BG66711B1 - Hall effect sensor with a tangential axis of magnetosensitivity - Google Patents

Abstract

The Hall effect sensor with a tangential axis of magnetosensitivity contains a semiconductor substrate (1) with impurity type conductivity, on one side of which a central rectangular ohmic contact (2) and four other ohmic contacts (3, 4, 5 and 6) are formed, also containing a current source (10), and the measured tangential magnetic field (11) is in the plane of the substrate (1) and is perpendicular to the long sides of the central contact (2). On the two long sides of the central contact (2) symmetrically there are one pair of identical ohmic contacts (3 and 4) and respectively (5 and 6), with the opposite ones (3 and 6) and (4 and 5) are connected to each other. The common points of connection through identical load resistors (7 and 8) are connected by a trimmer (9), the midpoint of which is connected to one of the terminals of the current source (10), the other terminal of which is connected to the central contact (2). The two common points of the connected contacts (3 and 6) and respectively (4 and 5) are the output (12) of the Hall effect sensor.

Description

(54) HALL SENSOR WITH TANGENTIAL AXIS OF MAGNETIC SENSITIVITY

Field of technology

The invention relates to a Hall sensor with a tangential axis of magnetosensitivity, applicable in the field of robotics and mechatronics, production automation, non-contact measurement of angular and linear displacements, positioning of objects in space, micro- and nanotechnologies, biomedical energy research, energy efficiency, control and measurement technology and low-field magnetometry, military affairs and security, etc.

BACKGROUND OF THE INVENTION

A Hall sensor with a tangential axis of magnetic sensitivity is known, containing a semiconductor substrate with an impurity-type conductivity, on one side of which three rectangular ohmic contacts are formed at equal distances from each other, located parallel to their long sides, one of which is central and relative to it on its two long sides are the other two, which are extreme. On the short sides of the central contact and at equal distances from it there is another side ohmic contact. The end contacts are connected to one terminal of a power source, the other terminal of which is connected to the central contact. The measured magnetic field is in the plane of the substrate and is perpendicular to the three parallel rectangular contacts, the two side contacts being the output of the Hall sensor [1,2].

The disadvantage of this Hall sensor with a tangential axis of magnetic sensitivity is the reduced value of the magnetic sensitivity as a result of: a) partial registration of the total Hall voltage on the substrate surface in the areas on the short sides of the central contact due to significant leakage on the supply current surface; b) the inappropriate location of the output contacts on the short sides of the rectangular central contact, the significant part of the current flowing in the areas of its two long sides.

Technical essence of the invention

It is an object of the invention to provide a Hall sensor with a tangential axis of magnetic sensitivity with an increased value of magnetic sensitivity.

This problem is solved with a Hall sensor with a tangential axis of magnetic sensitivity, containing a semiconductor substrate with an impurity type of conductivity, on one side of which is formed a central ohmic contact with a rectangular shape. On its two long sides and symmetrically on them there is a pair of identical ohmic contacts as the opposite ones are connected to each other. The common connection points through load resistors of the same value are connected to a trimmer, the middle point of which is connected to one terminal of a current source, the other terminal of which is connected to the central contact. The measured magnetic field is in the plane of the substrate and is perpendicular to the long sides of the central contact, the two common points of the connected contacts being the output of the Hall sensor.

An advantage of the invention is the high magnetic sensitivity as a result of the registered maximum value of the generated Hall voltage from the supply current.

Another advantage is the ability to fully compensate (reset) the parasitic output voltage in the absence of a magnetic field (offset) by varying the resistance of the trimmer.

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 sensor with a tangential axis of magnetic sensitivity contains a semiconductor substrate 1 with an impurity type of conductivity, on one side of which a central ohmic contact 2 with a rectangular shape is formed. On its two long sides and symmetrically on them there is a pair of identical ohmic contacts 3 and 4, and 5 and 6 as the opposite 3 and 6, and respectively 4 and 5 are connected to each other. The common connection points through the same value load resistors 7 and 8 are connected to trimmer 9, the average

Descriptions of issued patents for inventions № 09.1 / 17.09.2018 point of which is connected to one terminal of the current source 10, the other terminal of which is connected to the central contact 2. The measured magnetic field 11 is in the plane of the substrate 1 and is perpendicular to the long sides of the central contact 2 as the two common points of the connected contacts 3 and 6, and 4 and 5, respectively, are the output 12 of the Hall sensor.

The operation of the Hall sensor with a tangential axis of magnetic sensitivity according to the invention is as follows.

When connecting the central contact 2 to one terminal of the current source 10 and the other to the midpoint of the trimmer 9, connected through the load resistors 7 and 8 with contacts 3 and 6, and respectively 4 and 5, in the areas under contacts 2, 3, 4 , 5 and 6 on the substrate 1 current components 1 _{2 3} , 1 ₂ 1 ₂ and 1 _{2 5} flow, the effective trajectories of which are curvilinear. They start from the central contact 2 and end at the end contacts 3 and 6 and respectively 4 and 5. The supply contacts 2, 3, 4, 5 and 6 are equipotential planes to which in the absence of an external magnetic field B 11, B = 0, the currents 1 ₂ , 1 ₃ , II and 1 ₆ are always perpendicular to the upper side of the pad 1 and penetrate deep into it. The current lines 1 _{2 3} , 1 _{2 6} , 1 ₂ and 1 ₂ in the rest of the volume of the pad 1 are parallel to its upper side. As a result of the structural symmetry of the sensor, the following relations between these components are in force: L = L = L = L, as L, + 1 + 1 + L = L. An important feature is that the directions of currents 1 ₃ and 1 ₆ and respectively I and 1 ₅ through contacts 3, 4, 5 and 6 are directional. Given the structural symmetry of contacts 3,4,5 and 6 with respect to the central 2, the curvilinear trajectories of the individual components of the supply current 1 ₂ are also symmetrical with respect to 2. In case of possible electrical asymmetry, a parasitic asymmetry voltage occurs at output 12 (offset). This disadvantage in the absence of a magnetic field B 11 (B = 0) is easily compensated (reset) V _{3 4} (B) = 0 or V _{5 6} (B) = 0 by changing the value of the resistance with the trimmer d 9 in the respective circuits, including contacts 3,4, 5 and 6.

The inclusion of a tangential (lateral) to the rectangular central contact 2 magnetic field B 11, perpendicular to its long sides leads to lateral and directional Lorentz deflection of the vertical current components 1 ₃ , 1 ₆ and II under contacts 3 and 6 and respectively 4 and 5, generated by the Lorentz forces F _L = qV _di x B, where q is the elementary load of the electron and a is the vector of the average drift velocity of the electrons. Depending on the mutual directions of the currents I ₃ , 1 II and the vector of the magnetic field B 11, the currents through the pairs of contacts 3 and 6, and respectively 4 and 5 increase or decrease simultaneously and these changes are of the same value. In fact, these contacts 3 and 6, and 4 and 5, respectively, are electrically connected, in which in a magnetic field B 11 the change of currents through them is directional, i. either increases or decreases. In this way the Hall current sensor mechanism ΔΙ _Η (Β) arises. Through the load resistors R ₍ 7 and R _; 8) the generated Hall current ΔΙ _Η (Β) is transformed into a Hall voltage V _H (B) = V ₁₂ , which is registered at the output 12. As a result, the sensitivity increases significantly compared to known Hall sensor, as the selected innovative design and switching scheme convert the maximum generated Hall effect on the surface of the semiconductor substrate 1 into output differential voltage 12, V _H (B) ξ V Therefore, no useful sensor signal is "lost", which is not registered with output 12, as is the situation with the Hall element described in [1], which is how the unexpected positive effect of the new technical solution was achieved.

The new transducer is a uniaxial sensor - it is sensitive to the magnetic field B 11, directed along one of the three mutually perpendicular axes x, y or z of the coordinate system, in this case it is the y-axis, which is tangential. If a magnetic field B 11 is applied to the sensor in Figure 1 along the x-axis or the z-axis, each of the current components to the left and right of the central contact 2 receives a simultaneous change in its Lorentz deflection current with a positive and negative sign, so that currents 1 ₃ and 1 ₆ simultaneously, for example, increase and components I and 1 ₅ decrease. As a result of the differential output 12 no change occurs, i. the respective additives are in-phase.

A further increase in the conversion efficiency of the new sensor can be achieved by placing it in a cryogenic environment, for example in liquid nitrogen, T = - 200 ° C. The result is associated with a drastic increase in the mobility of current carriers. For the purposes of the low-field magneto52

Descriptions of issued patents for inventions № 09.1 / 17.09.2018 metric it is expedient to use concentrators of the magnetic field of ferrite or μ-metal.

The technological implementation of the Hall sensor with a tangential axis of magnetic sensitivity is based on silicon integrated microelectronic processes such as CMOS or BiCMOS, using silicon pads or a conversion zone with p-type conductivity.

Claims (1)

Patent claims A Hall sensor with a tangential axis of magnetic sensitivity, comprising a semiconductor substrate with an impurity-type conductivity, on one side of which a central rectangular ohmic contact and four other identical ohmic contacts are formed, a current source with the measured magnetic field in the substrate plane and is perpendicular to the long sides of the central contact, characterized in that on both long sides of the central contact and symmetrically on them there is a pair of the four ohmic contacts (3 and 4) and (5 and 6), as the opposite contacts 3 and 6) and respectively (4 and 5) are connected to each other, and their common connection points through the same value load resistors (7 and 8) are connected to a trimmer (9), the middle point of which is connected to one terminal of the current source (10), the other terminal of which is connected to the central contact (2), the two common points of the connected contacts (3 and 6), and respectively (4 and 5) being the output (12) of the Hall sensor.