CN211263740U - Magnetic field/acceleration integrated sensor - Google Patents
Magnetic field/acceleration integrated sensor Download PDFInfo
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- CN211263740U CN211263740U CN201921572747.9U CN201921572747U CN211263740U CN 211263740 U CN211263740 U CN 211263740U CN 201921572747 U CN201921572747 U CN 201921572747U CN 211263740 U CN211263740 U CN 211263740U
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Abstract
The utility model discloses a magnetic field acceleration integrated sensor, the sensor is including setting up magnetic field sensor and the acceleration sensor on same chip, and magnetic field sensor magnetism sensing unit includes silicon magnetic-sensing triode and hall magnetic field sensor, and wherein, hall magnetic field sensor dopes nanometer silicon film nc-Si with the normal position H (n is n silicon film nc-Si to the hall magnetic field sensor+) As a magnetic sensitive layer, the sensitive unit of the acceleration sensor is mainly an in-situ doped nano polycrystalline silicon thin film resistor, and the simultaneous measurement of a three-dimensional magnetic field and triaxial acceleration can be realized. The utility model discloses accomplish integrated sensor chip preparation on SOI wafer device layer based on micro-electronic machining techniqueAnd the chip packaging is realized through a bonding process and an inner lead pressure welding technology, and the chip packaging structure has the characteristics of small volume, easiness in batch production and the like.
Description
Technical Field
The utility model relates to a sensor technical field, concretely relates to monolithic integrated sensor that many physical quantities, many parameters detected simultaneously especially relate to a magnetic field acceleration integrated sensor.
Background
With the rapid development and application requirements of scientific technology, the sensor technology is emphasized, and nowadays, a single sensitive unit is developed into an integrated sensor capable of measuring multiple physical quantities and multiple directions simultaneously, and the integrated sensor is widely applied to the fields of modern industry, automotive electronics, aerospace, deep sea exploration and the like.
By analyzing the measurement principle of the space three-dimensional magnetic field and the acceleration in three directions, the result shows that the sensitive unit has great differences in the aspects of a sensitive mechanism, substrate material conductive type selection, a manufacturing process method and the like. At present, the magnetic field sensor which can be used for integration mainly comprises a Hall magnetic field sensor, a magnetosensitive diode, a magnetosensitive triode, a split drain field effect transistor (MAGFET) and the like, and the monocrystalline silicon substrate is preferably selected as a p-type conductive type for the magnetic field sensor which can be integrated by combining the consideration of main factors influencing the magnetosensitive characteristic of the magnetic field sensor; by analyzing the characteristics of the piezoresistive acceleration sensor, it is preferable that the single crystal silicon substrate be of n-type conductivity. In the prior art, incompatibility often exists in the process of manufacturing an integrated chip, so that a three-dimensional magnetic field sensor and a three-axis acceleration sensor are difficult to integrate.
Therefore, there is a need for a monolithically integrated magnetic field/acceleration sensor that can achieve simultaneous measurement of three-dimensional magnetic field and three-axis acceleration with good compatibility.
SUMMERY OF THE UTILITY MODEL
In order to overcome the above problems, the present inventors have conducted intensive studies and, as a result, found that: a monolithic integrated magnetic field/acceleration sensor is manufactured on an SOI wafer (p-type high-resistance Si of a device layer, the resistivity rho is more than or equal to 100 omega cm), a silicon magnetosensitive triode with a three-dimensional structure and a phosphorus-doped nano silicon film nc-Si: H (n is n+) Hall magnetic field sensor as magnetic sensitive layer as magnetic field transmitterThe sensitive unit of sensor utilizes boron-doped nano-polysilicon film resistor as the sensitive element of acceleration sensor, can realize the simultaneous measurement to three-dimensional magnetic field and triaxial acceleration, thereby has accomplished the utility model discloses.
Particularly, the present invention is directed to a magnetic field/acceleration integrated sensor, wherein the sensor includes a magnetic field sensor and an acceleration sensor disposed on the same chip to realize simultaneous measurement of a three-dimensional magnetic field and a three-axis acceleration;
the magnetic field/acceleration integrated sensor takes an SOI (silicon on insulator) sheet as a substrate, wherein the SOI sheet comprises a device layer 1, a supporting silicon 2 and a first silicon dioxide layer 3;
the thickness of the device layer 1 is 20-50 microns, and the thickness of the supporting silicon 2 is 420-550 microns;
the magnetic field sensor comprises four silicon magnetosensitive triodes which are arranged on the device layer 1 and have a three-dimensional structure and a Hall magnetic field sensor H,
the four silicon magnetosensitive triodes are combined in pairs to form two magnetosensitive units which are respectively used for detecting magnetic fields in the x-axis direction and the y-axis direction;
the Hall magnetic field sensor H is used for detecting a magnetic field in the z-axis direction;
a suspension structure is etched in the middle of the acceleration sensor, and the suspension structure comprises a mass block located in the center and four double-L-shaped beams located on two sides of the mass block;
the mass blocks are two, namely a first mass block m1And a second mass m2；
Each double-L-shaped beam comprises two single-L-shaped beams, and the four double-L-shaped beams comprise eight single-L-shaped beams which are respectively a first single-L-shaped beam L1Second single L-shaped beam L2Third single L-shaped beam L3Fourth single L-shaped beam L4Fifth single L-shaped beam L5Sixth single L-shaped beam L6Seventh single L-shaped beam L7And an eighth single L-shaped beam L8。
The utility model discloses the beneficial effect who has includes:
(1) the magnetic field/acceleration integrated sensor provided by the utility model can realize the simultaneous measurement of a space three-dimensional magnetic field and three-axis acceleration;
(2) the utility model provides a magnetic field acceleration integrated sensor selects the device layer to be p type<100>The SOI wafer of crystal orientation high-resistance monocrystalline silicon is used as a substrate, and a Hall magnetic field sensor in a magnetic sensitive unit of the magnetic field sensor is doped with a nano silicon film nc-Si in situ+) As the magnetic sensitive layer, the sensitive unit of the acceleration sensor is mainly an in-situ doped nano-polysilicon thin film resistor, so that the problem that the substrate conduction types of two different physical quantity measuring sensitive units are different is solved;
(3) the utility model provides a magnetic field acceleration integrated sensor's integrated processing method realizes magnetic field acceleration sensor chip technology preparation based on MEMS technique and normal position doping CVD method to realize the chip encapsulation through bonding technology and interior lead wire pressure welding technique, have characteristics such as small, easily batch production.
Drawings
Fig. 1 shows a schematic front view of a magnetic field/acceleration integrated sensor according to a preferred embodiment of the present invention;
fig. 2 is a schematic diagram of a back structure of a magnetic field/acceleration integrated sensor according to a preferred embodiment of the present invention;
fig. 3 shows an equivalent circuit diagram of a magnetic field sensor according to a preferred embodiment of the present invention;
fig. 4 shows an equivalent circuit diagram of an acceleration sensor according to a preferred embodiment of the present invention;
5-a-5-e show the integrated manufacturing process flow chart of the magnetic field/acceleration integrated sensor of the present invention;
6-a-6-c show experimental characteristic curves of a magnetic field sensor according to a preferred embodiment of the present invention along the x-axis, y-axis and z-axis directions;
fig. 7 shows an experimental characteristic curve of an acceleration sensor according to a preferred embodiment of the present invention.
The reference numbers illustrate:
1-a device layer; 2-supporting silicon; 3-a first silicon dioxide layer; 4-a second silicon dioxide layer; 5-an isolation groove; 6-a metallic aluminum layer; an H-Hall magnetic field sensor; SMST 1-first silicon magnetosensitive triode; SMST 2-second silicon magnetosensitive triode; SMST 3-third silicon magnetosensitive triode; SMST 4-fourth silicon magnetosensitive triode; b is1-a first base; b is2-a second base; b is3-a third base; b is4-a fourth base; c1-a first current collector; c2-a second current collector; c3-a third collector electrode; c4-a fourth collector electrode; e1-a first emitter; e2-a second emitter; e3-a third emitter; e4-a fourth emitter; rL1-a first collector load resistance; rL2-a second collector load resistance; rL3-a third collector load resistance; rL4-a fourth collector load resistance; v1-an x-axis first output voltage; v2-an x-axis second output voltage; v3-a y-axis first output voltage; v4-a y-axis second output voltage; vDD-a power source; GND-ground; i isH1-a first control current pole; i isH2-a second control current pole; vH1-a first hall output; vH2-a second hall output; rH1-a first equivalent resistance; rH2-a second equivalent resistance; rH3-a third equivalent resistance; rH4-a fourth equivalent resistance; m is1-a first mass; m is2-a second mass; l is1-a first single L-beam; l is2-a second single L-beam; l is3-a third single L-beam; l is4-a fourth single L-beam; l is5-a fifth single L-beam; l is6-a sixth single L-beam; l is7-a seventh single L-beam; l is8-an eighth single L-beam; l is9-a first intermediate beam; l is10-a second intermediate beam; rx1-a first piezo-resistor in x-direction; rx2-a second piezo-resistor in the x-axis direction; rx3-a third piezo-resistor in the x-axis direction; rx4-a fourth piezo-resistor in the x-direction; ry1-a y-axis direction first piezo-resistor; ry2-a second piezoresistor in the y-axis direction; ry3-a third varistor in the y-direction; ry4-a fourth varistor in the y-direction; rz1-a first piezo-resistor in z-direction; rz2-a second piezoresistor in the z-axis direction; rz3-a third piezo-resistor in z-direction; rz4-a fourth piezoresistor in the z-axis direction; vxout1-an x-axis first output voltage; vxout2-an x-axis second output voltage; vyout1-a y-axis first output voltage; vyout2-a y-axis second output voltage; vzout1-a z-axis first output voltage; vzout2△ R-relative change of resistance value of the resistor under the influence of external acceleration or magnetic field.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and embodiments. The features and advantages of the present invention will become more apparent from the description. In which, although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The utility model provides a magnetic field acceleration integrated sensor, as shown in FIG. 1, the sensor is including integrated magnetic field sensor and the acceleration sensor who sets up on same chip to realize the simultaneous measurement of three-dimensional magnetic field and triaxial acceleration.
According to a preferred embodiment of the present invention, the integrated magnetic field/acceleration sensor uses an SOI wafer as a substrate, and the SOI wafer includes a device layer 1 and a supporting silicon 2.
The inventor researches and discovers that compared with the traditional silicon chip, the device manufactured on the SOI chip has smaller parasitic capacitance and can improve the speed of the device.
In a further preferred embodiment, the device layer 1 is p-type <100> crystal orientation high-resistance monocrystalline silicon, and the thickness of the device layer 1 is 20 to 50 μm, preferably 25 to 35 μm.
Wherein the resistivity p of the device layer is greater than 100 Ω -cm.
In a further preferred embodiment, the supporting silicon 2 is p-type <100> crystal orientation high-resistance monocrystalline silicon, and the thickness thereof is 420 to 550 μm, preferably 450 to 525 μm, and more preferably 475 to 500 μm.
Preferably, a first silicon dioxide layer 3 is arranged between the device layer 1 and the support silicon 2, and the thickness of the first silicon dioxide layer 3 is 500 nm-800 nm.
The inventor researches and discovers that in the process of monolithically integrating a three-dimensional magnetic field sensor and a three-axis acceleration sensor, the monolithic integrated magnetic field/acceleration sensor is manufactured on an SOI (silicon on insulator) sheet of which the device layer is p-type <100> crystal orientation high-resistance monocrystalline silicon, so that the three-dimensional magnetic field and the three-axis acceleration can be simultaneously measured.
More preferably, a second silicon dioxide layer 4 is disposed on the upper surface of the device layer 1, and the thickness of the second silicon dioxide layer 4 is 400nm to 600 nm.
According to a preferred embodiment of the present invention, as shown in fig. 1, the magnetic field sensor comprises four silicon magnetosensitive triodes with a three-dimensional structure and a hall magnetic field sensor H disposed on the device layer 1, wherein,
the four silicon magnetosensitive triodes are combined in pairs to form two magnetosensitive units which are respectively used for detecting magnetic fields in the x-axis direction and the y-axis direction;
the Hall magnetic field sensor H is used for detecting a magnetic field in the z-axis direction.
In a further preferred embodiment, the hall magnetic field sensor is arranged at the center of the magnetic field sensor, and the four silicon magnetotriodes are arranged at the edge of the magnetic field sensor.
The p-type high-resistance monocrystalline silicon is used as the device layer and the substrate, so that the sensitivity of the magnetic field sensor is improved.
In a further preferred embodiment, the four silicon magnetosensitive transistors are a first silicon magnetosensitive transistor SMST1, a second silicon magnetosensitive transistor SMST2, a third silicon magnetosensitive transistor SMST3 and a fourth silicon magnetosensitive transistor SMST4,
wherein the first silicon magnetic sensing triode SMST1 and the second silicon magnetic sensing triode SMST2 are symmetrically arranged along the x axis of the magnetic field sensor at the two sides of the center of the three-dimensional magnetic field sensor chip,
and the third silicon magnetic sensing triode SMST3 and the fourth silicon magnetic sensing triode SMST4 are symmetrically arranged at two sides of the center of the three-dimensional magnetic field sensor chip along the y axis of the magnetic field sensor.
Preferably, the first silicon magnetic sensing triode SMST1 and the second silicon magnetic sensing triode SMST2 are arranged in the direction opposite to the magnetic sensing direction of the y axis, and the third silicon magnetic sensing triode SMST3 and the fourth silicon magnetic sensing triode SMST4 are arranged in the direction opposite to the magnetic sensing direction of the x axis.
According to a preferred embodiment of the present invention, a base region and a collector region are further formed on the upper surface of the device layer 1, and an emitter region is formed on the lower surface of the device layer 1.
In a further preferred embodiment, metal Al layers 6 are deposited on the surfaces of the base region, the collector region and the emitter region to form a base electrode, a collector electrode and an emitter electrode of the silicon magnetic sensitive triode respectively.
As shown in fig. 1, the first base B of the first silicon magnetosensitive triode SMST1 is formed on the upper surface of the device layer 11And a first collector electrode C1The second base B of the second silicon magnetic sensitive triode SMST22And a second collector electrode C2The third base B of the third silicon magnetic sensitive triode SMST33And a third collector electrode C3The fourth base B of the fourth silicon magnetic sensitive triode SMST44And a fourth collector electrode C4。
As shown in fig. 2, a first emitter E of a first silicon triode SMST1 is formed on the lower surface of the support silicon 21A second emitter E of a second silicon magnetoresistor SMST22A third emitter E of a third silicon magnetosensitive triode SMST33A fourth emitter E of a fourth silicon triode SMST44。
In a further preferred embodiment, a collector load resistor is formed on the upper surface of the device layer 1 on the side of the collector of the silicon magnetosensitive triode.
Wherein, as shown in fig. 1, the first collector C of the first silicon magnetosensitive triode SMST11A first collector load resistor R is formed on one sideL1Second collector C of second silicon magnetic sensitive triode SMST22One side of the second collector load resistorRL2Third collector C of third silicon magnetosensitive triode SMST33A third collector load resistor R is formed on one sideL3Fourth collector C of fourth silicon magnetosensitive triode SMST44A fourth collector load resistor R is formed on one sideL4。
Preferably, the four collector load resistors are all n-And (4) carrying out type doping.
According to a preferred embodiment of the present invention, as shown in fig. 1 and 3, the first collector C of the first silicon triode SMST11And a first collector load resistor RL1Connected to form a first output voltage V on x-axis at the junction1，
A second collector C of the second silicon magnetic sensitive triode SMST22And a second collector load resistor RL2Connected to form a second output voltage V on x-axis at the junction2。
In a further preferred embodiment, the first base electrode B1A second base electrode B2A first collector load resistor RL1And a second collector load resistance RL2Are connected with a power supply V together at the other endDD。
The emitter of the first silicon magnetic sensing triode SMST1 and the emitter of the second silicon magnetic sensing triode SMST2 are connected to the ground GND in common.
In the present invention, two silicon magnetosensitive triodes (SMST1 and SMST2) and two collector load resistors (R) connected to each otherL1And RL2) A first differential test circuit is constructed for detecting the magnetic field in the x-axis direction.
According to a preferred embodiment of the present invention, the third collector C of the third silicon triode SMST33And a third collector load resistor RL3Connected to form a first y-axis output voltage V at the junction3，
A fourth collector C of the fourth silicon magnetic sensitive triode SMST44And a fourth collector load resistor RL4Connected to form a second y-axis output voltage V at the junction4。
In a further preferred embodiment, the third base electrode B3A fourth base electrode B4A third collector load resistor RL3And a fourth collector load resistance RL4Are connected with a power supply V together at the other endDD。
The emitter of the third silicon magnetic sensing triode SMST3 and the emitter of the fourth silicon magnetic sensing triode SMST4 are connected with the ground GND in common.
In the present invention, two silicon magnetosensitive triodes (SMST3 and SMST4) and two collector load resistors (R) connected to each otherL3And RL4) A second differential test circuit is constructed for detecting the magnetic field in the y-axis direction.
According to a preferred embodiment of the present invention, the hall magnetic field sensor H comprises a magnetically sensitive layer, two control current poles and two hall output terminals, wherein,
the two control current poles are the first control current pole IH1And a second control current electrode IH2The two Hall output ends are a first Hall output end VH1And a second Hall output terminal VH2。
In a further preferred embodiment, as shown in fig. 3, the first control current pole IH1And a first Hall output terminal VH1Is equivalent to a first equivalent resistance RH1First control current pole IH1And a second Hall output terminal VH2Is equivalent to a second equivalent resistance RH2Second control current pole IH2And a first Hall output terminal VH1Is equivalent to a third equivalent resistor RH3Second control current pole IH2And a second Hall output terminal VH2Is equivalent to a fourth equivalent resistance RH4。
In a further preferred embodiment, as shown in fig. 3, the first equivalent resistance RH1And a third equivalent resistor RH3Connected to form a first output voltage V of z-axisz1Said second equivalent resistance RH2And a fourth equivalent resistance RH4Are connected with each other, the joint forms a z-axisSecond output voltage Vz2。
In the utility model, four equivalent resistors RH1、RH2、RH3And RH4A wheatstone bridge configuration is formed for sensing the magnetic field in the z-direction.
According to a preferred embodiment of the present invention, the magnetic sensitive layer of the Hall magnetic field sensor is a phosphorus-doped nano-silicon thin film nc-Si: H (n)+) The doping amount of the phosphorus is 5E13-3～1E15cm-3。
In the utility model discloses in, phosphorus-doped nano silicon film makes the upper surface on device layer 1 with the mode of normal position doping, can show the magnetic sensitivity characteristic that improves hall magnetic field sensor among the three-dimensional magnetic field sensor, and can guarantee the uniformity that x axle, y axle and the three direction of z axle detected.
In combination with the main factors affecting the characteristics of the hall magnetic field sensor, when the doped phosphorus is too much, the magnetic sensitivity is reduced, and when the doped phosphorus is too little, the output impedance is too much affected.
In a further preferred embodiment, the thickness of the magnetic sensitive layer of the hall magnetic field sensor in the magnetic field sensor is 50nm to 120 nm.
Due to the multi-directionality of the spatial three-dimensional magnetic field, two or more magnetic sensitive components are required to be combined for use, and in the prior art, a silicon magnetic sensitive triode is adopted for measuring the magnetic field in the x-axis direction and the y-axis direction so as to ensure the detection consistency in the x-axis direction, the y-axis direction and the z-axis direction.
According to the utility model discloses a preferred embodiment, on device layer 1, make isolation trench 5 around every silicon magnetic sensing triode to prevent the mutual influence between silicon magnetic sensing triode and other devices.
In a further preferred embodiment, the isolation trenches 5 are n+And (4) carrying out type doping.
The inventor researches and discovers that in a device layer (A)<100>Crystal orientation high resistance p type monocrystalline silicon) to form n+The type-doped isolation groove ensures that the inside and the outside of the isolation groove are P-type, the isolation groove and the inner and outer contact surfaces of the device layer form a PN junction, and the PN junction has a single structureThe silicon magnetic sensitive triode is electrically conductive, so that a contact surface (an inner contact surface or an outer contact surface) is always not conducted, each silicon magnetic sensitive triode is successfully isolated from other devices, the conduction between the devices is prevented, the mutual interference is avoided, and the stability of the sensor is improved.
According to a preferred embodiment of the present invention, as shown in fig. 1, a suspension structure is etched at a middle position of the acceleration sensor, and the suspension structure includes a mass block located at a central position and four double L-shaped beams located at two sides of the mass block;
wherein, the mass block has two, respectively is the first mass block m1And a second mass m2；
Each double-L-shaped beam comprises two single-L-shaped beams, and the four double-L-shaped beams comprise eight single-L-shaped beams which are respectively a first single-L-shaped beam L1Second single L-shaped beam L2Third single L-shaped beam L3Fourth single L-shaped beam L4Fifth single L-shaped beam L5Sixth single L-shaped beam L6Seventh single L-shaped beam L7And an eighth single L-shaped beam L8。
Preferably, the first single L-shaped beam L1Second single L-shaped beam L2Fifth single L-shaped beam L5And a seventh single L-shaped beam L7The X-axis or Y-axis direction center line is arranged on one side of the X-axis or Y-axis direction center line and is parallel to the X-axis or Y-axis direction center line;
the third single L-shaped beam L3Fourth single L-shaped beam L4Sixth single L-shaped beam L6And an eighth single L-shaped beam L8The X-axis or Y-axis direction center line is arranged on the other side of the X-axis or Y-axis direction center line and is parallel to the X-axis or Y-axis direction center line.
The utility model discloses in, set up every two L type roof beams into two single L type roof beams and link to each other, form eight single L type beam structures, can obviously improve the sensitivity of x axle direction and y axle direction, make the sensitivity of x axle direction, y axle direction be close to the sensitivity of z axle direction, promote the sensitive characteristic of each direction and tend to unanimity.
In a further preferred embodiment, in the first mass m1And a second mass m2A first middle beam L is arranged between the two9And a second intermediate beam L10；
Preferably, the first mass m1And a second mass m2Are symmetrically arranged along the direction of the x axis or the direction of the y axis at the center of the acceleration sensor,
the first intermediate beam L9And a second intermediate beam L10Are symmetrically arranged along the direction of the x axis or the direction of the y axis at the center of the acceleration sensor,
the first intermediate beam L9And a second intermediate beam L10Are all connected with the first mass block m1And a second mass m2Is vertically arranged.
In a further preferred embodiment, the first mass m1And a second mass m2Are all equal to the maximum thickness of the magnetic field/acceleration integrated sensor;
the first single L-shaped beam L1To eighth single L-shaped beam L8First intermediate beam L9And a second intermediate beam L10Are all the same as the thickness of the device layer 1.
The present invention is directed to a mass block and a sensor, wherein the thickness of the mass block and the sensor is a distance between upper and lower surfaces along a z-axis direction.
According to a preferred embodiment of the present invention, the first mass m1A second single L-shaped beam L is connected with one side of the first middle beam back to the second middle beam2Fourth single L-shaped beam L4Seventh single L-shaped beam L7And an eighth single L-shaped beam L8；
At the second mass m2A first single L-shaped beam L is connected with one side of the first middle beam back to the second middle beam1Third single L-shaped beam L3Fifth single L-shaped beam L5And a sixth single L-shaped beam L6。
The L-shaped beam, the middle beam and the mass block jointly form a structure of the triaxial acceleration sensor.
In a further preferred embodiment, the first single L-shaped beam L1Second single L-shaped beam L2The third listL-shaped beam L3And a fourth single L-shaped beam L4Are respectively provided with a first piezoresistor R in the x-axis directionx1And a second piezoresistor R in the x-axis directionx2And a third piezoresistor R in the x-axis directionx3And a fourth varistor R in the x-axis directionx4；
Wherein, the first piezoresistor R in the x-axis directionx1And a second piezoresistor R in the x-axis directionx2And a third piezoresistor R in the x-axis directionx3And a fourth varistor R in the x-axis directionx4Are arranged parallel to each other.
In a further preferred embodiment, as shown in fig. 1 and 4, the first piezoresistor R in the x-axis directionx1And a second varistor R in the x-axis directionx2Is connected to form a first output voltage V of x-axis at the junctionxout1(ii) a The third piezoresistor R in the x-axis directionx3And a fourth varistor R in the x-axis directionx4Is connected to form a second output voltage V of x-axis at the junctionxout2；
Preferably, the first piezoresistor R in the x-axis directionx1And the other end of the first varistor R and the x-axis direction of the second varistor Rx4Are connected with a power supply V together at the other endDDThe second piezoresistor R in the x-axis directionx2And the other end of the third varistor R in the x-axis directionx3The other ends of the first and second electrodes are commonly Grounded (GND).
Wherein the first single L-shaped beam L1A second single L-shaped beam L2And a third single L-shaped beam L3And a fourth single L-shaped beam L4Four piezoresistors (R) of the rootx1、Rx2、Rx3、Rx4) A first wheatstone bridge is formed for detecting acceleration in the x-axis direction. Under the action of acceleration along the x-axis direction, the output end V of the Wheatstone bridgexout1And Vxout2The change can realize the detection of the acceleration of the x axis.
According to a preferred embodiment of the present invention, the fifth single L-shaped beam L5Sixth single L-shaped beam L6Seventh single L-shaped beam L7And an eighth single L-shaped beam L8The roots are respectively provided with a first voltage-sensitive capacitor in the y-axis directionResistance Ry1And a second piezoresistor R in the y-axis directiony2And a third piezoresistor R in the y-axis directiony3And a fourth varistor R in the y-axis directiony4，
Wherein, the first piezoresistor R in the y-axis directiony1And a second piezoresistor R in the y-axis directiony2And a third piezoresistor R in the y-axis directiony3And a fourth varistor R in the y-axis directiony4Are arranged parallel to each other.
In a further preferred embodiment, the first piezoresistor R in the y-axis directiony1And a second piezoresistor R in the y-axis directiony2Is connected with each other, and a first output voltage V of a y axis is formed at the connection partyout1(ii) a Third piezoresistor R in y-axis directiony3And a fourth varistor R in the y-axis directiony4Is connected with one end of the first output voltage source, and a y-axis second output voltage V is formed at the connection partyout2。
In a further preferred embodiment, the first varistor R is arranged in the y-directiony1And the other end of the second varistor R and the y-axis direction of the fourth varistor Ry4Are connected with a power supply V together at the other endDDSecond piezoresistor R in y-axis directiony2And the other end of the third varistor R in the y-axis directiony3The other ends of the first and second electrodes are commonly grounded.
Wherein, the fifth single L-shaped beam L5Sixth single L-shaped beam L6Seventh single L-shaped beam L7And an eighth single L-shaped beam L8Four piezoresistors (R) of the rooty1、Ry2、Ry3、Ry4) A second wheatstone bridge is formed for detecting acceleration in the y-axis direction. Under the action of acceleration along the y-axis direction, the output end V of the Wheatstone bridgeyout1And Vyout2And the detection of the acceleration of the y axis can be realized by changing the acceleration sensor.
According to a preferred embodiment of the present invention, the first intermediate beam L9And a first mass m1And a second mass m2The root parts of the joints are respectively provided with a first piezoresistor R in the z-axis directionz1And a second piezoresistor R in the z-axis directionz2；
At the second intermediate beam L10And a first mass m1And a second mass m2The root parts of the joints are respectively provided with a third piezoresistor R in the z-axis directionz3And a fourth piezoresistor R in the z-axis directionz4；
Wherein the first piezoresistor R in the z-axis directionz1And a second piezoresistor R in the z-axis directionz2Are arranged in a mutually vertical way,
the third piezoresistor R in the z-axis directionz3And a fourth piezoresistor R in the z-axis directionz4Are arranged perpendicular to each other.
In a further preferred embodiment, the first piezoresistor R in the z-axis directionz1And a second piezoresistor R in the z-axis directionz2Is connected with one end of the first output voltage V, and a first output voltage V of a z axis is formed at the connection partzout1(ii) a Third piezoresistor R in z-axis directionz3And a fourth piezoresistor R in the z-axis directionz4Is connected with one end of the first output voltage source, and a second output voltage V of a z axis is formed at the connection positionzout2。
In a further preferred embodiment, the first piezoresistor R in the z-axis directionz1And the other end of the first varistor R and the z-axis direction of the second varistor Rz4Are connected with a power supply V together at the other endDDSecond piezoresistor R in z-axis directionz2And the other end of the third varistor R in the z-axis directionz3The other ends of the first and second electrodes are commonly grounded.
Wherein, four piezoresistors (R) in the z-axis direction at the root parts of the first middle beam and the second middle beamz1、Rz2、Rz3、Rz4) A third wheatstone bridge is formed for detecting acceleration in the z-axis direction. Under the action of acceleration along the z-axis direction, the output end V of the Wheatstone bridgezout1And Vzout2The z-axis acceleration can be detected by changing the position of the sensor.
Where Δ R in fig. 4 represents the relative change amount of the resistance value of the resistor when the chip is affected by external acceleration or a magnetic field.
According to a preferred embodiment of the present invention, the piezoresistors in the x-axis, y-axis and z-axis directions are boron-doped nano-polysilicon thin-film resistors, preferably p-type boron-doped nano-polysilicon thin-film resistors.
The utility model discloses in, when making magnetic field sensor and acceleration sensor integration, adopt the SOI wafer of p type <100> crystal orientation high resistance monocrystalline silicon as the substrate, can produce certain influence to piezoresistive acceleration sensor's sensitivity, for solving compatible problem, the utility model discloses well preferred adoption p type mixes boron nanometer polycrystalline silicon film resistor as acceleration sensor's sensitive component to guarantee acceleration sensor's sensitivity.
The research of the inventor finds that the boron-doped nano polycrystalline silicon film has more excellent piezoresistive characteristics than other conventional polycrystalline silicon films, has small temperature coefficient of strain factor and small temperature coefficient of resistance, and can realize pressure-sensitive test with high sensitivity and wide working temperature range. Therefore, the acceleration sensor can be ensured to have high sensitivity on the p-type substrate, and the monolithic integrated sensor can simultaneously measure the three-dimensional magnetic field and the three-axis acceleration.
In a further preferred embodiment, the doping amount of boron is 1E13-3～1E15cm-3。
The inventor researches and discovers that when the doping amount of boron is too high, heavy doping is formed, so that the resistivity of the piezoresistor is lower, and when the external acceleration acts, the piezoresistive coefficient is reduced, the output voltage of a Wheatstone bridge is lower, and the pressure-sensitive characteristic is influenced; when the doping amount of boron is too low, light doping is formed, so that the resistivity of the piezoresistor is higher, and when the external acceleration acts, the resistance value variation of the resistor is not obvious, the output voltage of the Wheatstone bridge is lower, and the voltage-sensitive characteristic is influenced.
In a further preferred embodiment, the thickness of the nano-polysilicon thin film is 60 to 100 nm.
According to the utility model relates to a preferred embodiment acceleration sensor's below still is provided with the glass piece, and it has groove structure, is connected with supporting silicon 2 bonding for two quality pieces of acceleration sensor can freely move in the recess.
In a further preferred embodiment, the glass sheet is a borosilicate glass sheet and has a thickness of 0.5 to 1 mm.
The utility model discloses in, the overload protection function that has of glass piece, it has avoided carrying out the complicated processing of attenuate to the quality piece for the quality piece that acceleration sensor central point put can freely remove in the recess of glass piece.
The utility model also provides a magnetic field acceleration integrated sensor's integrated technological method, preferably be used for preparing above-mentioned magnetic field acceleration integrated sensor, as shown in 5-a ~ 5-e, the method includes following step:
The method comprises the following steps of cleaning a monocrystalline silicon substrate by adopting an RCA standard cleaning method, wherein the cleaning is carried out as follows: the SOI slice is boiled by concentrated sulfuric acid until white smoke is emitted, is washed by a large amount of 15 deionized water after being cooled, and is respectively washed by an electronic cleaning solution No. 1 APM (SC-1) and an electronic cleaning solution No. 2 HPM (SC-2), wherein the No. 1 solution comprises the following main components in volume ratio: ammonia water, hydrogen peroxide and water in a ratio of 1:1:5 (the concentration of ammonia water is 27 percent, and the concentration of hydrogen peroxide is 30 percent), wherein the main components and the volume ratio of the No. 2 solution are as follows: hydrochloric acid, hydrogen peroxide and water in a ratio of 1:1:5 (the concentration of hydrochloric acid is 37 percent and the concentration of hydrogen peroxide is 30 percent), cleaning twice respectively, then washing with a large amount of deionized water, and finally putting into a spin dryer for spin-drying.
According to a preferred embodiment of the present invention, the SOI wafer includes a device layer 1 and a supporting silicon 2;
the device layer 1 is p-type <100> crystal orientation high-resistance monocrystalline silicon, and the thickness of the device layer 1 is 20-50 microns, preferably 25-35 microns.
In a further preferred embodiment, the resistivity of the device layer 1 is greater than 100 Ω · cm.
In a further preferred embodiment, the supporting silicon 2 is p-type <100> crystal orientation high-resistance monocrystalline silicon, and the thickness thereof is 420 to 550 μm, preferably 450 to 525 μm, and more preferably 475 to 500 μm.
Preferably, a first silicon dioxide layer 3 is arranged between the device layer 1 and the support silicon 2, and the thickness of the first silicon dioxide layer 3 is 500 nm-800 nm.
And 2, oxidizing for the first time, and growing thin oxygen on the device layer 1 to be used as an ion implantation buffer layer.
Wherein the thin oxygen is silicon dioxide, and the thickness of the thin oxygen is 30-50 nm.
According to a preferred embodiment of the present invention, n+The doping concentration of the type doping is 5E14-3～1E15cm-3。
The inventors have found that PN junction isolation is facilitated with the above doping concentrations.
The annealing temperature and the vacuum treatment time have the advantages that the high-temperature annealing can activate impurity ions and eliminate damage caused by ion implantation, the vacuum treatment can prevent oxygen and other substances in the atmosphere from influencing the chip, if the annealing temperature is too low or the time is too short, the damage caused by ion implantation cannot be well eliminated, the ions cannot reach the substitution position, and the surface crystallization state is not good; if the annealing temperature is too high or the processing time is too long, the implanted ions may be displaced, and the dislocation and defect density are easily caused.
Wherein p is+Heavily doped type 1E13-3～1E15cm-3。
And 6, annealing at high temperature to form impurity distribution.
According to a preferred embodiment of the present invention, the high temperature annealing treatment is performed as follows: and (3) processing the mixture for 20-30 min in a vacuum environment at 600-1200 ℃.
The annealing temperature and the vacuum treatment time have the advantages that: the high-temperature annealing can activate impurity ions, and the vacuum treatment can prevent oxygen and other substances in the atmosphere from influencing the chip. If the annealing temperature is too low or the annealing time is too short, the damage of ion implantation cannot be well eliminated, ions cannot reach a substitution position, and the surface crystallization state is not good; too high an annealing temperature or too long a processing time may cause the implanted ions to be displaced, easily resulting in dislocation and defect densities.
And 7, cleaning the SOI wafer, and growing a silicon dioxide layer on the upper surface of the device layer 1 by adopting a chemical vapor deposition method.
Wherein the thickness of the grown silicon dioxide layer is 500-600 nm.
Step 8, photoetching for the fourth time, and growing the phosphorus-doped nc-Si: H (n) in situ by adopting a chemical vapor deposition method+) To form phosphorus doped nc-Si: H (n)+) The thin film acts as the hall magnetic field sensor magnetically sensitive layer (as shown in fig. 5-b).
According to a preferred embodiment of the present invention, the in-situ grown nc-Si is H (n)+) The thickness of the film is 50-120 nm.
In a further preferred embodiment, the doping amount of phosphorus is 5E13-3～1E15cm-3。
And 9, cleaning the SOI wafer, and growing the boron-doped nano polycrystalline silicon film on the upper surface of the device layer 1 in situ by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
According to a preferred embodiment of the present invention, the deposition temperature is 600 ℃ to 650 ℃, preferably 620 ℃.
In a further preferred embodiment, the thickness of the in-situ grown boron-doped nano-polysilicon film is 60 to 100 nm.
In a further preferred embodiment, the doping amount of boron is 1E13-3～1E15cm-3。
And 11, cleaning the silicon wafer, and growing a silicon dioxide layer on the upper surface of the device layer 1 by adopting a chemical vapor deposition method to serve as an insulating layer.
Wherein the thickness of the grown silicon dioxide layer is 400-600 nm.
And step 12, carrying out sixth photoetching, and etching a lead hole on the upper surface of the device layer 1.
And step 13, performing seventh photoetching, and etching the window of the C-shaped silicon cup emission area and the mass block of the acceleration sensor chip on the back of the support silicon 2 by adopting a deep groove etching technology (ICP).
Wherein, a deep trench etching technology (ICP) is adopted to etch the first silicon dioxide layer 3.
Step 14, n is performed at the emitter window supporting the back of the silicon 2+And forming an emitter region by type heavy doping, and then carrying out high-temperature annealing treatment.
Wherein the high-temperature annealing comprises the following steps: and (3) processing the mixture for 20-30 min in a vacuum environment at 600-1200 ℃.
Wherein the thickness of the metal aluminum layer is 0.5-1.0 μm.
And step 16, cleaning the silicon wafer, and growing a silicon dioxide layer on the upper surface of the device layer 1 by adopting a chemical vapor deposition method to serve as a passivation layer.
Wherein the thickness of the grown silicon dioxide layer is 500-600 nm.
Step 17, performing ninth photoetching, and etching the passivation layer to form a pressure welding point; the wafer is then cleaned and alloyed to form ohmic contacts (as shown in figure 5-d).
According to a preferred embodiment of the present invention, the alloying treatment is performed as follows: the treatment is carried out at 300-500 ℃ for 10-50 min, preferably at 400-450 ℃ for 20-40 min, and more preferably at 420 ℃ for 30 min.
And 18, performing tenth photoetching and deep groove etching (ICP) on the silicon wafer device layer 1, etching to the first silicon dioxide layer 3, and releasing the L-shaped beam structure (shown in figure 5-e).
And 19, bonding the SOI sheet with a borosilicate glass sheet with an overload protection structure.
The borosilicate glass sheet is provided with a groove structure and is in bonding connection with the supporting silicon 2, so that the two mass blocks of the acceleration sensor can freely move in the grooves.
Preferably, the thickness of the material is 0.5-1 mm.
The utility model discloses in, accomplish monolithic integration three-dimensional magnetic field/triaxial acceleration sensor chip preparation on SOI wafer device layer (p type <100> crystal orientation high resistance monocrystalline silicon) based on micro-electro-mechanical systems (MEMS) to realize the chip package through bonding technology and interior lead wire pressure welding technique, can realize measuring three-dimensional magnetic field and triaxial acceleration's while. The magnetic field/acceleration integrated sensor prepared by the method has the characteristics of small volume and easiness in batch production.
Examples
Example 1
The magnetic field/acceleration integrated sensor is manufactured integrally according to the following steps:
The method comprises the following steps of cleaning a monocrystalline silicon substrate by adopting an RCA standard cleaning method, wherein the cleaning is carried out as follows: the SOI slice is boiled by concentrated sulfuric acid until white smoke is emitted, is washed by a large amount of 15 deionized water after being cooled, and is respectively washed by an electronic cleaning solution No. 1 APM (SC-1) and an electronic cleaning solution No. 2 HPM (SC-2), wherein the No. 1 solution comprises the following main components in volume ratio: ammonia water, hydrogen peroxide and water in a ratio of 1:1:5 (the concentration of ammonia water is 27 percent, and the concentration of hydrogen peroxide is 30 percent), wherein the main components and the volume ratio of the No. 2 solution are as follows: hydrochloric acid, hydrogen peroxide and water in a ratio of 1:1:5 (the concentration of hydrochloric acid is 37 percent and the concentration of hydrogen peroxide is 30 percent), cleaning twice respectively, then washing with a large amount of deionized water, and finally putting into a spin dryer for spin-drying.
The device layer is p-type <100> crystal orientation high-resistance monocrystalline silicon, the thickness is 30 mu m, the resistivity is larger than 100 omega cm, the supporting silicon is p-type <100> crystal orientation high-resistance monocrystalline silicon, the thickness is 490 mu m, and the thickness of the first silicon dioxide layer 3 is 600 nm.
And 2, oxidizing for the first time, and growing thin oxygen (silicon dioxide) on the device layer to be used as an ion implantation buffer layer.
Wherein the thin oxygen has a thickness of 40 nm.
wherein n is+The doping concentration of the type doping is 5E14-3cm-3。
Wherein p is+Heavily doped type 1E13-3cm-3。
And 6, annealing at high temperature to form impurity distribution.
Wherein the high-temperature annealing treatment is carried out as follows: and (4) processing for 25min in a vacuum environment at 1000 ℃.
And 7, cleaning the SOI wafer, and growing a silicon dioxide layer on the upper surface of the device layer by adopting a chemical vapor deposition method.
Wherein the thickness of the grown silicon dioxide layer is 550 nm.
Step 8, photoetching for the fourth time, and growing the phosphorus-doped nc-Si: H (n) in situ by adopting a chemical vapor deposition method+) To form phosphorus doped nc-Si: H (n)+) The film is used as a magnetic sensitive layer of the Hall magnetic field sensor.
Wherein the in-situ grown nc-Si is H (n)+) Thickness of the filmIs 90 nm; the doping amount of the phosphorus is 5E13- 3cm-3。
And 9, cleaning the SOI wafer, and growing the boron-doped nano polycrystalline silicon film on the upper surface of the device layer in situ by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
Wherein the deposition temperature is 620 ℃, the thickness of the in-situ grown boron-doped nano-polysilicon film is 80nm, and the doping amount of boron is 1E13-3cm-3
And 11, cleaning the silicon wafer, and growing a silicon dioxide layer on the upper surface of the device layer by adopting a chemical vapor deposition method to serve as an insulating layer.
Wherein the thickness of the grown silicon dioxide layer is 40 nm.
And step 12, carrying out sixth photoetching, and etching a lead hole on the upper surface of the device layer.
And step 13, carrying out seventh photoetching, and etching the window of the C-shaped silicon cup emission region on the back of the support silicon 2 by adopting a deep groove etching technology (ICP).
Wherein, a deep groove etching technology (ICP) is adopted to etch the silicon dioxide layer to the first silicon dioxide layer.
Step 14, n is performed at the emitter window supporting the back of the silicon 2+And forming an emitter region by type heavy doping, and then carrying out high-temperature annealing treatment.
Wherein n is+The doping concentration of the type doping is 5E13-3cm-3。
Wherein the high-temperature annealing treatment comprises the following steps: and (3) processing for 28min in a vacuum environment at 850 ℃.
Wherein the thickness of the metal aluminum layer is 0.8 μm.
And step 16, cleaning the silicon wafer, and growing a silicon dioxide layer on the upper surface of the device layer by adopting a chemical vapor deposition method to serve as a passivation layer.
Wherein the thickness of the grown silicon dioxide layer is 550 nm.
Step 17, performing ninth photoetching, and etching the passivation layer to form a pressure welding point; and then cleaning the silicon wafer, and carrying out alloying treatment to form ohmic contact.
Wherein the alloying treatment is performed as follows: treating at 420 deg.C for 30 min.
And 18, photoetching for the tenth time, etching the silicon wafer device layer by using a deep groove etching technology (ICP), etching to the first silicon dioxide layer, and releasing the L-shaped beam structure.
And 19, bonding the SOI sheet with a borosilicate glass sheet with an overload protection structure.
The borosilicate glass sheet is provided with a groove structure, the thickness of the groove structure is 0.5-1 mm, and the borosilicate glass sheet is bonded and connected with the supporting silicon.
Example 2
The method used in this example is similar to example 1, except that in step 1, the device layer has a thickness of 50 μm and the support silicon has a thickness of 420 μm.
Example 3
The method used in this example is similar to that of example 1, except that in step 3, the high temperature annealing treatment is performed as follows: and (4) processing for 8h at 1200 ℃ in a vacuum environment.
Example 4
The method used in this example is similar to that of example 1, except that, in step 6, the high temperature annealing treatment is carried out as follows: and treating at 600 deg.C under vacuum for 30 min.
Example 5
This example is similar to example 1 except that in step 8, the in situ grown nc-Si is H (n)+) The thickness of the film was 50 nm.
Example 6
Method used in the present exampleSimilar to example 1, except that in step 8, the in-situ grown nc-Si is H (n)+) The thickness of the film was 120 nm.
Example 7
The process used in this example is similar to example 1, except that in step 8, the amount of phosphorus doped is 1E15cm-3。
Example 8
The procedure used in this example is similar to that of example 1, except that, in step 9, the deposition temperature is 650 ℃.
Example 9
The method used in this example is similar to example 1, except that in step 9, the in-situ grown boron-doped nano-poly silicon thin film has a thickness of 60 nm.
Example 10
The method used in this example is similar to example 1, except that in step 9, the in-situ grown boron-doped nano-poly silicon thin film has a thickness of 100 nm.
Example 11
The method used in this example is similar to example 1, except that in step 9, the boron doping amount is 1E15cm-3。
Example 12
The method used in this example is similar to that of example 1, except that in step 17, the alloying treatment is carried out as follows: treating at 400 deg.C for 40 min.
Example 13
The method used in this example is similar to that of example 1, except that in step 17, the alloying treatment is carried out as follows: treating at 450 deg.C for 20 min.
Examples of the experiments
Experimental example 1
A three-dimensional magnetic field sensor characteristic test system is built by adopting instruments such as a magnetic field generator (CH-100), a programmable linear direct current power supply (RIGOL DP832A) and a digital multimeter (Agilent 34410A), and under the condition of room temperature, the working voltage is 5V, and the base electrode is injected with current (I)b) Respectively 1mA, 2mA, 3mA and 4mA and 5mA under, right the utility model discloses embodiment 1 magnetic field sensor carry out characteristic test, exert respectively along x axle, y axle and the magnetic field (-500mT ~ 500mT of z axle direction, the step length is 100mT) to magnetic field sensor, gather magnetic field sensor's first difference structure, second difference structure and hall element's output voltage respectively, the relation curve of magnetic field sensor output voltage and external magnetic field is as shown in 6-a ~ 6-c.
FIG. 6-a is a graph showing the relationship between the output voltage of the first differential structure of the magnetic field sensor and the variation of the applied magnetic field along the x-axis direction; FIG. 6-b is a graph of the output voltage of the second differential structure of the magnetic field sensor as a function of the applied magnetic field along the y-axis; FIG. 6-c is a graph of output voltage of a Hall element of the magnetic field sensor as a function of applied magnetic field when the magnetic field is oriented along the z-axis.
As can be seen from fig. 6-a and 6-b, when the applied magnetic field is constant, the output voltages of the first differential structure and the second differential structure of the magnetic field sensor along the x-axis and the y-axis directions increase with the increase of the base injection current; when the base injection current is constant, the output voltages of the first differential structure and the second differential structure of the magnetic field sensor along the directions of the x axis and the y axis are increased along with the increase of an external magnetic field; as can be seen from fig. 6-c, when the input voltage is constant at 5V, the output voltage of the hall element detecting the magnetic field in the z-axis direction increases with the increase of the applied magnetic field.
A triaxial acceleration sensor characteristic test system is built by adopting instruments such as a standard vibration table (vibrating ESS-050), a programmable linear direct current power supply (RIGOL DP832A) and a digital multimeter (Agilent 34410A), under the condition of room temperature and the working voltage of 5V, accelerations (0-30 g, the step length is 5g) along the directions of an x axis, a y axis and a z axis are respectively applied to the acceleration chip described in the embodiment 1, the output voltages of a first Wheatstone bridge, a second Wheatstone bridge and a third Wheatstone bridge of the acceleration chip are respectively collected, and the relation curve of the output voltage of the acceleration sensor and the applied acceleration is shown in FIG. 7.
The curve A is a relation curve of the output voltage of the first Wheatstone bridge changing along with the external acceleration when the external acceleration is along the x-axis direction, the curve B is a relation curve of the output voltage of the second Wheatstone bridge changing along with the external acceleration when the external acceleration is along the y-axis direction, and the curve C is a relation curve of the output voltage of the third Wheatstone bridge changing along with the external acceleration when the external acceleration is along the z-axis direction.
As can be seen from fig. 7, when the operating voltage is constant, the output voltages of the first wheatstone bridge, the second wheatstone bridge and the third wheatstone bridge of the acceleration sensor increase linearly with the increase of the applied acceleration.
Therefore, when the power voltage is 5.0V and the base injection current is 5mA, the sensitivity of the sensor x-axis direction magnetic field sensor is 154mV/T, the sensitivity of the sensor y-axis direction magnetic field sensor is 158mV/T, and the sensitivity of the sensor z-axis direction magnetic field sensor is 91 mV/T; the sensitivity of the acceleration sensor in the x-axis direction is 0.95mV/g, the sensitivity of the acceleration sensor in the y-axis direction is 0.61mV/g, and the sensitivity of the acceleration sensor in the z-axis direction is 0.14 mV/g. Therefore, integrated sensor can realize detecting three-dimensional magnetic field and triaxial acceleration simultaneously to the sensitivity of the three direction of x, y and z that obtains is close unanimous.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", and the like indicate the position or positional relationship based on the operation state of the present invention, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the connection may be direct or indirect via an intermediate medium, and may be a communication between the two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The present invention has been described above in connection with preferred embodiments, which are merely exemplary and illustrative. On this basis, can be right the utility model discloses carry out multiple replacement and improvement, these all fall into the utility model discloses a protection scope.
Claims (10)
1. The magnetic field/acceleration integrated sensor is characterized by comprising a magnetic field sensor and an acceleration sensor which are arranged on the same chip so as to realize the simultaneous measurement of a three-dimensional magnetic field and three-axis acceleration;
the magnetic field/acceleration integrated sensor takes an SOI (silicon on insulator) sheet as a substrate, wherein the SOI sheet comprises a device layer (1), a supporting silicon (2) and a first silicon dioxide layer (3);
wherein the thickness of the device layer (1) is 20-50 μm, and the thickness of the supporting silicon (2) is 420-550 μm;
the magnetic field sensor comprises four silicon magnetosensitive triodes which are arranged on the device layer (1) and have a three-dimensional structure and a Hall magnetic field sensor (H),
the four silicon magnetosensitive triodes are combined in pairs to form two magnetosensitive units which are respectively used for detecting magnetic fields in the x-axis direction and the y-axis direction;
the Hall magnetic field sensor (H) is used for detecting a magnetic field in the z-axis direction;
a suspension structure is etched in the middle of the acceleration sensor, and the suspension structure comprises a mass block located in the center and four double-L-shaped beams located on two sides of the mass block;
the mass blocks are two, respectively first mass blocks (m)1) And a second mass (m)2)；
Each double-L-shaped beam comprises two single-L-shaped beams, and the four double-L-shaped beams comprise eight single-L-shaped beams which are respectively a first single-L-shaped beam (L)1) Second single L-shaped beam (L)2) Third single L-shaped beam (L)3) Fourth single L-shaped beam (L)4) Fifth single L-shaped Beam (L)5) Sixth single L-shaped beam (L)6) Seventh single L-shaped beam (L)7) And eighth single L-shaped beam (L)8)。
2. The sensor of claim 1, wherein the four silicon magnetosensitive transistors are a first silicon magnetosensitive transistor (SMST1), a second silicon magnetosensitive transistor (SMST2), a third silicon magnetosensitive transistor (SMST3), and a fourth silicon magnetosensitive transistor (SMST4), respectively,
wherein the first silicon magnetic sensitive triode (SMST1) and the second silicon magnetic sensitive triode (SMST2) are symmetrically arranged along the x axis of the magnetic field sensor at two sides of the center of the magnetic field sensor chip,
and the third silicon magnetosensitive triode (SMST3) and the fourth silicon magnetosensitive triode (SMST4) are symmetrically arranged at two sides of the center of the magnetic field sensor chip along the y axis of the magnetic field sensor.
3. The sensor of claim 1, wherein the magnetic sensitive layer of the Hall magnetic field sensor is a phosphorus-doped nano-silicon thin film nc-Si: H (n)+)，
The thickness of the magnetic sensitive layer is 50 nm-120 nm.
4. A sensor according to claim 1, characterized in that an isolation trench (5) is made on the device layer (1) around each silicon magnetoresistor transistor to prevent interaction between the silicon magnetoresistor transistor and other devices;
the isolation groove (5) is n+And (4) carrying out type doping.
5. A sensor according to claim 1, characterized in that in the first mass (m)1) And a second mass (m)2) A first middle beam (L) is arranged between the two9) And a second intermediate beam (L)10)，
The first intermediate beam (L)9) And a second intermediate beam (L)10) Are all connected with the first mass block (m)1) And a second mass (m)2) Is vertically arranged.
6. Sensor according to claim 5, characterized in that the first mass (m)1) And a second mass (m)2) Are all equal to the maximum thickness of the magnetic field/acceleration integrated sensor;
the first single L-shaped beam (L)1) To eighth single L-shaped beam (L)8) A first intermediate beam (L)9) And a second intermediate beam (L)10) Are all the same as the thickness of the device layer (1).
7. Sensor according to claim 5, characterized in that in the first single L-shaped beam (L)1) Second single L-shaped beam (L)2) Third single L-shaped beam (L)3) And a fourth single L-shaped beam (L)4) Are respectively provided with a first piezoresistor (R) in the x-axis directionx1) And a second piezoresistor (R) in the x-axis directionx2) And a third piezoresistor (R) in the x-axis directionx3) And a fourth varistor (R) in the x-axis directionx4)；
In the fifth single L-shaped beam (L)5) Sixth single L-shaped beam (L)6) Seventh single L-shaped beam (L)7) And eighth single L-shaped beam (L)8) Are respectively provided with a first piezoresistor (R) in the y-axis directiony1) And a second piezoresistor (R) in the y-axis directiony2) And a third piezoresistor (R) in the y-axis directiony3) And a fourth varistor (R) in the y-axis directiony4)；
At the first intermediate beam (L)9) And a first mass (m)1) And a second mass (m)2) The root parts of the joints are respectively provided with a first piezoresistor (R) in the z-axis directionz1) And a second piezoresistor (R) in the z-axis directionz2)；
At the second intermediate beam (L)10) And a first mass (m)1) And a second mass (m)2) The root parts of the joints are respectively provided with a third piezoresistor (R) in the z-axis directionz3) And a fourth piezoresistor (R) in the z-axis directionz4)。
8. The sensor of claim 7, wherein the piezoresistors in the x-axis, y-axis and z-axis directions are all boron-doped nano-polysilicon thin film resistors.
9. A sensor according to claim 1, characterized in that a glass plate is also arranged below the acceleration sensor, which has a groove structure, bonded to the supporting silicon (2), so that the two masses of the acceleration sensor can move freely in the grooves.
10. The sensor of claim 9, wherein the glass sheet is a borosilicate glass sheet having a thickness of 0.5 to 1 mm.
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| CN110632538A (en) * | 2019-09-20 | 2019-12-31 | 黑龙江大学 | Magnetic field/acceleration integrated sensor and integration process method |
| CN114778891A (en) * | 2022-05-09 | 2022-07-22 | 北京信息科技大学 | Three-axis accelerometer |
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| CN110632538A (en) * | 2019-09-20 | 2019-12-31 | 黑龙江大学 | Magnetic field/acceleration integrated sensor and integration process method |
| CN110632538B (en) * | 2019-09-20 | 2021-08-24 | 黑龙江大学 | Magnetic field/acceleration integrated sensor and integration process method |
| CN114778891A (en) * | 2022-05-09 | 2022-07-22 | 北京信息科技大学 | Three-axis accelerometer |
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