BG113750A - Vector 2-d magnetic field sensor - Google Patents

Abstract

The vector 2-D magnetic field sensor, measuring simultaneously and independently the two planar components of the magnetic field, contains a current source (1) and a semiconductor substrate (2) with p-type impurity conductivity. On one side of it are embedded four identical rectangular regions of the same semiconductor with n-type conductivity - clockwise first (3), second (4), third (5) and fourth (6). The long sides of the adjacent regions (3) and (4), (4) and (5), (5) and (6), (6) and (3) are at right angles to each other. The long sides of the opposite rectangular regions first (3) and third (5), respectively second (4) and fourth (6) are located along straight lines, with their short sides being symmetrical to the common center O of regions (3), (4), (5) and (6). On the upper surfaces of each of the regions (3), (4), (5) and (6) are formed at equal distances three ohmic contacts, from outside to inside for the first region (3) - first (7), second (8) and third (9), for the second (4) - fourth (10), fifth (11) and sixth (12), for the third (5) - seventh (13), eighth (14) and ninth (15), and for the fourth region (6) - tenth (16), eleventh (17) and twelfth (18) contacts. The first contact (7) is electrically connected to the sixth (12), the fourth (10) to the seventh (13), the ninth (15) to the tenth (16) and the twelfth (18) to the third (9). The common points of the fourth (10) and seventh (13), and respectively the third (9) and twelfth (18) contacts are connected to the terminals of the current source (1). The measured magnetic field (19) is in the plane of the substrate (2) and has an arbitrary orientation. The pairs of opposite middle contacts second (8) and eighth (14), and respectively fifth (11) and eleventh (17) are the differential outputs (20) and (21) for the two orthogonal planar components of the magnetic field (19).

Description

VECTOR 2-D MAGNETIC FIELD SENSOR

TECHNICAL FIELD

The invention relates to a vector 2-D magnetic field sensor applicable in the field of control and measurement technology; medicine, including robotic and minimally invasive surgery; weak-field and high-precision magnetometry; robotic systems; navigation; remote measurement of angular and linear displacements; automotive industry and electric vehicle construction; automation, including contactless control; 2-D positioning of objects in the plane; energy; security - ground, air and underwater surveillance devices; counterterrorism, etc.

PRIOR ART

A vector 2-D magnetic field sensor is known, measuring simultaneously and independently the two planar components of the magnetic field, containing an n-type semiconductor (silicon) square substrate, on one side of which a central ohmic contact with a square shape is formed. At distances and symmetrically with respect to its four sides, there is successively one rectangular inner ohmic contact and one rectangular outer ohmic contact. The four outer contacts are connected and through a power supply are connected to the central contact. The measured magnetic field is in the plane of the substrate and has an arbitrary orientation. The pairs of inner contacts opposite to the central one are the outputs for the two orthogonal planar components of the magnetic field, [1-10].

A disadvantage of this vector 2-D magnetic field sensor is the parasitic inter-channel influence, introducing metrological errors in the output Hall voltages (the action of the vector sensor is the Hall effect) as a result of leakage of part of the current from the components between the center and end contacts along the surface of the substrate.

Another disadvantage is the reduced accuracy due to the high values of the parasitic voltages on both outputs in the absence of a magnetic field (offset) due to the lack of restrictive zones channeling the flow of the supply current components.

TECHNICAL ESSENCE

The objective of the invention is to create a vector 2-D magnetic field sensor with increased accuracy through minimized metrological error from inter-channel influence and reduced offset of the output channels.

This problem is solved with a vector 2-D magnetic field sensor, measuring simultaneously and independently the two planar components of the magnetic field, containing a current source and a semiconductor substrate with /3-type impurity conductivity. On one side of it, four identical rectangular regions of the same semiconductor with p-type conductivity are built in clockwise order: first, second, third and fourth. The long sides of the adjacent regions are at right angles to each other, with the long sides of the opposite rectangular regions first and third, respectively second and fourth, being located in straight lines. The short sides are symmetrical with respect to the common center O of the p-type regions. On the upper surfaces of each of the regions, three ohmic contacts are formed at equal distances, from outside to inside for the first region - first, second and third, for the second - fourth, fifth and sixth, for the third - seventh, eighth and ninth, and for the fourth region - tenth, eleventh and twelfth contacts. The first contact is electrically connected to the sixth, the fourth to the seventh, the ninth to the tenth and the twelfth to the third. The common points of the fourth and seventh, and respectively the third and twelfth are connected to the terminals of the current source. The measured magnetic field is in the plane of the substrate and has an arbitrary orientation. The pairs of opposite middle contacts second and eighth, and respectively fifth and eleventh are the differential outputs for the two orthogonal planar components of the magnetic field.

An advantage of the invention is the high measurement accuracy of the two sensor outputs due to the absence of inter-channel influence given the well-localized components of the supply current in the embedded i-type regions, and the drastically minimized leakage of the surface parasitic current.

Another advantage is the increased metrological resolution through the increased signal-to-noise ratio from the minimized parasitic offset through the innovative pairing of rectangular areas and localized current supply components, providing lower magnetic induction detection values.

Another advantage is the high magnetic sensitivity (magnetic field conversion efficiency) of the two sensor outputs as a result of the channeled flow of the supply current components, the reduction offset and the absence of inter-channel influence in the two Hall voltages, which are the metrological information about the orthogonal components of the magnetic field vector.

DESCRIPTION OF THE APPENDIX FIGURES

The invention is explained in more detail with an exemplary embodiment thereof, given in the attached Figure 1, which represents a schematic plan of the vector 2-D magnetic field sensor.

EXAMPLES OF IMPLEMENTATION

The vector 2-D magnetic field sensor, measuring simultaneously and independently the two planar components of the magnetic field, contains a current source 1 and a semiconductor substrate 2 with p-type impurity conductivity. On one side of it are embedded four identical rectangular regions of the same semiconductor with l-type conductivity - clockwise first 3, second 4, third 5 and fourth 6. The long sides of the adjacent regions 3 and 4, 4 and 5, 5 and 6, 6 and 3 are at right angles to each other. The long sides of the opposite rectangular regions first 3 and third 5, respectively second 4 and fourth 6 are located in straight lines. The short sides are z

symmetrical with respect to the common center O of regions 3, 4, 5 and 6. On the upper surfaces of each of the regions 3, 4, 5 and 6, three ohmic contacts are formed at equal distances, from outside to inside for the first region 3 first 7, second 8 and third 9, for the second 4 - fourth 10, fifth 11 and sixth 12, for the third 5 - seventh 13, eighth 14 and ninth 15, and for the fourth region 6 - tenth 16, eleventh 17 and twelfth 18 contacts. The first contact 7 is electrically connected to the sixth 12, the fourth 10 to the seventh 13, the ninth 15 to the tenth 16 and the twelfth 18 to the third 9. The common points of the fourth 10 and the seventh 13, and respectively of the third 9 and the twelfth 18 are connected to the terminals of the current source 1. The measured magnetic field 19 is in the plane of the substrate 2 and has an arbitrary orientation. The pairs of opposite middle contacts second 8 and eighth 14, and respectively fifth Pi eleventh 17 are the differential outputs 20 and 21 for the two orthogonal planar components of the magnetic field 19.

The operation of the vector 2-D magnetic field sensor according to the invention is as follows. When the terminals of the current source 1 are connected to the common points of the fourth 10 and seventh 13, and respectively the third 9 and twelfth 18 contacts, as well as the symmetry of the structure with respect to point O, in the n-type regions 3, 4, 5 and 6 two by two identical and oppositely directed supply currents flow (Ζι/2) = /3 = |-/s|> (Λ/2) = /4 = |-Д|· The connection of regions 3, 4, 5 and 6 with the current source 1 and contacts 7-12; 1013;15-16 and 9-18 minimizes the possible presence of electrical asymmetry by flowing equalizing currents in the regions. As a result, the offsets of outputs 20 and 21 are reduced, which increases the accuracy and metrological resolution of the 2-D sensor. In addition, the serial connection of regions 3 and 4, and 5 and 6, respectively, eliminates the need to use load resistors in the implementation of the 2-D sensor, complicating the technological processes.

Essentially, the four identical n-regions 3, 4, 5 and 6 with the equidistantly located ohmic contacts 7-8-9; 10-11-12; 13-14-15 and 16-17-18 represent three-contact Hall elements (TC) with planar magnetic susceptibility. They are also known as vertical and were discovered in 1983 by Rumenin and Kostov, and improved by Lozanova, [5-7]. Over the years, they have been upgraded through various modifications of integrated silicon technologies, especially CMOS, [for example, 1-4,9,10 as well as the literature cited therein]. Their functioning is based on the curvilinear trajectories of the supply current components in the four regions 3, 4, 5 and 6. The measured magnetic field B 19 is in the x-y plane of the substrate 2, and has an arbitrary orientation. The two mutually perpendicular magnetic fields B _x and B _y act on the moving carriers of components / ₇ . ₉ , -/13-15? /10-12 ^and -Λ6-18 through the Lorentz forces, F _L ,i = ±^V _dr x B, where q is the elementary charge of the electron, and V _dr is the average drift velocity of the electrons in the silicon «-regions. Since the currents /7-9,-/13-15, Do-12 and -/1618 are confined in regions 3, 4, 5 and 6, the deflecting action of the Lorentz forces ±F _L;i is maximally effective. As a result of the Lorentz deflection /% in the thus formed n-type three-contact (ZC) Hall configurations, for example, the trajectories of components, /7.9 and /u-12, are “contracted” and, respectively, at -/13-15 and -Z16-18 are “expanded”. In these processes, the current carriers either “rise” to the surface of regions 3 and 4, or “descend” to their lower side. In the first case, additional negative charges are generated on the middle contacts 8 and 11 and the corresponding Hall potentials are negative, and in the second - contacts 14 and 17 acquire a positive potential. As a result, the Travel differential voltages V 2 i(®y) 20 and V ₂ i(®y) 21 are generated on the output terminals 11 and 17, and 14 and 8, respectively, i.e. the information indicators for the values and directions of the two orthogonal components B _x and B _y of the field vector B 19. In essence, the configuration of Figure 1 is a functional integration of four (3) Hall elements with planar magnetic susceptibility. According to the action of the Hall effect, the output voltages E ₂ o(^ _x ) 20 and V ₂ i(B _y ) 21 are linear and odd functions of the fields ±B _X and ±B _y , and of the current ±/ _ь The increased magnetic susceptibility is due to the limited components of the current C in p-regions 3, 4, 5 and 6. This innovative approach eliminates the leakage of currents on the surface. At the same time, the orthogonality of the corresponding current lines with respect to the two planar vectors B _x and B _y of the field B 19 is improved. The limitation of the currents reduces one of the significant disadvantages of vector magnetometry - the interchannel influence when measuring the magnetic fields B _x and B _y . The sequential connection in pairs of regions 3 and 4, and 5 and 6, respectively, eliminates the need for explicit use of current generator 1. The absolute value of the field B 11 in the x-y plane and the angle Θ of the vector B 11 relative to a fixed reference axis in the same plane are given by the expressions: |B| = (B _x + /? _y ² ) ^1/2 and Θ = tan (y _y (B _y )/V _x (B _x y), [2.8-10]. The high metrological resolution when detecting the minimum value of the magnetic induction 2? _min is achieved with the increased signal-to-noise ratio as a result of the minimized offset and the increased conversion efficiency (sensitivity).

The unexpected positive effect of the new technical solution lies in the built-in four n-regions 3, 4, 5 and 6, located at right angles, respectively two by two lying in a straight line, as well as the innovative electrical connection of the ohmic contacts. This approach implements opposite directions of the current components in the opposite regions 3 and 5 and 4 and 6, respectively. As a result, high conversion efficiency, increased measurement accuracy, high resolution, simultaneous and independent measurement of the plane components B _x and B _y of the field vector B 19 is achieved.

The vector 2-D magnetic field sensor can be implemented with various modifications of the integrated silicon technology - CMOS, BiCMOS, SOS, and if necessary, micromachining silicon processes can be used. The optimal depth of the p-regions 3, 4, 5 and 6 is about 5-7 μιη. The new 2-D magnetometer also functions in the cryogenic temperature range.

APPENDIX: one figure

LITERATURE

[1] Infineon Technologies AG, Vertical Hall effect device, US Patent, US9425385 B2/23.08.2016.

[2] C.S. Roumenin, Microsensors for magnetic field, in "MEMS - a practical guide to design, analysis and applications", Ch. 9, ed. by J. Korvink and O. Paul, William Andrew Publ., USA, 2006, pp. 453-523; ISBN: 0-8155-1497-2.

[3] R. Popovic, "Integrated Hall element", US Patent No. 4,782,375/01.11.1988.

[4] C. Schot, Vertical Hall sensor, US Patent Appl., No. US 2010/0133632 Al/03.06.2010.

[5] C.S. Rumenin, P.T. Kostov, Planar Hall sensor, BG Author's certificate No. BG 37208/26.12.1983.

[6] Ch.S. Roumenin, Parallel-field triple Hall device, Compt. rendus ABS, 39(11)(1986) 65-68

[7] S.V. Lozanova, C.S. Roumenin, Parallel-field silicon Hall effect microsensors with minimal design complexity, IEEE Sensors Journal, 9(7) (2009) 761-766.

[8] A. Bolshakova, R.L. Golyaka, O.Yu. Makshto, T.A. Marusenkova, Ηοβϊ construction of thin-film 2-D and 3-D sensors in the magnetic field", magazine "Zlektronika i svyaz", No. 2-3, (2009) 6-10 (in Ukrainian).

[9] S. Sander, M.-S. Vecchi, M. Cornils, O. Paul, From three-contact vertical Hall elements to symmetrized vertical Hall sensor with low offset, Sens. Actuators, A240 (2016) 92-102.

[10] C. Roumenin, Solid State Magnetic Sensors - Handbook of Sensors and Actuators, Elsevier, Amsterdam-Lausanne-New York, 1994, pp. 450; ISBN: 0 444 89401.

Claims (2)

Vector 2-D magnetic field sensor, measuring simultaneously and independently both planar components of the magnetic field, containing a current source and a semiconductor substrate with p-type impurity conductivity, the measured magnetic field being in the plane of the substrate and having an arbitrary orientation, CHARACTERIZED in that on one side of the p-substrate (2) are embedded four identical rectangular regions of the same semiconductor with p-type conductivity - clockwise first (3), second (4), third (5) and fourth (6), the long sides of the adjacent regions (3) and (4), (4) and (5), (5) and (6), (6) and (3) are at right angles to each other, the long sides of the opposite rectangular regions first (3) and third (5), respectively second (4) and fourth (6) are located in straight lines with their short sides being symmetrical with respect to the common center O of regions (3), (4), (5) and (6), on the upper surfaces of each of the regions (3), (4), (5) and (6) are formed at equal distances three ohmic contacts, from outside to inside for the first region (3) - first (7), second (8) and third (9), for the second (4) - fourth (10), fifth (11) and sixth (12), for the third (5) - seventh (13), eighth (14) and ninth (15), and for the fourth region (6) - tenth (16), eleventh (17) and twelfth (18) contacts, the first contact (7) is electrically connected to the sixth (12), the fourth (10) to the seventh (13), the ninth (15) to the tenth (16) and twelfth (18) to the third (9), the common points of the fourth (10) and seventh (13), and respectively of the third (9) and twelfth (18) contacts are connected to the terminals of the current source (1), the pairs of opposite middle contacts second (8) and eighth (14), and fifth (11) and eleventh (17), respectively, are the differential outputs (20) and (21) for the two orthogonal planar components of the magnetic field (19).