BG113272A - Planar magnetically sensitive sensor - Google Patents

Abstract

The planar magnetosensitive sensor contains a semiconductor parallelepiped substrate (1) with n-type impurity conductivity, on one side of which, at distances from each other, five rectangular ohmic contacts are successively formed - from left to right first (2), second (3), third (4), fourth (5) and fifth (6) - all parallel to each other with the long sides and current source (7). The first (2) and fifth (6), and respectively the second (3) and fourth (5) contacts are symmetrically located with respect to the third (4), which is central. The first (2) and fifth (6) contacts are connected and through the current source (7) are connected to the central contact (4). The surface of the pad (1) between the first (2) and the second (3), as well as between the second (3) and the central (4) contact, and respectively between the central (4) and the fourth (5), as well as between the fourth (5) and the fifth (6) contact is covered with a thin dielectric layer (8) of constant thickness, on the parts of which metal gate electrodes are formed - from left to right first (9) and second (10), and respectively third (11) and fourth (12). The second contact (3) is connected to the third (11) and fourth (12) gate electrodes, and the fourth contact (5) to the first (9) and second (10) gate electrodes. The second (3) and fourth (5) contacts are the differential output (13) of the sensor, the measured magnetic field (14) being parallel to both the plane of the substrate (1) and the long sides of the contacts (2), ( 3), (4), (5) and (6).

Description

PLANAR MAGNETIC SENSOR

TECHNICAL FIELD

The invention relates to a planar magnetosensitive sensor applicable in the field of quantum communication, artificial intelligence security systems, sensorics, medicine including robotic and minimally invasive surgery, 3D telemedicine and laparoscopy, robotics, mechatronics, contactless automation including remote measurement of angular and linear displacements, navigation, micro- and nano-technologies, space exploration, electric vehicles and hybrid vehicles, energy, control and measurement equipment and weak-field magnetometry, counterterrorism, military affairs, etc.

PRIOR ART

A planar magnetosensitive sensor is known, comprising a semiconductor parallelepiped substrate with i-type impurity conductivity, on one side of which five rectangular ohmic contacts are formed sequentially at distances from each other - from left to right first, second, third, fourth and fifth - all parallel to each other with the long sides and a current source. The first and fifth, and respectively the second and fourth contacts are symmetrically arranged with respect to the third contact, which is central. The first and fifth contacts are connected and are connected to the third contact through the current source. The second and fourth contacts are the differential output of the sensor, as the measured magnetic field is parallel to both the plane of the substrate and the long sides of the ohmic contacts, [1-9].

A disadvantage of this sensor is the reduced sensitivity as a result of the low mobility of the current carriers in the silicon semiconductor used in its integrated technological implementation.

Another disadvantage is the reduced measurement accuracy due to low sensitivity, leading to a noticeable presence in the output voltage of characteristic sensor flaws such as parasitic offset, nonlinearity, temperature drift, internal 1 // (flicker) noise, hysteresis, etc.

TECHNICAL ESSENCE

The objective of the invention is to create a planar magnetosensitive sensor with increased sensitivity and high metrological accuracy.

This problem is solved with a planar magnetosensitive sensor containing a semiconductor parallelepiped substrate with i-type impurity conductivity, on one side of which at distances from each other five rectangular ohmic contacts are formed sequentially - from left to right first, second, third, fourth and fifth - all parallel to each other with the long sides and a current source. The first and fifth, and respectively the second and fourth contacts are symmetrically arranged relative to the third, which is central. The first and fifth contacts are connected and through the current source are connected to the central contact. The surface of the substrate between the first and second as well as between the second and central contact, and respectively between the central and fourth as well as between the fourth and fifth contacts is covered with a thin dielectric layer of constant thickness, on the parts of which metal gate electrodes are formed - from left to right first and second, and respectively third and fourth. The second contact is connected to the third and fourth gate electrodes, and the fourth contact is the first and second gate electrodes. The second and fourth contacts are the differential output of the sensor, as the measured magnetic field is parallel to both the substrate plane and the long sides of the ohmic contacts.

An advantage of the invention is the high sensitivity due to the increased Hall field in the volume of the substrate, respectively the potentials on the pairs of gate electrodes on both sides of the central contact with corresponding polarity, generating additional electrical charges of opposite sign under the dielectric layer.

Another advantage is the increased measurement accuracy as a result of the high sensitivity at an unchanged level of sensor deficiencies - parasitic offset, nonlinearity, temperature drift, internal (flicker) noise, hysteresis, etc.

Another advantage is the increased resolution when measuring the minimum magnetic induction, due to the high sensitivity simultaneously with the increased signal-to-noise ratio of the sensor, which provides more detailed detection of the topology of the magnetic field.

DESCRIPTION OF THE APPENDIX FIGURES

The invention is explained in more detail with an exemplary embodiment thereof, given in the attached Figure 1.

EXAMPLES OF IMPLEMENTATION

The planar magnetosensitive sensor contains a semiconductor parallelepiped substrate 1 with i-type impurity conductivity, on one side of which five rectangular ohmic contacts are formed sequentially at distances from each other - from left to right, first 2, second 3, third 4, fourth 5 and fifth 6 - all parallel to each other with the long sides and a current source 7. The first 2 and the fifth 6, and respectively the second 3 and the fourth 5 contacts are symmetrically arranged relative to the third 4, which is central. The first 2 and the fifth 6 contacts are connected and through the current source 7 are connected to the central contact 4. The surface of the substrate 1 between the first 2 and the second 3 as well as between the second 3 and the central 4 contact, and respectively between the central 4 and the fourth 5 as well as between the fourth 5 and the fifth 6 contact is covered with a thin dielectric layer 8 of constant thickness, on the parts of which metal gate electrodes are formed - from left to right first 9 and second 10, and respectively third 11 and fourth 12. The second contact 3 is connected to the third 11 and fourth 12 gate electrode, and the fourth contact 5 - to the first 9 and second 10 gate electrode. The second 3 and fourth 5 contacts are the differential output 13 of the sensor as the measured magnetic field 14 is parallel to both the plane of the substrate 1 and the long sides of contacts 2, 3, 4, 5 and 6.

The operation of the planar magnetosensitive sensor according to the invention is as follows. When the current source 7 is switched on to the connected contacts 2 - 6, and the central 4, in the two symmetrical configurations with respect to contact 4, supply currents / ₄₂ and - D flow in the substrate 1 of equal value and opposite direction _; 6, / ₄ ,2 = |- L,b|· Ohmic contacts, 2, 4 and 6 represent equipotential planes, to which in the absence of an external magnetic field B 14, B = 0, the current components through them / ₂ , C and / ₆ are always perpendicular to the upper surface of the substrate 1, penetrating deep into its volume. The current lines / _{4 2} and / ₄₆ in the remaining part of the volume of the structure 1 are parallel to the upper side, Figure 1.

The measured magnetic field B 14 parallel to the long sides of the rectangular contacts 2, 3, 4, 5 and 6 creates a lateral deflection of the current lines by the Lorentz forces F _L;i = qV^ x B in the two symmetrical configurations relative to the supply contact 4, 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 substrate 1. As a result of this Lorentz deflection by the forces F _Lj i, the trajectories of the oppositely directed components / _4;2 and - / _4;6 are “contracted” or “expanded” respectively. Depending on the mutual directions of the currents / _4>2 and - / _{4 6} on the one hand, and the magnetic field vector B 14 on the other, opposite in sign and equal in value Hall potentials and +^ ₅ are generated on the output contacts 3 and 5. Thus, through the Hall effect, generalized by Ch. For all types of solid-state structures, including those with planar magnetic susceptibility [6-8], the output voltage Kipz(^) 13 of the sensor arises.

Due to the low electron mobility μ _η in silicon, the main semiconductor in integrated microelectronic technologies, significant values of the sensitivity at room temperature, μ _η (Τ = 300 K) ~ 1200 cm V's' cannot be expected. As is well known, the conversion efficiency or sensitivity S is directly proportional to the electron mobility μ _η , S ~ μ _η , [6-9]. However, the processes develop differently in the presence of gate electrodes 9, 10, 11 and 12, Figure 1. They are separated from the interfaces of the upper plane of the substrate 1 by a dielectric layer 8, parts of which are of constant thickness. The dielectric layer 8 is primarily made of silicon dioxide SiO ₂ as in the well-known MOS transistors. The innovative connection of the gate electrodes 9 and 10 with the output contact 5, and respectively the pair of gate electrodes 11 and 12 with the output contact 3 induces through the potentials -^ ₃ and +φ ₅ a field effect in the MOS structures thus formed, [10]. If in the l-type substrate 1, as is our case, the gate potential is positive + φ ₅ , in the interface zones under the gate electrodes 9 and 10, additional electrons are extracted from the volume by the field effect, i.e. the negative component of the Hall field increases. At a negative gate voltage -φ^ in the surface regions under the gates 11 and 12 an electron depletion mode is realized, i.e. the positive component of the field also increases. The polarities of the gate potentials ±V _G ^are in the same direction as the action of the Lorentz force ±F _L - Therefore, the described process increases both the resulting Hall potentials +^ ₅ and <pz. and the output voltage of the microsensor Kip3C^) 13. As a result of the technical solution in Figure 1, the magnetic sensitivity S and the measurement accuracy of the field B 14 increase. At the same time, the high signal Vouti ₃ (^) 13 also leads to an increase in the signal-to-noise ratio (S/N) with unchanged negative factors such as parasitic offset, nonlinearity, temperature drift, internal (flicker) noise and hysteresis. Therefore, the resolution when measuring the minimum magnetic induction B _min increases, which provides a more detailed determination of the topology of the magnetic induction B 14.

The unexpected positive result of the new technical solution is that in Hall sensors a non-standard approach is used to increase sensitivity - the field effect, typical of MOS structures. By this method, the Hall potentials themselves -^z and +^ ₅ are used to generate additional uncompensated loads of opposite sign to those of the Lorentz deviation F _{ on the corresponding parts of the upper surface of the sensor. This amplifies the output voltage WashzX#) = K _and cz(^) 13. An important feature is that the sensor is implemented in a single technological cycle, which is also an advantage.

The planar magnetosensitive sensor can be implemented with CMOS or BiCMOS technologies, with the conversion zone of the configuration representing a deep n-type well 1 in a p-type substrate. The choice of well 1 with n-type impurity conductivity is dictated by the fact that in electronic semiconductors the mobility of current carriers μ _η , determining the speed V _dr , i.e. the magnetosensitivity, is significantly higher, compared to p-type materials. The integrated technology allows the new sensor together with the signal processing circuitry K^3X^) 13 to be implemented on a common silicon chip, forming an intelligent microsystem (MEMS). The functioning of the proposed planar magnetosensitive sensor is feasible in a wide temperature range, including at cryogenic temperatures. For even higher sensitivity for weak-field magnetometry and counterterrorism purposes, the chip can be placed between two identical elongated magnetic field concentrators B 14 made of ferrite or μmetal.

APPENDIX: one figure

LITERATURE

[1] H.S. Rumenin, P.T. Kostov, Semiconductor Hall element, Author. certificate BG No. 39283 with priority from 08.01.1985.

[2] R. Popovic, Integrated Hall element, US Patent 4,782,375/01.11.1988.

[3] R. Popovic, The vertical Hall-effect device, IEEE Electron Device Letters, 5(9) (1984) pp. 357-358.

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

[5] C.S. Roumenin, P.T. Kostov, Silicon Hall-effect microsensor, Compt. rendus Acad. Bulgaria Sci., 39(5) (1986) 63-66.

[6] Ch. Roumenin, Solid State Magnetic Sensors, Elsevier, Amsterdam, 1994, p. 450; ISBN: 0 444 89401.

[7] 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.

[8] T. Kaufmann, On the offset and sensitivity of CMOS-based five-contact vertical Hall devices, MEMS Technology and Engineering, v. 21, Der Andere Verlag, 2013, p. 147; ISBN: 978-3-86247-374-8.

[9] R. Steiner, Rotary switch and current monitor by Hall-based Microsystems, Phys. Electr. Lab. Publ. (ETH) Zurich, 1999; ISBN: 3-89649-446-5.

[10] SM Sze, Physics of Semiconductors, ^2nd ed., Wiley-Intersc. Publ., John Wiley & Sons, New York, 1994.

Claims (1)

A planar magneto-sensitive sensor containing a semiconductor parallelepiped substrate with i-type impurity conductivity, on one side of which five rectangular ohmic contacts are successively formed at distances from each other - from left to right first, second, third, fourth and fifth - all parallel to each other are with the long sides and a current source, the first and fifth, and respectively the second and fourth contacts are symmetrically located with respect to the third, which is central, the first and fifth contacts are connected and through the current source are connected to the central contact, the second and fourth contacts are the differential output of the sensor as the measured magnetic field is parallel both to the plane of the substrate and to the long sides of the ohmic contacts, CHARACTERIZED in that the surface of the substrate (1) between the first (2) and the second (3) as well as between the second (3) and the central (4) contact, and respectively between the central (4) and the fourth (5) as well as between the fourth (5) and the fifth (6) contact is covered with a thin dielectric layer (8) of constant thickness, on the parts of which metal gate electrodes are formed - from left to right first (9) and second (10), and respectively third (11) and fourth (12), the second contact ( 3) is connected to the third (11) and fourth (12) gate electrodes, and the fourth contact (5) - to the first (9) and second (10) gate electrodes.