BG66714B1 - Three-component magnetic field microsensor - Google Patents

Abstract

The three-component magnetic field sensor contains a square-shaped n-type semiconductor substrate (1), with clockwise contacts forming identical ohmic contacts - first (2), second (3), third (4) and fourth (5). The first (2) and third (4) contacts and respectively the second (3) and fourth (5) contacts are arranged diagonally. The sensor also contains a current source (7) and three outputs (8, 9 and 10). With successive combinations of connecting the contacts , the three mutually perpendicular components (11, 12 and 13) of the magnetic field are measured, which is in any direction relative to the substrate. In the centre of the same side of the substrate (1) there is another,fifth ohmic contact (6), with two successive combinations of connecting the contacts (2, 3, 4, 5 and 6) to measure the three components (11, 12 and 13) ) in the magnetic field. The output (8) for the first component (11) of the magnetic field are the first (2) contact and the third (4) contact, which through identical resistors (14 and 15) are connected to a trimmer (16), the midpoint of which is connected through the current source (7) to the fifth contact (6), and the output (9) for the second, orthogonal to the plane of the substrate (1) of the component (12) of the magnetic field, are the second (3) and fourth (5) contacts. The output (10) for the third component (13) are the second (3) and fourth (5) contacts, which through identical resistors (14 and 15) are connected to the trimmer (16), the midpoint of which is connected through the current source ( 7) with the fifth contact (6).

Description

Field of technology

The invention relates to a three-component microsensor for magnetic field, applicable in the field of cognitive intelligent systems, micro- and nanotechnologies, robotics and mechatronics, control and measurement technology and low-field magnetometry, sensors, positioning of objects in the plane and space, space engineering , biomedicine, geomagnetism, non-contact measurement of angular and linear displacements, energy and energy efficiency, military affairs, security, etc.

BACKGROUND OF THE INVENTION

A three-component magnetic field microsensor is known, sequentially measuring the three components of the magnetic field vector, comprising a n-type semiconductor substrate, on one side of which are formed ohmic contacts, a current source, three outputs and with three consecutive contact connection combinations the three mutually perpendicular components of the magnetic field with an arbitrary direction with respect to the substrate. The pad has a square shape, at the four ends of one side are formed sequentially clockwise ohmic contacts - first, second, third and fourth as the first and third, and respectively the second and fourth are located diagonally. The outputs for the first component of the magnetic field are the second and third ohmic contacts, and the first and fourth are connected to the current source. The outputs for the second component are the third and fourth, and the first and second contacts are connected to the power supply, and the outputs for the third component are the second and fourth contacts, and the first and third are connected to the power supply [1].

The disadvantage of this three-component microsensor for magnetic field is the high values of the parasitic voltages of the outputs in the absence of the magnetic field (offsets) as a result of the inevitable resistive voltage drop during current flow through the respective power contacts.

Another disadvantage is the complicated interface circuitry of the microsensor from the need for three consecutive combinations of connecting contacts to measure the three components of the magnetic field.

Technical essence of the invention

It is an object of the invention to provide a three-component microsensor for a magnetic field with reduced offsets of the three outputs and simplified circuitry by reducing the number of sequential circuit combinations of connecting contacts for measuring the three components of the magnetic field.

This problem is solved with a three-component magnetic field microsensor containing a p-type semiconductor substrate with a square shape, at the four ends of one side are formed sequentially clockwise identical ohmic contacts - first, second, third and fourth, first and third, and respectively the second and the fourth are located diagonally and in the center of the same side of the substrate there is another - fifth ohmic contact, current source, three outputs and with two consecutive combinations of contacts the three mutually perpendicular components of the magnetic field are measured. direction relative to the pad. The output for the first component of the magnetic field is the first and third ohmic contact, which through equal load resistors are connected to a trimmer, the midpoint of which is connected through the current source to the fifth ohmic contact, and the output for the second, orthogonal to the substrate component of the magnetic field are the second and fourth ohmic contacts. The outputs for the third component are the second and fourth contacts, which are connected via equal load resistors to a trimmer, the midpoint of which is connected through the current source to the fifth ohmic contact.

An advantage of the invention is the greatly reduced values of the offsets of the three outputs for the components of the magnetic field, as a result of the complete compensation of the offsets by the trimmer.

Another advantage is the simplified circuitry due to the need for two instead of three combinations of connecting contacts.

Another advantage is the increased signal-to-noise ratio of the individual output channels during measurement

Descriptions of issued patents for inventions № 09.1 / 17.09.2018 of the magnetic components, due to the maximum reduction of the parasitic offsets in the absence of a magnetic field.

Explanation of the attached figures

The invention is illustrated in more detail by the accompanying drawings, in which:

Figure 1 shows a construction of the three-component microsensor for magnetic field;

Figures 2 and 3 show the two different serial combinations of connecting the ohmic contacts to the current source and the outputs for measuring the mutually perpendicular components of the magnetic field.

Examples of the invention

The three-component microsensor for magnetic field contains a p-type semiconductor substrate 1 with a square shape, at the four ends of one side are formed sequentially clockwise identical ohmic contacts - first 2, second 3, third 4 and fourth 5, first 2 and third 4 , and respectively the second 3 and the fourth 5 are arranged diagonally and in the center of the same side of the pad 1 there is another - fifth ohmic contact 6, current source 7, three outputs 8, 9 and 10 as with two consecutive combinations of connecting contacts 2, 3,4,5 and 6 measure the three mutually perpendicular components 11,12 and 13 of the magnetic field, which is in an arbitrary direction relative to the substrate 1. The output 8 for the first component 11 of the magnetic field are the first 2 and third 4 ohmic contact, which through the same value load resistors 14 and 15 are connected to a trimmer 16, the midpoint of which is connected through the current source 7 to the fifth ohmic contact 6, and the output 9 for the second, orthogonal to the plane of the substrate 1 the magnetic field components 12 are the second 3 and the fourth 5 ohmic contacts. The output 10 for the third component 13 is the second 3 and the fourth 5 contacts, which are connected to the trimmer 16 through equal load resistors 14 and 15, the midpoint of which is connected through the current source 7 to the fifth ohmic contact 6.

The operation of the three-component microsensor for magnetic field according to the invention is as follows.

The measurement of the three mutually perpendicular components 11, 12 and 13 of the magnetic field B is performed by two consecutive circuit combinations of connecting contacts 2, 3, 4, 5 and 6. The first combination refers to the connection of contacts 2 and 4 to one output of the source 7, and the fifth 6 (central) to the other output of the current source 7. In this case between contact 6 and respectively contacts 2 and 4 there are two equal in value supply currents I ₂ = const and -1 = const, Figure 1 and Figure 2. In the absence of magnetic field B = 0 their effective trajectories are curvilinear and symmetrical with respect to contact 6 start and end on the low-impedance planar contacts 2, 4 and 6, representing equipotential planes. In the areas below them, the current trajectories are initially perpendicular to the upper surface of the p-substrate 1. The sections of the trajectories of the two currents 1 _{6 2} and 1 _{6 4} in the rest of the volume of the p-substrate 1 are parallel to its upper side. Given the chosen structural symmetry of the microsensor - its square shape, the trajectories should also be symmetrical to the central contact 6, Figure 1 and Figure 2. Completely identical to the described is the second circuit combination, when the current source 7 includes contacts 6 and 3 and 5 respectively , Figure 1 and Figure 3. The same value load resistors 14 and 15, R ₁ = R ₂ , in both consecutive circuit combinations guarantee the mode of operation of the 3-D sensor current generator and equality of components I _{6 2} = I ₆ = const or I _{6 3} = I ₆ = const. Through the current source 7, the operation of the microsensor is adjusted so that the currents through ohmic contacts 2, 3, 4 and 5, in both connection combinations are equal, I ₂ = I = I ₃ = I = const. If in case of structural asymmetry there is an inequality of these currents, their alignment is done with the trimmer 16. In this way the inevitable parasitic offsets of the three outputs 8,9 and 10 in the absence of magnetic field B (B = 0) are easily compensated by varying the value of the resistances by the trimmer 16 in the respective circuits containing contacts 2, 3, 4, 5 and 6.

The application of an external magnetic field B with an arbitrary orientation in space relative to the substrate 1, through its three mutually perpendicular components Β _χ , B and Β _χ leads to the emergence of three laterally deflecting respective currents 1 _{6 2} , - 1 _{6 4} , 1 _{6 3} and - 1 _{6 5} Lorentz forces, F _L = qV _di х В, where q is the elementary load of the electron, a is the vector of the average drift velocity of the carriers. IN

Descriptions of issued patents for inventions № 09.1 / 17.09.2018 result of the Lorentz deflection F the trajectories of the opposite currents to contact 6 currents I -1 and 1 ₆ -1 ₆ "shrink" and respectively "expand". Depending on the directions of the magnetic components 11, 12 and 13, each of the pairs of opposite currents increases or decreases at the expense of the other (currents through the diagonally located contacts 2 and 4, and 3 and 5, respectively). Due to the operating mode of the current generator I ₂ = I = I ₃ = I = const as a result of the load resistors 14 and 15, instead of changes of the individual current components through contacts 2 and 4, and respectively 3 and 5 of the action of the respective magnetic components 8 and 10, Hall-opposite potentials are generated on these terminals. This leads, through the Hall effect, to the occurrence on both differential outputs 8 and 10 of Hall voltages V _{2 4} (B) ξ V _g (B) 8 and V _{3 5} (B) ξ V ₁₀ (B) 10. These output signals are linear and odd functions of the magnetic vector components 11 and 13. Therefore, through these two successive combinations of connecting contacts 2, 3, 4, 5 and 6 and the current source 7, metrological information is obtained for the two planar components 11 and 13 of the magnetic vector B The application of a magnetic field 12 orthogonally to the plane of the substrate 1 leads by lateral force F _l to a lateral displacement of the horizontal parts of the current lines I ₆ -1 I and -1 ₅ , which are parallel to the upper plane of the substrate 1. Since 1 _{6 2} and -1 _{6 4} are opposite, then the Lorentz deflections of these currents are opposite. Therefore, in the first circuit combination of connecting contacts 2, 3, 4, 5 and 6, Figure 2, a Hall voltage V _{3 5} (B) ξ V ₉ (B) is also generated on the diagonally arranged terminals 3 and 5, which carries metrological information about the magnetic field component 12. The first connection combination measures two of the magnetic components 11 and 12 at the same time. The Hall V ₂₄ voltage (B) could be used with the same success in the second circuit connection combination of contacts 2, 3, 4, 5 and 6. , the current source 7 and the resistors 14 and 15. The two series connection combinations provide metrological information for the three mutually perpendicular components 11, 12 and 13 of the magnetic field vector, which in the known solution is achieved by three. This simplifies the circuitry of the 3-D microsensor. Drastically reducing the parasitic offset of the three outputs 8 and 10 also improves the signal-to-noise ratio by increasing the resolution of the microsensor.

An important feature is that each of the two successive connection configurations of contacts 2, 3, 4, 5 and 6, Figure 2 and Figure 3, performs suppression of either of the outputs 8, 9 or the voltages of the other two components of the magnetic field B. These signals are in-phase additions in the respective differential output 8 or 10 and are compensated there. This reduces the parasitic interchannel influence. The structural symmetry of the new 3-D magnetic field microsensor also helps to overcome this shortcoming, which is fundamental in vector magnetometry. The absolute value of the total vector of the magnetic field B is given by the well-known expression: | = (B _g ² + B9 ² + B10 ² ) ¹² .

The unexpected positive effect of the new technical solution lies in the possibility to extract information with only five ohmic contacts 2,3,4, 5 and 6, one current source 7 and two different sequential ways of switching on these contacts, Figure 2 and Figure 3. for the full magnetic vector B. Thus the metrological problem is extended not in space but in time, which is an essential innovative approach in vector magnetometry.

The possible surface flow of currents on the surface of the substrate 1 can be limited by forming a deep square-shaped p-ring enclosing contacts 2, 3, 4 and 5.

The 3-D microsensor can be implemented with standard CMOS technology or micromachining and can be integrated together with the signal processing peripheral electronics. The realization of the two successive circuit configurations of connection of contacts 2, 3, 4, 5 and 6, Figure 2 and Figure 3, is carried out by means of a multiplexer. The operation of the new magnetometer is feasible in a wide temperature range.

Claims (1)

Patent claims 1. A three-component microsensor for a magnetic field, containing a square-shaped n-type semiconductor substrate, the same ohmic contacts being formed sequentially clockwise at the four ends of one side - first, second, third and fourth, as the first and third, Descriptions of issued patents for inventions № 09.1 / 17.09.2018 and respectively the second and fourth are arranged diagonally; current source and three outputs, with successive combinations of contact contacts measuring the three mutually perpendicular components of the magnetic field, which is in an arbitrary direction relative to the substrate, characterized in that in the center of the same side of the substrate (1) there is a fifth ohmic contact (6), and the successive combinations of connecting contacts (2,3,4, 5 and 6) for measuring the three mutually perpendicular components (11, 12 and 13) of the magnetic field are two, as the output (8) for the first component ( 11) of the magnetic field are the first (2) and the third (4) contact, which through equal value load resistors (14 and 15) are connected to a trimmer (16), the middle point of which is connected through the current source (7) to the fifth contact (6), and the output (9) for the second, orthogonal to the plane of the substrate (1) component (12) of the magnetic field are the second (3) and fourth (5) contact, as the output (10) for the third component ) are the second (3) and the fourth (5) contact, which through the same under Art The load resistors (14 and 15) are connected to the trimmer (16), the middle point of which is connected through the current source (7) to the fifth contact (6).