BG113014A - Integrated hall effect sensor with an in-plane sensitivity - Google Patents

Abstract

The integrated Hall sensor with an in-plane sensitivity comprises two semiconductor wafers of an n-type conductivity, arranged in parallel - first (1) and second (2), and a current source (3). On one side of the wafers (1 and 2) are formed in series from left to right five and respectively three ohmic rectangular contacts, parallel to their long sides - first (4), second (5), third (6), fourth (7) and fifth (8) on wafer (1), and first (9), second (10) and third (11) of the second (2) wafer. Contact (6) of the first (1) and contact (10) of the wafer (2) are central and relative to them the first (4) and the fifth (8), and respectively the second (5) and the fourth (7) contact of the wafer (1), as the first (9) and third (11) contacts of the second (2) wafer are arranged symmetrically. Close to the two long sides of the contacts (6 and 10), in parallel and at equal distances from them, there is a deep zone (12) with p-type conductivity, the length of which is equal to that of the contacts (6 and 10). The two terminals of the current source (3) are connected to the contacts (6 and 10). The first contact (4) of wafer (1) is connected to the contact (9) of the second (2) one, and the fifth contact (8) of the first (1) wafer is connected to contact (11) of the wafer (2). The first (4) and fourth (7) contacts, and respectively the second (5) and fifth (8) contacts of the wafer (1) are connected. The differential output (13) of the sensor is the first (9) and third (11) contact of the wafer (2), and the measured magnetic field (14) is parallel to both the planes of the wafers (1 and 2) and the long sides of the contacts (4, 5, 6, 7, 8, 9, 10 and 11).

Description

The invention relates to an integrated Hall sensor with plane sensitivity applicable in the field of sensorics; robotics and mechatronics, including robotic and minimally invasive surgery; biomedicine; quantum communication; security systems with artificial intelligence and military affairs; electric cars and hybrid vehicles; unmanned aerial vehicles; machine building and production automation; non-contact measurement of angular and linear displacements; low-field magnetometry; energy; counter-terrorism including underwater, ground and air surveillance and prevention; navigation, etc.

BACKGROUND OF THE INVENTION

An integrated Hall sensor with plane sensitivity is known, containing two identical semiconductor pads with i-type impurity conductivity - first and second, located in parallel and a current source. On one side of each of the pads, five rectangular ohmic contacts are formed successively from left to right and at equal distances, parallel to their long sides - first, second, third, fourth and fifth. The first and fifth, and the second and fourth contacts, respectively, are symmetrical with respect to the third. The first and fifth contacts are interconnected. The second contact of the first pad is connected to the fourth of the second, and the fourth contact of the first pad is connected to the second contact of the second. The two terminals of the current source are connected to the second and fourth contact of the first pad. The differential output of the Hall sensor 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, [1-7].

The disadvantage of this integrated Hall sensor with plane sensitivity is the low conversion efficiency (magnetic sensitivity) due to the planned on the same surface of the pads of the input and output contacts as the supply current flows for the most part horizontally. The action of the magnetic field by the Lorentz deflection force on the horizontal current is insignificant and the sensitivity is generated by the vertical component of the current.

Another disadvantage is the complicated design of the sensor, containing ten contacts with a total of four connections between them, which limit the technological implementation through integrated microelectronic processes.

Another disadvantage is the reduced measurement accuracy due to the low sensitivity and the increased level of intrinsic Ι / f (flicker) noise from the passage of the horizontal component of the supply current through the output Hall contacts.

TECHNICAL ESSENCE

The object of the invention is to provide an integrated Hall sensor with plane sensitivity, which has a high conversion efficiency (magnetic sensitivity), a simplified design by reducing the number of contacts and connections between them, and increased measurement accuracy by reducing its own Ι / f noise.

This problem is solved with an integrated Hall sensor with plane sensitivity, containing two semiconductor pads with i-type impurity conductivity, located in parallel - first and second, and a current source. On one side of each pad are formed successively from left to right five and three ohmic rectangular contacts, respectively, parallel to their long sides - first, second, third, fourth and fifth on the first pad, and first, second and third on the second. The third contact of the first and second contacts of the second pad are central and relative to them the first and fifth, and respectively the second and fourth contacts of the first pad as the first and third contacts of the second are arranged symmetrically. Near the two long sides of the central contacts, parallel and at equal distances from them, there is a deep zone with p-type impurity conductivity, the length of which is equal to that of the third contacts. The two terminals of the power source are connected to the central contacts. The first contact of the first pad is connected to the first contact of the second, and the fifth contact of the first is connected to the third contact of the second pad. The first and fourth, and respectively the second and fifth contacts of the first pad are connected. The differential output of the Hall sensor is the first and third contacts of the second pad, and the measured magnetic field is parallel to both the planes of the pads and the long sides of the pins.

An advantage of the invention is the increased magnetic sensitivity as a result of: 1. the strongly reduced horizontal components of the supply current in the two substrates from the formed deep p-type zones on the long sides of the central contacts, determining the penetration of the supply current deep into the volume of structures of magnetically controlled vertical components; 2. the closely spaced first and second, and respectively fourth and fifth contacts of the first substrate by their connection unite the significant directional changes in the magnetic field of the vertical current components, generated by their Lorentz deviation.

Another advantage is the simplified design of the Hall sensor, containing a total of eight instead of ten ohmic contacts, which contributes to the technological implementation.

Another advantage is the reduced Ι / f flicker noise through the sensor construction, containing deep /? - type enclosing zones equal in length to the central contacts, which drastically reduces the horizontal current components so that they do not pass through the output contacts.

An advantage is also the increased resolution when measuring the minimum magnetic induction as a result of the increased signal-to-noise ratio by means of the high sensitivity and the reduced flicker noise.

Another advantage is the high measuring accuracy as a result of the increased sensitivity and the reduced ί / f noise from the removed passage of the horizontal components of the supply current through the contacts.

Another advantage is the minimized parasitic offset of the output through the direct connections of the contact pairs of the first substrate, compensating for inevitable parasitic potentials and improving the electrical symmetry with respect to the output.

Another advantage is the increased stability of the output voltage to temperature fluctuations due to the operation of the Hall sensor in the current generator mode formed by the internal resistances of the pads.

DESCRIPTION OF THE ATTACHED FIGURES

The invention is illustrated in more detail by an embodiment thereof, given in the attached Figure 1, representing the cross section of the integrated Hall sensor.

EXAMPLES OF IMPLEMENTATION

The integrated Hall sensor with plane sensitivity contains two semiconductor pads with p-type impurity conductivity, located in parallel - first 1 and second 2, and current source 3. On one side of the pads 1 and 2 are formed successively from left to right five and respectively three ohmic rectangular contacts parallel to their long sides - first 4, second 5, third 6, fourth 7 and fifth 8 on the first pad 1, and first 9, second 10 and third 11 on the second 2. The third contact 6 on the first 1 and the second contact 10 on the second pad 2 are central and the first 4 and the fifth 8, and respectively the second 5 and the fourth 7 contacts of the first pad 1 as well as the first 9 and the third 11 contacts of the second 2 are arranged symmetrically. Near the two long sides of the central contacts 6 and 10, in parallel and at equal distances from them there is a deep zone 12 with p-type impurity conductivity, the length of which is equal to that of contacts 6 and 10. The two terminals of the current source 3 are connected to the central contacts 6 and 10. The first contact 4 of the first substrate 1 is connected to the first contact 9 of the second 2, and the fifth contact 8 of the first 1 is connected to the third contact 11 of the second substrate 2. The first 4 and fourth 7 contacts , and respectively the second 5 and the fifth 8 contacts of the first pad 1 are connected. The differential output 13 of the Hall sensor are the first 9 and third 11 contacts of the second pad 2, and the measured magnetic field 14 is parallel to both the planes of the pads 1 and 2 and the long sides of the pins 4, 5, 6, 7, 8, 9, 10 and 11.

The operation of the integral Hall sensor with plane sensitivity according to the invention is as follows. When the central contacts 6 and 10 are connected to the current source 3, and the electrodes 4c9, 8 to 11, 4 to 7, and 5 to 8 are connected according to Figure 1, the currents D1, / b, 5 flow in the volumes of the two pads 1 and 2. ^and - b, b - C #, ^and respectively and - / 10,11. Due to the symmetry of structures 1 and 2 with respect to contacts 6 and 10, and the method of connection, these current components are equal and oppositely directed. The trajectories of the electrons in pads 1 and 2 are curvilinear, because in the absence of magnetic field B 14 the ohmic planar contacts 4, 5, 6, 7, 8, 9, 10 and 11 through which the supply current components flow are equipotential planes. Therefore, the current lines are initially perpendicular to the upper surfaces of pads 1 and 2, then change their direction and in a certain area in their volumes are parallel to the upper planes. In addition, the deep p-type enclosing zones 12, equal in length to the rectangular central contacts 6 and 10, do not allow the presence of horizontal current components on the surface of the structures 1 and 2. Usually, according to the silicon technology used, the depth of the p-zones 12 varies up to about 12-15 cm. As a result, the penetration depth w of the current lines at a fixed concentration of the doping donor impurity ND in i-type Si pads 1 and 2 also depends on the ratio M between the width 1 \ of contacts 4, 5, 6, 7, 8, 9, 10 and 11, and the distances 12 between them, Μ = / ι // 2, [1, 2, 5 - 7]. The maximum depth w at the most commonly used in microelectronics concentration of alloying donor impurities ND ~ 10 ¹⁵ cm ' ³ in Si and contact width up to about 5-10 μm is about w ~ 30 - 40 μm. At the same time, pad 2 with contacts 9, 10 and 11 represents the first plane-sensitive Hall microsensor with three ohmic contacts. This class of elements was created and developed by Rumenin and Lozanova, [5, 8 - 10]. The load resistors that are connected to the end electrodes 9 and 11 of these microsensors, [8], in the new solution of Figure 1 are replaced by the internal resistances R9> i ₀ , Rio.ii »R4,6 and R ₆ , s of both pads 1 and 2. These resistors determine the operating mode of the current generator. The resistances R ₉₁₀ = Rio, and ^and R4,6 = Re, 8 are the same due to the structural symmetry of the pads 1 and 2 with respect to contacts 10 and 6. Usually at the differential output V _H (B) = V ₉ , _n (B) 13, formed by contacts 9 and 11, in the absence of an external magnetic field B 14, B = 0, a parasitic voltage or offset unrelated to the magnetic induction is present. Its minimization in our case is achieved by the innovative solution of Figure 1. The direct connections of the pairs of contacts 4 - 7 and 5 - 8 shorten the parasitic offset potentials in structures 1 and 2 to the potentials of output contacts 9 and 11 by the flow of equalizing currents. Such a possibility is absent in the known decision.

The current generator mode, which is carried out simultaneously for both structures 1 and 2, stabilizes the temperature drift at the output 13 of the sensor from the influence of temperature T. This is due to the clearly regulated influence of such operating temperature T on the kinetic and galvanomagnetic processes in semiconductors. structures, [5].

In the presence of an external magnetic field B 14, in the pads 1 and 2, forming the integrated sensor and representing a five-contact and three-contact Hall element, the current components Dd, / b, 5, - / b, 7> - ^and respectively / y, 9 and - / 10,11 are subjected to the deflecting side action of the Lorentz forces Рщ [1, 2, 5 - 10]. The topology of the current lines as a result of the originally modified instrument structure 1 is mainly vertical in the areas of contacts 4 and 5, as well as 7 and 8. At the same time, the pairs of electrodes 4-5 and 7-8 are located close enough to each other. Therefore, the Lorentz deviation of the current lines, depending on the polarities of the current source Es 3 and the magnetic field B 14, leads to a significant change in the currents through the contacts. For example, components - ASB) and - decrease, and components + \ C (B) ^and + increase. The change of these currents has the same value. Therefore, by connecting contacts 4 - 7 and 5 - 8, the significant directional changes in the magnetic field B 14 of the current components through them are combined. The situation is similar for configuration 2 with the currents through contacts 9 and 11 in field B 14. Through the load resistors Rg, io, Rio, n, ^ 4,6 and R6, _{8 the} changes of the Hall currents are transformed into a change of the output voltage V ^ (B) = Vg ^ (B). Therefore, the solution of Figure 1 leads to a substantial increase in the magnetic sensitivity of the sensor. The new configuration has a simplified construction. It contains eight contacts and a reduced number of connections, which facilitates its technological implementation. The drastic minimization of the horizontal magnetically uncontrolled current components in the two pads 1 and 2 reduces their passage through the output contacts 4 and 5, and 7 and 8. For this reason, the intrinsic Ι / f noise is reduced. It is no longer necessary to reduce its application of the current spinning method [1, 6, 7], which requires additional circuit resources, increasing the effective chip area and additional power consumption as the heat output leads to deterioration of the metrological quality of the output signal. . Simultaneously with the increased magnetosensitivity and the increased signal-to-noise ratio, the resolution in detecting the minimum magnetic induction B _m i _{n also increases} , which is a key characteristic for the purposes of low-field magnetometry. On the other hand, the accuracy increases due to the synergy of high sensitivity, reduced parasitic offset, reduced noise and temperature stabilization of the output 13.

The unexpected positive effect of the new technical solution lies in the original construction, the non-standard connection of the contacts 4 with 7, and 5 with 8 as well as their close location. Only by modifying the instrument design and without the use of additional circuit approaches, high sensitivity and signal-to-noise ratio are achieved, offset and temperature drift are reduced and metrological accuracy is increased.

The integrated Hall sensor is realized with CMOS, BiCMOS or micromachining microelectronic technologies as the two conversion zones of the five-contact and three-contact elements 1 and 2 are deep i-type silicon pockets in / ltype pads. The ohmic contacts 4, 5, 6, 7, 8, 9, 10 and 11 represent highly doped n ⁺ regions, most commonly formed by epitaxy. The Hall microsensor can operate over a wide temperature range, including in a cryogenic environment, which dramatically increases sensitivity and reduces noise, improving overall performance in applications. For even higher conversion efficiency for low-field magnetometry, counterterrorism and navigation, the pad chip (eg n-type silicon pockets) 1 and 2 can be located between two identical ferrite or μ-metal field B concentrators. The new sensor solution is basic for building highly sensitive 2D and 3D magnetometers.

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

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

[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] Ch. Roumenin, “Solid State Magnetic Sensors”, Elsevier, 1994, p. 417, ISBN: 0 444 89401 2; “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.

[6] S. Oh, D. Hwang, H. Chae, “4-Contact structure of vertical-type CMOS Hall device for 3-D magnetic sensor”, IEICE Electr. Expr., 16 (4) (2018) pp.1-8.

[7] C. Sander, M.-C. Vecchi, M. Cornils, O. Paul, “From three-contact vertical Hall elements to symmetrized vertical Hall sensors with low offset”, Sens. Actuat., A 240 (2016) pp. 92-102.

[8] Ch.S. Rumenin, P.T. Kostov, "Planar Hall Sensor", Author. witness. № BG 37208 B1 / 26.12.1983.

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

[10] C.S. Roumenin, Parallel-field Hall microsensors - An overview, Sensors and Actuators, A 30 (1992) 77-87.

Claims (1)

PATENT CLAIMS Integral Hall sensor is a plane sensitivity containing two semiconductor pads with i-type impurity conductivity, located in parallel - first and second, and a current source, on one side of the first pad are formed in series from left to right five ohmic rectangular contacts parallel to their long sides first, second, third, fourth and fifth, the third contact of the first pad is central with respect to it the first and fifth, and respectively the second and fourth contacts are located symmetrically, the measured magnetic field is parallel to both the planes of the pads and the long sides of the contacts, CHARACTERIZED is that on one side of the second pad (2) there are three ohmic rectangular contacts in series from left to right, parallel to their long sides - first (9), second (10) and third (11) as the second (10) is central, and the first (9) and third (11) contacts are located symmetrically with respect to it, close to the two long sides of contacts (6) and (10), respectively. regularly and at equal distances from them there is a deep zone (12) with p-type impurity conductivity, the length of which is equal to that of contacts (6) and (10), the two terminals of the current source (3) are connected to the central contacts (6) and (10), the first contact (4) of the first pad (1) is connected to the first contact (9) of the second (2), and the fifth contact (8) of the first (1) is connected to the third contact ( 11) on the second pad (2), the first (4) and the fourth (7) contact, and respectively the second (5) and the fifth (8) contact of the first pad (1) are connected, as the differential output (13) of the sensor of The living room is the first (9) and third (11) contact of the pad (2).