BG66660B1 - Integral hall sensor with parallel axis of magneto sensitivity - Google Patents

Abstract

The integral sensor of Hall with parallel axis of magneto sensitivity contains a solid-state substrate (1) with a mixed-type conductivity, on one side of which are formed of distances from each other, the seven consistently rectangular ohmic contacts -first (2), second (3), third (4), fourth (5), fifth (6), sixth (7) and seventh (8), all located along the long sides. Contact 5 is the central and the long sides are positioned symmetrically contacts-pairs (2) and (8), (3) and (7), and (4) and (6). Contacts (3) and (7) are united with both the conclusion of the trimmer (9), the midpoint of which is associated with one conclusion of current source (10), the conclusion of which is incorporated with contact (5). Contacts (2) and (4) are directly electrically linked. The magnetic field (11) is applied perpendicular to the cross-sectional area of the pad (1) and is parallel to the long sides of the contacts as the output (12) Hall sensor with parallel axis of magneto sensitivity are the contacts (6) and (8).

Description

Field of technology

The invention relates to an integrated Hall sensor with a parallel axis of magnetic sensitivity, applicable in the field of systems engineering, including bioengineering, micro- and nanotechnology, robotics and mechatronics, non-contact measurement of angular and linear displacements, positioning of objects in the plane and space research, contactless automation, energy and energy efficiency, control and measurement technology and low-field magnetometry, military affairs and security, etc.

BACKGROUND OF THE INVENTION

An integrated Hall sensor with a parallel axis of magnetic sensitivity is known, comprising a semiconductor substrate with impurity-type conductivity, on one side of which are formed at distances from each other five rectangular ohmic contacts located parallel to their long sides, one of which is central and relative to it, the other four are located symmetrically on the two long sides - two of which are external and the other two - internal. The external contacts are connected to one terminal of a power source, the other terminal of which is connected to the central contact. The magnetic field is applied perpendicular to the cross section of the substrate and is parallel to the long sides of the rectangular contacts as the internal contacts are the output of the integrated Hall sensor [1, 2].

A disadvantage of this integrated Hall sensor with a parallel axis of magnetic sensitivity is the limited conversion efficiency (sensitivity), due to the use of only the Hall voltage generated on the substrate surface between the central and two end contacts registered with the internal contacts.

Another disadvantage is the presence of a parasitic output voltage in the absence of a magnetic field (offset) as a result of inevitable electrical asymmetry caused by geometric asymmetry in the location of the contacts relative to the central, as well as technological imperfections.

Technical essence of the invention

It is an object of the invention to provide an integrated Hall sensor with a parallel axis of magnetic sensitivity with increased conversion efficiency and compensated offset.

This problem is solved with an integrated Hall sensor with a parallel axis of magnetic sensitivity, containing a semiconductor substrate with impurity type of conductivity, on one side of which are formed at distances from each other seven rectangular ohmic contacts as follows - first, second, third, fourth , fifth, sixth and seventh, all located parallel to their long sides. The fourth contact is central and on its two long sides are symmetrically located the pairs of contacts - first and seventh, second and sixth, and third and fifth. The pair of contacts - second and sixth are connected to the two terminals of the trimmer, the middle point of which is connected to one terminal of the current source, the other terminal of which is connected to the central contact. The first and third contacts are directly electrically connected. The magnetic field is applied perpendicular to the cross section of the pad and is parallel to the long sides of the rectangular contacts as the output of the Hall sensor are the fifth and seventh contacts.

An advantage of the invention is the increased conversion efficiency (sensitivity) as a result of the series connection of the outputs of two functionally integrated Hall elements in a common semiconductor substrate.

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.

Another advantage is the reduced level of its own noise, as one of the output contacts - the seventh is outside the flow zone of the supply current, which is the main noise factor in semiconductor structures.

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 integrated Hall sensor with a parallel axis of magnetic sensitivity contains a semiconductor substrate 1 with an impurity type of conductivity, on one side of which are formed at distances from each other seven rectangular ohmic contacts as follows - first 2, second 3, third 4, fourth 5, fifth 6, sixth 7 and seventh 8, all parallel to their long sides. The fourth contact 5 is central and on its two long sides are symmetrically located the pairs of contacts - first 2 and seventh 8, second 3 and sixth 7, and third 4 and fifth 6. The pair of contacts - second 3 and sixth 7 are connected to the two terminals of trimmer 9, the midpoint of which is connected to one terminal of the current source 10, the other terminal of which is connected to the central contact 5. The first 2 and third 4 contacts are directly electrically connected. The magnetic field is applied perpendicular to the cross section of the pad 1 and is parallel to the long sides of the rectangular contacts 2, 3, 4, 5, 6, 7 and 8, with output 12 of the Hall sensor being the fifth 6 and seventh 8 contacts.

The operation of the integrated Hall sensor with a parallel axis of magnetic sensitivity according to the invention is as follows. When the central contact 5 is connected to one terminal of the current source 10 and the other to the midpoint of the trimmer 9, which is connected to the pair of contacts 3 and 7, between contacts 5 and 3, and respectively 5 and 7 flow components I and I of the supply current 1 ₅ , the effective trajectories of which are curvilinear. They start from contact 5 and end at the planar contacts 3 and 7. The supply contacts 3, 5 and 7 are equipotential planes to which in the absence of an external magnetic field B 11 the current lines 1 ₅ , 1 ₃ and Ι _γ are always perpendicular. The effective current trajectories 1 _{5 3} and 1 _{5 7} in the rest of the volume of the pad 1 are parallel to its upper side. An important feature is that the current directions I ₃ and I ₇ are opposite as I = □ -1 □ +1 Given the thus chosen structural symmetry of the ohmic contacts 2, 3, 4, 6, 7 and 8 with respect to the central 5, both components 1 ₅ and 1 _{5 7} of the trajectory of the supply current I are also symmetrical with respect to contact 5.

The inclusion of the magnetic field B 11, perpendicular to the cross section of the substrate 1, leads to the appearance in the plane of the section of laterally deflecting moving electrons in the two curvilinear trajectories I and I of Lorentz forces F _L = qV _{d |} x B, where q is the elementary load of the electron, and a is the vector of the average drift velocity of the carriers. As a result of this Lorentz deflection in the surface areas, where contacts 2, 4, 6 and 8 are located, additional electrical loads are generated from the Hall effect, figure 1. This leads to the appearance of two Hall voltages on these contacts from the magnetic field B 11 V _2g (B) and V (B). In this case, the Hall potentials on contacts 2 and 4, and 6 and 8, respectively, have the opposite sign. The direct electrical connection of contacts 2 and 4 performs a sequential summation of these two Hall voltages: V _{2 g} (B) + V _{4 6} (B) = V _{6 g} (B). Thus, the magnetic sensitivity of the Hall sensor increases significantly. Therefore, the differential output 12 of the sensor V _6g (B) - contacts 6 and 8 gives metrological information about the polarity (sign) and the value of the magnetic field B 11. It should be noted that as a result of the structural symmetry of the Hall sensor with parallel axis magnetosensitivity to the central contact 5 as an output 12 can equally serve contacts 2 and 4, V ₂₄ (B) at directly electrically connected contacts 6 and 8. The rest, the supply part of the sensor structure remains unchanged.

The inevitable offset of the output 12 in the absence of a magnetic field B 11 (B = 0) is easily compensated (reset) V _{6 g} (B) = 0 by changing the value of the resistance in the respective circuits including contacts 3 and 4, which is done with trimmer d 9. The reduced level of intrinsic (internal) flicker noise Ι / f is the result of the location of one of the output contacts 8 outside the flow zone of the supply current, which is the main noise factor in semiconductor structures.

The technological implementation of the new Hall sensor is based on integrated microelectronic processes such as CMOS or BiCMOS, using silicon pads and a conversion zone with p-type conductivity. An additional increase in sensitivity can be achieved by forming a deep ring with p - type conductivity, surrounding the ohmic contacts 2, 3, 4, 5, 6, 7 and 8 close enough. This drastically reduces the flow of supply current on the surface of the substrate. 1 and the direction of most of the moving current carriers is perpendicular to the magnetic vector B 11, which leads to a more significant effect of the Lorentz force F

The unexpected positive effect of the new technical solution is the possibility through the original design and electrical connections between the contacts to use as an output signal 12 most efficiently all Hall voltages generated in magnetic field B 11 by the current 1 ₅ . These are the Hall voltages both in the inner zone of the element V ₄₆ (B) (similar to the known solution) and the Hall voltage V _{2 8} (B), generated outside contacts 3 and 7 and not used so far as a means of increasing the magnetic sensitivity . In fact, the new technical solution is a functional integration of two Hall elements with a parallel axis of sensitivity in the semiconductor substrate 1, with a common converting region and one current source 10.

Experiments with samples of the Hall sensor with a parallel axis of sensitivity, realized with silicon planar technology, found that the magnetic sensitivity is at least 1.5 times higher than that of the known technical solution.

Claims (1)

Patent claims 1. An integrated Hall sensor with a parallel axis of magnetic sensitivity, comprising a semiconductor substrate with an impurity-type conductivity, on one side of which rectangular ohmic contacts are formed at distances from each other, all located parallel to their long sides, one of which is central and relative to it are symmetrically arranged in pairs, the current source as the magnetic field is applied perpendicular to the cross section of the substrate and is parallel to the long sides of the contacts, characterized in that the ohmic contacts are seven as follows - first (2), second ( 3), third (4), fourth (5), fifth (6), sixth (7) and seventh (8), the fourth contact (5) is the central one and on its two long sides are symmetrically located the pairs of contacts - first ) and seventh (8), second (3) and sixth (7), and third (4) and fifth (6), the pair of contacts (3 and 7) being connected to two trimmer terminals (9), the midpoint of which is connected to one terminal of the current source (10), the other m terminal of which is connected to the central contact (5), and the first (2) and third (4) contact are directly electrically connected, as the output (12) of the Hall sensor are the fifth (6) and seventh (8) contact.