Magnetic field vector sensor and integration process method

Abstract

The invention discloses a magnetic field vector sensor which comprises an SOI substrate and six magneto-sensitive devices which are arranged on the SOI substrate and have plane structures, a first pair of differential structures is formed by the first magneto-sensitive device and the second magneto-sensitive device and used for detecting a magnetic field in the x direction, and a second pair of differential structures is formed by the second magneto-sensitive device and used for detecting a magnetic field in the x direction. The third magneto-sensitive device and the fourth magneto-sensitive device form a second pair of differential structures for detecting a y-direction magnetic field, and the fifth magneto-sensitive device and the sixth magneto-sensitive device form a third pair of differential structures for detecting a z-direction magnetic field. The magnetic field vector sensor disclosed by the invention can complete magnetic field vector detection of a detected point in a space, has relatively high magnetic sensitivity consistency and relatively low cross interference, and is simple in structure process, low in cost and easy to produce in batches.

Description

Technical Field

[0001] The invention relates to a magnetic field vector sensor and an integrated process method, belonging to the technical field of magnetic field detection. Background Art

[0002] With the continuous development of modern magnetic field measurement technology, magnetic field vector measurement technology provides more accurate and rich data for magnetic field analysis by synchronously measuring the size and direction of each component of the magnetic field in space, significantly improving the accuracy of the data inversion process, and showing its unique advantages and broad application prospects in the fields of geomagnetic navigation, medical imaging, and military target detection.

[0003] However, most existing magnetic field vector sensors are usually composed of a combination of multiple magnetic sensitive components, and have problems such as inconsistent magnetic sensitivity centers, high cross-interference, and poor magnetic sensitivity consistency, resulting in insufficient measurement accuracy.

[0004] In addition, the complex working conditions and wiring complexity of the sensor also increase the difficulty of system integration and maintenance costs, seriously restricting the further development and application of magnetic field vector sensors.

[0005] Due to the above reasons, it is necessary to conduct in-depth research on the existing magnetic field vector sensors to solve the above problems. Summary of the invention

[0006] In order to overcome the above problems, the inventors propose a magnetic field vector sensor and a manufacturing method thereof, including an SOI substrate and planarized magnetic sensitive devices, namely, a first magnetic sensitive device to a sixth magnetic sensitive device, arranged on the SOI substrate, each magnetic sensitive device including a magnetic sensitive area, a load resistor and a dielectric isolation area.

[0007] In a preferred embodiment, the SOI substrate includes a device layer, an insulating layer and a supporting substrate arranged in sequence from top to bottom. The magnetic sensitive area and the load resistor of the magnetic field vector sensor are arranged on the upper surface of the device layer, and the dielectric isolation wall runs through the upper and lower surfaces of the device layer, thereby effectively isolating the magnetic sensitive device from the load resistor and the substrate, reducing the influence of parasitic effects on device characteristics, and limiting the deflection of carriers, thereby reducing the cross-interference of magnetic sensitivity of each magnetic sensitive device.

[0008] In a preferred embodiment, the first to fourth magnetic sensitive devices form a ring structure. The carriers in the emitter region are deflected along the normal direction by the magnetic field in the x or y direction and collected by the collector region, so the base region, collector region and emitter region of the same magnetic sensitive device are located on a straight line. The straight line where the first and second magnetic sensitive devices are located is perpendicular to the x direction, and the straight line where the third and fourth magnetic sensitive devices are located is perpendicular to the y direction.

[0009] In a preferred embodiment, the fifth magnetic sensor and the sixth magnetic sensor are arranged at the central position of the ring structure. The carriers in the emitter region are deflected in the plane by the z-direction magnetic field and collected by the collector region, so the base region, collector region and emitter region of the same magnetic sensor are distributed in an L shape.

[0010] In a preferred embodiment, the first to sixth magnetic sensors are combined in pairs to form three pairs of differential structures. x The first pair of differential structures are placed in opposite magnetic sensitive directions to form an x-direction magnetic sensitive unit for detecting the x-direction magnetic field. y The second pair of differential structures are placed in opposite magnetic sensitive directions to form a y-direction magnetic sensitive unit for detecting the y-direction magnetic field. z The third pair of differential structures are placed in opposite magnetic sensitive directions to form a z-direction magnetic sensitive unit for detecting the magnetic field in the z-direction, and the magnetic sensitive centers of the three pairs of differential structures coincide in space.

[0011] The present invention also discloses a magnetic field vector sensor integration process method for manufacturing the magnetic field vector sensor, comprising the following steps:

[0012] S1. Prepare wafers, and select SOI wafers, wherein the device layer is p-type silicon with a resistivity greater than or equal to 100 Ω·cm, and the thickness of the device layer is 10-30 μm, preferably 15 μm.

[0013] S2, clean the SOI wafer, perform zero-pass photolithography, and etch the alignment mark using dry etching technology;

[0014] S3, one-step photolithography, the photolithography process is carried out according to the steps of coating, pre-baking, exposure, development, hardening, etching and stripping to form a dielectric isolation window and make a dielectric isolation area;

[0015] S4, secondary photolithography, etching the load resistor window, ion implantation, forming an n-type doped region;

[0016] S5, three times of photolithography, etching to form the base window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming p + Type doped region;

[0017] S6, four times of photolithography, etching to form the collector window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region;

[0018] S7, five times of photolithography, etching to form the windows of the emitter regions of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region;

[0019] S8. After the ion implantation process, high temperature annealing is performed. The annealing temperature is 800-1200°C, preferably 1000°C, and the annealing time is 15-40 minutes, preferably 30 minutes. An insulating layer is grown on the SOI device layer, and six times of photolithography is performed to etch lead holes;

[0020] S9, cleaning the SOI wafer, evaporating a metal layer, preferably with a thickness of 0.5±0.1 μm, performing seven photolithography steps, reverse etching the metal layer, forming metal interconnects or bonding pads, wherein the metal layer is preferably aluminum-silicon-copper;

[0021] S10, growing a passivation layer, performing eight photolithography steps, etching the passivation layer, and forming a pad window. The passivation layer is preferably Si3N4, and has a thickness of 100 to 200 nm, preferably 150 nm.

[0022] S11, cleaning the SOI wafer, and forming an ohmic contact by alloying process; according to a preferred embodiment of the present invention, the alloying treatment is carried out in a vacuum environment, and the treatment temperature is 350-500°C, preferably 420°C. In a further preferred embodiment, the alloying treatment time is 20-40 minutes, preferably 30 minutes. Among them, the temperature and time of the alloying treatment can enhance the adhesion of the aluminum electrode, eliminate the Schottky barrier, and form an ohmic contact.

[0023] S12, spin-coating a dicing protective glue on the surface of the SOI wafer. After the SOI wafer is diced, using an acetone solution to remove the chip surface protective glue, cleaning, and performing non-magnetic chip packaging to complete the process of manufacturing the magnetic field vector sensor.

[0024] The beneficial effects of the present invention include:

[0025] (1) By adjusting the distribution positions of the base region, collector region and emitter region in the magnetic sensor device, the transmission direction of the carriers is effectively adjusted to form a planar magnetic sensor device, which can realize the magnetic field vector detection of the measured position in space;

[0026] (2) By adjusting the size, doping concentration and device layer thickness of the base region, collector region and emitter region of the two magnetic sensors, the consistency of the magnetic sensitivity of the two magnetic sensors is effectively adjusted, and the cross-interference of magnetic sensitivity is reduced;

[0027] (3) The three magnetic sensitive units all have a differential output structure, which can improve the magnetic sensitivity, reduce the cross-interference of magnetic sensitivity, and effectively improve the temperature characteristics.

[0028] Description of Figure Numbers:

[0029] 1-device layer;

[0030] 2-support substrate;

[0031] 3-Insulation layer;

[0032] 4a-first magnetic sensor base region;

[0033] 4b- a second magnetic sensor base region;

[0034] 4c-the third magnetic sensitive device base region;

[0035] 4d-the fourth magnetic sensor base region;

[0036] 4e-fifth magnetic sensor base region;

[0037] 4f-sixth magnetic sensor base region;

[0038] 5a-first magnetic sensor collector region;

[0039] 5b- a collector region of the second magnetic sensor device;

[0040] 5c-third collector region;

[0041] 5d- fourth magnetic sensor collector region;

[0042] 5e- fifth magnetic sensor collector region;

[0043] 5f-sixth magnetic sensor collector region;

[0044] 6a-first magnetic sensitive device emission area;

[0045] 6b-second magnetic sensitive device emission area;

[0046] 6c-the third magnetic sensitive device emission area;

[0047] 6d-the fourth magnetic sensitive device emission area;

[0048] 6e-fifth magnetic sensitive device emission area;

[0049] 6f-sixth magnetic sensitive device emission area;

[0050] 4-base region;

[0051] 5- collector area;

[0052] 6-launch area;

[0053] 7- Pressure welding point;

[0054] 8- dielectric isolation wall;

[0055] B-base;

[0056] C-collector;

[0057] E-emitter;

[0058] R B - Base load resistor;

[0059] R L - Collector load resistance;

[0060] V DD -power supply;

[0061] GND-ground terminal;

[0062] V out - Output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A schematic diagram of the structure of a magnetic field vector sensor according to a preferred embodiment of the present invention is shown;

[0064] Figure 2 A schematic diagram showing the position distribution of the base region, the collector region and the emitter region of the first to fourth magnetic sensitive devices in the magnetic field vector sensor structure according to a preferred embodiment of the present invention is shown;

[0065] Figure 3 A schematic diagram showing the position distribution of the base region, the collector region and the emitter region of the fifth magnetic sensitive device and the sixth magnetic sensitive device in the magnetic field vector sensor structure according to a preferred embodiment of the present invention is shown;

[0066] Figure 4 An equivalent circuit diagram of the differential structure of the first magnetic sensitive device and the second magnetic sensitive device, and the third magnetic sensitive device and the fourth magnetic sensitive device in the magnetic field vector sensor structure according to a preferred embodiment of the present invention is shown;

[0067] Figure 5 An equivalent circuit diagram of a differential structure of a fifth magnetic sensor and a sixth magnetic sensor in a magnetic field vector sensor structure according to a preferred embodiment of the present invention is shown;

[0068] Figure 6 The I of the first to fourth magnetic sensor devices when B=0T in the embodiment is shown. C -V CE characteristic;

[0069] Figure 7 The I of the fifth and sixth magnetic sensors when B=0T in the embodiment is shown. C -V CE characteristic;

[0070] Figure 8 A schematic diagram of the TCAD simulation structure of the magnetic field vector sensor in the embodiment is shown;

[0071] Fig. 9 The first magnetic sensor in the embodiment is shown in FIG. x= +0.3T, B x =0T, B x = I at -0.3T C -V CE Characteristic curve;

[0072] Fig.10 The second magnetic sensor in the embodiment is shown in FIG. x = +0.3T, B x =0T, B x = I at -0.3T C -V CE Characteristic curve;

[0073] Fig.11 The third magnetic sensor in the embodiment is shown in FIG. y = +0.3T, B y =0T, B y = I at -0.3T C -V CE Characteristic curve;

[0074] Fig.12 The fourth magnetic sensor in the embodiment is shown in FIG. y = +0.3T, B y =0T, B y = I at -0.3T C -V CE Characteristic curve;

[0075] Fig.13 The fifth magnetic sensor in the embodiment is shown in FIG. z = +0.3T, B z =0T, B z = I at -0.3T C -V CE Characteristic curve;

[0076] Fig.14 The sixth magnetic sensor device in the embodiment is shown in FIG. z = +0.3T, B z =0T, B z = I at -0.3T C -V CE Characteristic curve; DETAILED DESCRIPTION

[0077] The present invention will be further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0078] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0079] According to a magnetic field vector sensor provided by the present invention, Figure 1 As shown, it includes an SOI substrate and six magnetic sensitive devices with a planar structure arranged on the SOI substrate, namely the first magnetic sensitive device to the sixth magnetic sensitive device. Each magnetic sensitive device includes a magnetic sensitive area, a load resistor and a dielectric isolation wall 8, and the magnetic sensitive area is arranged in the corresponding dielectric isolation wall. In the present invention, the base regions of the first to sixth magnetic sensitive devices are respectively represented as the first magnetic sensitive device base region 4a, the second magnetic sensitive device base region 4b, the third magnetic sensitive device base region 4c, the fourth magnetic sensitive device base region 4d, the fifth magnetic sensitive device base region 4e, and the sixth magnetic sensitive device base region 4f; the collector regions of the first to sixth magnetic sensitive devices are respectively represented as the first magnetic sensitive device collector region 5a, the second magnetic sensitive device collector region 5b, the third magnetic sensitive device collector region 5c, the fourth magnetic sensitive device collector region 5d, the fifth magnetic sensitive device collector region 5e, and the sixth magnetic sensitive device collector region 5f; the emitter regions of the first to sixth magnetic sensitive devices are respectively represented as the first magnetic sensitive device emitter region 6a, the second magnetic sensitive device emitter region 6b, the third magnetic sensitive device emitter region 6c, the fourth magnetic sensitive device emitter region 6d, the fifth magnetic sensitive device emitter region 6e, and the sixth magnetic sensitive device emitter region 6f.

[0080] In the present invention, the x direction and the y direction are defined to be located on the upper surface of the SOI substrate, and the x direction and the y direction are perpendicular to each other, and the z direction is perpendicular to the upper surface of the SOI substrate and satisfies the right-hand rule with the x direction and the y direction.

[0081] According to a preferred embodiment of the present invention, the SOI substrate comprises a device layer 1, an insulating layer 3 and a support substrate 2 arranged in order from top to bottom. The dielectric isolation wall runs through the upper and lower surfaces of the device layer and has a thickness of 1-2 μm, preferably 1.5 μm.

[0082] Furthermore, the SOI device layer 1 is a p-type silicon with a resistivity greater than or equal to 100Ω·cm, and the device layer thickness is 10 to 30μm, preferably 15μm. The insulating layer 3 and the isolation medium are preferably SiO2, and the insulating layer thickness is 0.2 to 0.8μm, preferably 0.5μm. The support substrate 2 is <100> The crystal orientation single crystal silicon wafer has a thickness of 300 to 500 μm, preferably 400 μm.

[0083] According to a preferred embodiment of the present invention, the first to fourth magnetic sensor devices have the same structure. Figure 2As shown, the first to fourth magnetic sensitive devices form a ring structure and are located around the chip.

[0084] Furthermore, the base region 4, collector region 5 and emitter region 6 of the first to fourth magnetic sensitive devices are distributed in a straight line, wherein the collector region is located in the middle of the magnetic sensitive region, and the base region and emitter region are located at both ends of the magnetic sensitive region.

[0085] In a preferred embodiment, the base load resistor R of the magnetic sensor device B and the collector load resistor R L The n-type lightly doped region is formed by implanting phosphorus ions, and the impurity ion concentration is 1E14~5E15 cm -3 , preferably 5E14 cm -3 , the resistance value is 1.0~3.0kΩ, preferably 2kΩ.

[0086] Preferably, in the first to fourth magnetic sensor devices, the distance between the base region and the collector region is 5 to 100 μm, preferably 20 μm, and the distance between the collector region and the emitter region is 10 to 30 μm, preferably 20 μm.

[0087] Preferably, in the first to fourth magnetic sensor devices, the base region is formed by implanting boron ions to form a p + Type doping, impurity concentration is 1E15~1E19 cm -3 , preferably 1E17 cm -3 ;p + The doped region is 10 to 40 μm long and 10 to 40 μm wide, preferably a square with a length and width of 30 μm, and a depth of 0.5 to 3 μm, preferably 1 μm.

[0088] Preferably, in the first to fourth magnetic sensor devices, the collector region is formed by injecting phosphorus ions to form n + Type doping, impurity concentration is 1E16~1E19 cm -3 , preferably 1E17 cm -3 ;n + The doped region is 10 to 50 μm long and 10 to 50 μm wide, preferably a square with a length and width of 30 μm, and a depth of 0.5 to 3 μm, preferably 1 μm.

[0089] Preferably, in the first to fourth magnetic sensor devices, the emitter region is formed by injecting phosphorus ions into n + Type doping, impurity concentration is 1E18~1E20 cm -3 , preferably 1E19 cm -3 The doped region is 10 to 40 μm long and 10 to 40 μm wide, preferably a square with a length and width of 30 μm; the doped region is 0.5 to 3 μm deep, preferably 1 μm.

[0090] According to a preferred embodiment of the present invention, the fifth magnetic sensor and the sixth magnetic sensor have the same structure. Figure 3 As shown, it is arranged at the central position of the annular structure formed by the first to fourth magnetic sensitive devices.

[0091] Furthermore, the collector regions of the fifth and sixth magnetic sensitive devices are located in the middle of the magnetic sensitive regions, the line connecting the base region and the collector region is perpendicular to the line connecting the emitter region and the collector region, and the magnetic sensitive regions are distributed in an "L" shape.

[0092] Preferably, in the fifth magnetic sensor device and the sixth magnetic sensor device, the distance between the base region and the collector region is 5 to 300 μm, preferably 100 μm, and the distance between the collector region and the emitter region is 5 to 20 μm, preferably 10 μm.

[0093] Preferably, in the fifth magnetic sensor and the sixth magnetic sensor, the base region is formed by implanting boron ions into a p + Type doping, impurity concentration is 1E15~1E19 cm -3 , preferably 1E17 cm -3 ;p + The doped region is 10 to 40 μm long and 10 to 40 μm wide, preferably a square with a length and width of 30 μm, and a depth of 0.5 to 3 μm, preferably 1 μm.

[0094] Preferably, in the fifth magnetic sensor and the sixth magnetic sensor, the collector region is formed by injecting phosphorus ions into n + Type doping, impurity concentration is 1E16~1E19 cm -3 , preferably 1E17 cm -3 ;n + The doped region is 10 to 50 μm long and 10 to 50 μm wide, preferably a rectangle with a length and width of 50 μm and 30 μm, and a depth of 0.5 to 3 μm, preferably 1 μm.

[0095] Preferably, in the fifth magnetic sensor and the sixth magnetic sensor, the emitter region is formed by injecting phosphorus ions into n + Type doping, impurity concentration is 1E18~1E20 cm -3 , preferably 1E19 cm -3 The doped region is 10 to 40 μm long and 10 to 40 μm wide, preferably a square with a length and width of 30 μm; the doped region is 0.5 to 3 μm deep, preferably 1 μm.

[0096] According to a preferred embodiment of the present invention, the first magnetic sensor and the second magnetic sensor are arranged along B xThe first pair of differential structures are placed in opposite magnetic sensitive directions to form an x-direction magnetic sensitive unit for detecting the x-direction magnetic field. y The second pair of differential structures are placed in opposite magnetic sensitive directions to form a y-direction magnetic sensitive unit for detecting the magnetic field in the y direction. The equivalent circuit of the x-direction and y-direction magnetic sensitive units is as follows: Figure 4 As shown, where V DD is the power supply voltage, V out is the output voltage, and GND is the ground terminal.

[0097] The fifth magnetic sensor and the sixth magnetic sensor are connected along B z The third pair of differential structures are placed in opposite magnetic sensitive directions to form a z-direction magnetic sensitive unit for detecting the z-direction magnetic field. Its equivalent circuit is as follows: Figure 5 As shown in Figure 2, the magnetic sensitive centers of the three pairs of differential structures coincide in space.

[0098] In a preferred embodiment, V DD is the power supply voltage, R B and R L The two ends are connected to the power supply and a pair of differential structure collectors, which are the base load resistors and collector load resistors of the two tubes. The constant current source is connected to the base of the magnetic sensitive device to provide base current to the differential structure magnetic sensitive unit. The emitter is grounded. The collector current of the differential structure magnetic sensitive unit is collected through the load resistor and expressed as the output voltage V out .

[0099] The present invention also discloses a magnetic field vector sensor integration process method, comprising the following steps:

[0100] S1, cleaning SOI wafer;

[0101] S2, one-time photolithography to form a dielectric isolation window and make a dielectric isolation wall;

[0102] S3, one-step photolithography, the photolithography process is carried out according to the steps of coating, pre-baking, exposure, development, hardening, etching and stripping to form a dielectric isolation window and make a dielectric isolation area;

[0103] S4, secondary photolithography, etching the load resistor window, ion implantation, forming an n-type doped region;

[0104] S5, three times of photolithography, etching to form the base window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming p + Type doped region;

[0105] S6, four times of photolithography, etching to form the collector window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region;

[0106] S7, five times of photolithography, etching to form the windows of the emitter regions of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region;

[0107] S8, after the ion implantation process, high temperature annealing. Grow an insulating layer on the SOI device layer, perform six times of photolithography, and etch lead holes;

[0108] S9, cleaning the SOI wafer, evaporating a metal layer, performing seven photolithography steps, and etching the metal layer to form metal interconnects or bonding pads;

[0109] S10, growing a passivation layer, performing eight photolithography steps, etching the passivation layer, and forming a bonding point window;

[0110] S11, cleaning the SOI wafer, and forming an ohmic contact through an alloying process;

[0111] S12, spin-coating a dicing protection glue on the surface of the SOI wafer, and after the SOI wafer is diced, performing non-magnetic chip packaging to complete the production of the magnetic field vector sensor.

[0112] Preferably, before S1, the SOI wafer is selected so that the device layer is p-type silicon with a resistivity greater than or equal to 100 Ω·cm. Further, the device layer has a thickness of 10 to 30 μm, preferably 15 μm.

[0113] Preferably, zero-pass photolithography is performed in S1, and the alignment mark is etched using dry etching technology.

[0114] Preferably, the photolithography process in S2 is carried out according to the steps of coating, pre-baking, exposure, development, hardening, etching and stripping to form isolation wall windows and manufacture dielectric isolation areas.

[0115] Preferably, in S3, after the ion implantation, rapid annealing is performed in a vacuum environment at 800-1000° C. for 30-40 seconds to repair lattice damage and activate impurities.

[0116] Preferably, in S5, during the ion implantation process, the implantation energy is 60 keV and the implantation dose is 1E19 cm -2 .

[0117] Preferably, in S7, the annealing temperature is 800-1200° C., preferably 900° C., and the annealing time is 15-40 min, preferably 30 min.

[0118] Preferably, in S8, the thickness of the metal layer during evaporation is preferably 0.5±0.1 μm, and the metal layer is aluminum silicon copper.

[0119] Preferably, in S9, the passivation layer is Si3N 4，The thickness is preferably 100 to 200 nm, more preferably 150 nm.

[0120] Preferably, in S10, the alloying is performed in a vacuum environment at a treatment temperature of 350-500°C, preferably 420°C.

[0121] In a further preferred embodiment, the alloying treatment lasts for 20 to 40 minutes, preferably 30 minutes. The alloying treatment temperature and time mentioned above can enhance the adhesion of the aluminum electrode, eliminate the Schottky barrier, and form an ohmic contact.

[0122] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0123] Example

[0124] Since the first to fourth magnetic sensors are magnetic sensors of the same structure, and the fifth and sixth magnetic sensors are magnetic sensors of the same structure, the first and fifth magnetic sensors are taken as examples to give the I values ​​of the two magnetic sensors at room temperature when B = 0T. C -V CE Features, such as Figure 6 and Figure 7 As shown. Set the scanning voltage between the collector and the emitter to be 0~6.0V (scanning step is 1V), and inject I B 0~5.0mA (interval is 1.0mA).

[0125] The simulation results show that when V CE When constant, I C Follow me B It increases with the increase of the I of the magnetic sensor device, and has the characteristics of a general bipolar transistor. C Less than I B , that is, β is less than 1; when I B At a certain time, I C With V CE increases with the increase of V CE When it reaches a certain value, the device output tends to saturate. C The change tends to be gentle, and the two magnetic sensitive device structures have similar electrical characteristics.

[0126] Slivaco TCAD software is used to build a three-dimensional structure simulation model of the magnetic field vector sensor. Figure 8The magnetic field vector sensor includes an SOI substrate and six magnetic sensors, namely, the first magnetic sensor to the sixth magnetic sensor, arranged on the SOI substrate, including a magnetic sensitive area, a load resistor, and a dielectric isolation area. The magnetic sensor has electrode points corresponding to the base area, the collector area, and the emitter area through lead holes, which are the base, the collector, and the emitter, respectively.

[0127] At room temperature, a magnetic field of 0T and ±0.3T was applied along the x direction, and the collector scanning voltage V CE 0.0V~6.0V (step is 1V), when the base current I B When the current is 5.0 mA, the influence of magnetic field on the characteristics of magnetic sensitive devices is studied. Fig. 9 and Fig.10 The I of the x magnetic sensitive unit (the first magnetic sensitive device and the second magnetic sensitive device) in the structural model is given as C -V CE The simulation curve of the characteristics changing with the magnetic field. The simulation results show that when the opposite x-direction magnetic field is applied, the collector current of the x-direction magnetic sensitive unit also changes in the opposite trend, proving that both the first magnetic sensitive device and the second magnetic sensitive device have positive and negative magnetic sensitive characteristics. At this time, the current magnetic sensitivity S of the x-direction magnetic sensitive unit x It is 2.63mA / T.

[0128] Under the same conditions, Fig.11 and Fig.12 The I of the magnetic sensitive unit (the third magnetic sensitive device and the fourth magnetic sensitive device) in the y direction in the structural model is given as C -V CE The simulation curve of the characteristics changing with the magnetic field. The simulation results show that when the opposite y-direction magnetic field is applied, the collector current of the y-direction magnetic sensitive unit also changes in the opposite trend, proving that the third magnetic sensitive device and the fourth magnetic sensitive device both have positive and negative magnetic sensitive characteristics. At this time, the current magnetic sensitivity S of the y-direction magnetic sensitive unit y It is 2.64mA / T.

[0129] Under the same conditions, Fig.13 and Fig.14 The I of the z-direction magnetic sensitive unit (the fifth magnetic sensitive device and the sixth magnetic sensitive device) in the structural model is given as C -V CE The simulation curve of the characteristics changing with the magnetic field. The simulation results show that when the magnetic field in the opposite z direction is applied, the collector current change of the z-direction magnetic sensitive unit also shows an opposite trend, proving that the fifth and sixth magnetic sensitive devices have positive and negative magnetic sensitive characteristics. At this time, the current magnetic sensitivity S of the z-direction magnetic sensitive unit z It is 2.60mA / T.

[0130] When the sensor is in working state, the output voltage of the magnetic sensitive unit is not only affected by the external magnetic field in the magnetic sensitive direction, but also by the external magnetic field in the non-sensitive direction. The magnetic sensitive device will have a certain cross interference. Although a single magnetic sensitive device has magnetic sensitivity cross interference, the cross magnetic sensitivity of the magnetic sensitive unit can be offset by using the differential structure. x , B y , B z The current magnetic sensitivity and cross magnetic sensitivity of the three magnetic sensitive units are simulated and analyzed in the 0.3T and -0.3T magnetic fields in the x direction. y , B z The output is 0 under the action, and the cross interference of the sensor magnetic sensitivity is 0; the magnetic sensitive unit in the y direction is at B x , B z There is a small output under the action of B and a small cross-interference of magnetic sensitivity, which are 0.4% and 0.7% respectively; the z-direction magnetic sensitive unit is in B x The output is 0 under B y There is a tiny output under the action, and there is a small magnetic sensitivity cross interference of 1.9%.

[0131] In summary, the current magnetic sensitivities of the x-direction magnetic sensitive unit, y-direction magnetic sensitive unit and z-direction magnetic sensitive unit of the magnetic field vector sensor are 2.63mA / T, 2.64mA / T and 2.60mA / T respectively, the magnetic sensitivity consistency reaches 98.5%, and the cross interference percentage is less than 2%.

[0132] The present invention has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, the present invention may be subjected to a variety of substitutions and improvements, all of which fall within the scope of protection of the present invention.

Claims

1. A magnetic field vector sensor, characterized in that: It includes an SOI substrate and six magnetic sensitive devices arranged on the SOI substrate, namely the first magnetic sensitive device to the sixth magnetic sensitive device. Each magnetic sensitive device includes a magnetic sensitive area, a load resistor and a dielectric isolation wall, and the magnetic sensitive area is arranged in the corresponding dielectric isolation wall.

2. The magnetic field vector sensor according to claim 1, characterized in that: The SOI substrate comprises a device layer, an insulating layer and a supporting substrate arranged in sequence from top to bottom, a dielectric isolation wall penetrates the device layer, and the magnetic sensitive area is made on the upper surface of the device layer and has a planar structure.

3. The magnetic field vector sensor according to claim 1, characterized in that: Among the first to fourth magnetic sensitive devices, the base region, collector region and emitter region of the same magnetic sensitive device are located on a straight line, and the straight line where the first magnetic sensitive device and the second magnetic sensitive device are located is perpendicular to the x-direction, and the straight line where the third magnetic sensitive device and the fourth magnetic sensitive device are located is perpendicular to the y-direction, so that the first to fourth magnetic sensitive devices form a ring structure.

4. The magnetic field vector sensor according to claim 3, characterized in that: In the fifth magnetic sensor and the sixth magnetic sensor, the base region, the collector region and the emitter region of the same magnetic sensor are distributed in an L shape, and the fifth magnetic sensor and the sixth magnetic sensor are arranged at the central position of the ring structure.

5. The magnetic field vector sensor according to claim 1, characterized in that: The first magnetic sensitive device and the second magnetic sensitive device are placed along opposite magnetic sensitive directions to form a first pair of differential structures, forming an x-direction magnetic sensitive unit for detecting the x-direction magnetic field component; the third magnetic sensitive device and the fourth magnetic sensitive device are placed along opposite magnetic sensitive directions to form a second pair of differential structures, forming a y-direction magnetic sensitive unit for detecting the y-direction magnetic field component; the fifth magnetic sensitive device and the sixth magnetic sensitive device are placed along opposite magnetic sensitive directions to form a third pair of differential structures, forming a z-direction magnetic sensitive unit for detecting the z-direction magnetic field component, and the magnetic sensitive centers of the three magnetic sensitive units coincide in space.

6. A magnetic field vector sensor integration process method for manufacturing the magnetic field vector sensor according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, prepare wafer, select SOI wafer; S2, clean the SOI wafer, perform zero-pass photolithography, and etch the alignment mark; S3, one-time photolithography to form a dielectric isolation window and make a dielectric isolation area; S4, secondary photolithography, etching the load resistor window, ion implantation, forming an n-type doped region; S5, three times of photolithography, etching to form the base window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming p + Type doped region; S6, four times of photolithography, etching to form the collector window of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region; S7, five times of photolithography, etching to form the windows of the emitter regions of the first magnetic sensor device to the sixth magnetic sensor device, ion implantation, forming n + Type doped region; S8, high temperature annealing, growing an insulating layer on the SOI device layer, six times of photolithography, etching lead holes; S9, cleaning the SOI wafer, evaporating a metal layer, performing seven photolithography steps, and etching the metal layer to form metal interconnects or bonding pads; S10, growing a passivation layer, performing eight photolithography steps, etching the passivation layer, and forming a bonding point window; S11, cleaning the SOI wafer, and forming an ohmic contact through an alloying process; S12, spin-coating a dicing protection glue on the surface of the SOI wafer, and after the SOI wafer is diced, performing non-magnetic chip packaging to complete the process of manufacturing the magnetic field vector sensor.

7. The magnetic field vector sensor integration process method according to claim 6, characterized in that: The metal layer is aluminum silicon copper, and the passivation layer is Si3N4.

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