in terms of an alignment. A strain sensor element has a pair of resistors arranged in predetermined directions on the substrate, as previously described. Furthermore, the tension sensor elements can differ in the location at which they are arranged.

Each of the tension sensor elements has a voltage source that supplies a tension sensor voltage U ₀ for each tension sensor element. In an alternative exemplary embodiment, each of the voltage sources for the tension sensor elements has its own temperature response, which enables improved temperature compensation.

Each of the tension sensor elements generates a tension sensor signal A ⁽¹⁾ , A ⁽ⁿ⁾ which is proportional to the tension sensor voltage U (1) | 0, U (n) | 0. The tension sensor signal is proportional to the mechanical tension at the location of the tension sensor element, so that the following applies for the nth tension sensor element:

Each of the tension sensor signals A ⁽¹⁾ , A ⁽ⁿ⁾ generated by the tension sensor elements is applied via an output of the respective tension sensor elements to a first (E ⁽¹⁾ ) to n-th (E ⁽ⁿ⁾ ) input of a combination device. The combination device carries out a linear combination of the tension sensor signals A ⁽¹⁾ , A ⁽ⁿ⁾ and generates a first output signal A1 and a second output signal A2. The first output signal A1 is applied to the positive input of a differential amplifier 92 via a first output 88 . The output of the differential amplifier 92 is applied to the first connection 12 of a Hall region 10 . A first Hall connection 18 and a second Hall connection 20 , at which the Hall voltage U _h is tapped as a differential voltage, are each connected to a first and second input of an average device 94 . An output of the mean device 94 is also connected to the negative input of the differential amplifier 92 . The second output 90 of the combination device 86 is also connected to a cover 22 of the Hall region 10 , the Hall region 10 being arranged in a trough of the substrate. Hall area 10 is also connected to a power generation device, so that the Hall probe system is operated in storm control, as was shown in FIG. 7a.

The combination device generates the first output signal A1 from the tension sensor signals A ⁽¹⁾ , A ⁽ⁿ⁾ using suitable weights for the tension sensor signals, in accordance with the regulation

A1 = a ⁽⁰⁾ + a ⁽¹⁾ .E ⁽¹⁾ +. , , + ⁾ + a ⁽ⁿ⁾ .E ⁽ⁿ⁾

Accordingly, the output signal A2 is generated with a second weighting in accordance with the following regulation:

A2 = b ⁽⁰⁾ + b ⁽¹⁾ .E ⁽¹⁾ +. , , + ⁾ + b ⁽ⁿ⁾ .E ⁽ⁿ⁾ .

The generation of the output signals A1 and A2 as weighted linear combinations from the tension sensor signals now has the advantage that certain tension components which have a strong influence on the change in the Hall voltage at the location of the Hall region 10 can be emphasized, so that the output signals A1 and A2 compensation can be performed with great accuracy.

In one embodiment, the combination device is designed such that only an addition of the strain sensor signals A ⁽¹⁾ , A ^{(n) is} carried out, the weighting being carried out by the electrical voltages U ₀ applied to the strain sensor elements. This has the advantage that the combination device 86 is of simple design, with the tension sensor voltage U ₀ nevertheless making it possible to emphasize individual tension components of the mechanical tension tensor and to set the weighting factors by setting the electric voltage value.

Furthermore, in a preferred embodiment for each tension sensor element has its own temperature response adjusted to the different temperature dependence of the Components of the mechanical stress tensor take into account and compensation with high accuracy perform.

The selection of the tension sensor elements with regard to doping, alignment and location on the substrate is determined by the criterion that the essential components of the mechanical tension tensor on the substrate are to be detected. The locations of the tension sensor elements should also be selected such that there is a deterministic conclusion with the simplest possible connection between the tensions present at the locations of the tension sensor elements and the tensions at the location of the Hall region and the location of the current-defining resistance at which the Hall voltage is influenced U _h takes place. To determine these selection criteria, it is necessary to carry out calculations, for example using a finite element method, of the stresses on the substrate and / or experimental measurements. With the aid of these calculated or experimentally obtained results, the tension sensor elements can then be selected together with the determination of the suitable weights of the linear combinations and the tension sensor voltage or the tension sensor voltage with a temperature profile.

The first signal A1 generated by the combination device 86 is applied via the first output 88 to the positive input of the differential amplifier 92 . The output signal A1 represents an electrical voltage which is to be applied between the common mode point of the Hall region 10 and a trough region in which the Hall region 10 is arranged, in order to compensate for the stresses present on the substrate. As has already been explained, the common mode potential can be detected by averaging the potentials at the first Hall connection 18 and the second Hall connection 20 . By now the potential of the first Hall terminal 18 to the first input of the averaging means 94 and the potential of the second Hall terminal 20 to the second input of the averaging means 94 is applied, is located at the output of the averaging means 94, a potential at which the potential of the common-mode Point of the Hall area 10 corresponds.

Since the common mode potential is applied to the negative input of the differential amplifier 92 , the differential amplifier 92 acts as an active part of a control circuit and adjusts the potential at the first connection 12 of the Hall region 10 so that the common mode potential is opposite Ground has a value that corresponds to the output signal A1. Since, in this exemplary embodiment, the Hall region 10 is arranged in a trough which is connected to ground, the common mode point, after performing the compensation described above, has an electrical voltage in relation to the trough region which corresponds to the desired output signal A1.

As has already been described, this affects the space charge zone in the Hall region 10 , which in turn influences the sensitivity in such a way that influences due to mechanical tension are reduced or compensated for.

As indicated by the arrows in FIG. 9, the sensitivity S is influenced by the piezoresistive influencing and piezo-Hall influencing in the Hall region 10 and the piezoresistive influencing of a resistance which defines the Hall current in the current generating device 96 .

It should be noted at this point that the value of the Hall current is not changed by the change in the common mode potential, since the Hall current in this exemplary embodiment is generated by the current generating device 96 in a current controller.

Furthermore, the second output signal A2 is applied to the cover 22 via the second output 86 of the combination device. Since the potential between the cover 22 and the common mode potential of the Hall region 10 is decisive for influencing, but the common mode potential is already set to a value by the differential amplifier 92 , the output signal A2 is applied to the cover 22 to set it to a defined potential. For this purpose, the output signal A2 must be suitably determined in the compensation device 26 , taking into account the fixed common mode potential.

Due to the suitable coordination of the coefficients in the linear combination, the tension sensor voltages and the arrangement of the voltage sensors on the silicon chip, this circuit compensates the disruptive piezo effects on the Hall probe and on the associated power generation device with great accuracy. In addition, as described above, by providing a defined temperature response of the tension sensor voltage for each tension sensor element, the compensation of the mechanical tension can be carried out in a wide temperature range, so that the magnetic sensitivity and consequently the Hall voltage is largely independent of mechanical tension of the chip. Legend: 10 Hall area
12 first connection
14 second connection
15 differential amplifiers
18 first Hall connection
20 second Hall connection
21 adding device
22 cover
23 voltage source
24 sensor device
25 voltage source
26 compensation device
26 a exit
26 b output
26 c entrance
26 d entrance
27 control device
28 first piezoresistive resistor of a first type
29 control device
30 second piezoresistive resistor of a first type
31 N-MOS transistor
32 first piezoresistive resistor of a second type
33 differential amplifier
34 second piezoresistive resistor of a second type
35 a resistance
35 b resistance
36 first node
37 resistance
38 second node
39 Magnetic field detection device
40 voltage source
41 differential amplifier
42 first tap
43 voltage source
44 second tap
45 resistance
46 piezoresistive resistor of a first type
48 piezoresistive resistor of a second type
50 voltage source
52 differential amplifier
54 transistor
56 current mirror device
58 tub
60 voltage source
62 Reference resistance
64 differential amplifiers
66 MOS transistor
68 Current mirror device
70 voltage source
72 differential amplifier
74 first transistor
76 second transistor
78 resistance
80 differential amplifiers
82 adjustable power source
84 resistance
86 combination device
88 first exit
90 second exit
92 differential amplifier
94 Averaging facility
96 power generation facility

Claims (29)

1. Hall probe system with the following features:
a conductive Hall region ( 10 ) through which a Hall current can flow and from which a Hall voltage can be tapped;
means ( 26 ; 27 ; 29 ) for generating an electrical control voltage as a function of an influencing parameter which represents an influence of an external variable on the conductive Hall region ( 10 ); and
an electrode region ( 22 ; 58 ) which is electrically insulated from the Hall region ( 10 );
in the case of a control voltage applied between the electrode area ( 22 ; 58 ) and the conductive Hall area ( 10 ), the Hall voltage is controlled by influencing the charge carriers available for the Hall current by the applied control voltage. 2. Hall probe system according to claim 1, wherein the Hall probe system has a substrate, wherein the Hall region ( 10 ), the control device and the electrode region ( 22 ; 58 ) are arranged in the substrate. 3. Hall probe system according to claim 1 or 2, wherein the electrode region ( 22 ) is electrically insulated from the Hall region ( 10 ) by an insulation layer which is arranged between the Hall region ( 10 ) and the conductive cover, the influencing of the for the Hall current available charge carriers by depleting or enriching charge carriers in the Hall area ( 10 ). 4. Hall probe system according to claim 1 or 2, in which the electrode region ( 58 ) is electrically insulated from the Hall region ( 10 ) by a space charge zone of a blocked pn junction, wherein an influencing of the charge carriers available for the Hall current by changing the expansion the space charge zone. 5. Hall probe system according to claim 4, in which the electrode region is a doped region ( 58 ) which adjoins the conductive Hall region ( 10 ), the doped region ( 58 ) having a doping type which is opposite to a doping type of the Hall region ( 10 ) , the electrically insulating space charge zone being formed between the Hall region ( 10 ) and the doped region ( 58 ). 6. Hall probe system according to claim 5, wherein the doped region ( 58 ) has a doping concentration which is greater than a doping concentration of the Hall region ( 10 ). 7. Hall probe system according to claim 6, wherein the doped region is either a doped cover, a doped well ( 58 ) of the substrate or the substrate. 8. Hall probe system according to claim 3, wherein the electrode region is a conductive cover ( 22 ), wherein the conductive cover has a continuous layer, a layer with slots, a lattice-shaped structure or a rod-shaped structure. 9. Hall probe system according to one of claims 1 to 8, wherein the electrode region ( 22 ; 58 ) has at least a first section and at least a second section which is electrically insulated from the first, the electrical control voltage for controlling the Hall voltage on the at least a first section is present, while a constant electrical voltage is present at the at least one second area. 10. Hall probe system according to claim 3, 8 or 9, wherein the electrode area is a conductive cover ( 22 ) having a plurality of mutually insulated layers. 11. Hall probe system according to one of claims 1 to 10, wherein the means ( 26 ; 27 ; 29 ) for generating an electrical control voltage further comprises means ( 12 , 15 , 18 , 20 , 21 ; 92 , 94 ) for regulating the electrical potential of the common mode point of the Hall region ( 10 ) to a predetermined potential. 12. Hall probe system according to one of claim 11, in which the device ( 12 , 15 , 18 , 20 , 21 ; 92 , 94 ) for regulating the electrical potential of the common mode point of the Hall region ( 10 ) is designed to measure the electrical voltage between the common mode point of the Hall probe and the electrode area ( 22 ; 58 ) to the electrical control voltage. 13. Hall probe system according to one of claims 1 to 12, wherein the device ( 26 ; 27 ; 29 ) is designed to generate an electrical control voltage in order to generate a second electrical control voltage as a function of an influencing parameter of the conductive Hall region ( 10 ), wherein the Hall probe system in addition to the one electrode area ( 22 ; 58 ) has a second electrode area which is insulated from the Hall area ( 10 ) and is designed to control the Hall voltage by influencing the charge carriers available for the Hall current by the applied second control voltage , 14. Hall probe system according to claim 13, wherein the one electrode region is a conductive cover ( 22 ) which is electrically insulated from the Hall region ( 10 ) by an insulation layer, while the second electrode region is a doped region ( 58 ) of the substrate which is connected to the conductive Hall area ( 10 ) adjoins. 15. Hall probe system according to one of claims 1 to 14, wherein the Hall probe system further comprises a magnetic field detection device ( 39 ) to detect the magnetic induction passing through the conductive Hall region ( 10 ) and wherein the device ( 26 ; 27 ; 29 ) for generating an electrical Control voltage is designed to generate the electrical control voltage depending on the detected magnetic induction such that a non-linear magnetic field influence on the Hall voltage is reduced by the application of the control voltage. 16. Hall probe system according to one of claims 1 to 14, wherein the Hall probe system further comprises a temperature detection device for detecting the temperature of the Hall region ( 10 ), and wherein the means ( 26 ; 27 ; 29 ) for generating an electrical control voltage is configured to generate the electrical control voltage as a function of temperature in such a way that temperature effects on the Hall voltage are reduced by the application of the control voltage. 17. Hall probe system according to one of claims 2 to 14, wherein the Hall probe system further comprises a strain sensor device ( 24 ) for detecting a mechanical strain of the substrate and for generating a strain sensor signal that depends on a mechanical strain of the substrate, and wherein the device ( 26 ; 27 ; 29 ) is configured to generate an electrical control voltage in order to receive the strain sensor signal and to generate the electrical control voltage using the strain sensor signal. 18. Hall probe system according to claim 17, in which the tension sensor device ( 24 ) has a tension sensor element which is arranged on the substrate, the tension sensor element having a voltage source ( 40 ; 50 ) for generating a current in the tension sensor element, the tension sensor signal (A) can be tapped as an electrical voltage on the tension sensor element. 19. Hall probe system according to claim 18, wherein the tension sensor element is an H-bridge circuit having a first and second branch, wherein in the first branch a first resistor of a first type ( 28 ) and a second resistor of a second type ( 34 ) in Are connected in series and between them a first tap point ( 42 ) is defined and a first resistor of the second type ( 32 ) and a second resistor of the first type ( 32 ) are connected in series in the second branch and between them a second tap point ( 44 ) is defined, wherein the voltage source ( 40 ) is designed to apply a voltage to the first and second branches, which are connected in parallel, and the tension sensor signal can be tapped at the first ( 42 ) and second ( 44 ) tapping point. 20. Hall probe system according to claim 18, wherein the tension sensor element is a circuit arrangement of a resistor of a first type ( 46 ), a resistor of a second type ( 48 ) and a current mirror device, the current mirror device ( 56 ) being designed to detect a current through the application of an electrical voltage by the voltage source ( 50 ) to the resistor of a first type ( 46 ) is generated in the resistor of a second type ( 48 ), the strain sensor signal being the voltage difference of the electrical voltage applied to the resistor of the first type ( 46 ) drops, and the electrical voltage can be tapped, which drops across the resistor of the second type ( 48 ). 21. Hall probe system according to claim 19 or 20, wherein the resistor of the first type ( 28 , 30 ; 46 ) is an integrated resistor having a current direction in a first direction of the substrate, and the resistor of the second type ( 32 , 34 ; 48 ) is an integrated resistor that has a current direction in a second direction of the substrate. 22. Hall probe system according to claim 21, wherein the substrate is a ( 100 ) substrate made of silicon and the resistor of the first type ( 28 , 30 ; 46 ) is a p-doped integrated resistor with a current direction in a [100] direction , and the resistor of the second type ( 32 , 34 ; 48 ) is a p-doped integrated resistor having a current direction in a direction rotated in a plane of the substrate by an angle of 90 ° with respect to the [100] direction is. 23. Hall probe system according to claim 21, wherein the substrate is a ( 100 ) substrate made of silicon and the resistor of a first type ( 28 , 30 ; 46 ) is an n-doped integrated resistor having a current direction in a direction that is rotated by + 45 ° in the plane of the substrate with respect to the [100] direction, and the resistor of a second type is an n-doped integrated resistor which has a current direction in a direction of the substrate which is in the plane of the substrate is rotated at an angle of 45 ° to the [100] direction. 24. Hall probe system according to one of claims 17 to 23, in which the tension sensor device ( 24 ) has a plurality of tension sensor elements, each of the tension sensor elements having a voltage source in order to apply an electrical voltage to each of the tension sensor elements, so that a tension sensor signal can be tapped at each tension sensor element, which depends on the mechanical tension and the sensor voltage applied by the voltage source, and wherein the means ( 26 ) for generating an electrical control voltage is designed to use the strain sensor signals to generate an electrical control voltage for reducing an influence of a mechanical tension on the Hall voltage. 25. Hall probe system according to one of claims 17 to 24, wherein the tension sensor element further comprises a temperature detection device for detecting a temperature of the substrate and outputting a temperature signal that depends on a temperature, and a temperature control device that is configured to use the temperature signal To control the voltage source ( 40 ; 50 ) in such a way that the electrical control voltage generated by the device ( 26 ) for generating an electrical control voltage reduces an influence of a mechanical tension on the Hall voltage for different temperatures. 26. Hall probe system according to claim 24 or 25, wherein the device ( 26 ) for generating an electrical control voltage comprises a combination device ( 86 ) which is designed to generate a first compensation signal (A1) by a first combination of the tension sensor signals and by a second combination of the strain sensor signals to generate a second compensation signal (A2), and wherein the means ( 26 ) for generating an electrical control voltage comprises a first compensation device ( 92 , 94 ) which receives the first compensation signal to use an influence thereof reduce mechanical tension of the substrate to the Hall voltage and has a second compensation device which receives the second compensation signal in order to reduce the influence of a mechanical tension of the substrate on the Hall voltage using the same. 27. A method for producing a Hall probe system comprising the following steps:
Generating a conductive Hall region ( 10 ) through which a Hall current can flow and from which a Hall voltage can be tapped;
Generating a device ( 26 ; 27 ; 29 ) for generating an electrical control voltage as a function of an influencing parameter which represents an influence of an external variable on the conductive Hall region ( 10 ); and
Generating an electrode area ( 22 ; 58 ) which is electrically insulated from the Hall area ( 10 ) and is designed to make the Hall voltage available at a control voltage applied between the electrode area ( 22 ; 58 ) and the conductive Hall area by influencing the Hall current to control standing charge carriers by the applied control voltage. 28. A method for controlling a Hall voltage that can be tapped from a Hall region ( 10 ), with the following steps: a) detecting an influence parameter of the Hall region ( 10 ), which represents an influence of an external variable on the conductive Hall region ( 10 ); b) generating an electrical control voltage as a function of the detected influencing parameter of the Hall region ( 10 ); c) applying the electrical control voltage between the electrode region ( 22 ; 58 ) and the conductive region in order to control the Hall voltage by influencing the charge carriers available for the Hall current. 29. The method according to claim 28, wherein step (a) detecting the mechanical tension of a substrate on which the conductive Hall region ( 10 ) is arranged, step (b) generating an electrical control voltage as a function of the mechanical tension of the substrate and Step (c) comprises applying the electrical control voltage between the electrode region ( 22 ; 58 ) and the conductive region in order to reduce an influence of the mechanical tension of the substrate on the Hall voltage.