High-integration-level matrix type magnetic sensing chip structure, circuit and manufacturing method

Abstract

The invention discloses a high-integration-level matrix type magnetic sensing chip structure and circuit and a manufacturing method thereof, and belongs to the technical field of semiconductor devices, the chip structure comprises a plurality of matrix elements, a switch matrix and a rear-end interface circuit, and each matrix element comprises a cross-shaped horizontal Hall element and a switch device; the switch matrix is composed of switch devices in matrix elements; the cross-shaped horizontal Hall element matrix is an N * M Hall matrix element formed by an integrated 1 * M Hall element matrix in each row; according to the invention, the structure and the circuit of the matrix type magnetic sensing chip which can be used for statically and dynamically measuring multi-dimensional magnetic field distribution in real time in severe environments such as high temperature, high pressure and high radiation are innovated and manufactured; dynamic and static measurement in a multi-dimensional magnetic field space can be achieved, error compensation is carried out through a circuit, it is ensured that the chip can stably work in the high-temperature, high-pressure and high-radiation environment, and it can be ensured that the chip has high linearity, sensitivity and accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a highly integrated matrix magnetic sensor chip structure, circuit and manufacturing method. Background Art

[0002] Accurate measurement of magnetic field is crucial to people's daily life. It involves whether other physical quantities such as position, speed, angle, etc. can be correctly identified, thus affecting the use of devices in power electronics, navigation and guidance, aerospace, biomedicine and other fields. Common magnetic field measurement methods include Hall effect method, fluxgate method, magnetoresistance effect method, nuclear magnetic resonance method, superconducting effect method and magneto-optical effect method. With the development of new generations of semiconductor materials, Hall magnetic sensors have been greatly developed, their performance has become more and more outstanding, and their application fields have continued to increase.

[0003] The first generation of semiconductor materials are silicon (Si) and germanium (Ge), the second generation of semiconductor materials are represented by gallium arsenide (GaAs), indium arsenide (InAs), and indium antimonide (InSb), and the third generation of semiconductor materials are represented by gallium nitride (GaN), silicon carbide (SiC), diamond, and zinc oxide (ZnO). The Hall magnetic sensor made of the first generation of semiconductor materials (typically Si) has a low material mobility, resulting in low device sensitivity; the second generation of semiconductor materials has a small bandgap, resulting in reliability problems such as device performance degradation or failure at high temperatures greater than 200°C. In recent years, the third generation of semiconductor materials have shown great potential in optoelectronic devices, power electronics, radio frequency microwave devices, lasers, and detection devices. Their unique properties such as large bandgap, high breakdown electric field, large thermal conductivity, high electron saturation velocity, and small dielectric constant make the devices prepared have the characteristics of high temperature resistance, high voltage resistance, radiation resistance, and high sensitivity, and can be effectively used even in harsh environments. The Hall magnetic sensor made of the third generation of semiconductor materials has good chemical stability and excellent high temperature reliability due to its large bandgap. In particular, taking the gallium nitride (GaN) Hall magnetic sensor as an example, its bandgap is 3.47eV, which ensures that the device has high stability and reliability in high temperature environments; its heterojunction structure has a naturally formed high-mobility two-dimensional electron gas (2DEG) channel, which ensures that the device has high sensitivity; its low intrinsic carrier concentration ensures low noise in the device. In addition to semiconductor materials, domestic reports also report Hall sensors made of two-dimensional materials (such as graphene). The low flake carrier concentration and single atomic layer thickness of graphene result in high carrier saturation velocity, which can achieve high sensitivity and optimize resolution. Its simple processing technology and natural flexibility and mechanical properties are expected to be widely used in flexible sensors.

[0004] At present, the Hall magnetic sensors that occupy a large market share are usually made of traditional silicon (Si), germanium (Ge) and other materials, and are mostly used in the single-point measurement state of the static magnetic field. It is impossible to measure the dynamic magnetic field and the magnetic field distribution in one-dimensional, two-dimensional, or even three-dimensional space. This requires the use of a multi-dimensional matrix Hall magnetic sensor to measure the magnetic field in real time or at multiple points. At the same time, in the single-point measurement state, there is usually a large measurement error due to factors such as disturbances in the position or angle of the sensor, and the subsequent circuit needs to be used to properly compensate for the error. Therefore, it is necessary to design a multi-dimensional matrix magnetic sensor with high sensitivity, high accuracy, and high integration to measure the magnetic field in real time or at multiple points. On the one hand, it can measure the dynamic magnetic field and observe the magnetic field distribution in real time; on the other hand, it can measure the static magnetic field, and compensate for the measurement error of the magnetic field through the matrix Hall magnetic sensor, simplifying the circuit while improving the measurement accuracy.

[0005] Most of the existing Hall magnetic sensors are linear horizontal Hall magnetic sensors that measure the magnetic field perpendicular to the device surface, which mainly include three types. One is a single material Hall sensor represented by Si material, which has a relatively mature process and is easy to integrate and produce, but is limited by the low mobility of Si material itself, and the sensitivity of this type of Hall sensor is often relatively low. The more mature products on the market include Infineon's TLE499X series, which are all linear Hall sensors with circuit integration and are commonly used in the field of steering torque sensing. The second type is a Hall sensor based on the second-generation semiconductor (InAs, InSb, GaAs, etc.) heterojunction structure. Although it can obtain higher sensitivity due to the high-mobility 2DEG at its heterojunction interface, the narrow bandgap of the material itself makes the device unable to work stably and reliably in a high temperature environment. The more mature products on the market are Asahi Kasei's HW series, HG series, and HQ series products. The HW series is the InSb Hall sensor with the highest sensitivity; the HG series is the GaAs Hall sensor with the most stable temperature characteristics among the three series; the HQ series is the InAs Hall sensor with balanced sensitivity and temperature characteristics among the three series. The third type is a Hall sensor based on a third-generation semiconductor (GaN, etc.) heterojunction structure. The third-generation semiconductor material has unique properties such as large bandgap, high breakdown electric field, large thermal conductivity, high electron saturation velocity, and small dielectric constant, which makes the devices made from it resistant to high temperature, high pressure, radiation, and high sensitivity, and can be effectively used even in harsh environments. However, there are currently no mature products on the market. These three Hall magnetic sensors can only be used in single-point measurement states of static magnetic fields, and cannot measure dynamic magnetic fields and magnetic field distribution in one-dimensional, two-dimensional, or even three-dimensional space. In particular, there are no mature products for the third type of Hall magnetic sensor in the market. At the same time, in a single-point measurement state, there is often a large measurement error due to factors such as disturbances in the position or angle of the sensor, and subsequent circuits are required to appropriately compensate for the error.

[0006] Therefore, it is even more necessary to use a matrix Hall magnetic sensor with integrated subsequent interface circuit to measure the magnetic field distribution in space in real time or at multiple points (including the magnetic field distribution under high temperature, high pressure, and high radiation environments). On the one hand, it can measure the dynamic magnetic field and observe the magnetic field distribution in real time; on the other hand, it can measure the static magnetic field and compensate for the measurement error of the magnetic field through the matrix Hall magnetic sensor, which simplifies the circuit and improves the measurement accuracy.

[0007] Existing Hall magnetic sensors are mostly used in single-point measurement of static magnetic fields, and cannot measure dynamic magnetic fields and magnetic field distribution in one-dimensional, two-dimensional or even three-dimensional space. At the same time, single-point measurement often has large measurement errors due to factors such as disturbances in the position or angle of the sensor, so subsequent circuits are required to appropriately compensate for the errors. Summary of the invention

[0008] In order to solve the problems existing in the above-mentioned prior art, the present invention proposes a highly integrated matrix magnetic sensor chip, including its structure, circuit and manufacturing method. The technical solution can be used for real-time, static and dynamic measurement of the multi-dimensional matrix magnetic sensor chip of the magnetic field distribution perpendicular to the device surface in the space, and structural and circuit innovations and manufacturing are carried out for this; dynamic and static measurement of the magnetic field in the multi-dimensional space can be realized, and error compensation is performed through the circuit, which not only ensures that the chip can work stably, but also ensures that it has high linearity, sensitivity and accuracy.

[0009] The technical solution is as follows:

[0010] A highly integrated matrix magnetic sensor chip structure comprises: a plurality of matrix elements, a switch matrix, and a back-end interface circuit, wherein the matrix elements comprise: a cross-shaped horizontal Hall element and a switch device; the switch matrix is ​​composed of the switch devices in the matrix elements; the cross-shaped horizontal Hall element matrix 2 is an N×M matrix array in which each row is an integrated 1×M Hall element matrix 1; for the cross-shaped horizontal Hall element matrix 2, the electrodes C2 of each Hall element are connected together and grounded, and electrodes S1 and S2 are only arranged at the leftmost and rightmost ends of each row of the 1×M Hall element matrix 1; the switch device comprises a gate G, a source S, and a drain D; the electrode C2 is connected to the source S through a metal interconnection line.

[0011] Furthermore, the "cross" shaped horizontal Hall element can be made of Si bulk material or two-dimensional electron gas channel materials such as GaN, GaAs, InSb, InAs, and GaO, or can be made of two-dimensional materials such as graphene.

[0012] Furthermore, the heterojunction structure composed of the two-dimensional electron gas channel material as the "cross"-shaped horizontal Hall element includes a substrate, a buffer layer, a channel layer, and a barrier layer. The two-dimensional electron gas channel material heterojunction structure composed of the buffer layer, the channel layer and the barrier layer are sequentially grown on the substrate, and a horizontal Hall element and a switching device are arranged above the channel layer; the main body of the horizontal Hall element is composed of a "cross"-shaped barrier layer, and the four ends of the barrier layer are respectively provided with electrodes C1, electrode C2, electrode S1, and electrode S2; the source level S and drain level D of the switching device are arranged on the channel layer, and a dielectric layer extending to the barrier layer is provided on the channel layer, and the gate G is arranged above the dielectric layer; the electrode C1 is connected to the source level S through a metal interconnection line.

[0013] Furthermore, the substrate is one of silicon, silicon carbide, sapphire, or a material homogeneous with the channel layer; the buffer layer is one of AlN, GaN, or a superlattice structure material.

[0014] Furthermore, the channel layer is one of GaN, GaAs, InSb, InAs, and GaO; and the barrier layer is a heterojunction material that can form a two-dimensional electron gas channel with the channel layer.

[0015] Furthermore, the dielectric layer is one of Al2O3, Si3N4, SiO2, and SiON; and the metal interconnection line is one of copper, tungsten, aluminum, and cobalt.

[0016] Furthermore, the thickness of the buffer layer is 10-100 nm; the thickness of the channel layer is 0.1-10 μm; the thickness of the barrier layer is 5-100 nm; and the thickness of the dielectric layer is 20-50 nm.

[0017] The present invention also includes a highly integrated matrix magnetic sensor chip circuit, including: a power module, an excitation power supply, a reference voltage source, an adjustable gain amplifier, a voltage regulator, an AD converter, a microprocessor, a switch matrix, and an N×M Hall matrix element. The power module is respectively connected to the reference voltage source, the switch matrix, and the microprocessor; the reference voltage source is respectively connected to the excitation power supply, the adjustable gain amplifier, and the voltage regulator; the excitation power supply is sequentially connected to the N×M Hall matrix element, the adjustable gain amplifier, the voltage regulator, the AD converter, and the microprocessor; the switch matrix is ​​connected to the N×M Hall matrix element and is controlled by the microprocessor.

[0018] Furthermore, the N×M Hall matrix element includes a "cross" shaped horizontal Hall element and a switch device; the switch matrix is ​​composed of the switch devices in the matrix element; the "cross" shaped horizontal Hall element matrix is ​​an N×M matrix array composed of an integrated 1×M Hall element matrix in each row; for the "cross" shaped horizontal Hall element matrix, the electrodes C2 of each Hall element are connected together and grounded, and electrodes S1 and S2 are only set at the leftmost and rightmost ends of each row of the 1×M Hall element matrix; the switch device includes a gate G, a source S, and a drain D; the electrode C2 is connected to the source S through a metal interconnection line.

[0019] The present invention also includes a method for manufacturing a highly integrated matrix magnetic sensor chip (for Si-based devices, a mature CMOS integrated circuit process or a silicon bipolar integrated circuit process is used, which is not described in detail. Here, the channel material heterojunction structure and the two-dimensional material device manufacturing process are mainly described), and the steps are as follows:

[0020] S1. Cleaning the substrate: preparing the substrate material, cleaning the substrate, and removing contaminants on the substrate surface;

[0021] S2. Epitaxial growth: For heterojunction structure devices of channel materials, epitaxially grow heterojunction structures and buffer layers of two-dimensional electron gas channel materials by using any of metal organic chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy; For two-dimensional material devices, grow two-dimensional materials by using any of mechanical stripping, reduction oxidation, silicon carbide surface epitaxial growth, and chemical vapor deposition CVD, and transfer the two-dimensional materials to a target substrate; the thickness of the generated channel layer is 0.1 to 10 μm, the thickness of the barrier layer on the channel layer is 5 to 100 nm, and the buffer layer is AlN, GaN or a superlattice structure, and its thickness is 10 to 100 nm;

[0022] S3, mesa etching: after the epitaxially grown sample is photolithographically developed, it is etched by inductively coupled plasma etching; the mesa etching depth is 50 to 800 nm; in step S4, the etching depth is 1 to 100 nm; in step S6, the etching depth is 1 to 100 nm; in step S7, the deposition thickness is 5 to 50 nm;

[0023] S4, shallow etching: After the sample isolated by mesa etching is developed by photolithography, shallow etching is performed by inductively coupled plasma etching. For heterojunction structure devices of channel materials, it is used to realize 2DEG contact with the mesa in the channel material; for two-dimensional material devices, it is used to form a conductive channel;

[0024] S5, ohmic contact electrode production: after photolithography and development, composite metal is deposited by electron beam evaporation system, and then rapid thermal annealing process is used to form good ohmic contact to produce electrodes C1, C2, S1, S2, source S, and drain D;

[0025] S6, gate groove etching: after the electrodes C1, C2, S1, S2, source S, and drain D are prepared, the gate groove is etched by inductively coupled plasma etching;

[0026] S7, gate dielectric deposition: after the gate groove is etched, the gate groove interface of the sample is treated by an alkaline solution containing nitrogen, and then the gate dielectric is deposited by any one of metal organic compound chemical vapor deposition, plasma chemical vapor deposition, atomic layer deposition, low pressure chemical vapor deposition, and magnetron sputtering;

[0027] S8, gate electrode production: after photolithography and development, composite metal is deposited by electron beam evaporation system, and gate electrode is formed after metal stripping;

[0028] S9, surface passivation: use plasma enhanced chemical vapor deposition, magnetron sputtering, atomic layer deposition, electron beam evaporation, any of which method to deposit SiO2 for device passivation;

[0029] S10, window opening: photolithography and etching of the passivation layer at the electrode to form a window;

[0030] S11, metal interconnection line fabrication: after photolithography and development, metal is deposited by electron beam evaporation system to form interconnection lines;

[0031] S12, electrode leads: using any of the methods of magnetron sputtering, electron beam evaporation, and thermal evaporation to deposit metal at the electrode to make pads and make leads;

[0032] S13, circuit connection: package the bare die with good leads, and connect each component of the back-end interface circuit on the same PCB board, so as to complete the circuit connection of the highly integrated matrix magnetic sensor chip;

[0033] S14. Appearance design: Carry out appearance design for the entire system and complete the production of the instrument.

[0034] The beneficial effects of the present invention are:

[0035] The highly integrated matrix magnetic sensor chip described in the present invention has the following characteristics:

[0036] 1) The device structure is simple and diverse. It can be made of Si material with mature technology and reliable performance. It can also be made of heterojunction structure composed of GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga2O3 / AlGaO and other materials. The naturally formed two-dimensional electron gas (2DEG) channel makes the device highly sensitive and has high electron mobility (the electron mobility of GaAs and InAs can reach 9000cm 2 / (V·s),40000cm 2 / (V·s)) makes them have excellent electron transport performance under both low and high fields, and are ideal channel materials for ultra-high-speed, low-power sensor devices. In addition, they can also be made of two-dimensional materials (such as graphene), with simple processes and easy compatibility with silicon-based CMOS processes, and can realize high-sensitivity Hall sensors with low temperature drift coefficients.

[0037] 2) Devices typically made of two-dimensional electron gas channel materials show great potential in optoelectronic devices, power electronics, radio frequency microwave devices, lasers and detection devices. For example, GaN materials have unique properties such as large bandgap, high breakdown electric field, large thermal conductivity, high electron saturation velocity, and small dielectric constant. The devices made from them have the characteristics of high temperature resistance, high voltage resistance, radiation resistance, and high sensitivity, and can be effectively used even in harsh environments.

[0038] 3) The highly integrated matrix magnetic sensor chip consists of N×M matrix elements, a switch matrix and a back-end interface circuit. Each matrix element contains a horizontal Hall element and a switch device. Each switch device is combined to form a switch matrix. The microprocessor generates a control signal to control the opening and closing of the Hall element excitation circuit. It has a simple structure and flexible operation.

[0039] 4) The highly integrated matrix magnetic sensor chip can not only measure accurate static magnetic fields, but also measure dynamic magnetic fields and observe magnetic field distribution in real time. It is easy to integrate with circuits. The back-end interface circuit ensures the scanning and acquisition of the Hall signal output by each matrix element. At the same time, the output voltages of multiple matrix elements can compensate for the output voltages of other matrix elements, simplifying the circuit while improving sensitivity and accuracy.

[0040] Beneficial effects brought by the technical solution of the present invention:

[0041] 1) The simple structure of combining Hall elements and switch devices into a matrix element can flexibly realize real-time, static and dynamic measurement of the magnetic field perpendicular to the device direction in one-dimensional, two-dimensional or even three-dimensional space, which is not available in a single Hall sensor;

[0042] 2) The device can be made of a variety of materials, such as Si materials, which have mature processes and reliable performance; it can also be made of heterojunction structures composed of materials such as GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga2O3 / AlGaO, etc. The naturally formed two-dimensional electron gas (2DEG) channel makes the device highly sensitive, and the high electron mobility (the electron mobility of GaAs and InAs can reach 9000cm2 / (V·s) and 40000cm2 / (V·s) respectively) makes them have excellent electron transport performance under both low and high fields, and is an ideal channel material for ultra-high-speed, low-power sensor devices; in addition, it can also be made of two-dimensional materials (such as graphene), which has a simple process and is easily compatible with silicon-based CMOS processes, and can realize high-sensitivity Hall sensors at a low temperature drift coefficient. Devices made of different materials can adapt to the chip structure, and chips made of different materials can be selected according to the application environment, which is not available in traditional Hall sensors;

[0043] 2) The integration of chip and circuit greatly improves the performance of the device, ensuring that the sensitivity of the device is greatly improved while the measured magnetic field range remains unchanged, with a maximum of 16.5mV / mT (when the measured magnetic field range is -100mT to 100mT and the excitation current is 1mA), which is nearly 300 times that of a single third-generation semiconductor Hall sensor (for example, the sensitivity of a single GaN horizontal Hall sensor at an excitation current of 1mA is 0.06mV / mT). At the same time, the linearity reaches 99.969%. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in combination with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0045] Figure 1 This is a schematic diagram of the structure of a highly integrated matrix magnetic sensor chip proposed in the present invention;

[0046] Figure 2 This is a structural block diagram of the back-end interface circuit (including the switch matrix) of the highly integrated matrix magnetic sensor chip proposed in the present invention;

[0047] Figure 3 A top view of the N×M Hall matrix process structure of a highly integrated matrix magnetic sensor chip proposed in the present invention;

[0048] Figure 4 This is a front view of a single matrix element process structure of a highly integrated matrix magnetic sensor chip proposed in the present invention;

[0049] Figure 5-Figure 16 A schematic diagram of the process for realizing the high-integration matrix magnetic sensor chip proposed in the present invention;

[0050] Figure 17-Figure 28 This is a process flow chart of a specific embodiment of this patent application;

[0051] Fig.29 The high-integration matrix magnetic sensor chip proposed in the present invention measures the magnetic field B and the Hall output voltage V of each matrix element in static measurement. o The experimental verification result diagram of the relationship between

[0052] Fig.30 This is a graph showing the experimental verification results of the relationship between the Hall output voltage of a single matrix element following the change of the magnetic field of the highly integrated matrix magnetic sensor chip proposed in the present invention under a sinusoidal magnetic field with a peak-to-peak value Bp-p of 17.798G and a frequency f of 5Hz. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Figures 1 to 7 The structure, circuit and manufacturing method of the highly integrated matrix magnetic sensor chip are further explained.

[0054] Example 1

[0055] In order to solve the problems existing in the above-mentioned prior art and realize the real-time, dynamic and static measurement of the magnetic field perpendicular to the device surface under high temperature, high pressure and high radiation environment, the present invention proposes a technical solution of a highly integrated matrix magnetic sensor chip. The technical solution includes chip structure, circuit and manufacturing method. Figure 1 The figure shows the structure of a highly integrated matrix magnetic sensor chip. The device consists of N×M matrix elements, a switch matrix, and a back-end interface circuit. Each matrix element contains a "cross-shaped" horizontal Hall element and a switch device. Figure 1 As shown, electrodes C1 and C2 are the excitation signal input terminals, and voltage V bias or current I bias , the potential difference is measured between electrodes S1 and S2 as the Hall output voltage V hall , or the electrodes S1 and S2 can be used as signal input terminals to input voltage or current, and the potential difference between electrodes C1 and C2 can be measured as the Hall output voltage. In the process, the electrodes C2 of each Hall element are connected together and grounded, and electrodes S1 and S2 are only set at the leftmost and rightmost ends of each row of 1×M Hall element matrix 1, and are respectively led out through a larger pad as two common detection terminals V hall+ / V hall- One end of the excitation electrodes C1 and C2 is grounded, and the other end is connected to the source S of the switch device through a metal interconnection process. At the same time, the gates G of the switch devices in each row of the matrix element are connected together and connected to the microprocessor row selection signal through wire bonding. The drains D of the switch devices in each column of the matrix element are connected together and connected to the source S of the column selection switch device in the switch matrix, and the gates G of the column selection switch devices in the switch matrix are connected to the microprocessor column selection signal through wire bonding. The excitation power supply V bias / I bias The excitation signal is input through the drain D of the column selection switch device. The row selection signal of the microprocessor controls the on and off of the switch device in each row of the matrix element, and the column selection signal controls the on and off of the column selection switch device in each column, so that the excitation and detection of the Hall element in any row and column can be realized at any time.

[0056] In addition, in order to reduce the measurement error and realize the real-time, static and dynamic measurement of magnetic field distribution, the back-end interface circuit is built, such as Figure 2 The figure shows the block diagram of the back-end interface circuit structure, which includes a power module, a switch matrix, an excitation power supply, a reference voltage source, an adjustable gain amplifier, a voltage regulator, an AD converter, and a microprocessor. The power module supplies power to the entire sensor chip; the excitation power supply provides an excitation current or voltage for the N×M Hall matrix elements; the microprocessor outputs a corresponding signal to control the switch of one or more switching devices, so that the excitation circuit in the corresponding matrix element is turned on or off; the reference voltage source provides a reference voltage V for the adjustable gain amplifier and the voltage converter. ref ; The output voltage V of the Hall element to the adjustable gain amplifier hall The device is amplified with an adjustable magnification factor to accurately measure various specific magnetic field ranges; the voltage regulator adjusts the amplified Hall output voltage to a voltage range that can be recognized by the AD converter, thereby converting the analog Hall output voltage signal V oa Converted into digital Hall output voltage signal V od ; Finally, the Hall output voltage signal V of each matrix element o The signals are sent to the microprocessor for signal analysis and processing, such as using other matrix elements to compensate for the Hall output voltage of a certain matrix element to reduce the measurement error, performing weighted averaging on the output results of multiple matrix elements and then outputting them, and drawing a magnetic field distribution diagram for the Hall output voltages of all matrix elements.

[0057] The technical solution and process structure of the present invention are as follows Figure 3-Figure 4As shown, in order to explain the process structure more clearly, the figure shows the top view of the N×M Hall matrix process structure and the formal diagram of the single matrix element process structure separately. The chip process structure includes a substrate, a buffer layer, a channel layer, a barrier layer, a dielectric layer, a metal interconnection line, an electrode C1, an electrode C2, an electrode S1, an electrode S2, a gate G, a source level S, and a drain level D. The substrate is a silicon, silicon carbide, sapphire or other substrate of the same material as the channel layer, on which a buffer layer and a two-dimensional electron gas channel material heterojunction structure are epitaxially grown. The heterojunction structure includes a channel layer and a barrier layer. Due to spontaneous polarization and piezoelectric polarization effects, a two-dimensional electron gas (2DEG) is formed at the heterojunction interface. The buffer layer can be AlN or GaN or other superlattice structure materials (thickness of 10-100nm), the channel layer is GaN, GaAs, InSb, InAs, GaO and other materials that can form a two-dimensional electron gas channel (thickness of 0.1-10μm), the barrier layer is AlGaN, InGaAs, AlGaAs, InAlN, AlGaO and other heterojunction materials that can form a two-dimensional electron gas channel with the channel layer (thickness of 5-100nm), the material composition in the barrier layer is not limited, the dielectric layer is Al2O3, Si3N4, SiO2, SiON and other oxides or nitrides (thickness of 20-50nm), and the metal interconnection line is usually made of copper, tungsten, aluminum, cobalt and other metals. The Hall element electrodes C1, C2, S1, S2, the switching device gate G, the source level S, and the drain level D in each matrix element are the same, and the electrode shape is not specifically limited, and can be rectangular, trapezoidal, etc. Except for the gate G, other electrodes need to form good ohmic contact with the semiconductor material.

[0058] The working principle of the high-integration matrix magnetic sensor chip proposed in the present invention is as follows: when a magnetic field B perpendicular to the direction of the device appears in the environment, the row selection signal and column selection signal output by the microprocessor control the switch device in a certain row matrix element and the column selection switch device in a certain column in the switch matrix to turn on, and at this time, an excitation voltage or an excitation current flows into the excitation terminals C1 and C2 of the Hall elements in the corresponding matrix elements, thereby generating a voltage or an excitation current at the output terminal S1 (V hall+ )、S2(V hall- ) induces a Hall output voltage signal, which is sent to the back-end interface circuit for a series of signal processing, including filtering, amplification, etc., and then output, which can realize magnetic field measurement at a specified position, dynamic magnetic field scanning, and multi-dimensional magnetic field distribution measurement perpendicular to the chip direction.

[0059] The invention proposes a highly integrated matrix magnetic sensor chip structure, circuit and manufacturing method. The device structure is characterized by: 1) The device structure is simple and diverse, and can be made of Si material with mature technology and reliable performance; it can also be made of a heterojunction structure composed of GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga2O3 / AlGaO and other materials. The naturally formed two-dimensional electron gas (2DEG) channel makes the device highly sensitive, and at the same time, the higher electron mobility (the electron mobility of GaAs and InAs can reach 9000cm 2 / (V·s),40000cm 2 / (V·s)) makes them have excellent electron transport performance under both low and high fields, and are ideal channel materials for ultra-high-speed, low-power sensor devices; in addition, they can also be made of two-dimensional materials (such as graphene), which has a simple process and is easily compatible with silicon-based CMOS processes, and can realize high-sensitivity Hall sensors at a lower temperature drift coefficient. 2) Devices typically made of two-dimensional electron gas channel materials have shown great potential in optoelectronic devices, power electronics, radio frequency microwave devices, lasers and detection devices. For example, GaN materials have unique properties such as large bandgap, high breakdown electric field, large thermal conductivity, high electron saturation velocity, and small dielectric constant, which make the devices prepared have the characteristics of high temperature resistance, high voltage resistance, radiation resistance, and high sensitivity, and can be effectively used even in harsh environments. 3) The highly integrated matrix magnetic sensor chip consists of N×M matrix elements, a switch matrix and a back-end interface circuit. Each matrix element contains a horizontal Hall element and a switch device. Each switch device is controlled by a row selection signal and a column selection signal generated by a microprocessor to control the opening and closing of the Hall element excitation circuit. It has a simple structure and flexible operation. 4) The highly integrated matrix magnetic sensor chip can not only measure accurate static magnetic fields, but also measure dynamic magnetic fields and observe magnetic field distribution in real time. It is easy to integrate with circuits. The back-end interface circuit ensures the scanning and collection of the Hall signal output by each matrix element. At the same time, the output voltages of multiple matrix elements can realize compensation for the output voltages of other matrix elements, simplifying the circuit while improving sensitivity and accuracy.

[0060] like Figure 5-Figure 16 As shown, the process of implementing the target device of the present invention is described as follows:

[0061] 1) Cleaning the substrate: Prepare 4-inch or 6-inch substrate material, clean the substrate, and remove contaminants on the substrate surface.

[0062] 2) Epitaxial growth: epitaxially grow a two-dimensional electron gas channel material heterojunction structure and a buffer layer using any of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and hydride vapor phase epitaxy (HVPE). The thickness of the generated channel layer is 0.1 to 10 μm, and the thickness of the barrier layer on the channel layer is 5 to 100 nm. The buffer layer can be AlN, GaN or a superlattice structure with a thickness of 10 to 100 nm.

[0063] 3) Terrace etching: After the epitaxially grown sample is photolithographically developed, it is etched using inductively coupled plasma (ICP) etching, and the terrace etching depth is 50 to 800 nm.

[0064] 4) Shallow etching: After the sample is isolated by mesa etching, it is developed by photolithography and then etched by inductively coupled plasma.

[0065] In-cell etching (ICP) is used for shallow etching to achieve 2DEG contact mesa, with an etching depth of 1 to 100 nm. 5) Ohmic contact electrode production: After photolithography and development, composite metal is deposited using an electron beam evaporation system, and then

[0066] A rapid annealing (RTA) process forms a good ohmic contact and manufactures electrodes C1, C2, S1, S2, a source S, and a drain D.

[0067] 6) Gate groove etching: After the electrodes C1, C2, S1, S2, source S, and drain D are prepared, the gate groove is etched using inductively coupled plasma (ICP) with an etching depth of 1 to 100 nm.

[0068] 7) Gate dielectric deposition: After the gate trench is etched, the sample is treated with an alkaline solution containing nitrogen to treat the gate trench interface. Then, the gate dielectric is deposited by metal organic chemical vapor deposition (MOCVD), plasma chemical vapor deposition (PECVD), atomic layer deposition (ALD), low pressure chemical vapor deposition (LPCVD), or magnetron sputtering. The deposition thickness is 5 to 50 nm. 8) Gate electrode production: After photolithography and development, the composite metal is deposited by an electron beam evaporation system. After metal stripping, the gate dielectric is formed.

[0069] Gate electrode.

[0070] 9) Surface passivation: plasma enhanced chemical vapor deposition (PECVD), magnetron sputtering, atomic layer

[0071] SiO2 is deposited by either ALD or electron beam evaporation (EB) to passivate the device. 10) Window opening: The passivation layer at the electrode is photolithographically etched and etched to form a window.

[0072] 11) Fabrication of metal interconnects: After photolithography and development, metal is deposited using an electron beam evaporation system to form interconnects.

[0073] 12) Electrode lead: Electrode lead wire is formed by magnetron sputtering, electron beam evaporation or thermal evaporation.

[0074] Deposit metal to make pads and make leads;

[0075] 13) Circuit connection: The bare die with good leads is packaged, and each component of the back-end interface circuit is connected to the same PCB board, thereby completing the circuit connection of the highly integrated matrix magnetic sensor chip.

[0076] 14) Appearance design: Carry out appearance design for the entire system and complete the production of the instrument.

[0077] The key technical points of the present invention are: firstly, a highly integrated matrix magnetic sensor chip is proposed, which is no longer a horizontal Hall sensor that measures the magnetic field perpendicular to the device surface alone, but connects multiple horizontal Hall elements with switch devices to form N×M (the specific values ​​of N and M can be determined according to the distribution of the measured magnetic field) matrix elements, and the switch device flexibly controls the collection of the Hall output signal, thereby realizing the measurement of the magnetic field distribution in one-dimensional, two-dimensional or even three-dimensional space, which is a structural innovation; secondly, the device can be made of a variety of materials, such as Si material, which has mature technology and reliable performance; it can also be made of GaAs / AlGaAs, GaN / AlGaN, It is made of heterojunction structure composed of materials such as InAs / InGaAs, Ga2O3 / AlGaO, etc. The naturally formed two-dimensional electron gas (2DEG) channel makes the device highly sensitive. At the same time, the high electron mobility (the electron mobility of GaAs and InAs can reach 9000cm2 / (V·s) and 40000cm2 / (V·s) respectively) makes them have excellent electron transport performance under low and high fields, and is an ideal channel material for ultra-high-speed, low-power sensor devices; in addition, it can also be made of two-dimensional materials (such as graphene), the process is simple and easy to be compatible with silicon-based CMOS process, and a highly sensitive Hall sensor can be realized under a low temperature drift coefficient. Devices made of different materials can be adapted to the chip structure, and chips made of different materials can be selected according to the application environment, which is an innovation in applicability; in addition, the chip structure is simple and easy to integrate with the back-end interface circuit, realizing multi-point measurement of multiple matrix elements, and improving the sensitivity and accuracy of the device, which is an innovation in performance. Therefore, the present invention application mainly protects the proposed chip structure design, instrument circuit structure and manufacturing process.

[0078] Example 2

[0079] The target device of the present invention is a highly integrated matrix magnetic sensor chip composed of N×M (the specific values ​​of N and M can be determined according to the distribution of the magnetic field measured in the environment) matrix elements. The specific embodiment is a matrix magnetic sensor chip composed of 1×10 Hall element matrix elements and a "cross-shaped" horizontal Hall element made of two-dimensional electron gas channel material (GaN / AlGaN heterojunction structure). Since the structure and process of each matrix element are the same, this embodiment only shows the production process of a single matrix element, such as Figure 17-Figure 28 The production process is described as follows:

[0080] 1) Substrate preparation: Prepare Si material substrate, clean the substrate material, and remove contaminants on the surface of the Si substrate.

[0081] 2) Epitaxial growth: AlGaN / GaN heterojunction structure and buffer layer AlN are grown by metal organic chemical vapor deposition (MOCVD). The generated GaN epitaxial layer is not intentionally doped, with a thickness of 5μm and a background electron concentration of less than 1×10 17 cm -3 The AlGaN barrier layer on the epitaxial layer is 25nm thick, with an Al component of 0.25. The buffer layer is AlN with a thickness of 50nm.

[0082] 3) Terrace etching: After the epitaxially grown samples were coated (using AZ6130 positive photoresist), spread (forward rotation at 600 rpm-3s, rear rotation at 1000 rpm-20s, and the final photoresist thickness was 2um), photolithography, and development (90 seconds), the heterojunction was etched using inductively coupled plasma etching (ICP) with an etching power of 200 W and a Cl-based gas of 150 sccm for etching for 250 seconds, ultimately forming an etching depth of about 400 nm.

[0083] 4) Shallow etching: After the mesa etching isolation, the sample was coated (using AZ6130 positive photoresist), spread (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness was 2um), photolithography, and development (90 seconds). Then, the heterojunction was etched using inductively coupled plasma etching (ICP) for 30s at an etching rate of 55nm / min, and finally an etching depth of about 25nm was formed.

[0084] 5) Ohmic contact electrode fabrication: After photolithography and development, four metal layers of Ti (20nm) / Al (100nm) / Ni (45nm) / Au (55nm) are deposited using an electron beam evaporation system, followed by rapid annealing (RTA)

[0085] The process is annealed for 30 seconds in a nitrogen environment at 850°C to form a good ohmic contact, and electrodes C1, C2, S1, S2, source S, and drain D are produced.

[0086] 6) Gate trench etching: After the electrodes C1, C2, S1, S2, source S, and drain D are prepared, the gate trench is etched using inductively coupled plasma (ICP) to etch the remaining AlGaN to 5 nm.

[0087] 7) Gate dielectric deposition: After the gate trench etching, the gate trench interface of the sample was treated with an alkaline solution containing nitrogen, and then the gate dielectric SiNO was deposited by plasma chemical vapor deposition (PECVD) with a deposition thickness of 20 nm.

[0088] 8) Gate electrode fabrication: After photolithography and development, four layers of metal Ti (20nm) / Al (100nm) / Ni (45nm) / Au (55nm) are deposited using an electron beam evaporation system. After metal stripping, a gate electrode is formed. 9) Surface passivation: Plasma enhanced chemical vapor deposition (PECVD) is used to deposit the gate electrode at 300°C.

[0089] A 300nm thick SiO2 passivation layer is deposited to weaken the influence of the ambient atmosphere on device characteristics.

[0090] 10) Window opening: The passivation layer at the electrode is corroded and the window lead is opened. The sample is coated with glue (using AZ6130

[0091] After positive photoresist), coating (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90 seconds), ICP etching is used to etch the electrode after surface passivation to form a window.

[0092] 11) Fabrication of metal interconnection lines: After photolithography and development, 500nm of metal aluminum Al is deposited by magnetron sputtering, and interconnection lines are formed after metal stripping.

[0093] 12) Electrode lead: Electrode lead wire is formed by magnetron sputtering, electron beam evaporation or thermal evaporation.

[0094] Deposit metal to make pads and make leads;

[0095] 13) Circuit connection: The bare die with good leads is packaged, and each component of the back-end interface circuit is connected to the same PCB board, thereby completing the circuit connection of the one-dimensional matrix Hall sensor chip.

[0096] 14) Appearance design: Carry out appearance design for the entire system and complete the production of the instrument.

[0097] Fig.29The Nth (N=1-10) matrix element in the sensor chip designed by the present invention is given in static measurement of magnetic field B and Hall output voltage V O The relationship between the excitation current I bias =1mA, the gain A in the adjustable gain amplifier circuit is adjusted to a fixed value of 275, and the reference voltage circuit provides a reference voltage V ref =1.65V, the measurement magnetic field range is -250mT~250mT. As can be seen from the figure, with the increase of the magnetic field in the environment, the Hall voltage detected by each matrix element through the back-end interface circuit also increases linearly, and the sensitivity of the 10 matrix elements is basically the same, which are 7.73mV / mT (N=1), 7.74mV / mT (N=2), 7.74mV / mT (N=3), 7.73mV / mT (N=4), 7.72mV / mT (N=5), 7.72mV / mT (N=6), 7.72mV / mT (N=7), 7.71mV / mT (N=8), 7.71mV / mT (N=9), 7.71mV / mT (N=10), which is about 120 times that of a single third-generation semiconductor Hall sensor. At the same time, the linearity is also high, reaching 99.898%, 99.969%, 99.928%, 99.941%, 99.899%, 99.899%, 99.899%, 99.9%, 99.9%, 99.902% respectively. This shows that when the magnetic field distribution in the environment is different, each matrix element can detect the magnitude of the magnetic field perpendicular to the matrix element, and the Hall output voltage V O It is reflected, thus achieving accurate real-time static measurement of magnetic field distribution.

[0098] Fig.30 The magnetic field B and the Hall output voltage V of a single matrix element of the sensor chip applied in the present invention under dynamic measurement are given. O , where the magnetic field source provides a sinusoidal alternating magnetic field with a peak-to-peak value Bp-p of 17.798G and a frequency f of 5Hz, and other test conditions are the same as the static test conditions. As can be seen from the figure, the Hall voltage detected by the matrix element through the back-end interface circuit follows the sinusoidal change of the magnetic field in the environment and also undergoes a sinusoidal change with a frequency of 5Hz, which means that at a lower frequency, each matrix element can basically follow the change of the magnetic field in the environment without distinction, thereby realizing real-time dynamic measurement of the magnetic field distribution.

[0099] In summary, the experimental verification results of this embodiment can illustrate that the high-integration matrix magnetic sensor chip designed in the present application can realize real-time static and dynamic measurement of the magnetic field distribution perpendicular to the device surface in one-dimensional, two-dimensional or even three-dimensional space, and has high sensitivity, linearity and accuracy.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A highly integrated matrix magnetic sensor chip structure, characterized in that: include: A plurality of matrix elements, a switch matrix, and a back-end interface circuit, wherein the switch matrix is ​​connected in sequence with the plurality of matrix elements and the back-end interface circuit, wherein the matrix element comprises: a "cross" shaped horizontal Hall element and a switch device; The switch matrix is ​​composed of switch devices in the matrix elements; the "cross" shaped horizontal Hall element matrix is ​​an N×M Hall matrix element composed of an integrated 1×M Hall element matrix in each row; for the "cross" shaped horizontal Hall element matrix, the electrodes C2 of each Hall element are connected together and grounded, and electrodes S1 and S2 are only set at the leftmost and rightmost ends of each row of the 1×M Hall element matrix; the switch device includes a gate G, a source S, and a drain D; the electrode C2 is connected to the source S through a metal interconnection line.

2. The highly integrated matrix magnetic sensor chip structure according to claim 1, characterized in that: The "cross" shaped horizontal Hall element is made of Si bulk material or two-dimensional electron gas channel materials such as GaN, GaAs, InSb, InAs, and GaO, or is made of graphene two-dimensional material.

3. The highly integrated matrix magnetic sensor chip structure according to claim 1, characterized in that: The heterojunction structure composed of two-dimensional electron gas channel material as the "cross" shaped horizontal Hall element includes a substrate, a buffer layer, a channel layer, and a barrier layer. The two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer and a barrier layer is grown in sequence on the substrate, and a horizontal Hall element and a switching device are arranged above the channel layer; the main body of the horizontal Hall element is composed of a "cross" shaped barrier layer, and electrodes C1, electrode C2, electrode S1, and electrode S2 are respectively arranged at the four ends of the barrier layer; the source level S and drain level D of the switching device are arranged on the channel layer, and a dielectric layer extending to the barrier layer is arranged on the channel layer, and the gate G is arranged above the dielectric layer; the electrode C2 is connected to the source level S through a metal interconnection line.

4. The highly integrated matrix magnetic sensor chip structure as claimed in claim 3, characterized in that: The substrate is one of silicon, silicon carbide, sapphire, or a material homogeneous with the channel layer; the buffer layer is one of AlN, GaN, or a superlattice structure material.

5. The highly integrated matrix magnetic sensor chip structure as claimed in claim 3, characterized in that: The channel layer is one of GaN, GaAs, InSb, InAs, and GaO; and the barrier layer is a heterojunction material that can form a two-dimensional electron gas channel with the channel layer.

6. The highly integrated matrix magnetic sensor chip structure as claimed in claim 3, characterized in that: The dielectric layer is one of Al2O3, Si3N4, SiO2, and SiON; the metal interconnection line is one of copper, tungsten, aluminum, and cobalt.

7. The highly integrated matrix magnetic sensor chip structure as claimed in claim 3, characterized in that: The thickness of the buffer layer is 10-100 nm; the thickness of the channel layer is 0.1-10 μm; the thickness of the barrier layer is 5-100 nm; and the thickness of the dielectric layer is 20-50 nm.

8. A highly integrated matrix magnetic sensor chip circuit, characterized in that: include: A power supply module, an excitation power supply, a reference voltage source, an adjustable gain amplifier, a voltage regulator, an AD converter, a microprocessor, a switch matrix, and an N×M Hall matrix element, wherein the power supply module is respectively connected to the reference voltage source, the switch matrix, and the microprocessor; The reference voltage source is connected to the excitation power supply, the adjustable gain amplifier, and the voltage regulator respectively; the excitation power supply is connected to the N×M Hall matrix element, the adjustable gain amplifier, the voltage regulator, the AD converter, and the microprocessor in sequence; the switch matrix is ​​connected to the N×M Hall matrix element and is controlled by the microprocessor.

9. The highly integrated matrix magnetic sensor chip circuit according to claim 8, characterized in that: The N×M Hall matrix element includes a "cross" shaped horizontal Hall element and a switch device; the switch matrix is ​​composed of the switch devices in the matrix element; the "cross" shaped horizontal Hall element matrix is ​​an N×M matrix array composed of an integrated 1×M Hall element matrix in each row; for the "cross" shaped horizontal Hall element matrix, the electrodes C2 of each Hall element are connected together and grounded, and electrodes S1 and S2 are only set at the leftmost and rightmost ends of each row of the 1×M Hall element matrix; the switch device includes a gate G, a source S, and a drain D; the electrode C1 is connected to the source S through a metal interconnection line.

10. A method for manufacturing a highly integrated matrix magnetic sensor chip, characterized in that: Here are the steps: S1. Cleaning the substrate: preparing the substrate material, cleaning the substrate, and removing contaminants on the substrate surface; S2. Epitaxial growth: For heterojunction structure devices of channel materials, epitaxially grow heterojunction structures and buffer layers of two-dimensional electron gas channel materials by using any of metal organic chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy; For two-dimensional material devices, grow two-dimensional materials by using any of mechanical stripping, reduction oxidation, silicon carbide surface epitaxial growth, and chemical vapor deposition CVD, and transfer the two-dimensional materials to a target substrate; the thickness of the generated channel layer is 0.1 to 10 μm, the thickness of the barrier layer on the channel layer is 5 to 100 nm, and the buffer layer is AlN, GaN or a superlattice structure, and its thickness is 10 to 100 nm; S3, mesa etching: after the epitaxially grown sample is photolithographically developed, it is etched by inductively coupled plasma etching; the mesa etching depth is 50 to 800 nm; in step S4, the etching depth is 1 to 100 nm; in step S6, the etching depth is 1 to 100 nm; in step S7, the deposition thickness is 5 to 50 nm; S4, shallow etching: After the sample isolated by mesa etching is developed by photolithography, shallow etching is performed by inductively coupled plasma etching. For heterojunction structure devices of channel materials, it is used to realize 2DEG contact with the mesa in the channel material; for two-dimensional material devices, it is used to form a conductive channel; S5, ohmic contact electrode production: after photolithography and development, composite metal is deposited by electron beam evaporation system, and then rapid thermal annealing process is used to form good ohmic contact to produce electrodes C1, C2, S1, S2, source S, and drain D; S6, gate groove etching: after the electrodes C1, C2, S1, S2, source S, and drain D are prepared, the gate groove is etched by inductively coupled plasma etching; S7, gate dielectric deposition: after the gate groove is etched, the gate groove interface of the sample is treated by an alkaline solution containing nitrogen, and then the gate dielectric is deposited by any one of metal organic compound chemical vapor deposition, plasma chemical vapor deposition, atomic layer deposition, low pressure chemical vapor deposition, and magnetron sputtering; S8, gate electrode production: after photolithography and development, composite metal is deposited by electron beam evaporation system, and gate electrode is formed after metal stripping; S9, surface passivation: use plasma enhanced chemical vapor deposition, magnetron sputtering, atomic layer deposition, electron beam evaporation, any of which method to deposit SiO2 for device passivation; S10, window opening: photolithography and etching of the passivation layer at the electrode to form a window; S11, metal interconnection line fabrication: after photolithography and development, metal is deposited by electron beam evaporation system to form interconnection lines; S12, electrode leads: using any of the methods of magnetron sputtering, electron beam evaporation, and thermal evaporation to deposit metal at the electrode to make pads and make leads; S13, circuit connection: package the bare die with good leads, and connect each component of the back-end interface circuit on the same PCB board, so as to complete the circuit connection of the highly integrated matrix magnetic sensor chip; S14. Appearance design: Carry out appearance design for the entire system and complete the production of the instrument.

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