WO2014190907A1 - 单芯片桥式磁场传感器 - Google Patents

单芯片桥式磁场传感器 Download PDF

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Publication number
WO2014190907A1
WO2014190907A1 PCT/CN2014/078662 CN2014078662W WO2014190907A1 WO 2014190907 A1 WO2014190907 A1 WO 2014190907A1 CN 2014078662 W CN2014078662 W CN 2014078662W WO 2014190907 A1 WO2014190907 A1 WO 2014190907A1
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WIPO (PCT)
Prior art keywords
sensing
magnetic field
arm
bridge
field sensor
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PCT/CN2014/078662
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English (en)
French (fr)
Inventor
迪克·詹姆斯·G
Original Assignee
江苏多维科技有限公司
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Filing date
Publication date
Application filed by 江苏多维科技有限公司 filed Critical 江苏多维科技有限公司
Priority to US14/894,258 priority Critical patent/US9817084B2/en
Priority to EP14803530.6A priority patent/EP3006951B1/en
Priority to JP2016515636A priority patent/JP6525335B2/ja
Publication of WO2014190907A1 publication Critical patent/WO2014190907A1/zh

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/02Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09Magnetoresistive devices
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R17/00Measuring arrangements involving comparison with a reference value, e.g. bridge
    • G01R17/10AC or DC measuring bridges
    • G01R17/105AC or DC measuring bridges for measuring impedance or resistance

Definitions

  • the present invention relates to the field of magnetic sensor technologies, and in particular, to a single-chip bridge magnetic field sensor with low offset. Background technique
  • the TMR (Tunnel MagnetoResistance) sensor is a new magnetoresistance effect sensor that has been used in industrial fields in recent years.
  • the sensor utilizes the tunnel magnetoresistance effect of the magnetic multilayer film material to induce the magnetic field, mainly in:
  • the resistance of the magnetic multilayer film changes obviously with the change of the magnitude and direction of the external magnetic field. Variety. It has a larger resistance change rate than the AMR (Anisotropic MagnetoResistance) and GMR (Giant MagnetoResistance) sensors that have been discovered and applied in practice, and is better than Hall sensors. Temperature stability.
  • GMR or TMR components are compatible with semiconductor standard manufacturing processes, high-sensitivity GMR or TMR sensors do not achieve low-cost mass production.
  • the yield of this sensor depends on the offset of the GMR or TMR component magnetoresistance output.
  • the magnetoresistance outputs of the GMR or TMR components that make up the bridge are difficult to match.
  • the idea of preparing GMR or TMR sensors on a single chip has been developed.
  • TMR sensor there are three main methods to achieve high-sensitivity GMR on a single chip.
  • a single-chip bridge sensor is realized by using two film forming processes or laser heating assisted domain local inversion methods to reverse the magnetization directions of the pinned layers of the magnetoresistive sensing elements in the arms.
  • Two film forming processes that is, depositing TMR elements with opposite pinning layers in two directions, which makes the fabrication process complicated, and affects the first deposited film during the second process annealing, which makes the front and the bottom two times
  • the consistency of the film is poor, which affects the overall performance of the sensor.
  • the laser heating auxiliary magnetic domain local inversion method refers to the local heating of the chip to assist the magnetic moment inversion after annealing in the same strong magnetic field, so that the magnetic moment of the pinning layer of the adjacent arm is opposite, thereby realizing a single chip.
  • Bridge sensor requires the use of dedicated equipment, which is expensive and the entire process takes a long time.
  • a single-chip bridge sensor is realized by tilting the magnetic moment of the free layer of the magnetoresistive sensing element on the arm. That is, the magnetization directions of the pinned layers of the magnetoresistive sensing elements on the arms are the same, and the magnetization directions of the free layers of the magnetoresistive sensing elements on the adjacent arms are different, but the magnetization direction of the free layer of each of the magnetoresistive sensing elements is The pinning layer has the same angle of magnetization. However, this method causes the dynamic range of the magnetic field that the sensor responds to decrease, resulting in a decrease in the sensitivity of the sensor.
  • FIG. 1 is a schematic structural view of a single-chip bridge magnetic field sensor in the prior art.
  • the structure comprises a silicon substrate 1, a shielding structure 2, an inductive element 3, a reference element 4, a gap 5, four pads 7-10 for input and output, respectively as a power supply terminal Vbias, a ground terminal GND, a voltage output terminal V+, V -, the direction of the sensing axis is 100.
  • the reference element 4 is located below the shield structure 2, and the sensing element 3 is located at the gap 5 of the two shield structures 2, and the shape of the shield structure 2 is square.
  • the connection between the sensing elements 3 constitutes a sensing arm, the connection between the reference elements 4 constitutes a reference arm, and the sensing element 3 and the reference element 4 are GMR sensing elements.
  • the silicon substrate 1 has a large length along the direction of the sensing axis 100, and the sensing element 3 and the reference element 4 are far apart, that is, the distance between the sensing arm and the reference arm is relatively large, and there is only one between the two.
  • the gap 5, which causes a waste of space on the chip, also makes the size of the chip relatively large.
  • the size of the chip is about 2mm X 0.5mm.
  • the spacing between the sensing arm and the reference arm is relatively large, it is difficult to balance the bridge, and the temperature on the two arms is different, resulting in a decrease in temperature compensation function.
  • the sensor is more likely to reach the saturation state of the magnetic field, and a non-uniform saturation magnetic field starts to be generated near the center of the shielding structure 2, and hysteresis is generated in the vicinity of the gap 5. Reduces the linearity of the sensor.
  • the object of the present invention is to overcome the above problems in the prior art and to provide a single-chip bridge magnetic field sensor which is small in size, low in cost, small in offset, high in sensitivity, and good in linearity.
  • the invention provides a single-chip bridge magnetic field sensor, which comprises:
  • a Wheatstone half-bridge or Wheatstone quasi-bridge deposited on the substrate comprising: a reference arm R1 comprising at least two rows/column of reference element strings, Each reference element string is electrically connected by one or more identical magnetoresistive sensing elements;
  • sensing arm Sl comprising at least two rows/column of sensing element strings, each sensing element string being electrically connected by one or more identical magnetoresistive sensing elements;
  • the reference element string and the sensing element string have the same number of rows/columns, and are arranged along the longitudinal/lateral direction.
  • the interval between the adjacent reference element strings and the sensing element string is the same;
  • At least three shielding structures each of which has a certain gap between each of the shielding structures, and each of the reference component strings is correspondingly provided with a shielding structure, and each sensing element string is located at a corresponding gap;
  • the magnetoresistive sensing element is one selected from the group consisting of AMR, GMR, and TMR sensing elements.
  • the magnetoresistive sensing element has a linear magnetic field sensor response characteristic.
  • the magnetoresistive sensing element has a multilayer film magnetic field sensor response characteristic.
  • the number of magnetoresistive sensing elements in the reference element string is the same as the number of magnetoresistive sensing elements in the sensing element string.
  • the single-chip bridge magnetic field sensor includes three pads, which are a first pad for supplying a bias voltage, a second pad for output, and a third for grounding, respectively.
  • a pad, the reference arm R1 and the sensing arm S 1 each have a first end and a second end, and the first pad is electrically connected to the first end of the reference arm R1,
  • the third pad is electrically connected to the first end of the sensing arm S1
  • the second pad is electrically connected to the second end of the reference arm R1 and the second end of the sensing arm S1, respectively.
  • the single-chip bridge magnetic field sensor comprises three pads, the first pads being a first pad for ground biasing, the second pad and the third pad for outputting, on the substrate
  • the deposited Wheatstone bridge includes two identical current sources II and 12, two of the current sources II and 12, the reference arm R1 and the sensing arm S1 each having a first end and a second end, the first pad is electrically connected to the first end of the reference arm R1, the first end of the sensing arm S1, and the first ends of the two current sources II and 12,
  • the second pad is electrically connected to the second end of the reference arm R1 and the second end of the current source 12, respectively, the third pad and the second end of the sensing arm S1
  • the second end of the current source II is electrically connected.
  • the shape of the shielding structure is an elongated shape extending in the horizontal/longitudinal direction
  • the constituent material is composed of one or more elements selected from the group consisting of Ni, Fe, Co, Si, B, Ni, Zr and Al. Ferromagnetic alloy.
  • the gain coefficient of the magnetic field at the gap between the shielding structures is 1 ⁇ Asns ⁇ 100, and the attenuation coefficient of the magnetic field above or below the shielding structure is 0 ⁇ Aref ⁇ 1.
  • the sensing element string, the reference element string and the pads are connected to each other by an electrical connection conductor.
  • the substrate may be printed on the substrate directly using CMOS, biased CMOS, the reference arm, the sensing arm and the pad.
  • the invention also provides a single-chip bridge magnetic field sensor, which comprises
  • the Wheatstone full bridge including a first bridge arm and a second bridge arm electrically connected to each other,
  • the first bridge arm includes:
  • a reference arm R1 comprising at least two rows/column of first reference element strings, each of the first reference element strings being one One or more identical magnetoresistive sensing elements are electrically connected;
  • the sensing arm si includes at least two rows/column of first sensing element strings, each of the first sensing element strings being electrically connected by one or more identical magnetoresistive sensing elements, the first reference element string and The first sensing element string has the same number of rows/columns, and is arranged along the longitudinal/lateral direction, and the interval between the first reference element string and the first sensing element string adjacent to each other is the same and both Is L;
  • the second bridge arm includes:
  • a reference arm R2 comprising at least two rows/columns of second reference element strings, each second reference element string being electrically connected by one or more identical magnetoresistive sensing elements;
  • the sensing arm S2 includes at least two rows/columns of second sensing element strings, each of the second sensing element strings being electrically connected by one or more identical magnetoresistive sensing elements, the second reference element string and
  • the second sensing element string has the same number of rows/columns, and is arranged along the longitudinal/lateral direction, and the interval between the two adjacent second reference element strings and the second sensing element string is the same and All are L;
  • first reference element string and the second reference element string or the first sensing element string and the second sensing element string are in close proximity
  • the two first reference element strings and the second reference element string or the first sensing element string and the second sensing element are spaced apart by 2L;
  • the shielding structure is provided with a certain gap between each of the two, and each of the first reference component string and the second reference component string is correspondingly provided with a shielding structure, and each of the first sensing component strings and the first Two sensing element strings are located at corresponding gaps;
  • the single-chip bridge magnetic field sensor includes four pads, and the four pads are a first pad for supplying a bias voltage, a second pad for output, and a third pad, respectively.
  • a fourth pad for grounding, the reference arm R1, the reference arm R2, the sensing arm S 1 and the sensing arm S2 respectively have a first end and a second end, the first pad and the reference arm R2, respectively
  • the second end is electrically connected to the first end of the sensing arm S1
  • the second pad is electrically connected to the second end of the reference arm R1 and the second end of the sensing arm S1, respectively.
  • the third pad is electrically connected to the first end of the sensing arm S2 and the first end of the reference arm R2, the fourth pad and the second end of the sensing arm S2 and the reference
  • the first end of the arm R1 is electrically connected.
  • the shape of the shielding structure is an elongated shape extending in the horizontal/longitudinal direction
  • the constituent material is composed of one or more elements selected from the group consisting of Ni, Fe, Co, Si, B, Ni, Zr and Al. Ferromagnetic alloy.
  • the gain coefficient of the magnetic field at the gap between the shielding structures is 1 ⁇ Asns ⁇ 100, the shielding structure
  • the attenuation coefficient of the magnetic field above or below is 0 ⁇ Aref ⁇ 1.
  • the sensing element string, the reference element string and the pads are connected to each other by an electrical connection conductor.
  • the magnetoresistive sensing element is one selected from the group consisting of AMR, GMR, and TMR sensing elements.
  • the magnetoresistive sensing element has a linear magnetic field sensor response characteristic.
  • the magnetoresistive sensing element has a multilayer film magnetic field sensor response characteristic.
  • the second reference element string has the same number of rows/columns of the first reference element string
  • the second sensing element string has the same number of rows/columns of the first sensing element string
  • the number of magnetoresistive sensing elements in the first reference element string, the number of magnetoresistive sensing elements in the first sensing element string, and the number of magnetoresistive sensing elements in the second reference element string And the number of magnetoresistive sensing elements in the second sensing element string are the same.
  • the substrate may be printed on the substrate directly using a CMOS, biased CMOS, the reference arm, the sensing arm and the pad.
  • the present invention has the following beneficial effects:
  • the pinning layers of the magnetoresistive sensing elements in the reference arm and the sensing arm have the same magnetization direction, so that it can be fabricated on a single chip without using two processes such as film formation or annealing.
  • the long strip-shaped shielding structure enables the sensor to have good linearity and high sensitivity, and also makes the output of the sensor not easily reach saturation, thereby increasing the dynamic range of the sensor operation.
  • FIG. 1 is a schematic structural view of a single-chip bridge magnetic field sensor in the prior art.
  • FIG. 2 is a schematic structural view of a single-chip full-bridge magnetic field sensor of the present invention.
  • FIG 3 is another schematic structural view of a single-chip full-bridge magnetic field sensor of the present invention.
  • Figure 4 shows the saturation curve of a rectangular and square shield structure.
  • FIG. 5 is a magnetic field distribution diagram of a single-chip bridge type magnetic field sensor in an external magnetic field according to the present invention.
  • Figure 6 is a plot of the position of the MTJ component on the reference and sensing arms versus the induced magnetic field strength.
  • Figure 7 is a response curve of a linear magnetic field sensor in the present invention.
  • Figure 8 is a full bridge circuit diagram of the present invention.
  • Figure 9 is a circuit diagram of a half bridge of the present invention.
  • Figure 10 is a schematic diagram of a quasi-bridge circuit of the present invention.
  • Figure 11 is a response curve of the multilayer film magnetic field sensor of the present invention.
  • FIG. 12 is a schematic structural view of a single-chip half-bridge magnetic field sensor of the present invention.
  • the sensor includes a substrate 1, a Wheatstone full bridge deposited on the substrate 1, eight shield structures 42 and four pads 7-10.
  • the Wheatstone full bridge includes a first bridge arm and a second bridge arm electrically connected to each other, the first bridge arm includes a reference arm R1 and a sensing arm S1, and the second bridge arm includes a reference arm R2 and a sensing arm S2, and the reference arm R1 R2 includes three rows of first reference component strings and three rows of second reference component strings, and the sensing arms S1 and S2 respectively include three rows of first sensing component strings, three rows of second sensing component strings, and each reference component string and each.
  • Each of the sensing element strings is electrically connected by one or more of the same magnetoresistive sensing elements, and the reference arm R1 and the sensing arm S1, the reference arm R2 and the sensing arm S2 shown in the figure are each composed of six identical magnetoresistances.
  • Sensing element composition The first reference element string and the first sensing element string are arranged along the longitudinal direction, the second reference element string and the second sensing element string are arranged along the longitudinal direction, and each of the two immediately adjacent first reference element strings and the first sensing The interval between each of the two adjacent second reference element strings and the second sensing element string is the same and is L.
  • the first bridge arm and the second bridge arm are adjacent to the second reference element string by the first reference element string; the interval between the two most adjacent first reference element strings and the second reference element string is 2L
  • the shielding structure 42 is provided with a certain gap 45 between the two, and the gap 45 has the same size.
  • Each of the first reference element string and the second reference element string is correspondingly provided with a shielding structure 42, the first sensing element string and the first The two sensing element strings are located at respective gaps 45.
  • the four pads 7-10 are a first pad 7 for supplying a bias voltage, a second pad 9 for output, and a third pad 10, a fourth pad 8 for grounding, a reference arm R1, the reference arm R2, the sensing arm S1 and the sensing arm S2 respectively have a first end and a second end, and the first pad 7 is electrically connected to the second end of the reference arm R2 and the first end of the sensing arm S1, respectively.
  • the second pad 9 is electrically connected to the second end of the reference arm R1 and the second end of the sensing arm S1, respectively, and the third pad 10 is respectively connected to the first end of the sensing arm S2 and the first end of the reference arm R2.
  • the fourth pad 8 is electrically connected to the second end of the sensing arm S2 and the first end of the reference arm R1.
  • the components of the sensor are connected by electrical connection conductors 6.
  • FIG. 1 It differs from FIG. 1 in that: at least three shield structures are used in the present invention, and eight shields are shown in FIG. Structure 42, while there are only two shield structures 2 in Figure 1; at least two gaps in the present invention, seven gaps 45 in Figure 2; and only one gap 5 in Figure 1; the sensor arm contains at least two rows/columns
  • the sensing element string 43 and the reference element string 44 are alternately discharged, and each sensing element string 43 is spaced apart from the adjacent reference element string 44 by a distance L, but for an even number of shielding structures 42 as shown in FIG.
  • two sensing element strings are adjacent in the middle, with a spacing of 2L therebetween.
  • the pitch L is small, preferably 20 to 100 um.
  • Both the sensing element string 43 and the reference element string 44 are electrically connected to one or more of the same AMR, GMR or TMR magnetoresistive sensing elements.
  • a reference structure 44 is disposed on the reference element string 44.
  • the sensing element string 43 is located at the gap 45 of the two shielding structures 42.
  • the shielding structure 42 is selected from the group consisting of Ni, Fe, Co, Si, B, Ni, Zr and Al. An elongated array of such soft ferromagnetic alloys composed of one or several elements, but is not limited to the above constituent materials.
  • the sensing arm, the reference arm and the pads 7-10 are connected by an electrical connection conductor 6.
  • the chip size of the present invention is 0.5 mm X 0.5 mm, which is smaller than the chip size in the prior art.
  • the size of the chip can be less than 0.5mm X 0.5mm depending on the application requirements.
  • the substrate 1 of the present invention can also be printed directly on the sensing arm, the reference arm and the pads 7-10 using CMOS, biased CMOS.
  • the senor with the long strip-shaped shield structure has a higher saturation point and better linearity than the square shield structure.
  • Figure 5 is a magnetic field distribution diagram of the inductive component string 43 and the reference component string 44 of Figure 2 in an applied magnetic field. As can be seen from the figure, the amplitude of the magnetic field induced by the sensing element string 43 at the gap 45 between the shielding structures 42 is increased, while the amplitude of the magnetic field induced by the reference element string 44 located below the shielding structure 42 is reduced.
  • sensing element string 43 is a collective term for the first sensing element string and the second sensing element string
  • reference element string 44 is a general term for the first reference element string and the second reference element string.
  • the magnetoresistive sensing elements are arranged in the lateral direction (which are arranged in a row in the drawing), the first reference element string and the first sensing element string are arranged in the longitudinal direction, the second reference element string and the second The sensing element strings are spaced apart in the longitudinal direction, the shielding structure extends in the lateral direction, and the gap extends in the lateral direction.
  • the magnetoresistive sensing elements are arranged in the longitudinal direction (which are arranged in a row in the drawing), the first reference element string and the first sensing element string are arranged in the longitudinal and lateral directions, the second reference element string and the The two sensing element strings are arranged in the lateral direction, the shielding structure extends in the longitudinal direction, and the case where the gap extends in the longitudinal direction is also covered by the protection scope of the present invention.
  • FIG. 3 is a schematic view showing another structure of the single-chip full-bridge magnetic field sensor of the present invention.
  • the difference from Fig. 2 is that seven shielding structures are used. 42
  • the outermost two shielding structures are discharged with reference element strings underneath, and the most middle one of the shielding structures is not discharged with reference element strings.
  • the first bridge arm and the second bridge arm are adjacent to the second inductive element string by the first inductive element string, and the interval between the two middle first inductive element strings and the second inductive element string is 2L.
  • the sensor includes a substrate 1, a Wheatstone half bridge deposited on the substrate 1, six shield structures 42 and three pads 7-9.
  • the Wheatstone half bridge includes a reference arm R1 and a sensing arm S1, and the reference arm R1 and the sensing arm S1 each include a 3-row reference element string 44 and a 3-row sensing element string 43, respectively, each reference element string 44 and each sensing element
  • Each of the strings 43 is electrically connected by one or more of the same magnetoresistive sensing elements, and six magnetoresistive sensing elements are shown.
  • the reference element string 44 and the sensing element string 43 are spaced apart in the longitudinal direction, and the spacing between the two adjacent reference element strings 44 and the sensing element string 43 is the same and both are L.
  • the shielding structure 42 is provided with a certain gap 45 between each of them. The length and width of each gap 45 are the same.
  • Each reference element string 44 is located below the shielding structure 42 and each sensing element string 43 is located at a corresponding gap 45. .
  • Both the sensing element string 43 and the reference element string 44 are electrically connected to one or more of the same magnetic resistance sensing elements such as AMR, GMR or TMR.
  • the shielding structure 42 is an elongated array of such a soft ferromagnetic alloy composed of one or more elements selected from the group consisting of Ni, Fe, Co, Si, B, Ni, Zr, and Al, but is not limited to the above Composition of materials.
  • the components of the sensor are connected by electrical connection conductors 6.
  • the magnetoresistive sensing elements are arranged in the lateral direction (which are arranged in a row in the drawing), the reference element string and the sensing element string are arranged in the longitudinal direction, the shielding structure extends in the lateral direction, and the gap extends in the lateral direction.
  • the magnetoresistive sensing elements are arranged in the longitudinal direction (the rows are arranged in the figure)
  • the reference element string and the sensing element string are arranged in the longitudinal and lateral directions
  • the shielding structure extends in the longitudinal direction
  • the gap extends in the longitudinal direction is also covered in the present case.
  • the single-chip bridge magnetic field sensor includes three pads 7-9, which are a first pad 7 for supplying a bias voltage, a second pad 9 for outputting, and a third pad 8 for grounding, the reference arm R1 has a first end and a second end, the sensing arm S1 has a first end and a second end, and the first pad 7 is electrically connected to the first end of the reference arm R1
  • the third pad 8 is electrically connected to the first end of the sensing arm S1
  • the second pad 9 is electrically connected to the second end of the reference arm R1 and the second end of the sensing arm S1, respectively.
  • the difference between this embodiment and the second embodiment is that a Wheatstone quasi-bridge circuit is used.
  • the single-chip bridge magnetic field sensor includes three pads, and the three pads are respectively used as ground pads for the first pad.
  • the Wheatstone quasi-bridge also includes two identical current sources II and 12, a reference arm R1 and a sensing arm S1, current sources II and 12, reference arm R1 and The sensing arms S1 each have a first end and a second end.
  • the first pad is electrically connected to the first end of the reference arm R1, the first end of the sensing arm S1, and the first ends of the two current sources II and 12.
  • the second pad is electrically connected to the second end of the reference arm R1 and the second end of the current source 12, and the third pad is electrically connected to the second end of the sensing arm S1 and the second end of the current source II. .
  • the magnetoresistive sensing element in the single-chip bridge magnetic field sensor of the present application can have a linear magnetic field sensor response characteristic and a multilayer film magnetic field sensor response characteristic.
  • the sensing element string 43 and the reference element string 44 in the single-chip linear bridge magnetic field sensor having linear response characteristics are MTJ elements, that is, TMR elements, which include the following components: pinning layer, tunnel barrier layer, magnetic free layer .
  • the pinning layer comprises an antiferromagnetic layer and at least one ferromagnetic layer
  • the antiferromagnetic layer may be composed of a material such as IrMn or PtMn
  • the material of the ferromagnetic layer may be Co, Fe, Ni, B, Pd, Tb
  • An alloy composed of Hf but is not limited to the alloy of the above materials.
  • the pinning layer may also include a synthetic ferromagnetic layer composed of two ferromagnetic layers coupled with a non-magnetic layer, and the materials of the two ferromagnetic layers may be NiFe, NiFeO, CoFe, Co, and Its composite material, non-magnetic layer material is generally Ru.
  • the material of the magnetic free layer may be an alloy composed of Co, Fe, Ni, B, Pd, Tb, and Hf, but is not limited to the alloy of the above materials.
  • the magnetization direction of the pinned layer is strictly maintained in one direction and does not change with the change of the direction of the applied magnetic field, and the magnetization direction of the magnetic free layer can freely respond to the applied magnetic field.
  • the tunnel barrier layer is an insulating material, usually an oxide, such as
  • the MTJ element has the following structure:
  • Silicon substrate/seed layer/pinning layer/tunnel barrier layer/free layer/bias layer/cover layer wherein the pinning layer is PtMn/CoFe/Ru/CoFeB, the tunnel barrier layer material is MgO, and the free layer is CoFeB/NiFe, the bias layer material is IrMn 0
  • the response curve 20 of the MTJ component in the single-chip bridge magnetic field sensor is shown in FIG.
  • the direction of the applied magnetic field 101 is parallel to the magnetization direction 19 of the pinned layer, and the intensity of the applied magnetic field is greater than -Bs+Bo 25, the magnetization direction 18 of the magnetic free layer is parallel to the direction of the applied magnetic field 101, and further with the pinned layer.
  • the magnetization direction 19 is parallel, and the magnetic resistance of the MTJ element is the smallest, that is, RL21.
  • the magnetization direction 18 of the magnetic free layer is parallel to the direction of the applied magnetic field 101, and further with the pinned layer.
  • the magnetization direction 19 is anti-parallel, and the magnetoresistance of the MTJ element is the largest, that is, R H 22.
  • the intensity of the applied magnetic field 101 is Bo 23
  • the magnetization direction 18 of the magnetic free layer is perpendicular to the magnetization direction 19 of the pinned layer.
  • the magnetic resistance of the MTJ element is intermediate between 21 and R H 22, S ⁇ (RL) +R H ) /2.
  • the sensing element string 43 and the reference element string 44 can also be GMR spin valve membrane structures with the same response curve as in Figure 6. As can be seen from Figure 7, the sensor has good linearity.
  • Figure 8 is a structural circuit diagram of a single-chip linear reference full-bridge magnetic field sensor.
  • two sensing arms S 1 52, S2 52' and two reference arms Rl 53, R2 53 ' are connected to form a full bridge
  • sensing arms S 1 52, S2 52' and reference arms R1 53, R2 53 ' Consists of one or more AMR, GMR or MTJ magnetoresistive sensing elements, and the pinning layers have the same magnetization direction.
  • the structure has four pads for respectively serving as a bias voltage Vbias , a half-bridge voltage output terminal (VI, V2) and a ground terminal GND, wherein V bias and one end of the reference arm R1 53 and one end of the sensing arm SI 52 Electrical connection, VI is electrically connected to the other end of the reference arm R1 53 and one end of the sensing arm S2 52', V2 and the sensing arm The other end of the SI 52 and one end of the reference arm R2 53 ' are electrically connected, and GND is electrically connected to the other end of the sensing arm S2 52' and the other end of the reference arm R2 53 '.
  • the output voltage of the full bridge is
  • FIG. 9 is a structural circuit diagram of a single-chip linear reference half-bridge magnetic field sensor.
  • the sensing arm S1 52 and the reference arm R1 53 are connected to form a half bridge, and the sensing arm S1 52 and the reference arm R1 53 are composed of one or more AMR, GMR or MTJ magnetoresistive sensing elements, and the magnetization of the pinned layer The directions are the same.
  • the structure has three pads for respectively serving as a bias voltage (V bias ), a half bridge voltage output terminal (VI ) and a ground terminal GND, wherein V bias is electrically connected to one end of the reference arm R1 53 , VI and the reference arm The other end of R1 53 and one end of the sensing arm S1 52 are electrically connected, and GND is electrically connected to the other end of the sensing arm S1 52.
  • V bias bias voltage
  • VI half bridge voltage output terminal
  • GND is electrically connected to the other end of the sensing arm S1 52.
  • the present invention also provides a better performance single-chip linear quasi-bridge magnetic field sensor, the circuit of which is shown in FIG. This circuit contains two current sources II 59 and 12 59', one sensing arm S1 52 and one reference arm R1 53. These two current sources are equal in magnitude and are all I bias .
  • the sensing arm S1 52 and the reference arm R1 53 are composed of one or more AMR GMR or MTJ magnetoresistive sensing elements, and the pinning layers have the same magnetization direction.
  • the structure has three pads, one of which is used as the ground GND, and the other two are used as the half bridge voltage output terminal (Vl V2), wherein GND is electrically connected to one end of the two current sources, and is coupled to the sensing arm S1 52 One end is electrically connected to one end of the reference arm R1 53 , and VI is electrically connected to the other end of the current source II 59 and the other end of the sensing arm S1 52 , and the other end of the V 2 and the current source 12 59 ′ and the other end of the reference arm R1 53 connection.
  • the reference component string 44 and the inductive component string 43 are MTJ components, which include the following components: pinning layer, tunnel barrier layer, magnetic freedom Floor.
  • the pinning layer comprises an antiferromagnetic layer and at least one ferromagnetic layer
  • the antiferromagnetic layer may be composed of a material such as IrMn or PtMn
  • the material of the ferromagnetic layer and the magnetic free layer may be Co, Fe, Ni, B
  • An alloy composed of Pd, Tb and Hf but is not limited to the alloy of the above materials.
  • the magnetization direction of the pinned layer is strictly maintained in one direction and does not change with the change of the direction of the applied magnetic field, and the magnetization direction of the magnetic free layer can freely respond to the applied magnetic field. However, in the absence of an applied magnetic field, the magnetization direction of the free layer is antiparallel to the magnetization direction of the pinned layer, which can be achieved by a leakage magnetic field from the pinned layer, or by using a pinned layer containing a synthetic ferromagnetic layer. The layer is then implemented by placing an antiferromagnetic layer over the free layer.
  • the tunnel barrier layer is an insulating material, usually an oxide, such as A1 2 0 3 or MgO.
  • the magnetization of the free layer is made by the stray magnetic field emitted from the pinning layer.
  • the direction is anti-parallel to the magnetization direction of the pinned layer, in which case the structure of the MTJ element is preferably as follows: silicon substrate/seed layer/pinning layer/tunnel barrier layer/free layer/cover layer.
  • the pinned layer is IrMn/CoFe/CoFeB
  • the tunnel barrier layer material is MgO
  • the free layer is CoFeB/NiFe.
  • Silicon substrate/seed layer/pinning layer/tunnel barrier layer/free layer/antiferromagnetic layer/protective layer wherein the pinned layer is IrMn/CoFe/Ru/CoFeB, the tunnel barrier layer material is MgO, free layer For CoFeB/NiFe, the antiferromagnetic layer material is IrMn 0
  • the response curve of the MTJ multilayer film bridge magnetic field sensor is shown in Figure 11.
  • the direction of the applied magnetic field 101 is parallel to the magnetization direction 19 of the pinned layer, and the intensity of the applied magnetic field is greater than -Bs 31 or Bs 32
  • the magnetization direction 18 of the magnetic free layer is parallel to the direction of the applied magnetic field 101, and further with the pinning layer.
  • the magnetization direction 19 is parallel, and the magnetic resistance of the MTJ element is the smallest, which is RL 28.
  • the applied magnetic field is 0, the magnetization direction 18 of the magnetic free layer is anti-parallel to the magnetization direction 19 of the pinned layer, and the magnetic resistance of the MTJ element is the largest, that is, R H 27.
  • the magnetic field between -Bs 31 and Bs 32 is the measurement range of a single-chip multilayer film bridge magnetic field sensor.
  • the curves 29, 30 are linear between -Bs 31 and Bs 32 with a slope of
  • the sensing element string 43 and the reference element string 44 may also be a GMR multilayer film structure composed of a plurality of layers of CoFe/Cu/CoFe, and the response curve is the same as that of Fig. 10. As can be seen from Figure 10, the sensor has good linearity.
  • the single-chip multilayer membrane bridge magnetic field sensor also has three structures, namely the reference full bridge, the reference half bridge, and the quasi-bridge.
  • the sensitivity calculation process of these three structural sensors is the same as that of the single-chip linear bridge magnetic field sensor, and will not be described in detail here. Only the results are given, which are respectively expressed as follows:
  • the sensitivity of the three structural sensors is related to the absolute value of the magnetic field strength B of the applied magnetic field, and therefore the response curve is symmetrical.
  • the sensor of the quasi-bridge structure has the same performance as the sensors of the other two structures.
  • the three-bridge, full-bridge, and quasi-bridge configurations are also available on single-chip bridged magnetic field sensors using CMOS, biased CMOS substrates.

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Abstract

一种单芯片桥式磁场传感器,该传感器包括基片(1)、参考臂、感应臂、屏蔽结构(42),焊盘(7,8,9,10)。其中参考臂、感应臂各自包含有至少两行/列由一个或多个相同磁电阻传感元件电连接构成的参考元件串(44)、感应元件串(43);参考元件串(44)与感应元件串(43)相互交错排放,磁电阻传感元件为选自AMR、GMR或者TMR传感元件中的一种,参考元件串(44)上对应设置有一屏蔽结构(42),感应元件串(43)位于两个屏蔽结构(42)之间的间隙(45)处,屏蔽结构(42)为由坡莫合金这种软磁材料制成的长条形阵列。此传感器可在准桥、半桥、全桥这三种电桥结构上得到实现。所述单芯片桥式磁场传感器具有以下优点:体积小、成本低、偏移量小、灵敏度高、线性度好、温度稳定性好。

Description

单芯片桥式磁场传感器 技术领域
本发明涉及磁传感器技术领域, 特别涉及一种具有低偏移的单芯片桥式磁场传感器。 背景技术
TMR (隧道磁电阻, Tunnel MagnetoResistance) 传感器是近年来开始应用于工业领域的 新型磁电阻效应传感器。 该传感器利用的是磁性多层膜材料的隧道磁电阻效应对磁场进 行感应, 主要表现在: 在磁性多层膜材料中, 随着外磁场大小和方向的变化, 磁性多层 膜的电阻发生明显变化。 它比之前所发现并已实际应用的 AMR (各向异性磁电阻, Anisotropic MagnetoResistance ) 禾口 GMR (巨磁电阻, Giant MagnetoResistance) 传感器 具有更大的电阻变化率, 同时相对于霍尔传感器具有更好的温度稳定性。
尽管 GMR或 TMR元件能与半导体标准制造工艺相兼容, 但高灵敏度的 GMR或 TMR 传感器并没有实现低成本大规模生产, 该传感器的成品率取决于 GMR或 TMR元件磁 电阻输出的偏移值, 组成电桥的 GMR或 TMR元件的磁电阻输出很难达到匹配一致。 为了实现低成本大规模生产出高灵敏度的 GMR或 TMR传感器, 从而产生了在单一芯 片上制备 GMR或 TMR传感器的想法, 目前主要有以下三种方法来实现在单一芯片上 制备高灵敏度的 GMR或 TMR传感器。
( 1 ) 通过采用两次成膜工艺或者激光加热辅助磁畴局部翻转法来使臂中磁电阻传感元 件的钉扎层的磁化方向相反, 从而实现单一芯片的桥式传感器。 两次成膜工艺, 即分两 次分别沉积钉扎层方向相反的 TMR 元件, 这使得其制作工艺复杂, 并且第二次工艺退 火时会影响第一次沉积的薄膜, 这使得前后两次成膜的一致性差, 从而影响传感器的整 体性能。 激光加热辅助磁畴局部翻转法, 是指在同一强磁场中退火之后, 采用激光对芯 片进行局部加热辅助磁矩翻转, 来使相邻臂的钉扎层的磁矩方向相反, 从而实现单一芯 片的桥式传感器。 但该方法需要使用专用设备, 设备昂贵, 并且整个过程耗时长。
(2) 通过倾斜臂上磁电阻传感元件的自由层的磁矩平衡方向来实现单一芯片的桥式传 感器。 即各臂上磁电阻传感元件的钉扎层的磁化方向相同, 相邻臂上磁电阻传感元件的 自由层的磁化方向不同, 但每个磁电阻传感元件的自由层的磁化方向与其钉扎层的磁化 方向的夹角相同。 但此种方法会导致传感器响应的磁场动态范围有所减小, 从而导致传 感器的灵敏度降低。
( 3 ) 使用磁屏蔽或者通量集中器的参考桥式传感器, 目前的这种传感器由于参考臂与 感应臂相隔很远, 致使其体积大, 成本高, 输出的偏移量也难以控制。
如图 1 所示, 现有技术中的一种单芯片桥式磁场传感器的结构示意图。 该结构包括硅基 片 1, 屏蔽结构 2, 感应元件 3, 参考元件 4, 间隙 5, 4个用于输入输出的焊盘 7-10, 分别作为电源供应端 Vbias, 接地端 GND, 电压输出端 V+, V -, 其感应轴方向为 100。 参考元件 4位于屏蔽结构 2的下方, 感应元件 3位于两个屏蔽结构 2的间隙 5处, 屏蔽 结构 2的形状为方形。 感应元件 3之间连接构成感应臂, 参考元件 4之间连接构成参考 臂, 感应元件 3和参考元件 4为 GMR传感元件。 硅基片 1在沿着感应轴方向 100具有 很大的长度, 并且感应元件 3和参考元件 4相距较远, 也就是感应臂和参考臂之间的间 距比较大, 并且二者之间只有一个间隙 5, 这会造成芯片上的空间浪费, 也使得芯片的 尺寸比较大, 此种设计而成的芯片尺寸大小约为 2mm X 0.5mm。 并且, 由于感应臂和 参考臂之间的间距比较大, 会使得电桥难以平衡, 并且会导致这两臂上的温度不同, 从 而导致其温度补偿功能降低。 此外, 由于采用了方形的屏蔽结构 2, 会致使传感器更容 易达到磁场的饱和状态, 在屏蔽结构 2 的中心附近就会开始产生非均匀的饱和磁场, 并 且在间隙 5附近会产生磁滞, 从而降低了传感器的线性度。
发明内容
本发明的目的在于克服现有技术存在的以上问题, 提供一种体积小、 成本低、 偏移量 小、 灵敏度高、 线性度好的单芯片桥式磁场传感器。
为实现上述技术目的, 达到上述技术效果, 本发明通过以下技术方案实现:
本发明提供了一种单芯片桥式磁场传感器, 它包括:
基片;
沉积在所述基片上的惠斯通半桥或惠斯通准桥, 所述惠斯通半桥或惠斯通准桥包括: 参考臂 Rl, 其包括至少两行 /列的参考元件串, 每个参考元件串由一个或者多个相同的 磁电阻传感元件电连接构成; 以及
感应臂 Sl, 其包括至少两行 /列的感应元件串, 每个感应元件串由一个或者多个相同的 磁电阻传感元件电连接构成;
所述参考元件串和所述感应元件串的行 /列数相同, 并沿纵 /横向相间隔排布,
相邻的所述参考元件串与所述感应元件串之间的间隔相同;
至少三个屏蔽结构, 所述屏蔽结构两两之间均设有一定的间隙, 每个参考元件串上对应 设置有一屏蔽结构, 每个感应元件串位于相应的间隙处;
多个用于输入输出的焊盘。 优选地, 所述磁电阻传感元件为选自 AMR、 GMR、 TMR传感元件中的一种。
进一步地, 所述磁电阻传感元件具有线性磁场传感器响应特性。
进一步地, 所述磁电阻传感元件具有多层膜磁场传感器响应特性。
优选地, 所述参考元件串中的磁电阻传感元件数量与所述感应元件串中的磁电阻传感元 件数量相同。
优选地, 所述单芯片桥式磁场传感器包括三个焊盘, 三个焊盘分别是用于供应偏置电压 的第一焊盘、 用于输出的第二焊盘以及用于接地的第三焊盘, 所述参考臂 Rl、 所述感 应臂 S 1各自均具有一个第一端和一个第二端, 所述第一焊盘与所述参考臂 R1的第一端 相电连, 所述第三焊盘与所述感应臂 S 1 的第一端相电连, 所述第二焊盘分别与参考臂 R1的第二端以及所述感应臂 S 1的第二端相电连。
优选地, 所述单芯片桥式磁场传感器包含有三个焊盘, 三个焊盘分别为用于接地偏置的 第一焊盘、 用于输出的第二焊盘与第三焊盘, 基片上沉积的所述惠斯通准桥包括两个相 同的电流源 II和 12, 两个所述电流源 II和 12、 所述参考臂 R1和所述感应臂 S 1各自均 具有一个第一端和一个第二端, 所述第一焊盘与所述参考臂 R1 的第一端、 所述感应臂 S 1的第一端以及两个所述电流源 II和 12的第一端相电连, 所述第二焊盘分别与所述参 考臂 R1 的第二端和所述电流源 12的第二端相电连, 所述第三焊盘与所述感应臂 S 1 的 第二端以及所述电流源 II的第二端相电连。
优选地, 所述屏蔽结构的形状为沿横 /纵向延伸的长条形, 其组成材料为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的一种或几种元素组成的铁磁合金。
优选地, 所述屏蔽结构之间的间隙处的磁场的增益系数为 1 <Asns <100, 所述屏蔽结构 上方或者下方处的磁场的衰减系数为 0 <Aref <1。
优选地, 所述感应元件串、 所述参考元件串与所述焊盘彼此之间均用电连接导体连接。 优选地, 所述基片可采用 CMOS、 偏置 CMOS , 将所述参考臂、 所述感应臂和所述焊盘 直接印制在所述基片上面。
本发明还提供了一种单芯片桥式磁场传感器, 它包括
基片;
沉积在所述基片上的惠斯通全桥, 所述惠斯通全桥包括相互电连接的第一桥臂和第二 桥臂,
所述第一桥臂包括:
参考臂 Rl, 其包括至少两行 /列的第一参考元件串, 每个第一参考元件串均由一 个或者多个相同的磁电阻传感元件电连接构成; 以及
感应臂 si, 其包括至少两行 /列的第一感应元件串, 每个第一感应元件串均由一 个或者多个相同的磁电阻传感元件电连接构成, 所述第一参考元件串和所述第一感应元 件串的行 /列数相同, 并沿纵 /横向相间隔排布, 两两紧邻的所述第一参考元件串与所述 第一感应元件串之间的间隔相同且均为 L;
所述第二桥臂包括:
参考臂 R2, 其包括至少两行 /列的第二参考元件串, 每个第二参考元件串均由一 个或者多个相同的磁电阻传感元件电连接构成; 以及
感应臂 S2, 其包括至少两行 /列的第二感应元件串, 每个第二感应元件串均由一 个或者多个相同的磁电阻传感元件电连接构成, 所述第二参考元件串和所述第二感应元 件串的行 /列数相同, 并沿纵 /横向相间隔排布, 两两相邻的所述第二参考元件串与所述 第二感应元件串之间的间隔相同且均为 L;
所述第一桥臂与所述第二桥臂之间通过所述第一参考元件串与所述第二参考元件串 或通过所述第一感应元件串与所述第二感应元件串相紧邻; 两个相紧邻的所述第一参考 元件串与所述第二参考元件串或所述第一感应元件串与所述第二感应元件之间的间隔为 2L;
至少三个屏蔽结构, 所述屏蔽结构两两之间均设有一定的间隙, 每个第一参考元件串 和第二参考元件串上对应设置有屏蔽结构, 每个第一感应元件串和第二感应元件串位于 相应的间隙处;
多个用于输入输出的焊盘。
优选地, 所述单芯片桥式磁场传感器包含有四个焊盘, 四个焊盘分别是用于供应偏置电 压的第一焊盘、 用于输出的第二焊盘以及第三焊盘、 用于接地的第四焊盘, 参考臂 Rl、 参考臂 R2、 感应臂 S 1和感应臂 S2分别具有一个第一端和一个第二端, 所述第一 焊盘分别与所述参考臂 R2的第二端和所述感应臂 S 1的第一端相电连, 所述第二焊盘分 别与参考臂 R1的第二端以及所述感应臂 S 1的第二端相电连, 所述第三焊盘分别与所述 感应臂 S2 的第一端以及所述参考臂 R2 的第一端相电连, 所述第四焊盘与所述感应臂 S2的第二端以及所述参考臂 R1的第一端相电连。
优选地, 所述屏蔽结构的形状为沿横 /纵向延伸的长条形, 其组成材料为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的一种或几种元素组成的铁磁合金。
优选地, 所述屏蔽结构之间的间隙处的磁场的增益系数为 1 <Asns <100, 所述屏蔽结构 上方或者下方处的磁场的衰减系数为 0 <Aref <1。
优选地, 所述感应元件串、 所述参考元件串与所述焊盘彼此之间均用电连接导体连接。 优选地, 所述磁电阻传感元件为选自 AMR、 GMR、 TMR传感元件中的一种。
进一步地, 所述磁电阻传感元件具有线性磁场传感器响应特性。
进一步地, 所述磁电阻传感元件具有多层膜磁场传感器响应特性。
优选地, 所述第二参考元件串与所述第一参考元件串的行 /列数相同, 所述第二感应元件 串与所述第一感应元件串的行 /列数相同。
优选地, 所述第一参考元件串中的磁电阻传感元件数量、 所述第一感应元件串中的磁电 阻传感元件数量、 所述第二参考元件串中的磁电阻传感元件数量和所述第二感应元件串 中的磁电阻传感元件数量均相同。
优选地, 所述基片可采用 CMOS、 偏置 CMOS, 将所述参考臂、 所述感应臂和所述焊盘 直接印制在所述基片上面。
与现有技术相比, 本发明具有以下有益效果:
( 1 ) 参考臂和感应臂中磁电阻传感元件的钉扎层的磁化方向相同, 所以无需采用两次 成膜或退火等工艺, 就可以实现在单一芯片上制备。
(2) 采用长条形屏蔽结构, 能使传感器具有良好的线性度和高灵敏度, 也使得传感器 的输出不容易达到饱和状态, 从而增大了传感器工作的动态范围。
( 3 ) 参考臂和感应臂交错排放, 并且二者之间间距很小, 使得传感器输出的偏移量降 低, 并且改善了温度补偿性能, 减小了体积, 从而降低了成本。
附图说明
为了更清楚地说明本发明实施例技术中的技术方案, 下面将对实施例技术描述中所需要 使用的附图作简单地介绍, 显而易见地, 下面描述中的附图仅仅是本发明的一些实施 例, 对于本领域普通技术人员来讲, 在不付出创造性劳动的前提下, 还可以根据这些附 图获得其他的附图。
图 1为现有技术中单芯片桥式磁场传感器的结构示意图。
图 2为本发明的单芯片全桥磁场传感器的结构示意图。
图 3为本发明的单芯片全桥磁场传感器的另一种结构示意图。
图 4为矩形和方形屏蔽结构的饱和曲线图。
图 5为本发明的单芯片桥式磁场传感器在外磁场中的磁场分布图。
图 6为参考臂和感应臂上 MTJ元件所在位置与所感应磁场强度的关系曲线。 图 7为本发明中的线性磁场传感器的响应曲线。
图 8为本发明的全桥电路图。
图 9为本发明的半桥电路图。
图 10为本发明的准桥电路图。
图 11为本发明中的多层膜磁场传感器的响应曲线。
图 12为本发明的单芯片半桥磁场传感器的结构示意图。
具体实施方式
下面结合附图及实施例对本发明的发明内容作进一步的描述。
实施例 1
图 2为本发明的单芯片全桥磁场传感器的结构示意图。 该传感器包括基片 1、 沉积在基 片 1上的惠斯通全桥、 8个屏蔽结构 42和四个焊盘 7-10。 该惠斯通全桥包括相互电连接 的第一桥臂和第二桥臂, 第一桥臂包括参考臂 R1和感应臂 Sl, 第二桥臂包括参考臂 R2 和感应臂 S2, 参考臂 Rl、 R2分别包括 3行第一参考元件串、 3行第二参考元件串, 感 应臂 Sl、 S2分别包括 3行第一感应元件串、 3行第二感应元件串, 每个参考元件串和每 个感应元件串各自均由一个或者多个相同的磁电阻传感元件电连接构成, 图中所示的参 考臂 R1和感应臂 Sl、 参考臂 R2和感应臂 S2均由 6个相同的磁电阻传感元件组成。 第 一参考元件串和第一感应元件串沿纵向相间隔排布, 第二参考元件串和第二感应元件串 沿纵向相间隔排布, 每两个紧邻的第一参考元件串与第一感应元件串之间、 每两个紧邻 的第二参考元件串与第二感应元件串之间的间隔相同且均为 L。 第一桥臂与第二桥臂之 间通过第一参考元件串与第二参考元件串相紧邻; 最中间相紧邻的两个第一参考元件串 与第二参考元件串之间的间隔为 2L; 屏蔽结构 42两两之间均设有一定的间隙 45, 间隙 45 的大小相同, 每个第一参考元件串和第二参考元件串上对应设置有一屏蔽结构 42, 第一感应元件串和第二感应元件串位于相应的间隙 45处。 四个焊盘 7-10分别是用于供 应偏置电压的第一焊盘 7、 用于输出的第二焊盘 9以及第三焊盘 10、 用于接地的第四焊 盘 8, 参考臂 Rl、 参考臂 R2、 感应臂 S1和感应臂 S2分别具有一个第一端和一个第二 端, 第一焊盘 7分别与参考臂 R2的第二端和感应臂 S1的第一端相电连, 第二焊盘 9分 别与参考臂 R1的第二端以及感应臂 S1的第二端相电连, 第三焊盘 10分别与感应臂 S2 的第一端以及参考臂 R2的第一端相电连, 第四焊盘 8与感应臂 S2的第二端以及所述参 考臂 R1的第一端相电连。 传感器中各元件之间均用电连接导体 6连接。
其与图 1不同之处在于: 本发明中采用的屏蔽结构至少为 3个, 图 2中显示有 8个屏蔽 结构 42, 而图 1中只有 2个屏蔽结构 2; 本发明中至少有两个间隙, 图 2中有七个间隙 45; 而图 1中只有一个间隙 5; 感应臂至少包含有两行 /列感应元件串 43, 参考臂至少包 含有两行 /列参考元件串 44, 图 2中显示有 6行感应元件串 43和 6行参考元件串 44, 而 图 1中感应元件串只有一行。 感应元件串 43与参考元件串 44相互交错排放, 每个感应 元件串 43与相邻的参考元件串 44之间均相隔间距 L, 但对于如图 2所示的偶数个屏蔽 结构 42, 正中间有两个参考元件串相邻, 其之间间距为 2L , 对于如图 3所示的奇数个 屏蔽结构 42, 正中间有两个感应元件串相邻, 其之间间距为 2L。 间距 L很小, 优选地 为 20~100 um。 感应元件串 43和参考元件串 44都为一个或者多个相同的 AMR、 GMR 或 TMR这种磁电阻传感元件电连接构成。 参考元件串 44上对应设有一屏蔽结构 42, 感应元件串 43位于两个屏蔽结构 42的间隙 45处, 屏蔽结构 42为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的一种或几种元素组成的这种软铁磁合金制成的长条形阵列, 但 并不限于以上组成材料。 感应臂、 参考臂和焊盘 7-10之间均用电连接导体 6连接。 优选 地, 本发明的芯片尺寸大小为 0.5mm X 0.5mm, 比现有技术中的芯片尺寸要小。 此外, 根据应用需求的不同, 芯片的尺寸还可以小于 0.5mm X 0.5mm。 本发明中的基片 1也可 采用 CMOS、 偏置 CMOS, 将感应臂、 参考臂和焊盘 7-10直接印制在其上面。
当外加磁场 101 的方向与屏蔽结构 42 的短边方向相同时, 方形和长条形屏蔽结构理论 上的磁化曲线如图 4所示。 其中曲线 11为方形屏蔽结构的磁化曲线, 曲线 12为长条形 屏蔽结构的磁化曲线。
从图 4 中可以看出, 与方形的屏蔽结构相比, 采用长条形的屏蔽结构的传感器更的饱和 点更高, 并且线性度更好。
图 5为图 2中感应元件串 43与参考元件串 44在外加磁场中的磁场分布图。 从图中可以 看出, 位于屏蔽结构 42之间的间隙 45处的感应元件串 43所感应到的磁场幅度增强, 而位于屏蔽结构 42下方的参考元件串 44所感应到的磁场幅度降低。
图 6为图 2中相应的感应元件串 43与参考元件串 44的所在位置与所感应磁场强度的关 系曲线, 其中, Bsns16为感应臂上感应元件串 43所感应的磁场强度, Bref为参考臂上参 考元件串 44 所感应的磁场强度, 外加磁场的强度 Bext=100G。 从图中可以得到: Bsns=160G, Bref=25G。 根据下面的公式 (1 ) 与 (2), 便可得知相应的增益系数 Asns和 衰减系数 Aref的大小。
Figure imgf000009_0001
Bref=Aref*Bext (2)
将 Bext=100G, Bsns=160G, Bref=25G 代入 卜而而 ^中. 枢可算出: Asns=1.6, Aref=0.25。 AsnJAref 的比值越大, 则意味着屏蔽结构的设计越好, 一般理想的是 AsnJAref>5, 此时就 有高灵敏度。 本设计中 AsnJAref=1.6/0.25=6.4>5 (3), 由此可见本申请中的单芯片桥式磁 场传感器具有高灵敏度, 屏蔽结构设计良好。
上面所提到的感应元件串 43 是第一感应元件串和第二感应元件串的统称, 参考元件串 44是第一参考元件串和第二参考元件串的统称。
在本实施例中, 磁电阻传感元件沿横向排布 (图中其成行排布), 第一参考元件串和第 一感应元件串沿纵向相间隔排布, 第二参考元件串和第二感应元件串沿纵向相间隔排 布, 屏蔽结构沿横向延伸, 间隙沿横向延伸。 但是显而易见的, 当磁电阻传感元件沿纵 向排布 (图中其成列排布), 第一参考元件串和第一感应元件串沿纵横向相间隔排布, 第二参考元件串和第二感应元件串沿横向相间隔排布, 屏蔽结构沿纵向延伸, 间隙沿纵 向延伸的情形也涵盖在本发明的保护范围内。
图 3是本发明的单芯片全桥磁场传感器的另一种结构示意图。 其与图 2的不同点在于采 用了 7个屏蔽结构 42, 最外侧的两个屏蔽结构下方都排放有参考元件串, 最中间的那个 屏蔽结构下方没有排放参考元件串。 第一桥臂和第二桥臂通过第一感应元件串与第二感 应元件串相紧邻, 最中间的两个第一感应元件串与第二感应元件串之间的间隔为 2L。 实施例 2
图 12为本发明的单芯片半桥磁场传感器的结构示意图。 该传感器包括基片 1、 沉积在基 片 1上的惠斯通半桥、 6个屏蔽结构 42以及 3个焊盘 7-9。 该惠斯通半桥包括参考臂 R1 和感应臂 Sl, 参考臂 R1和感应臂 S1各自分别包括 3行参考元件串 44和 3行感应元件 串 43, 每个参考元件串 44和每个感应元件串 43各自均由一个或者多个相同的磁电阻传 感元件电连接构成, 图中所示的为 6个磁电阻传感元件。 参考元件串 44和感应元件串 43沿纵向相间隔排布, 两两紧邻的参考元件串 44与感应元件串 43之间的间隔相同且均 为 L。 屏蔽结构 42两两之间均设有一定的间隙 45, 各间隙 45的长度和宽度均相同, 每 个参考元件串 44位于屏蔽结构 42的下方, 每个感应元件串 43位于相应的间隙 45处。 感应元件串 43和参考元件串 44都为一个或者多个相同的 AMR、 GMR或 TMR这种磁 电阻传感元件电连接构成。 屏蔽结构 42为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的 一种或几种元素组成的这种软铁磁合金制成的长条形阵列, 但并不限于以上组成材料。 传感器中各元件之间均用电连接导体 6连接。
在本实施例中, 磁电阻传感元件沿横向排布 (图中其成行排布), 参考元件串和感应元 件串沿纵向相间隔排布, 屏蔽结构沿横向延伸, 间隙沿横向延伸。 但是显而易见的, 当 磁电阻传感元件沿纵向排布 (图中其成列排布), 参考元件串和感应元件串沿纵横向相 间隔排布, 屏蔽结构沿纵向延伸, 间隙沿纵向延伸的情形也涵盖在本发明的保护范围 内。
在本实施例中, 单芯片桥式磁场传感器包括三个焊盘 7-9, 三个焊盘分别是用于供应偏 置电压的第一焊盘 7、 用于输出的第二焊盘 9以及用于接地的第三焊盘 8, 参考臂 R1具 有第一端以及第二端, 感应臂 S1具有第一端和第二端, 第一焊盘 7与参考臂 R1的第一 端相电连, 第三焊盘 8与感应臂 S1的第一端相电连, 第二焊盘 9分别与参考臂 R1的第 二端以及感应臂 S1的第二端相电连。
实施例 3
本实施例与第二实施例的区别在于采用惠斯通准桥电路, 该单芯片桥式磁场传感器包含 有三个焊盘, 三个焊盘分别为用于接地偏置的第一焊盘、 用于输出的第二焊盘与第三焊 盘, 惠斯通准桥还包括两个相同的电流源 II和 12、 一个参考臂 R1和一个感应臂 Sl, 电 流源 II和 12、 参考臂 R1和感应臂 S1各自均具有一个第一端和一个第二端, 第一焊盘 与参考臂 R1的第一端、 感应臂 S1的第一端以及两个电流源 II和 12的第一端相电连, 第二焊盘分别与参考臂 R1的第二端和电流源 12的第二端相电连, 第三焊盘与感应臂 S1 的第二端以及电流源 II的第二端相电连。
实施例 4
本申请中的单芯片桥式磁场传感器中的磁电阻传感元件可具有线性磁场传感器响应特性 和多层膜磁场传感器响应特性。
具有线性响应特性的单芯片线性桥式磁场传感器中的感应元件串 43和参考元件串 44为 MTJ 元件, 也即 TMR 元件, 其包括以下组成部分: 钉扎层, 隧道势垒层, 磁性自由 层。 其中, 钉扎层包括一反铁磁层和至少一层铁磁层, 反铁磁层可以由 IrMn或者 PtMn 等材料组成, 铁磁层的材料可以为 Co、 Fe、 Ni、 B、 Pd、 Tb和 Hf 组成的一种合金, 但 不限于上述材料组成的合金。 钉扎层也还可以包括一合成铁磁层, 该合成铁磁层由两个 铁磁层和一非磁性层耦合构成, 这两个铁磁层的材料可以是 NiFe、 NiFeO、 CoFe、 Co 及其复合材料, 非磁性层材料一般采用 Ru。 磁性自由层的材料可以为 Co、 Fe、 Ni、 B、 Pd、 Tb 和 Hf 组成的一种合金, 但不限于上述材料组成的合金。 钉扎层的磁化方向 严格保持在一个方向上, 并且不随外加磁场方向的改变而改变, 磁性自由层的磁化方向 可以自由响应外加磁场。 但在没有外加磁场的情况下, 自由层的磁化方向要与钉扎层的 磁化方向垂直, 这可以通过在磁性自由层上方设置一偏置层, 或者使用一偏置磁铁, 或 者使用材料的形状各向异性来实现。 隧道势垒层为绝缘材料, 通常为氧化物, 例如
A1203或者 MgO。 优选地, MTJ元件为以下结构:
硅基片 /种子层 /钉扎层 /隧道势垒层 /自由层 /偏置层 /覆盖层, 其中钉扎层为 PtMn/CoFe/Ru/CoFeB , 隧道势垒层材料为 MgO, 自由层为 CoFeB/NiFe, 偏置层材料为 IrMn0
单芯片桥式磁场传感器中 MTJ元件的响应曲线 20, 如图 7所示。 当外加磁场 101 的方 向与钉扎层的磁化方向 19平行, 同时外加磁场的强度大于 -Bs+Bo 25时, 磁性自由层的 磁化方向 18与外加磁场 101的方向平行, 进而与钉扎层的磁化方向 19平行, 此时 MTJ 元件的磁阻最小, 即为 RL 21。 当外加磁场 101的方向与钉扎层的磁化方向 19反平行, 同时外加磁场的强度大于 Bs+Bo 26时, 磁性自由层的磁化方向 18与外加磁场 101的方 向平行, 进而与钉扎层的磁化方向 19 反平行, 此时 MTJ 元件的磁阻最大, 即为 RH22。 当外加磁场 101 的强度为 Bo 23时, 磁性自由层的磁化方向 18与钉扎层的磁化 方向 19垂直, 此时, MTJ元件的磁阻为 21和 RH22的中间值, S卩 (RL +RH ) /2。 - Bs+Bo 25与 Bs+Bo 26之间的磁场便是单芯片线性桥式磁场传感器的测量范围。 从图中 可以看出, 曲线 21在 -Bs+Bo 25与 Bs+Bo 26之间呈线性, 其斜率为
( RH-RL) /2BS=AR/AB (4)
在 -Bs+Bo 25与 Bs+Bo 26之间的磁场所对应的磁阻
Figure imgf000012_0001
再根据公式 (1 ) 与 (2), 便可以得到感应臂和参考臂上的磁阻:
Figure imgf000012_0002
感应元件串 43 和参考元件串 44也可以为 GMR 自旋阀膜结构, 其响应曲线与图 6相 同。 从图 7中可以看出, 该传感器具有良好的线性度。
实施例 5
图 8为单芯片线性参考全桥磁场传感器的结构电路图。 图中, 两个感应臂 S 1 52, S2 52' 和两个参考臂 Rl 53, R2 53 ' 相间隔连接构成一全桥, 感应臂 S 1 52, S2 52' 和参考臂 R1 53, R2 53 ' 由一个或多个 AMR、 GMR或者 MTJ磁电阻传感元件构成, 并且其钉扎层的 磁化方向均相同。 该结构具有 4个焊盘, 分别用来作为偏置电压 Vbias, 半桥电压输出端 (VI , V2) 以及接地端 GND, 其中 Vbias与参考臂 Rl 53的一端和感应臂 SI 52的一端 电连接, VI与参考臂 R1 53的另一端以及感应臂 S2 52' 的一端电连接, V2与感应臂 SI 52的另一端以及参考臂 R2 53 ' 的一端电连接, GND与感应臂 S2 52' 的另一端和参 考臂 R2 53 ' 的另一端电连接。 该全桥的输出电压为
ζΑ → ^ Β (8)
— i— — vfa 3gb.^s― ~~ - ~ ^ ^ is.s
Δ I Δ
则传感器的灵敏度可表
0 (9)
对于很小的外加磁场, 即磁场强度 B很小, 则上式 (9) 可近似化为
Figure imgf000013_0001
图 9为单芯片线性参考半桥磁场传感器的结构电路图。 图中, 感应臂 S1 52和参考臂 R1 53连接构成一半桥, 感应臂 S1 52和参考臂 R1 53 由一个或多个 AMR、 GMR或 MTJ 磁电阻传感元件构成, 并且其钉扎层的磁化方向均相同。 该结构具有 3个焊盘, 分别用 来作为偏置电压 (Vbias), 半桥电压输出端 (VI ) 以及接地端 GND, 其中 Vbias与参考臂 R1 53 的一端电连接, VI与参考臂 R1 53 的另一端以及感应臂 S1 52的一端电连接, GND与感应臂 S1 52的另一端电连接。 该半桥的输出电压
则传感器的灵敏度可表示为 V _
Figure imgf000013_0002
对于很小的外加磁场, 即磁场强度 Β很小, 则上式 (12) 可近似化为
从式 (9) 和 (12) 可以看出, 当外加磁场很大时, 即磁场强度 B 值很大, 上面两种全 桥和半桥磁场传感器的灵敏度 V/Vbias与磁场强度 B不再成线性关系, 这使得这两种传感 器的应用受到限制, 为此, 本发明还提供了一种性能更好的单芯片线性准桥式磁场传感 器, 其电路如图 10所示。 此电路包含两个电流源 II 59和 12 59', 一个感应臂 S1 52和一个参考臂 R1 53。 这两个 电流源大小相等, 均为 Ibias。 感应臂 S1 52和参考臂 R1 53 由一个或多个 AMR GMR 或 MTJ磁电阻传感元件构成, 并且其钉扎层的磁化方向均相同。 该结构具有 3个焊盘, 其中一个用来作接地端 GND, 另外两个作为半桥电压输出端 (Vl V2), 其中 GND与 两个电流源的一端电连接, 并与感应臂 S1 52的一端和参考臂 R1 53的一端电连接, VI 与电流源 II 59的另一端以及感应臂 S1 52的另一端电连接, V2与电流源 12 59' 的另一 端以及参考臂 R1 53的另一端电连接。 此电路输出的总电压为 γ _ ¥1 _ ¥2 - - A^l (-j B * % as 传感器的灵敏度 v (15) 从上式 (15) 可以看出, 灵敏度 V/Ibias与外加磁场的磁场强度 B始终成线性关系。 如果 I bias=VbiaJ2RL, 则准桥式磁场传感器的灵敏度与全桥式磁场传感器的灵敏度相同, 但准 桥式磁场传感器有更好的线性度和对称性, 其更适用于工作动态范围比较大的磁场。 实施例 6
本申请的另外一种应用是多层膜桥式磁场传感器, 该传感器中的参考元件串 44 和感应 元件串 43为 MTJ元件, 其包括以下组成部分: 钉扎层, 隧道势垒层, 磁性自由层。 其 中, 钉扎层包括一反铁磁层和至少一层铁磁层, 反铁磁层可以由 IrMn或者 PtMn等材料 组成, 铁磁层和磁性自由层的材料可以为 Co, Fe, Ni, B, Pd, Tb和 Hf组成的一种合金, 但不限于上述材料组成的合金。 钉扎层的磁化方向严格保持在一个方向上, 并且不随外 加磁场方向的改变而改变, 磁性自由层的磁化方向可以自由响应外加磁场。 但在没有外 加磁场的情况下, 自由层的磁化方向要与钉扎层的磁化方向反平行, 这可以通过来自于 钉扎层的漏磁场来实现, 或者通过采用含有合成铁磁层的钉扎层, 再在自由层上方设置 一反铁磁层来实现。 隧道势垒层为绝缘材料, 通常为氧化物, 例如 A1203或者 MgO 当外加磁场比较小, 例如磁场强度 Bs<200G时, 利用从钉扎层里发出的杂散磁场使自由 层的磁化方向与钉扎层的磁化方向反平行, 此时优选地 MTJ元件的结构如下: 硅基片 /种子层 /钉扎层 /隧道势垒层 /自由层 /覆盖层。
其中钉扎层为 IrMn/CoFe/CoFeB, 隧道势垒层材料为 MgO, 自由层为 CoFeB/NiFe 当外加磁场比较大, 例如磁场强度 Bs>200G 时, 利用含有采用含有合成铁磁层的钉扎 层, 再在自由层上方设置一反铁磁层使自由层的磁化方向与钉扎层的磁化方向反平行, 此时优选地 MTJ元件的结构如下:
硅基片 /种子层 /钉扎层 /隧道势垒层 /自由层 /反铁磁层 /保护层, 其中钉扎层为 IrMn/CoFe/Ru/CoFeB , 隧道势垒层材料为 MgO, 自由层为 CoFeB/NiFe, 反铁磁层材料 为 IrMn0
MTJ多层膜桥式磁场传感器的响应曲线, 如图 11所示。 当外加磁场 101 的方向与钉扎 层的磁化方向 19平行, 同时外加磁场的强度大于 -Bs 31或者 Bs 32时, 磁性自由层的磁 化方向 18与外加磁场 101 的方向平行, 进而与钉扎层的磁化方向 19平行, 此时 MTJ 元件的磁阻最小, 即为 RL 28。 当外加磁场为 0, 磁性自由层的磁化方向 18与钉扎层的 磁化方向 19反平行, 此时 MTJ元件的磁阻最大, 即为 RH27。 -Bs 31与 Bs 32之间的磁 场便是单芯片多层膜桥式磁场传感器的测量范围。 从图中可以看出, 曲线 29、 30在 -Bs 31与 Bs 32之间呈线性, 其斜率为
( RL-RH) /BS=AR/AB ( 16)
在 -Bs 31与 Bs 32之间的磁场所对应的磁阻
R (Bext) =RH-(AR/AB)*IBextl ( 17)
再根据公式 (1 ) 与 (2), 便可以得到感应臂和参考臂上的磁阻:
此外, 感应元件串 43 和参考元件串 44 也可以为 GMR 多层膜结构, 该结构由多层 CoFe/Cu/CoFe构成, 其响应曲线与图 10相同。 从图 10中可以看出, 该传感器具有很好 的线性度。
与单芯片线性桥式磁场传感器相同, 单芯片多层膜桥式磁场传感器也有三种结构, 即参 考全桥, 参考半桥, 准桥。 这三种结构传感器的灵敏度计算过程与单芯片线性桥式磁场 传感器的三种结构相同, 在此就不再详述, 只给出结果, 分别表示如下:
参考全桥: (20)
Figure imgf000015_0002
参考半桥: AR (21)
R^ - A B
V AB
AR
2Ra + U— + A B
AB 准桥: V (22)
Figure imgf000016_0001
从上面三式可以看出, 这三种结构传感器的灵敏度与外加磁场的磁场强度 B的绝对值有 关, 因此其响应曲线成对称性。 此外, 准桥式结构的传感器与其他两种结构的传感器的 性能相同。
半桥、 全桥、 准桥这三种电桥结构也可在采用 CMOS、 偏置 CMOS 的基片的单芯片桥 式磁场传感器上得到实现。
以上所述仅为本发明的优选实施例而已, 并不用于限制本发明, 对于本领域的技术人员 来说, 本发明可以有各种更改和变化。 凡在本发明的精神和原则之内, 所作的任何修 改、 等同替换、 改进等, 均应包含在本发明的保护范围之内。

Claims

权利要求:
1.一种单芯片桥式磁场传感器, 其特征在于: 它包括
基片;
沉积在所述基片上的惠斯通半桥或惠斯通准桥, 所述惠斯通半桥或惠斯通准桥包括: 参考臂 Rl, 其包括至少两行 /列的参考元件串, 每个参考元件串由一个或者多个相同的磁电 阻传感元件电连接构成; 以及
感应臂 Sl, 其包括至少两行 /列的感应元件串, 每个感应元件串由一个或者多个相同的磁电 阻传感元件电连接构成;
所述参考元件串和所述感应元件串的行 /列数相同, 并沿纵 /横向相间隔排布,
相邻的所述参考元件串与所述感应元件串之间的间隔相同;
至少三个屏蔽结构, 所述屏蔽结构两两之间均设有一定的间隙, 每个参考元件串上对应设置 有一屏蔽结构, 每个感应元件串位于相应的间隙处;
多个用于输入输出的焊盘。
2. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件为选 自 AMR、 GMR、 TMR传感元件中的一种。
3. 根据权利要求 2所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件具有 线性磁场传感器响应特性。
4. 根据权利要求 2所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件具有 多层膜磁场传感器响应特性。
5. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述参考元件串中的磁电 阻传感元件数量与所述感应元件串中的磁电阻传感元件数量相同。
6. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述单芯片桥式磁场传感 器包括三个焊盘, 三个焊盘分别是用于供应偏置电压的第一焊盘、 用于输出的第二焊盘以及 用于接地的第三焊盘, 所述参考臂 Rl、 所述感应臂 S1 各自均具有一个第一端和一个第二 端, 所述第一焊盘与所述参考臂 R1 的第一端相电连, 所述第三焊盘与所述感应臂 S1 的第 一端相电连, 所述第二焊盘分别与参考臂 R1 的第二端以及所述感应臂 S1 的第二端相电 连。
7. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述单芯片桥式磁场传感 器包含有三个焊盘, 三个焊盘分别为用于接地偏置的第一焊盘、 用于输出的第二焊盘与第三 焊盘, 所述惠斯通准桥还包括两个相同的电流源 (11, 12), 两个所述电流源 (11, 12)、 所 述参考臂 R1 和所述感应臂 SI 各自均具有一个第一端和一个第二端, 所述第一焊盘与所述 参考臂 R1的第一端、 所述感应臂 S1的第一端以及两个所述电流源 (11, 12) 的第一端相电 连, 所述第二焊盘分别与所述参考臂 R1的第二端和电流源 12的第二端相电连, 所述第三焊 盘与所述感应臂 S1的第二端以及电流源 II的第二端相电连。
8. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述屏蔽结构的形状为沿 横 /纵向延伸的长条形, 其组成材料为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的一种或几 种元素组成的铁磁合金。
9. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述屏蔽结构之间的间隙 处的磁场的增益系数为 1 <Asns <100, 所述屏蔽结构上方或者下方处的磁场的衰减系数为 0 <Aref <1。
10. 根据权利要求 1 所述的单芯片桥式磁场传感器, 其特征在于, 所述感应元件串、 所述参 考元件串与所述焊盘彼此之间均用电连接导体连接。
11. 根据权利要求 1所述的单芯片桥式磁场传感器, 其特征在于, 所述基片采用 CMOS、 偏 置 CMOS, 将所述参考臂、 所述感应臂和所述焊盘直接印制在所述基片上面。
12.一种单芯片桥式磁场传感器, 其特征在于: 它包括
基片;
沉积在所述基片上的惠斯通全桥, 所述惠斯通全桥包括相互电连接的第一桥臂和第二桥臂, 所述第一桥臂包括
参考臂 Rl, 其包括至少两行 /列的第一参考元件串, 每个第一参考元件串均由一个或者多个 相同的磁电阻传感元件电连接构成; 以及
感应臂 Sl, 其包括至少两行 /列的第一感应元件串, 每个第一感应元件串均由一个或者多个 相同的磁电阻传感元件电连接构成;
所述第一参考元件串和所述第一感应元件串的行 /列数相同, 并沿纵 /横向相间隔排布, 两两 紧邻的所述第一参考元件串与所述第一感应元件串之间的间隔相同且均为 L;
所述第二桥臂包括:
参考臂 R2, 其包括至少两行 /列的第二参考元件串, 每个第二参考元件串均由一个或者多个 相同的磁电阻传感元件电连接构成; 以及
感应臂 S2, 其包括至少两行 /列的第二感应元件串, 每个第二感应元件串均由一个或者多个 相同的磁电阻传感元件电连接构成;
所述第二参考元件串和所述第二感应元件串的行 /列数相同, 并沿纵 /横向相间隔排布, 两两 相邻的所述第二参考元件串与所述第二感应元件串之间的间隔相同且均为 L; 所述第一桥臂与所述第二桥臂之间通过所述第一参考元件串与所述第二参考元件串或通过所 述第一感应元件串与所述第二感应元件串相紧邻; 两个相紧邻的所述第一参考元件串与所述 第二参考元件串或所述第一感应元件串与所述第二感应元件之间的间隔为 2L;
至少三个屏蔽结构, 所述屏蔽结构两两之间均设有一定的间隙, 每个第一参考元件串和第二 参考元件串上对应设置有屏蔽结构, 每个第一感应元件串和第二感应元件串位于相应的间隙 处;
多个用于输入输出的焊盘。
13. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于: 所述单芯片桥式磁场传 感器包含有四个焊盘, 四个焊盘分别是用于供应偏置电压的第一焊盘、 用于输出的第二焊盘 以及第三焊盘、 用于接地的第四焊盘, 参考臂 Rl、 参考臂 R2、 感应臂 SI和感应臂 S2分别 具有一个第一端和一个第二端, 所述第一焊盘分别与所述参考臂 R2 的第二端和所述感应臂 S1 的第一端相电连, 所述第二焊盘分别与参考臂 R1 的第二端以及所述感应臂 S1 的第二端 相电连, 所述第三焊盘分别与所述感应臂 S2 的第一端以及所述参考臂 R2 的第一端相电 连, 所述第四焊盘与所述感应臂 S2的第二端以及所述参考臂 R1的第一端相电连。
14. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述屏蔽结构的形状为 沿横 /纵向延伸的长条形, 其组成材料为选自 Ni、 Fe、 Co、 Si、 B、 Ni、 Zr和 Al中的一种或 几种元素组成的铁磁合金。
15. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述屏蔽结构之间的间 隙处的磁场的增益系数为 1 <Asns <100, 所述屏蔽结构上方或者下方处的磁场的衰减系数为 0 <Aref <1。
16. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述感应元件串、 所述 参考元件串与所述焊盘彼此之间均用电连接导体连接。
17. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件为 选自 AMR、 GMR、 TMR传感元件中的一种。
18. 根据权利要求 17 所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件具 有线性磁场传感器响应特性。
19. 根据权利要求 17 所述的单芯片桥式磁场传感器, 其特征在于, 所述磁电阻传感元件具 有多层膜磁场传感器响应特性。
20. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述第二参考元件串与 所述第一参考元件串的行 /列数相同, 所述第二感应元件串与所述第一感应元件串的行 /列数 相同。
21. 根据权利要求 12 所述的单芯片桥式磁场传感器, 其特征在于, 所述第一参考元件串中 的磁电阻传感元件数量、 所述第一感应元件串中的磁电阻传感元件数量、 所述第二参考元件 串中的磁电阻传感元件数量和所述第二感应元件串中的磁电阻传感元件数量均相同。
22. 根据权利要求 12所述的单芯片桥式磁场传感器, 其特征在于, 所述基片采用 CMOS、 偏置 CMOS, 将所述参考臂、 所述感应臂和所述焊盘直接印制在所述基片上面。
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