BG66764B1 - Hall effect integral element with a parallel axis of magnetic sensitivity - Google Patents

Abstract

The Hall effect integral element with a parallel axis of magnetic sensitivity comprises an n- type semiconductor wafer (1) on one side of which are formed five identical rectangular ohmic contacts at an equal distance from each other - first (2), second (3), third (4), fourth (5) and fifth (6), as the third one is central and a current source (7). There are two more differential analog multiplexers (8 and 9) with two inputs and one output, a rectangular pulse generator (10), two differential amplifiers - the first (11) and the second (12), and a duel-channel tracking-memory circuit ( 13). The first (2) and second (3), as well as the fourth (5) and fifth (6) contacts are connected respectively to the inputs of the multiplexers (8 and 9), whose control inputs are connected to the rectangular pulse generator (10). The output of one of the multiplexer (8) is connected to one output of the current source (7), whose second output is connected to the third ohmic contact (4), the output of the other multiplexer (9) is connected to the input of the first amplifier (11), the output of which is coupled to the inputs of the tracking-memory circuit (13) whose control inputs are coupled to the pulse generator (10). The outputs of the tracking-memory circuit (13) are connected to the input of the second amplifier (12) in such a way that the signals supplied to its input are subtracted. The measured magnetic field (14) is applied perpendicular to the cross section of the wafer (1) as the output (15) of the Hall effect integral element with a parallel axis of magnetic sensitivity is the is the output of the second amplifier (12).

Description

(54) INTEGRATED ELEMENT OF A LIVING ROOM WITH A PARALLEL AXIS OF MAGNETIC SENSITIVITY

Field of technology

The invention relates to an integral Hall element with a parallel axis of magnetosensitivity, applicable in the field of control and measurement technology, low-field magnetometry, sensors, robotics, mechatronics and cognitive intelligent systems, micro- and nano-technologies, space research, systems engineering, bioengineering , non-contact measurement of angular and linear displacements, energy, military affairs, security, etc.

BACKGROUND OF THE INVENTION

An integral Hall element with a parallel axis of magnetic sensitivity is known, containing a n-type semiconductor substrate, on one side of which five rectangular ohmic contacts are formed at distances from each other - first, second, third, fourth and fifth, the third contact is central , as the first and the fifth, and respectively the second and the fourth contact are symmetrical in relation to it and the current source, one terminal of which is connected to the central and the other to the first and the fifth contact. The outputs of the Hall element are the second and fourth contacts, the measured magnetic field being perpendicular to the cross section of the substrate [1].

There is also an integral Hall element with a parallel axis of magnetic sensitivity, containing a p-type semiconductor substrate, on one side of which are formed at distances from each other five rectangular ohmic contacts - first, second, third, fourth and fifth, the third contact is central, as the first and fifth, and respectively the second and fourth contacts are symmetrical to it and the current source, one terminal of which is connected to the central and the other to the second and fourth contact. The outputs of the Hall element are the first and the fifth contact, as the measured magnetic field is perpendicular to the cross section of the substrate [2].

The disadvantage of these two integral Hall elements with a parallel axis of magnetic sensitivity is the high values of parasitic voltages at the outputs in the absence of a magnetic field (offsets) as a result of inevitable geometric asymmetry in the technological implementation of ohmic contacts relative to the central one.

Another disadvantage is the intrinsic and temperature drift of the offset due to internal deformations in the semiconductor substrate during chip encapsulation, technological imperfections, heat dissipation during operation, aging processes, etc., which worsens the metrological accuracy.

Technical essence of the invention

It is an object of the invention to provide an integral Hall element with a parallel axis of magnetic sensitivity with a strongly reduced value of the parasitic offset at the output and its drift.

This problem is solved with an integral Hall element with a parallel axis of magnetic sensitivity, containing a n-type semiconductor substrate, on one side of which are formed at equal distances from each other five identical rectangular ohmic contacts - first, second, third, fourth and fifth. , as the third contact is central, current source, two differential analog multiplexers, with two inputs and one output, control generator of rectangular pulses, two differential amplifiers - first and second, and two-channel monitoring-memory circuit. The first and second contacts, as well as the fourth and fifth contacts, are connected respectively to the inputs of the multiplexers whose control inputs are connected to the rectangular pulse generator. The output of one multiplexer is connected to one terminal of the current source, the second terminal of which is connected to the third ohmic contact. The output of the other multiplexer is connected to the input of the first differential amplifier, the output of which is connected to the inputs of the tracking-memory circuit, whose control inputs are connected to the pulse generator. The outputs of the two-channel memory-monitoring circuit are connected to the input of the second differential amplifier, so that the signals supplied to its input are subtracted. The measured magnetic field is applied perpendicular to the cross section of the substrate, as the output of the integral Hall element with a parallel axis of magnetic sensitivity is the output of

Descriptions of issued patents for inventions № 12.1 / 17.12.2018 the second differential amplifier.

An advantage of the invention is the strongly reduced value of the parasitic offset at the output of the Hall integral element, because in the output signals of the sequentially formed configurations of integral elements, the Hall voltages are of opposite sign and equal in value, and the offsets are of equal sign and are approximately equal and when subtracting the signals with the second differential amplifier, the two offsets are subtracted and the Hall voltages are summed.

The compensated drift (own and temperature) of the offset is also an advantage due to the common for both elements of Hall pad and contacts, as in the dynamic configuration of the sensors the value and behavior of the drift are the same, and when the signals are extracted it is compensated.

Another advantage is the doubled magnetosensitivity as a result of the doubled signal at the output of the Hall integral element.

An advantage is the improved signal-to-noise ratio, ie. the resolution of the Hall element when detecting a minimal magnetic field as a result of the strongly reduced parasitic offset and its drift, as well as the doubled sensitivity.

Explanation of the attached figure

The invention is illustrated in more detail by one of its embodiments given in the attached figure 1.

Examples of the invention

The Hall integral with a parallel axis of magnetic sensitivity contains a n-type semiconductor substrate 1, on one side of which are formed at equal distances from each other five identical rectangular ohmic contacts - first 2, second 3, third 4, fourth 5 and fifth 6 , the third 4 being a central current source 7, two differential analog multiplexers 8 and 9 with two inputs and one output, a rectangular pulse generator 10, two differential amplifiers - first 11 and second 12, and a two-channel memory-memory circuit 13 The first 2 and the second 3, as well as the fourth 5 and the fifth 6 contacts are connected respectively to the inputs of the multiplexers 8 and 9, whose control inputs are connected to the rectangular pulse generator 10. The output of one multiplexer 8 is connected to one terminal of the current source 7. , the second terminal of which is connected to the third ohmic contact 4. The output of the second multiplexer 9 is connected to the input of the first differential amplifier 11, the output of which is connected to inputs of the tracking circuit 13, the control inputs of which are connected to the pulse generator 10. The outputs of the two-channel tracking circuit 13 are connected to the input of the second differential amplifier 12, so as to subtract the signals supplied to its input. . The measured magnetic field 14 is applied perpendicular to the cross section of the substrate 1, the output 15 of the Hall integral with a parallel axis of magnetic sensitivity is the output of the second differential amplifier 12.

The operation of the Hall integral with a parallel axis of magnetic sensitivity according to the invention is as follows. By forming on the surface of the p-type the semiconductor substrate 1 of rectangular ohmic contacts 2, 3, 4, 5 and 6 of equal size and located at equal distances, maximum symmetry of the transport processes in the structure 1 is achieved with respect to the central contact 4 when the current source is switched on. 7. By corresponding switching (switching) with the two multiplexers 8 and 9 of the four contacts 2, 3, 5 and 6, two configurations of the Hall element are realized in succession as follows: the first contains as input (supply) contacts the central 4 and the two end 2 and 6, and the outputs are the second 3 and the fourth 5 contacts; in the second configuration, the power supplies are the central 4, the second 3 and the fourth 5 contacts, and the outputs are the first 2 and the fifth 6. These two alternating configurations of Hall elements are realized by the rectangular pulse generator 10, which synchronizes the overall operation of the device. of switching the multiplexers 8 and 9, and the current source 7 to the respective planar contacts 2,3, 5 and 6. The two Hall microsensors realized in this way have a parallel axis of sensitivity - they are sensitive to the magnetic field B 14 applied perpendicular to the transverse cross section of the pad 1, i.e. parallel to the long sides of the rectangular contacts 2,3,4,5 and 6. The trajectories of motion

Descriptions of issued patents for inventions № 12.1 / 17.12.2018 of the current carriers in the substrate 1 in the absence of magnetic field B 14, B = 0, are curvilinear - they start and end at the corresponding for the given configuration supply ohmic contacts 2-4-6 or 3-4-5, representing equipotential planes. Below these contacts 2-4-6 or 3-4-5 the current lines are vertical to the upper surface (figure 1), after which they become parallel to it.

As a result of inevitable asymmetry (geometric errors) of the contacts 2 and 6, and respectively 3 and 5 relative to the central electrode 4 in the technological implementation, parasitic output voltages (offsets) occur in the absence of the magnetic field 14 V = 0, V _{3 5} (0 ) 0 0 and V _{; 6} (0) ψ 0. Since the semiconductor substrate 1 is common to the two configurations of the Hall elements and the five planar contacts 2, 3, 4, 5 and 6 are the same for the two microsensors, the Hall elements thus formed are in fact “ merge ”and have a common conversion zone. Therefore, the two offsets V, ₅ (0) and V ₂ (0) are expected to be almost equal in value and to have the same sign, V _{3 5} (0) «V _{2 6} (0).

The application of the magnetic field B perpendicular to the cross section of the substrate 1, i. parallel to the long sides of the rectangular ohmic contacts 2, 3, 4, 5 and 6 leads to a lateral deviation of the current lines from the Lorentz force F _L for the given Hall configuration, F _L = q V _di x B, where q is the elementary electron load, and V _di is the vector of the average drift velocity of the electrons. As a result of this Lorentz deflection F, the trajectories of the 4 currents opposite to the central contact "shrink" and "expand" accordingly. This leads, through the Hall effect, to the appearance on the surface of the substrate 1 at the respective contacts 3 - 5 for one and 2 - 6 for the other, a configuration of Hall voltages V _{3 5} (B) and - V _{2 6} (B). A key result of the implemented configurations of the elements is that the respective Hall voltages V _{3 5} (B) and - V _{2 6} (B) are equal in value, but have the opposite sign, V ₃₅ (B) = - V ₂₆ ). This is achieved by the common for the Hall configurations central contact 4 and the unchanged in both cases direction of the supply current I Symmetrical to the contact 4 electrodes 3 and 5, and respectively 2 and 6 are either output or supply. These functional purposes are determined by the two differential analog multiplexers 8 and 9 controlled by the pulse generator 10. By means of the two-channel tracking-memory circuit 9, the differential voltages V ₃ and V previously amplified by the first differential amplifier 11 _{; 6} of the two Hall configurations are stored. These two signals V ₃₅ and V ₂₆ include the "pure" Hall voltages V _{3 5} (B) and - V _{2 6} (B), respectively, the offsets V _{3 5} (0) and V _{2 6} (0), which are indistinguishable. from the magnetosensitive signals. Through the second differential amplifier 12 the signals V ₃ and V _{2 6} are output:

V ₃ , ₅ - V _{2 6} = [V _{3 5} (0) + V _{3 5} (B)] - [V _{2 6} (0) - V _{2 6} (B)] = 2V _H (B) + [V _{3 5} (0) - v _{2 6} (0)]

According to this expression, as a result of the subtraction of the two voltages generated by the Hall configurations V ₃ and V _{; 6} , the output signal 15 of the second differential amplifier 12 is doubled to 2V _H (B), and the residual offset V _off (0) ξ V _{3 5} (0) - V _{2 6} (0) is drastically reduced. Ego why the magnetosensitivity of the integral Hall element with a parallel axis of sensitivity is doubled and the residual parasitic offset is almost completely compensated V _ff (0) «0. Given the strongly reduced offset at the output 15 of the Hall element, its own Ι / f (flicker) ) noise from structure 1 decreases and the signal-to-noise ratio increases. Thus, the resolution for detecting minimal magnetic induction B is improved. The intrinsic and temperature drift of the offset is generated mainly by internal deformations in the substrate 1 during the encapsulation of the chip, the realization of the metallized busbars, the thin-layer conductive and dielectric layers on the surface, technological imperfections, heat dissipation during operation and other processes. In the general case, these drift stresses have a chaotic behavior, changing over time, which makes them compensated by trimming, thermostating and more. inefficient. The stated reasons are irreversible, but are the same for both integral Hall elements. The switching frequency of the two phases of the pulse generator 10, determining the Hall configurations, is selected so that for two consecutive cycles there is no change in the drift. The output of the output signals of the two sensors with the differential amplifier 12 also compensates for the drift in the output 15. This significantly improves the metrological accuracy.

The unexpected positive effect of the new technical solution lies in the possibility with only five ohmic contacts 2, 3, 4, 5 and 6 and change of their purpose - input / output to be

Descriptions of issued patents for inventions № 12.1 / 17.12.2018 implement two functionally integrated in a common conversion zone Hall element, from the joint action of which new properties are achieved. As a result, the offset is drastically reduced, its drift is significantly minimized, the magnetic sensitivity is doubled and the resolution is increased - qualities that are absent in the famous Hall elements. The new technical solution is also a contribution to the method of current spinning in the magnetic field sensors.

The integral Hall element can be realized with CMOS technology, as the conversion zone is a deep p-type pocket 1. The choice of p-type semiconductor pad 1 is dictated by the fact that in p-type semiconductors the mobility of current carriers, determining the speed of movement of current carriers, i.e. of magnetic sensitivity is significantly higher compared to p-type materials. Deeper penetration of the current I under the central contact 4, respectively more effective influence of the Lorentz force F _L on the current lines, can be achieved by forming around this rectangular electrode 4 a limiting p-ring. If necessary, all components of the Hall integral with a parallel axis of sensitivity can be realized on a common silicon chip, forming an intelligent microsystem. The operation of the new sensor is feasible in a wide temperature range. For even higher sensitivity, the pad 1 with contacts 2, 3, 4, 5 and 6 is located between two identical elongated concentrators of the magnetic field B 14 of ferrite or μ-metal.

Claims (1)

Patent claims 1. Integral Hall element with a parallel axis of magnetic sensitivity, containing a n-type semiconductor substrate, on one side of which are formed at distances from each other five rectangular ohmic contacts - first, second, third, fourth and fifth, the third being central , as well as a current source, as the measured magnetic field is applied perpendicular to the cross section of the substrate, characterized in that all contacts (2, 3, 4, 5 and 6) are the same and are located at equal distances from each other, there is two more differential analog multiplexers (8 and 9) with two inputs and one output, a rectangular pulse control generator (10), two differential amplifiers - first (11) and second (12), and a two-channel tracking-memory circuit (13 ), the first (2) and second (3) as well as the fourth (5) and fifth (6) contacts being connected to the inputs of the multiplexers (8 and 9), respectively, whose control inputs are connected to the rectangular pulse generator (10). ), where the output of ed The multiplexer (8) is connected to one terminal of the current source (7), the second terminal of which is connected to the third ohmic contact (4), the output of the other multiplexer (9) is connected to the input of the first differential amplifier (11). which is connected to the inputs of a tracking memory circuit (13), the control inputs of which are connected to the rectangular pulse generator (10), the outputs of the two-channel tracking memory circuit (13) being connected to the input of the second differential amplifier (12), that to subtract the signals applied to its input, and the output (15) of the integral Hall element with a parallel axis of magnetic sensitivity is the output of the second differential amplifier (12).