High-sensitivity two-dimensional electron gas channel structure magnetic sensing matrix chip and manufacturing method thereof

Abstract

The invention discloses a high-sensitivity two-dimensional electron gas channel structure magnetic sensing matrix chip and a manufacturing method, and belongs to the technical field of semiconductor devices. A shift register is sequentially connected with a magnetic sensing matrix and a rear-end interface circuit; the magnetic sensing matrix comprises a plurality of matrix elements, each matrix element is of a two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer and a barrier layer which are sequentially grown on a substrate, and a horizontal Hall element and a switching device are arranged above the channel layer. The one-dimensional matrix type Hall sensor chip based on the two-dimensional electron gas channel can be used for statically and dynamically measuring one-dimensional magnetic field distribution in real time in severe environments such as high temperature, high pressure and high radiation, and innovation and manufacturing in structure and circuit are carried out on the one-dimensional matrix type Hall sensor chip based on the two-dimensional electron gas channel; dynamic and static measurement in a one-dimensional magnetic field 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 sensitive two-dimensional electron gas channel structure magnetic sensor matrix chip and a manufacturing method thereof. 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 width is 3.47eV, ensuring 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, ensuring that the device has high sensitivity; its lower intrinsic carrier concentration ensures lower noise in the device.

[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 line space or even three-dimensional space. This requires the use of matrix Hall magnetic sensors 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 high-sensitivity and high-accuracy Hall magnetic sensor matrix chip 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 the measurement error of the magnetic field can be compensated by the Hall magnetic sensor matrix chip, which simplifies the circuit and improves 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 line space 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 Hall magnetic sensor matrix chip based on a two-dimensional electron gas channel structure with an integrated subsequent interface circuit to measure the one-dimensional magnetic field distribution (including the one-dimensional magnetic field distribution under high temperature, high pressure, and high radiation environments) in real time or at multiple points. On the one hand, the dynamic magnetic field can be measured and the magnetic field distribution can be observed in real time; on the other hand, the static magnetic field can be measured and the measurement error of the magnetic field can be compensated by the Hall magnetic sensor matrix chip, which simplifies the circuit and improves the measurement accuracy.

[0007] The existing third-generation semiconductor Hall magnetic sensors are mostly used in single-point measurement of static magnetic fields. They cannot measure dynamic magnetic fields and magnetic field distribution in one-dimensional line space or even three-dimensional space. This requires the use of Hall magnetic sensor matrix chips to measure magnetic fields in real time or at multiple points. At the same time, in the single-point measurement state, there are usually 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 magnetic sensor matrix chip with a high-sensitivity two-dimensional electron gas channel structure and a manufacturing method. This technical solution innovates and manufactures the structure and circuit of a magnetic sensor matrix chip based on a two-dimensional electron gas channel structure, which can be used for real-time, static and dynamic measurement of one-dimensional magnetic field distribution in harsh environments such as high temperature, high pressure and high radiation. It can realize dynamic and static measurement of one-dimensional magnetic field and perform error compensation through circuits, which not only ensures that the chip can work stably in high temperature, high pressure and high radiation environments, but also ensures that it has high linearity, sensitivity and accuracy.

[0009] The technical solution is as follows:

[0010] A magnetic sensing matrix chip structure of a high-sensitivity two-dimensional electron gas channel structure comprises: a magnetic sensing matrix, a shift register, and a back-end interface circuit, wherein the shift register is sequentially connected to the magnetic sensing matrix and the back-end interface circuit; the magnetic sensing matrix comprises a plurality of matrix elements, wherein the matrix elements comprise: a substrate, a buffer layer, a channel layer, and a barrier layer, wherein a two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer, and a barrier layer is sequentially grown on the substrate, and a horizontal Hall element and a switch device are arranged above the channel layer; the main body of the horizontal Hall element is composed of a "cross"-shaped barrier layer, wherein four ends of the "cross"-shaped barrier layer are respectively provided with electrodes C1, C2, S1, and S2; the switch device comprises a gate G, a source S, and a drain D, wherein the source S and the drain D are arranged on the channel layer, 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 S through a metal interconnection line.

[0011] 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.

[0012] 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.

[0013] Furthermore, the dielectric layer is Al 2 O 3 、Si 3 N 4 、SiO 2 , one of SiON; the metal interconnection line is made of one of copper, tungsten, aluminum, and cobalt.

[0014] 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.

[0015] The present invention also includes a back-end interface circuit of a magnetic sensing matrix chip with a high-sensitivity two-dimensional electron gas channel structure, comprising: a power module, an excitation power circuit, a reference voltage source circuit, an adjustable gain amplifier circuit, a voltage regulation circuit, an AD conversion circuit, a microprocessor, a shift register, and a magnetic sensing matrix. The power module is respectively connected to the reference voltage source circuit and the microprocessor; the reference voltage source circuit is respectively connected to the excitation power circuit, the adjustable gain amplifier circuit, and the voltage regulation circuit; the excitation power circuit is sequentially connected to the magnetic sensing matrix, the adjustable gain amplifier circuit, the voltage regulation circuit, the AD conversion circuit, and the microprocessor; and the shift register is respectively connected to the magnetic sensing matrix and the microprocessor.

[0016] Furthermore, the magnetic sensing matrix includes a number of matrix elements, which include: a substrate, a buffer layer, a channel layer, and a barrier layer. A two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer and a barrier layer is 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 electrodes C1, electrode C2, electrode S1, and electrode S2 are respectively arranged at the four ends of the "cross"-shaped barrier layer; the switching device includes a gate G, a source S, and a drain D, and the source S and the drain D 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 S through a metal interconnection line.

[0017] The present invention also includes a method for manufacturing a magnetic sensing matrix chip with a high-sensitivity two-dimensional electron gas channel structure, the steps of which are as follows:

[0018] S1. Cleaning the substrate: preparing the substrate material, cleaning the substrate, and removing contaminants on the substrate surface;

[0019] S2. Epitaxial growth: epitaxially growing a two-dimensional electron gas channel material heterojunction structure and a buffer layer by using any of metal organic compound chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy;

[0020] S3, mesa etching: after the epitaxially grown sample is photolithographically developed, it is etched using inductively coupled plasma etching;

[0021] S4, shallow etching: After the sample isolated by mesa etching is photolithographically developed, shallow etching is performed using inductively coupled plasma etching to achieve 2DEG contact with the mesa;

[0022] S5. Ohmic contact electrode production: After photolithography and development, composite metal is deposited by electron beam evaporation system, and then a rapid annealing process is used to form a good ohmic contact;

[0023] 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;

[0024] 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;

[0025] 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;

[0026] S9, surface passivation: use plasma enhanced chemical vapor deposition, magnetron sputtering, atomic layer deposition, electron beam evaporation or any other method to deposit SiO 2 Passivate the device;

[0027] S10, window opening: photolithography and etching of the passivation layer at the electrode to form a window;

[0028] S11, metal interconnection line fabrication: after photolithography and development, metal is deposited by electron beam evaporation system to form interconnection lines;

[0029] S12. Electrode leads: Use any of the following methods: magnetron sputtering, electron beam evaporation, or thermal evaporation to deposit metal at the electrode to make a pad and then make leads.

[0030] Furthermore, in step S2, the thickness of the generated channel layer is 0.1-10 μm, the thickness of the barrier layer on the channel layer is 5-100 nm, and the buffer layer is AlN, GaN or a superlattice structure, and its thickness is 10-100 nm.

[0031] Furthermore, in step S3, the mesa etching depth is 50-800 nm; in step S4, the etching depth is 1-100 nm; in step S6, the etching depth is 1-100 nm; in step S7, the deposition thickness is 5-50 nm.

[0032] The beneficial effects of the present invention are:

[0033] The magnetic sensing matrix chip of the highly sensitive two-dimensional electron gas channel of the present invention has the following characteristics:

[0034] 1) Device heterojunction structure (such as GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga 2 O 3 / AlGaO and other materials) has a naturally formed two-dimensional electron gas channel, a high concentration of two-dimensional electron gas (2DEG) at the heterojunction interface, and high device sensitivity; 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 properties under both low and high fields, and are ideal channel materials for ultra-high-speed, low-power sensor devices.

[0035] 2) 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.

[0036] 3) The magnetic sensor matrix chip consists of a magnetic sensor matrix, a shift register and a back-end interface circuit. Each matrix element contains a Hall element and a switching device. Each switching device is controlled by a shift register to control the opening and closing of the Hall element excitation circuit. It has a simple structure and flexible operation.

[0037] 4) The magnetic sensing matrix chip based on the two-dimensional electron gas channel structure 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, and 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.

[0038] Beneficial effects brought by the technical solution of the present invention:

[0039] 1) The simple structure of combining Hall elements and switch devices into a matrix element can flexibly realize the real-time, static and dynamic measurement of magnetic field in one-dimensional line space, which is not available in a single Hall sensor;

[0040] 2) The use of two-dimensional electron gas channel materials (such as GaN), whose unique properties ensure that the device can work stably in harsh environments such as high temperature (up to 400°C), high voltage (up to 1000V), and high radiation, is not available in sensors made of narrow bandgap materials such as first-generation semiconductors (such as Si and Ge);

[0041] 3) 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

[0042] 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:

[0043] Figure 1 A top view of the highly sensitive two-dimensional electron gas channel structure magnetic sensor matrix chip proposed in the present invention (only a single matrix element is shown);

[0044] Figure 2 A front view of the high-sensitivity two-dimensional electron gas channel structure magnetic sensor matrix chip proposed in the present invention (only a single matrix element is shown);

[0045] Figure 3 This is a structural block diagram of the back-end interface circuit (including shift register) of the high-sensitivity two-dimensional electron gas channel structure magnetic sensor matrix chip proposed in the present invention;

[0046] Figure 4-Figure 15 A schematic diagram of the process for realizing the high-sensitivity two-dimensional electron gas channel structure magnetic sensing matrix chip proposed in the present invention;

[0047] Figure 16-Figure 27 This is a process flow chart of a specific embodiment of this patent application;

[0048] Fig.28The high-sensitivity two-dimensional electron gas channel structure magnetic sensor matrix chip proposed in the present invention has a static measurement of the magnetic field B of each matrix element and the Hall output voltage V o The experimental verification result diagram of the relationship between

[0049] Fig.29 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 magnetic sensing matrix chip with a high-sensitivity two-dimensional electron gas channel structure 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

[0050] 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 16-27 The magnetic sensor matrix chip with a high-sensitivity two-dimensional electron gas channel structure and its manufacturing method are further explained.

[0051] Example 1

[0052] In order to solve the problems existing in the above-mentioned prior art and realize the real-time, dynamic and static measurement of one-dimensional magnetic field under high temperature, high pressure and high radiation environment, the present invention proposes a technical solution of a highly sensitive two-dimensional electron gas channel structure magnetic sensor matrix chip, which includes chip structure, circuit and manufacturing method. Figure 1 The schematic diagram of the chip structure is shown in Figure 1. The device consists of several Hall magnetic sensor matrix elements, shift registers, and back-end interface circuits. Each matrix element contains a horizontal Hall element and a switch device. The Hall element is based on the Hall effect and is made of two-dimensional electron gas channel materials. Due to the spontaneous polarization and piezoelectric polarization effects, a high electron mobility (typical value is 2000cm) without intentional doping is generated at the heterojunction interface. 2 / V﹒ s) of 2DEG, so that the device prepared by this method has higher sensitivity. Figure 1-Figure 2 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. The switch of each switch device is controlled by the shift register, thereby controlling the on and off of the matrix element excitation circuit. Multiple matrix elements are arranged in a determinant to form a magnetic sensor matrix chip.

[0053] 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 3 The figure shows the block diagram of the back-end interface circuit structure, which includes a power module, an excitation power circuit, a reference voltage circuit, an adjustable gain amplifier circuit, a voltage regulation circuit, an AD conversion circuit, a microprocessor, and a shift register. The power module supplies power to the entire sensor chip; the excitation power circuit provides an excitation current or voltage for the magnetic sensor matrix; the microprocessor controls the shift register to output a corresponding digital 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 circuit provides a reference voltage V for the adjustable gain amplifier circuit and the voltage conversion circuit. ref The adjustable gain amplifier circuit amplifies the output voltage of the Hall element. The adjustable gain enables the device to be adapted to accurately measure various specific magnetic field ranges. The voltage regulator circuit adjusts the amplified Hall output voltage to a voltage range that can be recognized by the AD conversion circuit, 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 one-dimensional magnetic field distribution diagram for the Hall output voltages of all matrix elements.

[0054] The technical solution and process structure of the present invention are as follows Figure 1-Figure 2 As shown, in order to explain the process structure more clearly, only the process structure of a single matrix element is shown. 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 S, and a drain D. The substrate is a substrate of silicon, silicon carbide, sapphire or other materials homogeneous with 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 to 100 nm), the channel layer can be GaN, GaAs, InSb, InAs, GaO and other materials that can form a two-dimensional electron gas channel (thickness of 0.1 to 10 μm), the barrier layer can be 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 to 100 nm), the material composition in the barrier layer is not limited, and the dielectric layer is Al 2 O 3 、Si3 N 4 、SiO 2 , SiON and other oxides or nitrides (thickness is 20-50nm), and metal interconnects are 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. The electrode shape is not specifically limited and can be rectangular, trapezoidal, etc. Except for the gate G, other electrodes need to form a good ohmic contact with the semiconductor material.

[0055] The working principle of the magnetic sensing matrix chip with a high-sensitivity two-dimensional electron gas channel structure proposed in the present invention is as follows: When a magnetic field B perpendicular to the device direction appears in the environment z When the shift register controls the switch device in the corresponding matrix element to turn on, an excitation voltage or current flows into the excitation terminals C1 and C2 of the Hall element in the corresponding matrix element, thereby generating a voltage 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 the magnetic field measurement of the specified position, dynamic magnetic field scanning, and one-dimensional magnetic field distribution measurement.

[0056] The invention proposes a high-sensitivity two-dimensional electron gas channel structure magnetic sensing matrix chip technology solution. The chip structure is characterized by: 1) device heterojunction structure (such as GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga 2 O 3 / AlGaO and other materials) has a naturally formed two-dimensional electron gas channel, with a high concentration of two-dimensional electron gas (2DEG) at the heterojunction interface, and the device has high sensitivity. 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 is an ideal channel material for ultra-high-speed, low-power sensor devices. 2) 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, 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 magnetic sensor matrix chip is composed of several Hall magnetic sensor matrix elements, shift registers and back-end interface circuits. Each matrix element contains a Hall element and a switch device. Each switch device is controlled by a shift register to control the opening and closing of the Hall element excitation circuit. It has a simple structure and flexible operation. 4) The magnetic sensing matrix chip with a highly sensitive two-dimensional electron gas channel structure can not only accurately measure static magnetic fields, but also measure dynamic magnetic fields and observe magnetic field distribution in real time. It is easy to integrate with circuits, and 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.

[0057] like Figure 4-Figure 15 As shown, the process of implementing the target device of the present invention is described as follows:

[0058] 1) Cleaning the substrate: Prepare 4-inch or 6-inch substrate material, clean the substrate, and remove contaminants on the substrate surface.

[0059] 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.

[0060] 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.

[0061] 4) Shallow etching: After the sample is isolated by mesa etching, it is developed by photolithography and then etched by inductively coupled plasma.

[0062] 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

[0063] The rapid thermal annealing (RTA) process forms a good ohmic contact.

[0064] 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.

[0065] 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.

[0066] Gate electrode.

[0067] 9) Surface passivation: plasma enhanced chemical vapor deposition (PECVD), magnetron sputtering, atomic layer

[0068] SiO is deposited by either ALD or electron beam evaporation (EB). 2 10) Window opening: Photolithography and etching of the passivation layer at the electrode to form a window.

[0069] 11) Fabrication of metal interconnects: After photolithography and development, metal is deposited using an electron beam evaporation system to form interconnects.

[0070] 12) Electrode leads: Use any of magnetron sputtering, electron beam evaporation (EB), and thermal evaporation to deposit metal at the electrode to make pads and wires.

[0071] The technical key points of the present invention are: firstly, a magnetic sensing matrix chip with a highly sensitive two-dimensional electron gas channel structure 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 (the specific value of N can be determined according to the complexity 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 the one-dimensional line space, which is a structural innovation; secondly, it adopts a two-dimensional electron gas channel material (such as GaN), which has unique properties such as large bandgap width, high breakdown electric field, large thermal conductivity, high electron saturation velocity, and small dielectric constant, so that the chip can stably work in high temperature (up to 400°C), high pressure (up to 1000V), and high radiation environment, especially in harsh environments such as aerospace, which is an innovation in applicability; in addition, the use of two-dimensional electron gas channel materials (such as GaAs / AlGaAs, GaN / AlGaN, InAs / InGaAs, Ga 2 O 3 / AlGaO and other materials), with a high concentration of two-dimensional electron gas (2DEG) at the heterojunction interface and a 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, which is also an innovation in applicability. Moreover, the chip structure is simple and easy to integrate with the back-end interface circuit, realizing multi-matrix element multi-point measurement, 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, circuit structure and manufacturing process.

[0072] Example 2

[0073] The target device of the present invention is a magnetic sensor matrix chip based on a two-dimensional electron gas channel material, which is composed of 1×N (the specific value of N can be determined according to the complexity of the measured magnetic field) matrix elements. The specific embodiment is composed of 1×10 matrix elements, and the chip is an AlGaN / GaN heterojunction structure. Since the structure and process of each matrix element are the same, this embodiment only shows the manufacturing process of a single matrix element, such as Figure 16-Figure 27 The production process is described as follows:

[0074] 1) Substrate preparation: Prepare Si material substrate, clean the substrate material, and remove contaminants on the surface of the Si substrate.

[0075] 2) Epitaxial growth: epitaxial growth using metal organic chemical vapor deposition (MOCVD)

[0076] AlGaN / GaN heterojunction structure and buffer layer AlN, the generated GaN epitaxial layer is not intentionally doped, the thickness is 5μm, and the background electron concentration is 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.

[0077] 3) Terrace etching: The epitaxially grown samples were coated (using AZ6130 positive photoresist), spread (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, and development (90

[0078] After 20 seconds, the heterojunction was etched by inductively coupled plasma (ICP) with an etching power of

[0079] 200W, 150sccm of Cl-based gas was introduced for etching for 250s, and finally an etching depth of about 400nm was formed.

[0080] 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.

[0081] 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)

[0082] The process is annealed at 850°C in a nitrogen environment for 30s to form a good ohmic contact.

[0083] 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.

[0084] 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 SiON was deposited by plasma chemical vapor deposition (PECVD) with a deposition thickness of 20 nm.

[0085] 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.

[0086] A 300nm thick SiO2 passivation layer is deposited to weaken the influence of the ambient atmosphere on device characteristics.

[0087] 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

[0088] After positive photoresist), coating (forward rotation 600rpm-3s, rear rotation 1000rmp-20s, the final photoresist thickness is 2um), photolithography, development (90 seconds), ICP etching is used to etch the electrode after surface passivation to form a window

[0089] 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.

[0090] 12) Electrode lead: Use magnetron sputtering to deposit 500nm of Al at the electrode, and then perform lead-out to lead out the electrode.

[0091] 13) Slicing and Cutting: Use a wafer cutting machine to slice and cut the prepared 4-inch or 6-inch wafer, and select each complete and scratch-free chip on the wafer.

[0092] 14) Wire bonding: Use epoxy resin glue to stick the selected chip to the PCB substrate, and perform wire bonding on the output electrode of the Hall element in each matrix element on the chip. Connect the bonding wire to the pad of the PCB substrate to ensure that each Hall voltage output electrode is led out through the PCB substrate.

[0093] 15) Circuit connection: Connect the PCB substrate carrying the magnetic sensor matrix and each component of the back-end interface circuit on the same PCB board to complete the circuit connection of the magnetic sensor matrix chip.

[0094] Fig.28 The magnetic field B and the Hall output voltage V of the Nth (N=1-10) matrix element in the magnetic sensor matrix chip designed by the present invention under static measurement are given. O The relationship between the excitation current I bias =1mA, the gain G 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 The reaction is achieved, thereby realizing accurate real-time static measurement of one-dimensional magnetic field distribution.

[0095] Fig.29 The magnetic field B and the Hall output voltage V of a single matrix element of the magnetic sensor matrix chip applied in the present invention are given in dynamic measurement. 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 also undergoes a sinusoidal change with a frequency of 5Hz following the sinusoidal change of the magnetic field in the environment, 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 one-dimensional magnetic field distribution.

[0096] In summary, the experimental verification results of this embodiment can illustrate that the magnetic sensor matrix chip with a two-dimensional electron gas channel structure designed in the present invention can meet the requirements of real-time static and dynamic measurement of one-dimensional magnetic field distribution in harsh environments, and has high sensitivity, linearity and accuracy.

[0097] 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 sensitive two-dimensional electron gas channel magnetic sensing matrix chip structure, characterized in that: include: A magnetic sensor matrix, a shift register, and a back-end interface circuit, wherein the shift register is sequentially connected to the magnetic sensor matrix and the back-end interface circuit; The magnetic sensing matrix includes a plurality of matrix elements, which include: a substrate, a buffer layer, a channel layer, and a barrier layer. A two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer, and a barrier layer is sequentially grown on the substrate, and a horizontal Hall element and a switch 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, C2, S1, and S2 are arranged at the four ends of the "cross"-shaped barrier layer respectively; the switch device includes a gate G, a source S, and a drain D, and the source S and the drain D 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 S through a metal interconnection line.

2. The magnetic sensing matrix chip structure of the high-sensitivity two-dimensional electron gas channel structure according to claim 1, 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.

3. The magnetic sensing matrix chip structure of the high-sensitivity two-dimensional electron gas channel structure as claimed in claim 1, characterized in that: The channel layer is one of GaN, GaAs, InSb, InAs, and GaO; and the barrier layer is a heterojunction material that forms a two-dimensional electron gas channel with the channel layer.

4. The magnetic sensing matrix chip structure of the high-sensitivity two-dimensional electron gas channel structure according to claim 1, 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.

5. The magnetic sensing matrix chip structure of the high-sensitivity two-dimensional electron gas channel structure as claimed in claim 1, 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.

6. A magnetic sensing matrix chip circuit with a highly sensitive two-dimensional electron gas channel structure, characterized in that: include: A power supply module, an excitation power supply circuit, a reference voltage source circuit, an adjustable gain amplifier circuit, a voltage regulating circuit, an AD conversion circuit, a microprocessor, a shift register, and a magnetic sensor matrix. The power supply module is respectively connected to the reference voltage source circuit and the microprocessor; the reference voltage source circuit is respectively connected to the excitation power supply circuit, the adjustable gain amplifier circuit, and the voltage regulating circuit; the excitation power supply circuit is sequentially connected to the magnetic sensor matrix, the adjustable gain amplifier circuit, the voltage regulating circuit, the AD conversion circuit, and the microprocessor; and the shift register is respectively connected to the magnetic sensor matrix and the microprocessor.

7. The magnetic sensing matrix chip circuit with a high sensitivity two-dimensional electron gas channel structure as claimed in claim 6, characterized in that: The magnetic sensing matrix includes a plurality of matrix elements, which include: a substrate, a buffer layer, a channel layer, and a barrier layer. A two-dimensional electron gas channel material heterojunction structure composed of a buffer layer, a channel layer, and a barrier layer is sequentially grown on the substrate, and a horizontal Hall element and a switch 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, C2, S1, and S2 are arranged at the four ends of the "cross"-shaped barrier layer respectively; the switch device includes a gate G, a source S, and a drain D, and the source S and the drain D 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 S through a metal interconnection line.

8. A method for manufacturing a magnetic sensing matrix chip with a high-sensitivity two-dimensional electron gas channel structure, 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: epitaxially growing a two-dimensional electron gas channel material heterojunction structure and a buffer layer by using any of metal organic compound chemical vapor deposition, molecular beam epitaxy, and hydride vapor phase epitaxy; S3, mesa etching: after the epitaxially grown sample is photolithographically developed, it is etched using inductively coupled plasma etching; S4, shallow etching: After the sample isolated by mesa etching is photolithographically developed, shallow etching is performed using inductively coupled plasma etching to achieve 2DEG contact with the mesa; S5. Ohmic contact electrode production: After photolithography and development, composite metal is deposited by electron beam evaporation system, and then a rapid annealing process is used to form a good ohmic contact; 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: Use any of the following methods: magnetron sputtering, electron beam evaporation, or thermal evaporation to deposit metal at the electrode to make a pad and then make leads.

9. The method for manufacturing a magnetic sensor matrix chip with a high-sensitivity two-dimensional electron gas channel structure as claimed in claim 8, characterized in that: In step S2, the thickness of the generated channel layer is 0.1-10 μm, the thickness of the barrier layer on the channel layer is 5-100 nm, and the buffer layer is AlN, GaN or a superlattice structure, and its thickness is 10-100 nm.

10. The method for manufacturing a magnetic sensor matrix chip with a high-sensitivity two-dimensional electron gas channel structure as claimed in claim 8, characterized in that: In step S3, the mesa etching depth is 50-800 nm; in step S4, the etching depth is 1-100 nm; in step S6, the etching depth is 1-100 nm; in step S7, the deposition thickness is 5-50 nm.

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