BG66433B1 - Two-dimensional vector magnetometer - Google Patents

Abstract

A two-component vector magnetometer is created, containing semiconductor substrate (1) with р-type conductivity and upon one of its sides there is a n-type epitaxial layer (2) composed of two equal and mutually perpendicular parts. At the ends of the n-type layer (2) and upon the same, at equal distance between each other, two identical ohmic contacts (3 and 4) and respectively (5 and 6) are formed. The contact pairs (3 and 4) and (5 and 6), via resistors of equal value (7, 8, 9 and 10) are connected to one of the outputs of the power source (11) each. The external magnetic field (12) measured is positioned in the substrate plane (1), and the differential outputs (13 and 14) for its two mutually perpendicular plane components are the pairs of ohmic contacts (3 and 4), and respectively (5 and 6).

Description

(54) TWO-DIMENSIONAL VECTOR MAGNETOMETER

Field of technology

The invention relates to a two-dimensional vector magnetometer applicable in the field of sensors and microsystems, non-contact measurement of angular and linear displacements, object positioning, systems engineering, automatic control, control and measurement technology, biomedical research and bioprocesses. low-field magnetometry, military affairs and security, etc.

BACKGROUND OF THE INVENTION

A two-component vector magnetometer is known, comprising a semiconductor substrate with p-type conductivity, on one side of which a n-type epitaxial layer is formed, consisting of two equal and mutually perpendicular parts. Near the two ends of the ptip layer and on it are formed a supply ohmic contact, and in the middle of the mutually perpendicular parts one Hall contact. The two power contacts are connected to a DC generator, to which two more trimmers are connected. The measured external magnetic field lies in the plane of the semiconductor substrate, and the outputs for its two mutually perpendicular components are one of the midpoints of the trimmers and one Hall contact, respectively [1].

The disadvantage of this two-component vector magnetometer is its low sensitivity when measuring the components of the magnetic field vector as a result of generating at its two outputs only half the values of the two evolving Hall voltages in the epitaxial layer.

Technical essence of the invention

It is an object of the invention to provide a two-component vector magnetometer with high magnetic sensitivity.

This problem is solved by a two-component vector magnetometer containing a semiconductor substrate with p-type conductivity, on one side of which a n-type epitaxial layer is formed, consisting of two equal and mutually perpendicular parts. Near the two ends of the p-type layer and on it are formed at equal distances from each other two identical ohmic contacts. Each pair of ohmic contacts through the same value load resistors is connected respectively to one of the terminals of the voltage source. The measured external magnetic field lies in the plane of the semiconductor substrate, and the differential outputs for its two mutually perpendicular plane components are the pairs of ohmic contacts, respectively.

An advantage of the invention is the high magnetic sensitivity due to the measurement with the two pairs of output contacts of the total Hall voltages generated in the p-type epitaxial layer of the two magnetic components.

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 two-component vector magnetometer comprises a semiconductor substrate 1 with a p-type conductive bridge, on one side of which a n-type epitaxial layer 2 is formed, consisting of two equal and mutually perpendicular parts. Near the two ends of the n-type layer 2 and on it are formed at equal distances from each other two identical ohmic contacts 3 and 4. and respectively 5 and 6. Each pair of ohmic contacts 3 and 4, and 5 and 6 through equal in value load resistors 7, 8,9 and 10 is connected respectively to one of the terminals of the voltage source 11. The measured external magnetic field 12 lies in the plane of the semiconductor substrate 1. and the differential outputs 13 and 14 for its two mutually perpendicular plane components are the pairs of ohmic contacts 3 and 4, and 5 and 6, respectively.

The operation of the two-component vector magnetometer according to the invention is as follows.

When switching on the pairs of ohmic contacts 3 and 4. and 5 and 6 through the same value load resistors (R ₍ ) 7, (III) 8 and respectively (R,) 9 and (R ₄ ) 10 (R ₁ = R, = R ₃ = R ₄ ) to the source of

66433 Bl voltage 11, in the p-layer 2 due to the structural and electrical symmetry of the microsensor four equal in value components I „I ₄ , L and 1 ₆ of the supply current I, 1, + 1 ₄ + I. + 1 ₍ = 1 _{5 The} individual trajectories of components I, 1 ₄ , I. and 1 ₆ are curvilinear in the areas below the respective contacts 3, 4, 5 and 6. In the rest of the n-type epitaxial layer 2 the supply current I is parallel to its sides, as I ~ V _dr , where V _dr is the average drift velocity of the electrons in the p-layer 2. The direction of the current I is strictly regulated in the two mutually perpendicular parts of the sensor from the well-defined conversion region in the p-layer 2, i.e. in the two equal parts of the layer 2 the directions of the current 1 are also mutually perpendicular, as a result of the symmetry of the two - component vector magnetometer and in the absence of an external magnetic field B 12, B = 0, of the two sensor outputs V (Bj 13 and V (B) 14 no parasitic voltages (offsets) In the case of offset / offsets via boron of one or two of the load resistors (R) 7, (K,) 8, (RJ 9 or (R ₄ ) 10 a reset is achieved, i. full compensation of parasitic voltages at outputs 13 and 14.

When an external magnetic field B 12 is applied, lying in the plane of the p-type semiconductor substrate 1, its two orthogonal components Β _χ and B (B = Β _χ + B) by the respective Lorentz forces F _Lx = qV _d Β _χ and F _{) y} = qV _d B deflect the electrons moving with speed V _dr in the two mutually perpendicular parts of the epitaxial layer 2. At a fixed direction of the supply current I. depending on the directions of the magnetic components B and B, these deviations are either upwards, where contacts 3 and 4, and 5 and 6, respectively, are formed, or in the opposite direction - to the p-pad 1, figure 1. As a result on contacts 3 and 4, and 5 and 6, respectively, develop the total Hall voltages V _Hx (B _y ) and V (B _v ) generated in the two mutually perpendicular parts of the n-type epitaxial layer 2. It is these two travel signals that form the two output differentials. voltages of the magnetometer V (B) 13 and V (B) respectively. 14. The differential outputs 13 and 14 completely suppress the even quadratic magnetic resistance MR ~ B ² occurring in the semiconductor structures simultaneously with the linear and odd from the magnetic field B 12 Hall effect. Therefore, the two output Hall signals 13 and 14 are linear and odd functions of the values and directions of the components B and B of the field X y to 12, and therefore guarantee high metrological quality of the two sensor outputs 13 and 14.

The unexpected positive effect of the proposed technical solution lies in the possibility to "take out" from the volume of the active sensor zone 2 through the unconventionally located pairs of contacts 3 and 4. and 5 and 6 full, not only halves, of those generated in p-type the epitaxial layer 2 Hall voltages. Another innovative feature of the solution is that the pairs of contacts 3 and 4, and respectively 5 and 6 are both supply (input) and output (running). An important feature of the two-dimensional vector magnetometer is that the signs (polarities) of the two output voltages V (B) 13 and V _v (B _v ) 14 coincide, which greatly facilitates their subsequent electronic processing. The absolute value of the vector of the magnetic field B 12 and the angle Θ of the field B 12 in the x-y plane of the pomegranate substrate 1 is given by the expressions: | = (Β _χ ² + Vu ² ) ^{| 2} and 0 = tan '(V (Bx) / V (BJ).

The experiments with samples of the new two-component vector magnetometer, realized on the basis of standard silicon bipolar technology according to the invention, and comparison of the results with those for the known solution show: at a fixed value of supply current 1, and a certain direction of magnetic field B 12 in the plane of the substrate 1, the magnetic sensitivities of the two X- and Y-sensor channels is equal and twice as large. One of the most important sensor parameters of the X- and Y-channels signal-to-noise ratio has also been improved. The two-dimensional vector magnetometer can also be implemented with CMOS or micromachining technologies. The parasitic influence between the X- and Y-sensor channels is sufficiently minimized. The Lorentz forces F and F, in the context of the proposed technical solution, act on the vertical sections of the curvilinear current components 1 ,, 1 I. and Ι _(ι under contacts 3. 4, 5 and 6. At the same time the influences of I and By magnetic respectively components on currents I and I, and respectively on currents 1, and 1 ₄ is in phase.

66433 Bl the influence of fields B and B on output voltages V (B) 14 and VJBJ 13 is maximally suppressed. The values of the load resistors (RJ 7, (1 <() 8, (R.) 9 and (R ₄ ) 10 should exceed by at least one order the internal resistance R of the n-type epitaxial layer 2 between contacts 3 and 4 , and respectively 5 and 6. This condition guarantees the mode of operation of the 2D microsensor current generator I = const.

Claims (1)

A two-component vector magnetometer comprising a semiconductor substrate with a conductivity type, on one side of which is formed a p-type epitaxial layer consisting of two equal and mutually perpendicular parts and a voltage source, the measured external magnetic field lying in the plane of the semiconductor pad, characterized in that near the two ends of the n-type epitaxial layer (2) and on it are formed at equal distances from each other two identical ohmic contacts (3 and 4), and respectively 5 and 6 ), each pair of ohmic contacts (3 and 4), and (5 and 6) through the same constant load resistors (7, 8. 9 and 10) is connected respectively to one of the terminals of the voltage source (11), and the differential outputs (13 and 14) for the two mutually perpendicular plane components of the magnetic field (12) are the pairs of ohmic contacts (3 and 4), and (5 and 6), respectively. Application: 1 figure Literature 1. Roumenin, Ch., Lozanova, S. CMOS 2D Hall microsensor with minimal design complexity, Electronics Letters, vol. 43 (9) 2007, pp. 511-513.