CN110632538B - Magnetic field/acceleration integrated sensor and integration process method - Google Patents
Magnetic field/acceleration integrated sensor and integration process method Download PDFInfo
- Publication number
- CN110632538B CN110632538B CN201910894125.6A CN201910894125A CN110632538B CN 110632538 B CN110632538 B CN 110632538B CN 201910894125 A CN201910894125 A CN 201910894125A CN 110632538 B CN110632538 B CN 110632538B
- Authority
- CN
- China
- Prior art keywords
- silicon
- magnetic field
- axis direction
- device layer
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
- B81C1/00523—Etching material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00841—Cleaning during or after manufacture
- B81C1/00849—Cleaning during or after manufacture during manufacture
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C3/00—Assembling of devices or systems from individually processed components
- B81C3/001—Bonding of two components
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/12—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/07—Hall effect devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P2015/0862—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with particular means being integrated into a MEMS accelerometer structure for providing particular additional functionalities to those of a spring mass system
Abstract
The invention discloses a magnetic field/acceleration integrated sensor and an integrated process method, wherein the sensor comprises a magnetic field sensor and an acceleration sensor which are arranged on the same chip, a magnetic sensitive unit of the magnetic field sensor comprises a silicon magnetosensitive triode and a Hall magnetic field sensor, and the Hall magnetic field sensor is doped with a nano silicon film nc-Si in situ H (n+) 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 invention completes the manufacture of the integrated sensor chip on the SOI wafer device layer based on the microelectronic machining technology, realizes the chip packaging through the bonding technology and the inner lead bonding technology, and has the characteristics of small volume, easy batch production and the like.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a monolithic integrated sensor for simultaneously detecting multiple physical quantities and multiple parameters, and particularly relates to a magnetic field/acceleration integrated sensor and an integrated process method.
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 monolithic integrated magnetic field/acceleration sensor and an integrated process thereof, which can simultaneously measure a three-dimensional magnetic field and a three-axis acceleration and have good compatibility.
Disclosure of Invention
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+) The hall magnetic field sensor as the magnetic sensitive layer is used as the sensitive unit of the magnetic field sensor, and the boron-doped nano polysilicon film resistor is used as the sensitive element of the acceleration sensor, so that the simultaneous measurement of the three-dimensional magnetic field and the three-axis acceleration can be realized, and the invention is completed.
Specifically, the present invention aims to provide the following:
in a first aspect, a magnetic field/acceleration integrated sensor is provided, wherein the sensor comprises a magnetic field sensor and an acceleration sensor arranged on the same chip, so as to realize the simultaneous measurement of a three-dimensional magnetic field and three-axis acceleration.
In a second aspect, there is provided an integrated process method for a magnetic field/acceleration integrated sensor, preferably for preparing the magnetic field/acceleration integrated sensor of the first aspect, wherein the method comprises the following steps:
step 6, annealing at high temperature to form impurity distribution;
step 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;
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;
step 9, cleaning the SOI wafer, and growing a boron-doped nano polycrystalline silicon film on the upper surface of the device layer 1 in situ by adopting a plasma chemical vapor deposition method;
and step 10, carrying out fifth photoetching to etch the boron-doped nano polycrystalline silicon film on the upper surface of the device layer 1 to form 12 piezoresistors.
In a third aspect, there is provided a magnetic field/acceleration integrated sensor prepared by the method of the second aspect.
The invention has the advantages that:
(1) the magnetic field/acceleration integrated sensor provided by the invention can realize simultaneous measurement of a space three-dimensional magnetic field and three-axis acceleration;
(2) the magnetic field/acceleration integrated sensor provided by the invention has the advantages that the selection device layer is p-type<100>The SOI wafer of crystal orientation high-resistance monocrystalline silicon is used as a substrate, and the Hall magnetic field sensor in the magnetic sensitive unit of the magnetic field sensor is doped with nano-silicon in situFilm nc-Si: H (n)+) 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 integrated process method of the magnetic field/acceleration integrated sensor provided by the invention realizes the chip process manufacturing of the magnetic field/acceleration sensor based on the MEMS technology and the in-situ doping CVD method, realizes the chip packaging through the bonding process and the inner lead pressure welding technology, and has the characteristics of small volume, easy batch production and the like.
Drawings
FIG. 1 shows a schematic front view of a magnetic field/acceleration integrated sensor in accordance with a preferred embodiment of the present invention;
FIG. 2 shows a schematic back side view of a magnetic field/acceleration integrated sensor in accordance with 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;
a-e in fig. 5 show a flow chart of an integrated manufacturing process of the magnetic field/acceleration integrated sensor according to the present invention;
FIGS. 6 a-c show experimental characteristics 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-a z-axis second output voltage; and the delta R is the relative variation of the resistance value of the resistor when the chip is influenced by external acceleration or a magnetic field.
Detailed Description
The present invention will be described in further detail below 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 invention provides a magnetic field/acceleration integrated sensor, which comprises a magnetic field sensor and an acceleration sensor which are integrated on the same chip, as shown in figure 1, so that the simultaneous measurement of a three-dimensional magnetic field and three-axis acceleration is realized.
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 comprises 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 magnetotransistors in a three-dimensional structure disposed on a device layer 1 and a hall magnetic field sensor H, 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 resistor RL2Third 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 silicon magnetFirst collector C of triode transistor 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 invention, two silicon magnetosensitive triodes (SMST1 and SMST2) and two collector load resistors (R) which are respectively connected with 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 compoundsPole tubes (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 invention, the hall magnetic field sensor H comprises a magnetically sensitive layer, two control current poles and two hall outputs, 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 RH4Connected to form a z-axis second output voltage Vz2。
In the present invention, four equivalent resistances 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 invention, the magnetic sensitive layer of the Hall magnetic field sensor is a phosphorus-doped nano silicon film nc-Si: H (n)+) The doping amount of the phosphorus is 5E13-3～1E15cm-3。
In the invention, the phosphorus-doped nano silicon film is manufactured on the upper surface of the device layer 1 in an in-situ doping mode, so that the magnetic sensitivity characteristic of a Hall magnetic field sensor in a three-dimensional magnetic field sensor can be obviously improved, and the detection consistency in the three directions of an x axis, a y axis and a z axis can be ensured.
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 a preferred embodiment of the present invention, an isolation trench 5 is formed on the device layer 1 around each silicon magnetosensitive transistor to prevent the silicon magnetosensitive transistor from interacting with 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 enables the inside and the outside of the isolation groove to be 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 one-way conductive characteristic, so that one contact surface (the inner contact surface or the outer contact surface) is always not conducted, and thus, 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 in the middle of the acceleration sensor, and the suspension structure includes a mass block located in the center and four double L-shaped beams located on 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.
In the invention, each double L-shaped beam is arranged into two single L-shaped beams which are connected to form eight single L-shaped beam structures, so that the sensitivity in the x-axis direction and the y-axis direction can be obviously improved, the sensitivity in the x-axis direction and the sensitivity in the y-axis direction are close to the sensitivity in the z-axis direction, and the sensitivity characteristics in all directions tend to be consistent.
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.
In the present invention, the thickness of the mass and the sensor are both the distance between the upper and lower surfaces along the z-axis direction.
According to a preferred embodiment of the invention, the first mass m is arranged in the first mass1A 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 L2Third single L-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 embodimentWherein the first piezoresistor R in the x-axis direction is shown in FIG. 1 and FIG. 4x1And 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 of the two are respectively provided with a 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 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 L is provided with a 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 z-axis direction is the firstA voltage dependent resistor Rz1And 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 all boron-doped nano-polysilicon thin film resistors, preferably p-type boron-doped nano-polysilicon thin film resistors.
In the invention, when the magnetic field sensor and the acceleration sensor are manufactured in an integrated mode, the SOI wafer of p-type <100> crystal orientation high-resistance monocrystalline silicon is used as the substrate, the sensitivity of the piezoresistive acceleration sensor can be influenced to a certain extent, and in order to solve the compatibility problem, the p-type boron-doped nano polycrystalline silicon film resistor is preferably used as a sensitive element of the acceleration sensor so as to ensure the sensitivity of the acceleration sensor.
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 a preferred embodiment of the invention, a glass plate is also arranged below the acceleration sensor, and the glass plate is provided with a groove structure and is in bonding connection with the supporting silicon 2, so that two masses of the acceleration sensor can freely move in the groove.
In a further preferred embodiment, the glass sheet is a borosilicate glass sheet and has a thickness of 0.5 to 1 mm.
According to the invention, the glass sheet has an overload protection function, so that the complicated process of thinning the mass block is avoided, and the mass block at the center of the acceleration sensor can freely move in the groove of the glass sheet.
The invention also provides an integrated process method of the magnetic field/acceleration integrated sensor, which is preferably used for preparing the magnetic field/acceleration integrated sensor, as shown in a-e in fig. 5, and the method comprises 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.
According to a preferred embodiment of the present invention, the SOI wafer comprises 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 is+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 (shown as b in fig. 5).
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 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 an ohmic contact (shown as d in figure 5).
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 trench 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 as e in figure 5).
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.
In the invention, the manufacture of a monolithic three-dimensional magnetic field/three-axis acceleration sensor chip is completed on an SOI wafer device layer (p-type <100> crystal orientation high-resistance monocrystalline silicon) based on a micro-electro-mechanical system (MEMS) technology, the chip packaging is realized through a bonding process and an inner lead pressure welding technology, and the simultaneous measurement of the three-dimensional magnetic field and the three-axis acceleration can be realized. 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)+) The thickness of the film is 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
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 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) Under the condition of 1mA, 2mA, 3mA, 4mA and 5mA respectively, the magnetic field sensor described in embodiment 1 of the present invention is subjected to characteristic test, magnetic fields (-500mT to 500mT, step length is 100mT) along the x-axis, y-axis and z-axis directions are applied to the magnetic field sensor respectively, output voltages of the first differential structure, the second differential structure and the hall element of the magnetic field sensor are respectively collected, and a relationship curve of the output voltage of the magnetic field sensor and an applied magnetic field is shown in fig. 6.
Wherein, a in fig. 6 is a relationship curve of the output voltage of the first differential structure of the magnetic field sensor along the x-axis direction changing with the applied magnetic field; b in FIG. 6 is a graph showing the variation of the output voltage of the second differential structure of the magnetic field sensor with the applied magnetic field when the magnetic field is along the y-axis direction; in fig. 6, c is a graph of the output voltage of the hall element of the magnetic field sensor as a function of the applied magnetic field when the magnetic field is in the z-axis direction.
As can be seen from a and b in fig. 6, 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 c in fig. 6, when the input voltage is constant at 5V, the output voltage of the hall element that detects the magnetic field in the z-axis direction increases as the applied magnetic field increases.
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.
As can be seen from the above, when the power supply voltage is 5.0V and the base injection current is 5mA, the sensitivity of the sensor in the x-axis direction magnetic field sensor is 154mV/T, the sensitivity of the sensor in the y-axis direction magnetic field sensor is 158mV/T, and the sensitivity of the sensor in the 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, the integrated sensor can realize the simultaneous detection of the three-dimensional magnetic field and the three-axis acceleration, and the obtained sensitivities in the x direction, the y direction and the z direction are close to the same.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", and the like indicate orientations or positional relationships based on operational states of the present invention, and are only used for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, 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 should be noted that, unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; 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 meanings 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, but these embodiments are merely exemplary and merely illustrative. On the basis of the above, the invention can be subjected to various substitutions and modifications, and the substitutions and the modifications are all within the protection scope of the invention.
Claims (7)
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 sheet as a substrate, the SOI sheet comprises a device layer (1), a supporting silicon (2) and a first silicon dioxide layer (3),
the device layer (1) is p-type <100> crystal orientation high-resistance monocrystalline silicon;
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), 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,
the magnetic sensitive layer of the Hall magnetic field sensor is a phosphorus-doped nano silicon film nc-Si: H (n+)；
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;
wherein the mass blocks have 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 total eight single-L-shaped beams of the four double-L-shaped beams 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)；
In the first mass block (m)1) And a secondMass block (m)2) A first middle beam L is arranged between the two9And a second intermediate beam L10；
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)；
The piezoresistors in the x-axis direction, the y-axis direction and the z-axis direction are all boron-doped nano polycrystalline silicon film resistors.
2. The sensor of claim 1,
the thickness of the device layer (1) is 20-50 mu m, and the thickness of the supporting silicon (2) is 420-550 mu m.
3. 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.
4. An integrated process for manufacturing an integrated magnetic field/acceleration sensor according to any one of claims 1 to 3, characterized in that it comprises the following steps:
step 1, cleaning an SOI (silicon on insulator) sheet, photoetching for the zeroth time, and manufacturing a register mark on a device layer (1);
step 2, oxidizing for the first time, and growing thin oxygen on the device layer (1) to be used as an ion implantation buffer layer;
step 3, carrying out first photoetching, and carrying out ion implantation on the upper surface of the device layer (1) to realize n+Carrying out type doping, and processing for 8-10 h at 600-1200 ℃ to form an isolation groove;
step 4, carrying out second photoetching, etching a load resistor window on the upper surface of the device layer (1), carrying out ion implantation, and carrying out n-Carrying out type doping to form a load resistor;
step 5, carrying out third photoetching, etching a base region window on the upper surface of the device layer (1), carrying out ion implantation, and carrying out p+Heavily doping to form a base region;
step 6, annealing at high temperature to form impurity distribution;
step 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;
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;
step 9, cleaning the SOI wafer, and growing a boron-doped nano polycrystalline silicon film on the upper surface of the device layer (1) in situ by adopting a plasma chemical vapor deposition method;
and 10, carrying out fifth photoetching to etch the boron-doped nano polycrystalline silicon film on the upper surface of the device layer (1) to form 12 piezoresistors.
5. The method of claim 4, further comprising, after step 10, the steps of:
step 11, cleaning a 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;
step 12, performing sixth photoetching, and etching a lead hole on the upper surface of the device layer (1);
step 13, performing seventh photoetching, and etching the window of the emission area of the C-shaped silicon cup and the mass block of the acceleration sensor on the back of the supporting silicon (2) by adopting a deep groove etching technology (ICP);
step 14, n is performed at the emitter window supporting the back of the silicon (2)+Forming an emitting region by type heavy doping, and then carrying out high-temperature annealing treatment;
step 15, cleaning a silicon wafer, and growing a metal aluminum layer on the upper surface of the device layer (1) and the lower surface of the supporting silicon (2) through magnetron sputtering to form a metal electrode; carrying out eighth photoetching, and reversely etching a metal aluminum layer on the upper surface of the device layer (1) to form a metal electrode;
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;
step 17, performing ninth photoetching, and etching the passivation layer to form a pressure welding point; then cleaning the silicon wafer, and carrying out alloying treatment to form ohmic contact;
step 18, performing tenth photoetching and deep groove etching technology to etch the silicon wafer device layer (1) to the first silicon dioxide layer (3) and release the L-shaped beam structure;
and 19, bonding the SOI sheet with a borosilicate glass sheet with an overload protection structure.
6. The method according to claim 4, wherein in step 6, 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 ℃.
7. The method according to claim 5, characterized in that in step 17 the alloying treatment is carried out as follows: treating at 300-500 deg.C for 10-50 min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910894125.6A CN110632538B (en) | 2019-09-20 | 2019-09-20 | Magnetic field/acceleration integrated sensor and integration process method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910894125.6A CN110632538B (en) | 2019-09-20 | 2019-09-20 | Magnetic field/acceleration integrated sensor and integration process method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110632538A CN110632538A (en) | 2019-12-31 |
| CN110632538B true CN110632538B (en) | 2021-08-24 |
Family
ID=68972047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910894125.6A Active CN110632538B (en) | 2019-09-20 | 2019-09-20 | Magnetic field/acceleration integrated sensor and integration process method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110632538B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114061796A (en) * | 2021-11-10 | 2022-02-18 | 中国电子科技集团公司第四十九研究所 | Silicon piezoresistive pressure sensor core and preparation method thereof |
| CN114440879A (en) * | 2022-01-27 | 2022-05-06 | 西人马联合测控（泉州）科技有限公司 | Sensor chip and preparation method thereof |
| CN115144797A (en) * | 2022-08-30 | 2022-10-04 | 深圳平创半导体有限公司 | Simulation test method for Hall mobility of JFET (junction field effect transistor) area in SiC MOSFET (Metal-oxide-semiconductor field Effect transistor) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102730617A (en) * | 2011-04-08 | 2012-10-17 | 美新半导体（无锡）有限公司 | Packaging structure of integrated magnetic and accelerometer and packaging method thereof |
| CN103076577A (en) * | 2012-08-03 | 2013-05-01 | 陈磊 | Design and manufacture technology of sensor chip for detecting magnetic field and acceleration |
| CN104627951A (en) * | 2013-11-07 | 2015-05-20 | 罗伯特·博世有限公司 | Micromechanical sensor device |
| CN107356885A (en) * | 2017-08-18 | 2017-11-17 | 黑龙江大学 | A kind of single-chip integration two-dimensional magnetic field sensor and its manufacture craft |
| CN109856425A (en) * | 2018-04-20 | 2019-06-07 | 黑龙江大学 | A kind of monolithic integrated tri-axial acceleration sensor and its manufacture craft |
| CN211263740U (en) * | 2019-09-20 | 2020-08-14 | 黑龙江大学 | Magnetic field/acceleration integrated sensor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120255357A1 (en) * | 2011-04-08 | 2012-10-11 | Dongmin Chen | Sensor package having integrated accelerometer and magnetometer |
-
2019
- 2019-09-20 CN CN201910894125.6A patent/CN110632538B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102730617A (en) * | 2011-04-08 | 2012-10-17 | 美新半导体（无锡）有限公司 | Packaging structure of integrated magnetic and accelerometer and packaging method thereof |
| CN103076577A (en) * | 2012-08-03 | 2013-05-01 | 陈磊 | Design and manufacture technology of sensor chip for detecting magnetic field and acceleration |
| CN104627951A (en) * | 2013-11-07 | 2015-05-20 | 罗伯特·博世有限公司 | Micromechanical sensor device |
| CN107356885A (en) * | 2017-08-18 | 2017-11-17 | 黑龙江大学 | A kind of single-chip integration two-dimensional magnetic field sensor and its manufacture craft |
| CN109856425A (en) * | 2018-04-20 | 2019-06-07 | 黑龙江大学 | A kind of monolithic integrated tri-axial acceleration sensor and its manufacture craft |
| CN211263740U (en) * | 2019-09-20 | 2020-08-14 | 黑龙江大学 | Magnetic field/acceleration integrated sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110632538A (en) | 2019-12-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110632538B (en) | Magnetic field/acceleration integrated sensor and integration process method | |
| US10775248B2 (en) | MEMS strain gauge sensor and manufacturing method | |
| JP2005308749A (en) | Wheatstone bridge mechanism for sensor | |
| CN103344374B (en) | Hidden-type MEMS pressure sensor sensitive chip and manufacturing method thereof | |
| JP2017516987A (en) | Monolithic three-axis linear magnetic sensor and manufacturing method thereof | |
| CN211263740U (en) | Magnetic field/acceleration integrated sensor | |
| CN107356885B (en) | Monolithic integrated two-dimensional magnetic field sensor and manufacturing process thereof | |
| JPH01251763A (en) | Vertical hall element and integrated magnetic sensor | |
| CN104062463B (en) | Piezoresistive acceleration sensor and manufacturing method thereof | |
| CN108428717A (en) | The device and method that mechanical stress senses on chip | |
| CN101233421B (en) | Magnetic tunnel junction sensor method | |
| KR20030026872A (en) | Acceleration sensor | |
| CN114061797A (en) | MEMS piezoresistive pressure sensor with double bridge structures and preparation method thereof | |
| CN103630854A (en) | Spatial 3D (Three-dimensional) magnetic field detection sensor | |
| JP2005049179A (en) | Semiconductor magnetic sensor and magnetic measuring device using the same | |
| KR100904994B1 (en) | Method for fabricating pressure sensor and structure of the same | |
| CN111880130B (en) | Space magnetic field vector sensor and manufacturing process method thereof | |
| JP3471986B2 (en) | Hall element and watt hour meter using the same | |
| CN113567869B (en) | Battery voltage monitoring miniature sensor and voltage monitoring method | |
| CN213398895U (en) | Space magnetic field vector sensor | |
| CN214625049U (en) | All-dielectric isolation silicon magnetic sensitive triode | |
| JP2715738B2 (en) | Semiconductor stress detector | |
| CN105047814A (en) | Si-based magnetic sensing device with low magnetic field and giant magnetoresistance, preparation method and performance testing method | |
| CN218941675U (en) | Three-dimensional silicon magneto-dependent triode with planarized electrode structure | |
| CN114823843A (en) | Manufacturing process of all-dielectric isolation silicon magnetic sensitive triode |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |