BG66804B1 - In-plane magnetosensitive hall effect device - Google Patents

Abstract

The in-plane magnetosensitive Hall effect device contains three identical in-plane magnetosensitive Hall effect sensors - the first (1), the second (2) and the third (3), consisting of an n-type semiconductor substrate (4, 5 and 6), as well as on one side of each of the pads (4, 5 and 6) are formed from left to right sequentially and at equal distances from one another three rectangular ohmic contacts, first (7, 8 and 9), second (10, 11 and 12) and thirds (13, 14 and 15), located parallel to their long sides, as the second contacts (10, 11 and 12) are central and symmetrically to them on both its long sides are located the other pairs of contacts (7 and 13), (8 and 14), (9 and 15). The contact (11) of the sensor (2) is connected to one of the terminals of the current source (16). The contact (8) of the sensor (2) is connected to the contact (7) of the sensor (1), the contact (14) of the sensor (2) is connected to the contact (15) of the sensor (3), and the contact (13) of the sensor (1) is connected to the contact (9) of the sensor (3) and to the other terminal of the current source (16). The contact (10) of the sensor (1) and the contact (12) of the sensor (3) are connected to the input of the first measuring amplifier (17), and the first (8) and third contact (14) of the sensor (2) are connected to the input of a second measuring amplifier (18). The contact (10) of the sensor (1) and the contact (8) of the sensor (2) are connected at the same time only to the non-inverting or respectively only to the inverting inputs of the amplifiers (17 and 18). The outputs of the amplifiers (17 and 18) are connected to the input of a differential amplifier (19) whose output is an output (20) of the Hall effect device. The magnetic field (21) is parallel to the long sides of the contacts (7, 8, 9, 10, 11, 12, 13, 14 and 15).

Description

(54) PLANE-MAGNETIC SENSITIVE DEVICE OF THE LIVING ROOM

Field of technology

The invention relates to a plane-magnetosensitive Hall device, applicable in the field of non-contact measurement of angular and linear displacements, positioning of objects in the plane and space, robotics and mechatronics, cognitive systems and automation, electrical engineering, biomedical control, energy technology and low-field magnetometry, military affairs and security, etc.

BACKGROUND OF THE INVENTION

A planar magnetic-sensitive Hall device is known, comprising a plane-magnetic Hall sensor, two load resistors of the same value and a current source. The Hall sensor consists of a semiconductor substrate with p-type impurity conductivity, on one side of which are formed at equal distances from each other three rectangular ohmic contacts - first, second and third, located parallel to their long sides, the second being central and relative to it symmetrically on its two long sides are the other two contacts. The first and third contacts through the load resistors are connected to one terminal of the current source, the other terminal of which is connected to the central contact. The measured magnetic field is parallel to both the plane of the substrate and the long sides of the rectangular contacts, and the first and third contacts are the output of the Hall device [1,2,3].

A disadvantage of this planar magnetic-sensitive Hall device is its limited sensitivity (conversion efficiency), due to the use of resistors in the output, which are passive components and determine at a fixed supply current only one Hall voltage.

Another disadvantage is the presence of parasitic output voltage in the absence of a magnetic field (offset) as a result of electrical asymmetry caused by geometric asymmetry in the location of the first and third contact relative to the central, inevitable technological imperfections, mechanical stresses most often from chip housing and etc.

Technical essence of the invention

It is an object of the invention to provide a plane-magnetic Hall-sensitive device with increased sensitivity and compensated offset.

This problem is solved with a plane-magnetic Hall sensor, containing three identical plane-magnetic Hall sensors - first, second and third, consisting of a semiconductor substrate with p-type impurity conductivity; as on one side of each of the pads are formed from left to right in series and at equal distances from each other three rectangular ohmic contacts - first, second and third, located parallel to their long sides, the second contacts being central and symmetrical to them from both long sides are located the remaining pairs of contacts. The central contact of the second Hall sensor is connected to one terminal of a power source. The first contact of the second sensor is connected to the first contact of the first sensor, the third contact of the second sensor is connected to the third contact of the third sensor, and the third contact of the first sensor is connected to the first contact of the third sensor and the second terminal. The central contact of the first sensor and the central contact of the third sensor are connected to the input of the first measuring amplifier, and the first and third contacts of the second sensor are connected to the input of the second measuring amplifier. The central contact of the first sensor and the first contact of the second sensor are connected simultaneously only to the non-inverting or only to the inverting inputs of the two measuring amplifiers. The outputs of these amplifiers are connected to the input of a differential amplifier, the output of which is the output of the Hall device, as the measured magnetic field is parallel to both the planes of the pads and the long sides of the rectangular contacts.

An advantage of the invention is the increased magnetic sensitivity as a result of subtraction by the differential amplifier at a fixed supply current of two Hall voltages with opposite sign.

Descriptions of issued patents for inventions № 01.2 / 31.01.2019

Another advantage is the possibility for maximum reduction or complete compensation (reset) of the parasitic output voltage of the Hall device (offset) by subtracting with the differential amplifier the output signals from the measuring amplifiers containing the individual offsets of the Hall sensors, which are almost equal and are with the same sign.

Another advantage is the increased measurement accuracy as a result of the compensation of the parasitic offset.

An advantage is the full technological compatibility of the three Hall sensors and operational amplifiers with planar silicon technologies used in the production of integrated circuits in microelectronics, which allows their simultaneous implementation on a common silicon chip, including additional interface electronics processing the output signal of the device. .

Explanation of the attached figure

The invention is illustrated in more detail by one of its embodiments given in the attached figure 1.

Examples of the invention

The planar magnetic-magnetic Hall device contains three identical plane-magnetic Hall sensors - first 1, second 2 and third 3, each of which consists of a semiconductor substrate 4, 5 and 6 with p-type impurity conductivity, as on one side of the each of the pads 4, 5 and 6 are formed from left to right in series and at equal distances from each other three rectangular ohmic contacts - first 7, 8 and 9, second 10, 11 and 12 and third 13, 14 and 15, located parallel to their long sides. The second contacts 10, 11 and 12 are central and relative to them symmetrically on their two long sides are respectively the other pairs of contacts 7 and 13, 8 and 14, 9 and 15. The central contact 11 of the second sensor 2 is connected to one terminal of the power source 16. The first contact 8 of the second sensor 2 is connected to the first contact 7 of the first sensor 1, the third contact 14 of the second sensor 2 is connected to the third contact 15 of the third sensor 3, and the third contact 13 of the first sensor 1 is connected to the first contact 9 of the third sensor 3 and the second terminal of the current source 16. The central contact 10 of the first sensor 1 and the central contact 12 of the third sensor 3 are connected to the input of the first measuring amplifier 17, and the first 8 and third contact 14 of the second sensor 2 are connected to the input of the second measuring amplifier 18. The central contact 10 of the first sensor 1 and the first contact 8 of the second sensor 2 are connected simultaneously only to the non-inverting or only to the inverting inputs of the two measuring amplifiers. and the amplifier 17 and 18. The outputs of these amplifiers 17 and 18 are connected to the input of a differential amplifier 19, the output of which is the output 20 of the Hall device, the measured magnetic field 21 being parallel to the planes of pads 4, 5 and 6, and on the long sides of the rectangular contacts 7, 8, 9, 10, 11, 12, 13, 14 and 15.

The operation of the planar magnetosensitive Hall device according to the invention is as follows. The area of the semiconductor substrate 4 between contacts 7 and 13 of the first sensor 1, the same area of the third sensor 3 between contacts 9 and 15, and the areas between contacts 11 and 8, respectively 11 and 14 of the second sensor 2 are essentially resistors R _n R _? R _n and R _{15 d} . For them are the relations R _n = R _n <R _? = R _{15 g} . The pairs of resistors R _n and R _? and R _n and R _{15 e, respectively,} are connected in series, they. R _ng + 1C ₁₃ = R _{int 3} and R _{n 14} + R _{15 d} = R _int2 . At the same time, the total resistors R and R are connected in parallel to the current source 16. As a result, two equal current components I and I _e, respectively, flow. Given the ratios between the resistors R = R <R ₇₁₃ = R _{15 e the} mode of operation of the three sensors 1, 2 and 3 is a current generator, I _s = 1 _{n 8 713} + 1ts 1415 ₉ ⁼ const. As can be seen from Figure 1, the circuitry of the Hall 2 sensor of the known solution [1-3] has been substantially modified. The load resistors, which are passive elements in the new proposal, have been removed and replaced with active Hall 1 and 3 sensors. Their operation is determined by the same supply current I ₇ and I _e controlling sensor 2. This concludes the first manifestation of the unexpected positive effect of the new technical solution. The flow of the current components I _{ng 713} and 1 _{n 1415 d} through the two pads 4 and 6 is of a resistive nature, they. for the equations R ₇₁₃ = R _{15 e} and R _n = R _n in the absence of magnetic field B 21 at the output V _g (B = 0) of the sensor 2 should

Descriptions of issued patents for inventions № 01.2 / 31.01.2019 no parasitic stress (offset), V _g (B = 0) = 0. In contrast to this idealized case for geometric asymmetry, technological imperfections, mechanical stresses, etc., occurred in the implementation of sensors 1, 2 and 3 always at this output V _{g 14} there is an offset V _{g 14} (B = 0) / 0. Due to the planarity of all rectangular ohmic contacts 7, 8, 9, 10, 11, 12 , 13, 14 and 15, which at field B = 0 represent equipotential planes, the current trajectories are initially directed vertically downwards in the volume of the pads 4, 5 and 6, then become parallel to the upper surface of the structures and finally become perpendicular to the respective upper surfaces. Therefore, the current lines in these plane-magnetic Hall sensors are curvilinear. According to the switching scheme of the first and third sensors 1 and 3, Figure 1, the directions of the equal in value supply currents in them are opposite. Given this mirror symmetry of the two structurally identical converters 1 and 3, they can be considered as functionally united in their operation. This means that the differential output V ₁₀₁₂ , formed by contacts 10 and 12 of the two sensors 1 and 3, in the absence of a magnetic field B = 0, ideally also lacks offset, V ₁₂ (B = 0) = 0. But also here as a result of geometric asymmetry, technological imperfections, mechanical stresses, etc. the output V _{10 is} always present offset V ₁₀₁₂ (B = 0) / 0. Taking into account the fact that all three Hall sensors 1, 2 and 3 are the same in geometry and construction, and are realized in a single cycle through the same with exceptional High quality processes of silicon integrated technology means that the offsets of the outputs V _{g 14} (B = 0) / (I and V ₁₀₁₂ (B = ()) # () should have the same sign and almost the same This concludes the second manifestation of the unexpected positive effect of the new technical solution.

When placing the planar-magnetosensitive Hall device in magnetic field B 21, the following galvanomagnetic processes take place. For example, if the polarity of the terminal of the current source 16 to which the contact is connected is negative and the magnetic field B 21 in the direction indicated in Figure 1, by the corresponding Lorentz forces F _L = qV _di x In the trajectories of the moving in the volumes of the pads 4 , 5 and 6 electrons with average drift V _{d |} speed change as follows. In the substrate 4 the current lines 1 ₇ are extended inwards in the volume and on the surface in the area with the contact 10 additional positive loads are generated by the Hall effect and the potential there becomes positive. In the pad 2, the current component I "shrinks" towards the upper surface, increasing the negative potential on the contact 8, while in the other part of this sensor 2 the component I extends inwards and the potential on the contact 14 becomes less negative, t .е. it is considered positive. In the substrate 6, the current lines 1 _{15 9} "shrink" in the direction of the upper surface and in the area with the contact 12 additional negative loads are generated by the Hall effect and the potential there becomes negative. As a result of the selected design of sensors 1 and 3, half of the evolving full Hall voltages in pads 4 and 6 are generated on contacts 10 and 12. However, the circuit with differential output V ₁₀₁₂ used in the new solution sums the two halves of the registered Hall voltages on contacts 10 and 12. At the same time, the differential outputs V _{g 14} (B) and V ₁₀₁₂ (B) fully compensate for the quadratic magnetic resistance MR —B ² , which degrades the metrology of the Hall device. Therefore, the original connection of the three sensors 1, 2 and 3 generates two Hall voltages V _{g 14} (B) and V ₁₀₁₂ (B), which have the same value V _{g 14} (B) = V ₁₀₁₂ ), but have the opposite sign V _{g 14} (B) = | - V ₁₂ (B) | This is the third manifestation of the unexpected positive effect of the new technical solution.

Since, in the general case, the Hall voltage is indistinguishable from the parasitic offset [2,3], the solution of Figure 1 extracts the pure metrological Hall component from the total signal, and the parasitic offset is drastically reduced. This is achieved by connecting contacts 10 and 12, and 8 and 14 to the inputs of the two measuring amplifiers 17 and 18. Thus, a suitable precise calibration and processing of the signals V _{g 14} (B) and V ₁₂ (B) is performed. The operation of the circuit is not affected by whether the outputs of sensors 1 and 2 are connected simultaneously to the inverting or non-inverting inputs of the amplifiers 17 and 18. respectively. Figure 1 shows one of the two connection options. Information about the value and sign of the measured magnetic field B 21 is obtained at the output 20 of the differential amplifier 19. Previously, the output voltages of the amplifiers 17 and 18, which are

Descriptions of issued patents for inventions № 01.2 / 31.01.2019 with opposite sign and contain almost equal, but with the same sign parasitic offsets are removed with the amplifier 19. As a result, the output voltage V ₂₀ (B) 20 of the Hall device is doubled , and the residual offset is practically compensated. Since the three Hall sensors are realized in a single technological cycle and have practically the same characteristics, the temperature drifts of the two offsets in the voltages V _{g 14} (V, T) and V ₁₂ (V, T) are perfectly coordinated and the achieved compensated offset and doubled (increased) magnetic sensitivity are maintained over a wide temperature range. In addition to these two advantages, the new solution provides increased measurement accuracy from compensated and temperature stabilized offset.

The realization of the new device with plane sensitivity can be carried out with the individual sensors of Hall 1, 2 and 3 and the operational amplifiers 17, 18 and 19 connected according to the scheme of Figure 1. Better characteristics and performance of the device can be achieved on the basis of silicon integrated processes CMOS or BiCMOS, using as pads 4, 5 and 6 n-type "pockets" formed in p-Si. The ohmic contacts 7, 8, 9, 10, 11, 12, 13, 14 and 15 are made, for example, by ion implantation and are strongly doped n ⁺ -regions in n-Si "pockets". Silicon planar technologies allow the simultaneous formation of Hall sensors 1,2 and 3 on a common chip together with the amplifiers 17,18 and 19 and the interface electronics for processing and normalization of the output signal 20. In such an embodiment, the new device is an integrated circuit.

In case the initial offsets of the two differential outputs V _{g 14} (B) and V ₁₀₁₂ (B) have a different sign, this can be corrected by switching on a low-resistance trimmer d, the end terminals of which are connected to contacts 9 and 13. , and its midpoint - with the corresponding terminal of the current source 16. This achieves the necessary setting of the offsets to have the same sign. If the internal resistances R. of sensors 1 and 3 are relatively low, which limits the development of high values of output voltage V _{g 14} (B) of sensor 2, additional resistors of the same value may be connected, for example to contacts 8 and 14. According to the concept of a fully symmetrical plane-magnetic Hall sensor, convenient for dynamic offset compensation by spinning the supply current, a circuit containing four identical three-contact sensors as those of Figure 1 connected in series by their end contacts can be used.

Claims (1)

Patent claims 1. Plane-magnetic Hall device, comprising a plane-magnetic Hall sensor, consisting of a semiconductor substrate with p-type impurity conductivity, on one side of which are formed from right to right at equal distances from each other three rectangular ohmic contacts - first, second and third, located parallel to their long sides, the second contact being central and relative to it symmetrically on its two long sides are the first and third contacts, also having a current source and a measured magnetic field parallel to the long sides of ohmic contacts, characterized in that there are two other Hall sensors - the second (2) and the third (3), identical to the plane-magnetic Hall sensor (1), one terminal of the current source (16) is connected to central contact (11) of the sensor (2), and the first contact (8) of the sensor (2) is connected to the first contact (7) of the sensor (1), the third contact (14) of the sensor (2) is connected to the third contact m (15) of the sensor (3), and the third contact (13) of the sensor (1) is connected to the first contact (9) of the sensor (3) and the other terminal of the current source (16), as central contacts ) of the sensors (1 and 3) are connected to the input of the first measuring amplifier (17), and the first (8) and third (14) contact of the sensor (2) are connected to the input of the second measuring amplifier (18), as the central contact (10) of the sensor (1) and the first contact (8) of the sensor (2) are connected simultaneously only to non-inverting or respectively only to inverting inputs of the amplifiers (17 and 18), the outputs of which are connected to the input of a differential amplifier (19), the output of which is the output (20) of the Hall device.