BG113767A - Two-dimensional magnetic field microsensor - Google Patents

Abstract

The two-dimensional magnetic field microsensor, measuring simultaneously and independently the two planar components of the magnetic field, contains two sources of direct current - the first (1) and the second (2), and a semiconductor substrate (3) with p-type impurity conductivity. On one side of it is embedded a square ring (4) of the same semiconductor with n-type conductivity, dividing the p-type substrate (3) into an outer and inner part. In the middle zones of the four sides of the n-ring (4) are formed in close proximity to each other two identical ohmic contacts - sequentially clockwise - the first (5) and second (6), third (7) and fourth (8), fifth (9) and sixth (10), and seventh (11) and eighth (12). Each pair of opposite contacts - the first (5) and the second (6), and the fifth (9) and the sixth (10), and the third (7) and the fourth (8), and the seventh (11) and the eighth (12), respectively, is arranged symmetrically with respect to a common center O (13) in the inner part of the p-type substrate (3). The second (6) and the third (7) contacts are electrically connected to the first source (1), and the sixth (10) and the seventh (11) - to the second source (2). The polarities of the power supply of the second (6) and the seventh (11), and of the third (7) and the sixth (10) contacts, respectively, are the same. The measured magnetic field (14) is in the plane of the substrate (3) and has an arbitrary orientation. The pairs of contacts first (5) and fifth (9), and fourth (8) and eighth (12) are the differential outputs (15 and 16) for the two orthogonal planar components of the field (14).

Description

TWO-DIMENSIONAL MAGNETIC FIELD MICROSENSOR

TECHNICAL FIELD

The invention relates to a two-dimensional magnetic field microsensor applicable in the field of control and measurement technology; quantum communication; medicine, including robotic and minimally invasive surgery, and endovascular intervention; low-field and high-precision magnetometry; robotic systems with artificial intelligence; energy; automotive industry and electric vehicle construction; remote measurement of angular and linear displacements; automation, including contactless control; 2D positioning of objects in the plane; security - ground, air and underwater surveillance devices; counterterrorism, etc.

PRIOR ART

A two-dimensional magnetic field microsensor is known, measuring simultaneously and independently the two planar components of the magnetic field, containing an n-type semiconductor (silicon) 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 source in voltage generator mode 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 differential outputs for the two orthogonal planar components of the magnetic field, [1-9].

A disadvantage of this two-dimensional magnetic field microsensor is the significant metrological errors in the two output voltages, corresponding to the in-plane components of the magnetic field, as a result of the parasitic inter-channel influence from leakage along the substrate surface of part of the currents between the central and four end contacts. This leads to the presence of parasitic signals and noise in the metrological information of the channels, sometimes comparable to the generated Hall voltages.

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) from the leakage of part of the currents between the central and end contacts along the surface of the substrate, as well as the structural defects in the conversion zone of the substrate.

TECHNICAL ESSENCE

The task of the invention is to create a two-dimensional magnetic field microsensor with minimized metrological errors of the output channels from the parasitic inter-channel influence, and increased accuracy by reducing the offsets of the two channels.

This task is solved with a two-dimensional magnetic field microsensor, measuring simultaneously and independently the two planar components of the magnetic field, containing two sources in the current generator mode - the first and the second, and a semiconductor substrate with /?-type impurity conductivity. On one side of it in the near-surface region, a square ring of the same semiconductor with n-type conductivity is embedded, dividing the /?-type substrate into an outer and inner part. In the middle zones of the four sides of the embedded ring, two identical ohmic contacts are formed close to each other, sequentially clockwise - the first and second, the third and fourth, the fifth and sixth, the seventh and eighth. Each pair of opposing contacts, the first and second, and the fifth and sixth, and respectively the third and fourth, and the seventh and eighth, is located symmetrically with respect to the common center O in the inner part of the /?-type substrate. The second and third contacts are electrically connected to the first source of direct current, and the sixth and seventh - to the second. The polarities of the second and seventh, and third and sixth, power contacts are the same. The measured magnetic field is in the plane of the substrate and is of arbitrary orientation. The pairs of contacts first and fifth, and fourth and eighth in the i-type ring are the differential outputs for the two orthogonal planar components of the magnetic field.

An advantage of the invention is the minimized metrological errors of the two output channels due to the greatly reduced inter-channel influence due to the formed restrictive i-type ring in which the supply currents flow and which eliminates their leakage along the surface.

Another advantage is the increased measurement accuracy of the two sensor outputs, since there is no mutual inter-channel influence from the well-localized components of the supply current in the ring, the drastically reduced parasitic offsets of the outputs from the greatly shortened (twice) trajectories of the current carriers between the respective supply electrodes, and the high symmetry of the configuration.

Another advantage is the high magnetic sensitivity of the outputs, due to the generation of full potentials, respectively Hall voltages, from the corresponding orthogonal planar components of the magnetic field by the supply currents in the square ring due to the drastically reduced surface leakage of the currents from the restrictive i-type ring.

Another advantage is the increased metrological resolution when detecting the minimum value of magnetic induction through the increased signal-to-noise ratio from the high magnetic sensitivity of the channels, the minimized parasitic offset and the innovative location of the registering Travel contacts outside the areas through which the supply currents flow. All this ensures lower values of induction detection.

DESCRIPTION OF THE APPENDIX FIGURES

The invention is explained in more detail with an exemplary embodiment thereof, given in the attached Figure 1, representing a plan of the two-dimensional sensor configuration.

EXAMPLES OF IMPLEMENTATION

The two-dimensional magnetic field microsensor, measuring simultaneously and independently the two planar components of the magnetic field, contains two sources in current generator mode - the first 1 and the second 2, and a semiconductor substrate 3 with p-type impurity conductivity. On one side of it, in the near-surface region, a square ring 4 of the same semiconductor with m-type conductivity is embedded, dividing the p-type substrate 3 into an outer and inner part. In the middle zones of the four sides of the built-in m-ring 4, two identical ohmic contacts are formed in close proximity to each other in a clockwise direction - first 5 and second 6, third 7 and fourth 8, fifth 9 and sixth 10, seventh 11 and eighth 12. Each pair of opposite contacts - the first 5 and second 6, and the fifth 9 and sixth 10, and respectively the third 7 and fourth 8, and seventh 11 and eighth 12 is located symmetrically with respect to the common center O 13 in the inner part of the p-type substrate 3. The second 6 and third 7 contacts are electrically connected to the first source 1, and the sixth 10 and seventh 11 - to the second 2. The polarities of the power supply second 6 and seventh 11, and respectively the third 7 and sixth 10 contacts are the same. The measured magnetic field 14 is in the plane of the substrate 3 and is of arbitrary orientation. The pairs of contacts first 5 and fifth 9, and fourth 8 and eighth 12 in the m-type ring 4 are the differential outputs 15 and 16 for the two orthogonal planar components of the magnetic field 14.

The operation of the two-dimensional magnetic field microsensor according to the invention is as follows. When the power contacts 6 and 7, and respectively 10 and 11 to the sources 1 and 2, operating in the DC generator mode, two power currents flow in opposite directions in the m-type ring 4. This result is achieved with the same electrical polarities of ohmic contacts 11, and respectively 7 and 10 through the two sources 1 and 2. In addition to electrical, this result can be achieved technologically by forming narrow /?-type barrier zones near contacts 5 and 8, or 9 and 12. Thus, the two sensor areas are separated, through which currents / ₆ ,7 and / ₁₀ ,ц of the configuration in Figure 1 pass. The DC generators 1 and 2, Ц = const and I ₂ = const set the equality of the flowing currents / _6>7 = |-/ _]0>11 |. In fact, depending on the polarity of the power contacts 7 and 11, the current lines / _6>7 and /ю,ц circulate in the ring 4 clockwise and counterclockwise. The current Ι^ _Ί starts from contact 6, flowing in the ring 4 changes its direction in a first approximation at a right angle and ends in contact 7. The current lines /ю,ц start from contact 11, also pass at a right angle in the ring 4 and end in contact 10, Figure 1. The electrical connection, determining the indicated polarities, is of key importance for the functioning of the microsensor. The square m-ring 4 precisely limits the currents, eliminating their leakage along the surface of the structure 3. In essence, this is the typical “pocket” 4 in CMOS technologies with a characteristic depth of up to 5 - 7 μιη, [2,3,5,8]. In this way, the parasitic interchannel influence is minimized and the metrological errors in the measurement of magnetic components B _x and B _y of the field B 14 are reduced. The absence of interchannel influence from the localized supply currents / _6;7 and / y,c in the ring 4, the drastically reduced parasitic offsets at outputs 15 and 16 from the strongly shortened trajectories of the current carriers between electrodes 6 and 7, 10 and 11 by about two times, as well as the high symmetry of the sensor configuration relative to the common center O 13 significantly increase the measurement accuracy. The reduced dimensions of the trajectories / ₆ ,7 and / ₁₀ ,c reduce the probability of the presence of structural defects in the corresponding parts of the «-ring 4, which are the main reason for the presence of the parasitic offsets.

The measured magnetic field B 14 is of arbitrary orientation in the x-y plane of the substrate 3. The two mutually perpendicular magnetic fields B _x and B _y act on the moving carriers in the curvilinear components / _6>7 and -/ю,ц in the ring 4 through the Lorentz forces, F _L ,i = ±<?Vdr x B, where q is the elementary charge of the electron, and V _dr is the vector of the average drift velocity of the electrons in the ring 4, [1,6,9]. Since the currents / _6>7 and |-/1 о,и| are limited, the deflecting action of the Lorentz forces F _L;i is maximally effective. As a result of the Lorentz deflection F _L in the “pocket” 4 with square geometry, the trajectories of the oppositely directed components / ₆ ,7 and -/ ₁₀ ,ц simultaneously “contract” and, respectively, “expand”. This behavior of the current carriers from the same trajectory leads to the simultaneous generation of positive and negative Hall potentials on the output contacts 5 and 9, and 8 and 12, respectively, for components B _x 15 and B _y 16. In this mechanism, the current carriers are deflected laterally by the force F _L in the volume of the ring 4 - in the areas under the output contacts 5 and 9, 8 and 12. In the first case, for example, simultaneously negative and positive charges are generated on contacts 5 and 9, and simultaneously positive and negative charges on output contacts 8 and 12. Since the currents 4.7 and /ю,ц are equal, the corresponding Hall voltages have the same value, V ₁₅ (B _X ) 15 and -Vi ₆ (B _y ) 16. The voltage V _U (B) in this manifestation of the Hall effect [1,6,9] has a higher value when the supply contact and one of the output contacts are located close to each other, as is done in the new solution. In essence, the configuration of Figure 1 is a functional combination of four-contact Hall elements with planar sensitivity, proposed and studied for the first time in [4]. According to the Hall effect, the output voltages V^(B) 15 and V ₁₆ (В) 16 are linear and odd functions of the fields ±В _X and ±В _У , and of the currents ± / _6>7 and ±/ю,н, i.e. they are the information indicators for the values and directions of the two orthogonal components B _x and B _y of the field vector B 14. The increased magnetic sensitivity is due to the components / ₆ ,7 and /ю,н limited in the p-ring 4. This innovative approach eliminates the leakage of currents in the near-surface region and improves the orthogonality of the corresponding current lines relative to the two planar vectors I B _x and B _y . Thus, the force F _L acts as effectively as possible on the individual parts of the trajectories of the current carriers, generating through them maximum Hall voltages on contacts 5 and 9, and 6 and 12. The limitation of the currents in the square p-ring 4 reduces one of the significant disadvantages of vector magnetometry - the mutual inter-channel influence when measuring the fields B _x and B _y . The use of power supply in the current generator mode 1 and 2, and not constant voltage as in the known vector microsensor, prevents the change of current in the ring 4 from the field B 14. In addition, at constant current, preservation of magnetic sensitivity is achieved with variation of temperature T. The new solution in Figure 1 also implements high metrological resolution for detecting the minimum value of the induction B _min for the purposes of weak-field magnetometry, seismology and counterterrorism. This is achieved with the increased signal-to-noise ratio as a result of the minimized offset, increased sensitivity and non-standard arrangement of the recording Hall electrodes 5 and 9, and 8 and 12, respectively. Contrary to their generally accepted location in the area of flow of the supply current, in the proposed sensor configuration the Hall terminals are outside the areas of the current lines / _6>7 and /ю,ц.

The absolute value of the field vector B 14 in the x-y plane and the angle Θ of the vector B 14 relative to a fixed reference axis in the same plane are given by the expressions: |B| = (B _x + T? _y ² ) ^1/2 and Θ = 1an\Y _y (By)/Y _x (B _x )), [1,9].

The unexpected positive effect of the new technical solution lies in the narrow ring structure 4 type CMOS "pocket" with functionally integrated four-contact Hall elements, which enable the simultaneous generation of channel magnetosensitivity through current components with changing geometry and the non-standard

I location of the output terminals 5-9 and 8-12 outside the flow areas of the supply currents 4.7 and /u,c. As a result, high | conversion efficiency, increased measurement accuracy, minimized offsets and high resolution of the two-dimensional microsensor are achieved. In this case, the metrological information about the direction and value of the planar magnetic components is obtained simultaneously and independently.

The two-dimensional magnetic field microsensor is implemented with the various modifications of integrated silicon technology - CMOS, BiCMOS, SOS

I and other processes. The depth of the p-ring 4 in the p-Si substrate 3 is about 5 - 7 | µm. The new magnetometer also functions in the cryogenic temperature range, and through the current generator mode I = const the sensitivity can be controlled without using complex circuitry.

APPENDIX: one figure

LITERATURE

[1] 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.

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

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

[4] 4. Rumenin, Hall Element, Author's Certificate BG No. 41974 B1/06.05.1986.

[5] R. Popovic, “Integrated Hall element”, US Patent no

782 375/01.11.1988.

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

[7] A. Bolshakova, R.L. Golyaka, O.Yu. Mayudo, T.A. Marusenkova, "Design of conductive loudspeaker 2-D and 3-D sensors in the magnetic field", Zlektronika i svyaz magazine, No. 2-3, (2009) 6-10 (in Ukrainian).

[8] 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.

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

Claims (1)

PATENT CLAIMS A two-dimensional magnetic field microsensor, measuring simultaneously and independently the two planar components of the magnetic field, comprising a power source, a semiconductor substrate and ohmic contacts, the measured magnetic field being in the plane of the substrate and having an arbitrary orientation, CHARACTERIZED in that the power sources are two (1) and (2) and are in the DC generator mode, the semiconductor substrate (3) has a p-type impurity conductivity, on one side of which is embedded a square ring (4) of the same semiconductor with i-type conductivity, dividing the p-type substrate (3) into an outer and inner part, in the middle zones of the four sides of the embedded p-ring (4) two identical ohmic contacts are formed close to each other - sequentially clockwise - first (5) and second (6), third (7) and fourth (8), fifth (9) and sixth (10), seventh (11) and eighth (12), each pair of opposite contacts - the first (5) and the second (6), and the fifth (9) and the sixth (10), and respectively the third (7) and the fourth (8), and the seventh (11) and the eighth (12) are arranged symmetrically with respect to a common center O (13) in the inner part of the p-type substrate (3), the second (6) and the third (7) contacts are electrically connected to the first source (1), and the sixth (10) and the seventh (11) - to the second (2) as the polarities of the power supply second (6) and the seventh (11), and respectively the third (7) and sixth (10) contacts are the same, the pairs of contacts first (5) and the fifth (9), and the fourth (8) and the eighth (12) in the l-ring (4) are the differential outputs (15) and (16) for the two orthogonal planar components of the magnetic field (14).