BG112436A - In-plane sensitive magnetic-field hall device - Google Patents

Abstract

The Hall magnetic-sensing device contains two identical semiconductor pads with n-type conductivity - first (1) and second (2), located parallel to each other and a current source (3). On one side of each of the pads (1) and (2) in series and at a distance from each other are formed from left to right four rectangular ohmic contacts - first (4), (5), second (6), (7) , third (8), (9) and fourth (10), (11). One terminal of the current source (3) is connected simultaneously to the contact (6) of the substrate (1) and the contact (11) of the substrate (2), and its other terminal - to the midpoint of a low-resistance trimmer (12), the end terminals of which are connected to the contact (10) of the first (1) and the contact (7) of the second pad (2), respectively. Contacts (4) and (5) are connected to each other. The contacts (8) and (9) are the differential output (13) of the Hall device, the measured magnetic field (14) being parallel both to the planes of the pads (1) and (2) and to the long sides of the contacts (4). ), (5), (6), (7), (8), (9), (10) and (11).

Description

PLANE-MAGNETIC SENSITIVE DEVICE OF THE LIVING ROOM

FIELD OF THE INVENTION

The invention relates to a plane-magnetic Hall device applicable in the field of micro- and nano-technologies, robotics and mechatronics, sensorics, robotic and 3D surgery, unmanned aerial vehicles and systems, electric vehicles and hybrid vehicles, cognitive systems with artificial intelligence , biomedical research, energy and energy efficiency, non-contact measurement of angular and linear displacements, navigation, control and measuring equipment and low-field magnetometry, military affairs and security, etc.

BACKGROUND OF THE INVENTION

A plane-magnetic Hall-sensitive device is known, containing two identical semiconductor pads with / z-type conductivity - first and second, located parallel to each other and a current source. On one side of each of the pads successively and at distances from each other are formed from left to right five rectangular ohmic contacts - first, second, third, fourth and fifth. The third contacts are central as the first and fifth, and respectively the second and fourth are symmetrically located relative to them. All first and fifth contacts are directly connected to each other. The second contact of the first pad is connected is the fourth of the second, and the fourth of the first - is the second contact of the second pad. The terminals of the current source are connected to the second and fourth contact of the first pad. The differential output of the Hall device are the two central contacts and the measured magnetic field is parallel to both the planes of the pads and the long sides of the contacts, [1 -4].

The disadvantage of this plane-magnetic Hall-sensitive device is the low sensitivity, since the outputs of the two five-pin Hall elements are connected in parallel, which is equivalent to an output voltage from only one Hall element.

Another disadvantage is the complicated construction of the device, containing ten ohmic contacts and a total of five connections between them.

TECHNICAL ESSENCE

It is an object of the invention to provide a plane-magnetic Hall-sensitive device with high sensitivity and a simplified construction with fewer contacts and connections between them.

This problem is solved with a plane-magnetic Hall-sensitive device containing two identical semiconductor pads of e / g-type conductivity - first and second, located parallel to each other and a current source. On one side of each of the pads, four rectangular ohmic contacts - first, second, third and fourth - are formed sequentially and at distances from each other. One terminal of the current source is connected simultaneously to the second contact of the first substrate and the fourth contact of the second substrate, and its other terminal to the midpoint of a low-resistance trimmer, the terminals of which are connected to the fourth contact of the first and second contacts of the second substrate. . The first two contacts are connected to each other. The two third contacts are the differential 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 contacts.

An advantage of the invention is the high magnetic sensitivity as a result of the two Hall voltages generated by the supply currents in the two pads, which are summed by the connections made between the contacts.

Another advantage is the simplified design of the device, containing a total of eight instead of ten contacts and three connections between them instead of five as in the known solution.

Another advantage is the possibility for full compensation of the parasitic voltage of asymmetry of the output in the absence of a magnetic field (offset) and minimization of its temperature drift with the help of the low-resistance trimmer included in the power supply circuit.

The advantage is the increased metrological accuracy and resolution of the high signal / noise level, due to the significant magnetic sensitivity of the device and the compensated offset of the output.

DESCRIPTION OF THE ATTACHED FIGURES

The invention is illustrated in more detail by an exemplary embodiment thereof, given in the attached Figure 1, representing its cross section.

EXAMPLES OF IMPLEMENTATION

The planar magnetosensitive Hall device contains two identical semiconductor pads with p-type conductivity - first 1 and second 2, located parallel to each other and current source 3. On one side of each of the pads 1 and 2 in series and at distances from each other are formed from left to right by four rectangular ohmic contacts - first 4, 5, second 6, 7, third 8, 9 and fourth 10, 11. One terminal of the current source 3 is connected simultaneously is the second contact 6 of the first pad 1 and the fourth contact 11 on the second pad 2 and its other terminal with the midpoint of a low-resistance trimmer 12, the terminals of which are connected respectively to the fourth pin 10 of the first 1 and the second pin 7 of the second pad 2. The two first contacts 4 and 5 are connected with each other. The two third contacts 8 and 9 are the differential output 13 of the Hall device as the measured magnetic field 14 is parallel both to the planes of the pads 1 and 2 and to the long sides of the contacts 4, 5, 6, 7, 8, 9, 10. and 11.

The operation of the planar magnetosensitive Hall device according to the invention is as follows. When contacts 6 and 11 are connected, and respectively 10 and 7 to the current source 3, equal and oppositely directed supply currents Ζ ₆ , ιο and - Ι _η , ι flow in the volume of the same pads 1 and 2, Figure 1. The current lines in both semiconductor structures 1 and 2 are curvilinear, because in the absence of magnetic field B 14 the planar supply contacts 6, 10, 7 and 11 through which the currents flow are equipotential planes. Therefore, the current lines are initially directed vertically in the volume of the pads 1 and 2, then change their direction and become parallel to their upper planes. The penetration depth w of the current lines at a fixed concentration of the doping donor impurity N _D ~ 10 ¹⁵ cm ' ³ in the n-type silicon substrates 1 and 2 is about w ~ 30 - 40 pm. Due to inevitable imperfections in the technology, misalignment of the masks, defects in the silicon wafers in the realization of the samples, etc., at the differential output V _out 13 of the Hall device there is a parasitic voltage of asymmetry (offset) in the absence of external magnetic field B = 0 14 This signal and its temperature drift introduce a significant error in the metrology of magnetic induction B. Therefore, its compensation (reset) is essential for accuracy. In the new solution, this problem is eliminated with the low-resistance trimmer r 12 between the supply contacts 10 and 7. By varying the value of r 12, full offset compensation can be achieved, i. ν _ολΛ (Β = 0) = 0.

In a magnetic field B 14 with a fixed orientation relative to the planes of the pads 1, 2, the Lorentz force F _L = qV x B, depending on the directions of the currents / _{6> 10} and - deforms in different ways the current lines, where q is the load of electron, and V is the average drift velocity of the carriers, [4, 5]. In one substrate, for example the first 1, the force F _L "shrinks" the trajectory / _{6> 10} to the upper surface with contacts 4, 6, 8 and 10 as the concentration of electrons in the area of contact 8 increases and in the area of contact 4 decreases. As a result, a voltage of Hall Vh4 occurs between electrodes 4 and 8, s (^) · In addition to the upward movement, most pronounced in the middle part of the current trajectory / _b e ₀ , the force F _L deflects laterally in opposite directions currents 1 ₆ and 1 ₁₀ below the two contacts 6 and 10. This leads to an additional concentration of current carriers with positive and negative signs respectively in the near-surface areas with Hall contacts 4 and 8. As a result, the volumetric resistance R _{6> 10} between contacts 6 and 10 changes linearly, which in turn increases the voltage of Hall Un4,8 (c) · The study shows that the additional change (increase / decrease) of the Hall signal Vh4, s (^) is about 30%, [6]. The complex sensor mechanism described above is identical to that in the second pad 2. There, however, the Lorentz force F _L "unfolds" the current lines (- Ι _{η> Ί} ) in the volume, ie. it reduces the concentration of electrons under contact 9 (in the middle part of the trajectory / t ₍₇ ). Therefore, between contacts 5 and 9 there is a Hall voltage - V _H 5.9 (B), which is the same value as in pad 1, but with the opposite sign of the current - / _n , 7 · The Lorentz force F _L also deflects laterally the currents / ₇ and 7c under contacts 7 and 11. This further changes the amount of current carriers in the surface areas with Hall contacts 5 and 9. The non-standard connection of contacts 4 and 5 of the two pads 1 and 2 sums the two Hall voltages Vo _Ut (#) = Vh4,8 (#) + | - Ун5,9 (^) 1 · Therefore the output signal Vout ^ ) 13 In addition, when offset is compensated, its temperature drift is minimal, which contributes to higher accuracy.The new plane-magnetic device contains eight, not ten ohmic contacts, and the connections between them are three, and not five, which greatly simplifies the design and circuitry father.

The unexpected positive effect of the new technical solution lies in the original design and non-standard connection of contacts 4-5, 6-11 and 10-7 on both pads 1 and 2. In addition, the power supply 3 can be in current generator or voltage generator mode, expanding so the circuit capabilities. In these sensor structures 1 and 2, by lateral deflection of the supply currents under contacts 6 and 10, and 7 and 11, respectively, linear modulation in the magnetic field B 14 of the resistors under the output contacts 8 and 9 is achieved, which further increases the magnetic sensitivity. The functional integration of the two four-contact Hall elements increases both the signal-to-noise ratio and the resolution for detecting the minimum value of the magnetic induction. As a result, the metrological accuracy of the device is improved.

The plane-magnetic Hall-sensitive device can be realized by CMOS, BiCMOS or micromachining technologies as in the silicon chip the conversion zones represent deep i-type pockets 1 and 2. The operation of the device is in a wide temperature range, including in cryogenic environment. For even higher sensitivity for the purposes of low-field magnetometry, navigation and counter-terrorism, pads 1 and 2 can be located between two identical ferrite or μ-metal magnetic field concentrators B 14.

APPENDIX: one figure

LITERATURE

[1] T. Kaufmann, “On the offset and sensitivity of CMOS-based five-contact vertical Hall devices”, in “MEMS Technology and Engineering”, v. 21, Der Andere Verlag, 2013, p. 147.

[2] R. Popovic, “Integrated Hall element”, U.S. Patent 4,782,375 / November 1, 1988.

[3] A.M.J. Huiser, H.P. Baltes, “Numerical modeling of vertical Hall-effect devices”, IEEE Electron Device Letters, 5 (9) (1984) pp. 482-484.

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

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

[6] T. Phetchakut, S. Poonsawat, A. Poyai, The effect of deviation current to 5 contacts vertical Hall devices, Proc, of the 13 ^th IEEE Intern. Conf, on Electrical Engin./Electronics, Computer, Telecommun. and Inform. Techn. (ECTI-CON), 2016

Claims (1)

PATENT CLAIMS, A planar magnetosensitive Hall device comprising identical semiconductor pads with / d-type conductivity, arranged parallel to each other and a current source, on one side of each of the pads in series and at distances from each other are formed from left to right by the same number of rectangular ohmic contacts as the measured magnetic field is parallel to the planes of the pads and the long sides of the contacts, CHARACTERIZED by the fact that the pads are two - first (1), second (2), on each of them there are four contact - first (4) and (5) second (6) and (7), third (8) and (9) and fourth (10) and (11), one terminal of the current source (3) is connected simultaneously with contact ( 6) on a pad (1) and a contact (11) on a pad (2), and its other terminal - with the midpoint of a low-resistance trimmer (12), the end terminals of which are connected respectively to a contact (10) of the first (1) and contact (7) of the second pad (2) as contacts (4) and (5) are connected to each other, two the third contacts (8) and (9) are the differential output (13) of the Hall device.