BG111840A - Integral 3d microsensor for magnetic field - Google Patents

Abstract

The integrated 3D microsensor for magnetic field contains the n-type semiconductor substrate (1) on one side of which are formed ohmic contacts - power and recording, all surrounded by deep rectangular p-type ring (9), power supply (11), three outputs (13, 15, 17) for measuring orthogonal components of the magnetic field (12) by means of three combinations of connecting contacts registrants. The magnetic field (12) has a random direction relative to the substrate (1). The power contacts are three (2, 3 and 4), two of them contacts (2 and 3) are the same rectangular shape and are parallel to their long sides. Among them symmetrically located third power socket (4), which is central and has a square shape. Between contacts (2 and 3) in the vicinity are located a pair of identical contacts who are registered - first (5) and second (6) to one power socket (2) and third (7) and fourth ( 8) to the other outlet (3). The pairs of contacts (5 and 6) and (7 and 8) are symmetrical in relation to the central contact (4). The short sides of the p-ring (9) are parallel to the long sides of the rectangular contacts (2 and 3). The contacts (2 and 3) through the trimmer (10) and a current source (11) are connected with the middle contact (4). The output (13) for a first component (14) of the magnetic field (12) are the third (7) and fourth (8) into contact with a combination of connection of the first (5) and fourth (8) and respectively the second (6) and third (7) contact. The output (15) for a second component (16) are the third (7) and fourth (8) into contact with a combination of connection of the first (5) and third (7) and respectively the second (6) and fourth (8) contact. The output (17) for the third component (18) are the second (6) and fourth (8) into contact with a combination of connection of the first (5) and second (6) and the third (7) and fourth (8) contact.

Description

The invention relates to an integrated 3-D microsensor for magnetic field, applicable in the field of robotics and mechatronics, positioning of objects in the plane and space, space research, sensors, non-contact measurement of angular and linear displacements, control and measuring equipment and low-field magnetometers cognitive intelligent systems, geomagnetism, micro- and nano-technologies, energy and energy efficiency, biomedicine, military affairs, security, etc.

BACKGROUND OF THE INVENTION

An integrated 3D 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 with three consecutive combinations of connection. these contacts measure the three mutually perpendicular components of the magnetic field in any direction with respect to the substrate. The pad has a square shape, at the four ends of one side are formed 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 current source, and the outputs for the third component are the second and fourth contacts, and the first and third are connected to the power source, [1,2].

The disadvantage of this integrated 3-D magnetic field microsensor is the high values of the parasitic voltages at the outputs in the absence of the magnetic field (offsets) as a result of the inevitable resistive voltage drop when current flows through the respective supply contacts.

Another disadvantage is the reduced accuracy in the sequential measurement of the three components of the magnetic vector as a result of the parasitic offsets of the outputs in the absence of a magnetic field.

TECHNICAL ESSENCE

The object of the invention is to provide an integrated 3D magnetic field microsensor with reduced offsets at the three outputs and with increased accuracy in measuring the components of the magnetic field.

This problem is solved with an integrated Z-D microsensor for magnetic field, containing a p-type semiconductor substrate, on one side of which at the distance from each other are formed two identical power ohmic contacts with a rectangular shape, parallel to their long sides, between symmetrically located is another central power ohmic contact with a square shape. Between the rectangular power contacts, near them and at the same distance are located a pair of registering ohmic contacts, which are the same - first and second to one rectangular contact, and respectively third and fourth to the other as the pairs of contacts are symmetrical to the central . The first contact is against the fourth and the second is against the third. All contacts are surrounded by a deep rectangular /? - ring type, the short sides of which are parallel to the long sides of the rectangular ohmic contacts. The rectangular power contacts through the trimmer and current source are connected to the middle one. The external magnetic field has an arbitrary direction with respect to the / z-type substrate. The outputs for the first component of the magnetic field are the third and fourth contacts with a combination of connecting the first and fourth, and the second and third contacts, respectively. The outputs for the second component are the third and fourth contacts with a combination of first and third connections, and second and fourth contacts, respectively. The outputs for the third component are the second and fourth contacts with a combination of first and second connections, and third and fourth contacts, respectively.

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 symmetry of the structure with respect to the central contact as well as the compensation of the offsets by the trimmer.

Another advantage is the increased measuring accuracy of the outputs as a result of their compensated offsets.

Another advantage is the increased signal-to-noise ratio of the output channels when measuring the components, due to the elimination of the need to switch the supply current through different contacts and the reduction of parasitic offsets in the absence of a magnetic field.

DESCRIPTION OF THE ATTACHED FIGURES

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

Figure 1 shows the construction of the integrated 3-D microsensor for magnetic field;

Figure 2 - the three consecutive combinations of connecting pairs of contact contacts for measuring the mutually perpendicular components of the magnetic field.

EXAMPLES OF IMPLEMENTATION

The integrated 3-D magnetic field microsensor comprises a / z-type semiconductor substrate 1, on one side of which two identical rectangular power ohmic contacts 2 and 3 are formed at a distance from each other, parallel to their long sides, between which symmetrically is located another central power ohmic contact 4 with a square shape. Between the supply contacts 2 and 3, near them and at the same distance are located a pair of registering ohmic contacts, which are the same - first 5 and second 6 to one rectangular contact 2, and respectively third 7 and fourth 8 to the other. 3 as the pairs of contacts 5 and 6, and 7 and 8 are symmetrical with respect to the central 4. The first contact 5 is against the fourth 8 and the second 6 is against the third 7. All contacts 2, 3, 4, 5, 6, 7 and 8 are surrounded by a deep rectangular / j-type ring 9, the short sides of which are parallel to the long sides of the rectangular supply contacts 2 and 3. The supply rectangular contacts 2 and 3 through trimmer 10 and current source 11 are connected to the middle 4. The external magnetic field 12 is an arbitrary direction with respect to the / z-type substrate 1. The output 13 for the first component 14 of the magnetic field 12 is the third 7 and the fourth 8 contact with a combination of connecting first 5 and fourth 8, and second 6 and third 7 contacts, respectively. The output 15 for the second component 16 is the third 7 and the fourth 8 contact is a combination of connecting the first 5 and the third 7, and the second 6 and the fourth 8 contacts, respectively. The output 17 for the third component 18 is the second 6 and the fourth 8 contact with a combination of connecting the first 5 and the second 6, and the third 7 and the fourth 8 contacts, respectively.

The operation of the integrated 3D magnetic field microsensor according to the invention is as follows. The key feature in the measurement of the complete magnetic vector B 12 is the nonlinear trajectory of the current carriers in semiconductor structures 1 with planarly located supply contacts 2, 3 and 4. The current lines start, for example, from contact 4 to contacts 2 and 3, Figure 1. In the absence of a magnetic field 12, contacts 2, 3 and 4 represent equipotential planes. Therefore, in the areas below them, the current lines I ₂ , h and C are vertically directed and the carriers penetrate deep into the volume of the semiconductor substrate 1. In the middle areas between the supply contacts 2-4 and 3-4, respectively, symmetrical and oppositely directed as a result of construction trajectories C, ₂ and - / 4,3 are parallel to the upper surface of the substrate 1. Therefore, the drift velocity V under contacts 2, 3 and 4 is perpendicular to the upper surface, and in the volume between them is parallel to this surface. According to Figure 1, for these two extreme cases the vector relations V = V _y and V = V * are valid. In the presence of a magnetic field 12, B 0, the origin of the magnetic sensitivity is determined by the occurrence of a Lorentz force F _L = qV x B, where q is the electron load. Its action in the separate parts of the two curvilinear trajectories, depending on the individual directions of the components B * 14, B _y 16 and B _z 18 is different (at a fixed current direction / ₄ ). The detection of output signals for each of the magnetic components 14, 16 and 18 is achieved by the innovative design of the integrated microsensor and one of the three connection combinations of the recording electrodes 5, 6, 7, and 8 shown in Figure 2. These recording contacts are Hall, i.e. on them are generated in a magnetic field B 12 voltages of Hall U _n . The magnetosensitivity along the x-axis, Figure 1 and Figure 2a, is determined by the Lorentz deflection of the current carriers in the yz plane: F _L = qV _y x B _x . In this case, additional potentials with opposite sign and with the same value _{are generated simultaneously in the magnetic field B x} 14 on the registering contacts 5 and 8, and on 6 and 7 respectively. In the connection shown in Figure 2a of the pairs of contacts 5 and 8, and respectively 6 and 7, having potentials with the same sign, the differential output 13 of the sensor is extracted Hall voltage V _{ti> x} , representing the information signal for component B _x , (1 ₂ = 1h). The magnetosensitivity along the y-axis, Figure 1 and Figure 26, is determined by the Lorentz deflection of the current carriers in the xz plane: F _t = qV _x x V _y . Thus, additional potentials with opposite sign and with the same value are generated simultaneously on Hall contacts 5 and 7, and respectively 6 and 8 in magnetic field B _{y 16.} The information about the component B _y 16 is determined by the Hall voltage _n y, y on the differential output 15. The magnetic sensitivity along the z axis, Figure 1 and Figure 2c, is established by the Lorentz deflection of the current carriers in the x-y plane: F _L = qV _x x B _z and F _l = qVy xB _z , i.e. the conversion efficiency of the z-axis sensor is determined simultaneously by the velocities V _x and V _y . This leads to "shrinkage" and "expansion" of the two symmetrical current trajectories / _{4, 2} and / ₄ . ₃ . Additional potentials with opposite sign and with the same value are generated simultaneously on Hall contacts 5 and 6, and respectively 7 and 8 in magnetic field B _{z 18.} The measurement of the component B _z 18 is defined by the Hall voltage V _H .z at the output 17. The location of the registration contacts 5, 6, 7, and 8 near the supply 2 and 3 is associated with higher values of Hall potentials, generated by the vertical current lines / ₂ and / ₃ in the zones under contacts 2 and 3. By establishing the three consecutive connection configurations presented in Figure 2 by means of a multiplexer with a corresponding frequency, the complete information about the vector B 12 is obtained. 12 is given by the relation In | = (В ² + В ² + Β ² ) ^υ2 .

Special analysis requires the parasitic influence in the general case of the generated signals from the two unmeasured components on the output channel of the registered third component. The solution used in our case of this fundamental problem of vector magnetometry is the symmetry of the structure with respect to the central contact 4, Figure 1, and the methods of connecting the respective output contacts 5, 6, 7 and 8 shown in Figure 2 in order to realize differential outputs 13, 15 and 17. For example, if the field Β _ζ 18 is measured, Figure 2c, the simultaneous action of the other two magnetic components B _x 14 and B _y 16 leads to in-phase additional potentials on the thus connected electrodes 5-6 and 7- 8. These parasitic potentials in this case are mutually compensated by the differential output V _H , z 17. The compensation of the interchannel parasitic influence is similar for the other sensor channels 13 and 15.

The unexpected positive effect of the new technical solution lies on the one hand in the ability to significantly minimize the offsets of the thus formed outputs 13, 15 and 17 of the symmetry of the 3-D microsensor relative to the central contact 4, and on the other - the innovative connection of output electrodes 5 , 6, 7 and 8, forming three differential outputs 13, 15 and 17, Figure 2. The proposed new solution is the development of the method for sequential measurement of the components of the magnetic field B 12 is the same conversion region in structure 1. In fact the metrological problem has been extended not in space but in time, which is a significant innovative approach in vector magnetometry, drastically increasing the sensory resolution, ie. registration of the field B 12 practically in the "point" The role of the deep p-type ring 9, surrounding the ohmic contacts 2, 3, 4, 5, 6, 7 and 8 is to separate the effective sensor area from the remaining volume of the substrate 1. According to this way in depth limiting surfaces are formed for the supply currents flowing in the structure 1, subjected to the Lorentz force Fl. The surface flow of currents is also limited by the p-ring 9.

The integrated 3-D magnetic field microsensor can be implemented with well-tested IC technologies. The magnetometer allows integration together with the signal processing peripheral electronics. Its action is in a wide temperature range.

APPENDIX: two figures with

LITERATURE

[1] Ch.S. Руменин, С.В. Lozanova, “Microsystem for measuring the three components of the magnetic field”, Patent for invention № EN 65970 B1 / 09.09.2010, per. № 109952 / 12.09.2007

[2] S. Lozanova, Ch. Roumenin, Four-contact Hall microdevice for subsequent 3-D magnetic field-measurement, Proc, of the EUROSENSORS XXII Conf., Dresden, Germany, 2008, pp. 239-242.

Claims (1)

<Integrated 3-D microsensor for magnetic field, containing / g-type semiconductor pad, on one side of which at distances from each other are formed ohmic contacts - power and register, all surrounded by a deep rectangular p-type ring, current source, three the output for measuring the mutually perpendicular components of the magnetic field by three combinations of connection of the registering contacts, and the magnetic field has an arbitrary direction relative to the substrate, CHARACTERIZED in that the supply contacts are three (2), (3) and (4), two of them (2) and (3) are identical, rectangular in shape and parallel to their long sides, between them is symmetrically located the third power contact (4), which is central and square in shape, between the power contacts (2). ) and (3), near them and at the same distance are located a pair of identical contacts, which are the registering - first (5) and second (6) to one power contact (2), and respectively third (7). ) and fourth (8) to another (3), the pairs of contacts (5) and (6), and (7) and (8) are symmetrical with respect to the central (4) with the first contact (5) against the fourth (8) and the second (6) against third (7), the short sides of the p-ring (9) are parallel to the long sides of the rectangular contacts (2) and (3), the supply contacts (2) and (3) through the trimmer (10) and the current source (11) are connected to the middle (4), the output (13) for the first component (14) of the magnetic field (12) is the third (7) and fourth (8) contact with a combination of connection first (5) and fourth (8), and respectively second (6) and third (7) contact, the output (15) for the second component (16) is the third (7) and fourth (8) contact with a combination of connection first (5) and third (7), and second respectively 6) and fourth (8) contact, and the output (17) for the third component (18) is the second (6) and fourth (8) contact with a combination of connection first (5) and second (6), and third respectively ) and fourth (8) contact.