CN2379915Y - Antimony-indium series compound semiconductor magnetic resistance type current sensor - Google Patents

Abstract

The utility model is an antimony-indium compound semiconductor magnetoresistive current sensor. It consists of a magnetoresistive chip, a conductor, a permanent magnet, a ferromagnetic sheet, and a substrate connection. One across the chip is connected in parallel with the other conductors bypassing the magnetoresistive element. The utility model is especially suitable for weak and small current occasions, has high sensitivity, good stability and is easy to manufacture.

Description

Antimony-indium compound semiconductor magnetoresistive current sensor

The utility model relates to an antimony-indium compound semiconductor magnetoresistive current sensor, which belongs to the electronic device technology, and particularly relates to the sensor manufacturing technology.

Current sensors made of magnetoresistive chips currently available on the market use nickel-iron-nickel-cobalt alloy thin-film magnetoresistive chips. Because the sensitivity of this kind of magnetoresistive chip is relatively low, and when the magnetic field increases to a certain extent, the magnetoresistance effect is prone to saturation and other shortcomings, so it needs a relatively strong current to induce a certain output voltage, and Need to prevent saturation when the current is too high. It usually only measures large currents above 1A to 20A, but in practical applications, it is often necessary to monitor weak currents below 1A or even below 0.1A, so it is not practical for small current applications. Moreover, if bias magnetization is to be added in the structure of this sensor, the magnetic lines of force should be parallel to the surface of the magnetoresistive chip during assembly, which brings certain difficulties to the assembly of the bias magnet in the manufacturing process.

The purpose of this utility model is to overcome and solve the low sensitivity and easy saturation of the existing magnetoresistive current sensor, so that a large current is required to induce a certain voltage, and it is necessary to prevent saturation from excessive current, which is not suitable for small current occasions. Due to the shortcomings and problems of practicality and difficulty in assembling bias magnetism in manufacturing, research and design a small volume, high sensitivity, obvious magnetoresistance effect, not easy to saturate, suitable for weak current applications, and more suitable for detecting currents less than 1A. Antimony-indium compound semiconductor magnetoresistive sensor with light weight, firm and compact structure and long service life.

The utility model is realized through the following technical solutions: the internal structure diagrams of antimony-indium compound semiconductor magnetoresistive current sensors are shown in Figures 1 and 2, and the principle diagram of current sensing is shown in Figure 3. The current sensor is composed of an antimony-indium compound semiconductor magnetoresistive chip 1, a conductor 2, a permanent magnet 3, a ferromagnetic material sheet 4, and a substrate 5 for supporting the magnetoresistive chip. The interconnection relationship is as follows: The resistance chip 1 is fixed on the substrate 5 by adhesive or conventional vacuum evaporation and sputtering methods (collectively referred to as magnetoresistive element), the substrate 5 is bonded with the ferromagnetic material sheet 4 by the adhesive, and the ferromagnetic material The sheet 4 is bonded to the permanent magnet 3 through an adhesive, and the entire conductor 2 spans the magnetoresistive chip 1, that is, the entire conductor 2 spans and is parallel to the surface or the back of the magnetoresistive chip 1, and two or more conductors can be used. Parallel connection, and only one of the conductors crosses the magnetoresistive chip, and the rest can bypass the magnetoresistive chip. In order to increase the detection range of the current sensor, a conductor 6 of a certain thickness can be added, which is connected in parallel with the conductor 2, but does not cross the magnetoresistive chip 1, as shown in FIG. 2 . This can make a part of the detected current of the external circuit flow through the conductor 2, and another part flow through the conductor 6, and the current intensity of both of them is related to the cross-sectional area of the conductors 2 and 6. For example, when the cross-sectional area of the conductor 6 is 9 times that of the conductor 2, the detection range can be extended to 10 times. In practical applications, the conductor 6 is one or more conductors. The working principle is: the magnetoresistance characteristic curve of the antimony-indium compound semiconductor is a parabolic curve as shown in FIG. 3 . In Fig. 3, R _B and R ₀ are the resistance values of the magnetoresistive element when there is a magnetic field and no magnetic field, respectively, and B(T) is the external magnetic field. It can be seen from Figure 3 that the value of R _B /R ₀ changes with the change of B(T) in a parabolic law. It is generally believed that when B(T) increases to a certain value, R _B /R ₀ has a linear functional relationship with B(T). The key of the present utility model is to select the B (T) value in that range that causes the relationship between R _B /R ₀ and B (T) to gradually change from the quadratic function relationship to the first-order function relationship as the operating point of the current sensor. It is realized by the permanent magnet 3 providing a bias magnetic field, assuming that it is at point _B1 in FIG. 3 . When the applied voltage is stable, the output signal (voltage or current) is also stable. If a signal A is applied to the input terminal, an output signal B will be obtained at the output terminal. When the conductor 2 in Fig. 1 is connected with the external measured circuit and the measured current flows through the conductor 2, the current will generate a magnetic field in the surrounding space of the conductor, which is superimposed or subtracted from the bias magnetic field provided by the permanent magnet 3, If the operating point is changed, the output voltage or current will also change accordingly. Suppose it moves from B ₁ to B _2. Since the slopes of the parabola at point ① and point ② are different, it is in the stage of gradual change from a quadratic function to a linear function. Corresponding to the input signal C equal to A, the corresponding output signal D is different from the original output signal B. When the new operating point falls on the rising section of the parabola, the slope of point ② is much greater than the slope of point ①. Therefore, the output The signal is enhanced; it can be seen that when there is a bias magnetic field, as long as the current in the conductor 2 changes, there will be a changing signal at the output end of the magnetoresistive element; both experimental results and theoretical analysis can prove that as long as the operating point is selected properly, For antimony-indium compound semiconductor magnetoresistive chips of various shapes and conductors 2 of various thicknesses, the output voltage or current obtained from the output terminal of the magnetoresistive element is always proportional to the current flowing through the conductor 2 and has a nearly linear relationship. The molecular expression of the antimony-indium compound semiconductor is InSb _1-x As _x (x=0～1), and its two extreme cases are: when x=0, it is indium antimonide (InSb); when x= When 1, it is indium arsenide (InAs), and in other cases it is ternary antimony indium arsenide (In-Sb-As compound). Since the magnetoresistance effect of the antimony-indium compound semiconductor is many times higher than that of the nickel-iron-nickel-cobalt material, a suitable antimony-indium compound semiconductor material can be selected to make the magnetoresistance element. Therefore, the utility model can be made to be able to detect weak currents above the milliampere level in the external measured circuit flowing through the conductor 2, thus expanding the application occasions of this type of sensor.

Compared with the existing magnetoresistive current sensor, the utility model has the following advantages and beneficial effects: (1) the utility model can detect weak currents above the milliampere level in the circuit to be tested, and is a semiconductor magnetoresistor with higher sensitivity (2) the utility model is a semiconductor magnetoresistive current sensor with small size, light weight, firm and compact structure and long service life; (3) due to antimony-indium The characteristics of compound semiconductors are different, or they have higher carrier mobility, or higher temperature stability, or it is easy to obtain a more perfect crystal during fabrication. Therefore, when making this magnetoresistive current sensor All can be properly selected according to the requirements of use; (4) the semiconductor magnetoresistive current sensor can be easily manufactured as long as the conventional method is used, and the structural characteristics of the semiconductor magnetoresistive current sensor have advantages such as reduced area and easy assembly .

The accompanying drawings of the description are further described as follows: Fig. 1 is a schematic diagram of the internal structure of an antimony-indium compound semiconductor magnetoresistive current sensor, and Fig. 2 is a schematic diagram of an antimony-indium compound semiconductor magnetoresistive current sensor that increases the detection range by adding parallel conductors Schematic diagram of the internal structure, Figure 3 is a schematic diagram of the antimony-indium compound semiconductor magnetoresistive current sensing function.

The embodiment of this semiconductor magnetoresistive current sensor can be as follows: as shown in Fig. 1～Fig. 2, and carry out design, material selection, manufacture, connection and assembly according to the connection relationship described in the above specification. This current sensor: (1) Substrate The magnetoresistive chip 1 on 5 is thin-film type or single-crystal type, and the thin-film type chip 1 can be made by conventionally used vacuum thermal evaporation and various sputtering feasible methods, while the single-crystal type can be made by commonly used grinding and thinning methods However, the thin-film magnetoresistive chip has higher sensitivity; the magnetoresistive chip can be made into various shapes according to different application requirements and can form a multi-terminal output form, and the magnetoresistive chip can be selected such as indium antimonide, arsenic Antimony-indium binary compounds such as indium and antimony-indium ternary compound semiconductor materials such as antimony indium arsenide, or quaternary antimony-indium compound semiconductor materials such as gallium indium arsenide; (2) permanent magnets 3 The purpose is to provide a bias magnetic field for the magnetoresistive chip, so its shape and material can be various shapes and different materials, and only need to be processed and manufactured by traditional sintering processing methods. During assembly, it is required that the permanent magnet 3 be installed directly below or directly above the magnetoresistive element combined with the magnetoresistive chip 1 and the substrate 5, and it is acceptable to use the S pole or the N pole to face the magnetoresistive element, but it is required that its magnetic force lines be as vertical as possible Through the surface of the magnetoresistive chip; (3) The ferromagnetic material sheet 4 sandwiched between the substrate 5 and the permanent magnet 3 plays the role of adjusting the bias magnetic field strength provided by the permanent magnet 3. In fact, it adjusts the magnetic resistance element The working point, and play a role in concentrating the spatial magnetic field generated by conductor 2. Ferromagnetic material sheet 4 also only needs to be processed and manufactured with traditional press processing method; (4) substrate 5 can be monocrystalline or polycrystalline materials such as silicon wafer, glass-ceramic sheet, mica sheet; (5) as described in the above description The mutual connection relationship of each part of the device is connected and glued firmly, and then inserted into its shell, and injected with epoxy resin to increase the firmness and moisture-proof performance, so that the present invention can be better implemented.

After long-term research and experiments, the inventor has made this magnetoresistive current sensor with indium antimonide, indium arsenide binary compound, antimony arsenic indium ternary compound and gallium indium arsenic antimony quaternary compound semiconductor magnetoresistive element. The results show that it is easy to manufacture, high in sensitivity, good in stability and remarkable in effect. Only a few examples are selected below and shown in Table 1. Table 1:

Claims (4)

1. An antimony-indium compound semiconductor magnetoresistive current sensor is characterized in that: it consists of an antimony-indium compound magnetoresistive semiconductor magnetoresistive chip (1), a conductor (2), a permanent magnet (3), a ferromagnetic The material thin sheet (4) and the substrate (5) used to support the magnetoresistive chip are jointly connected to each other. On the sheet (5), the base sheet (5) is bonded to the ferromagnetic material sheet (4) through an adhesive, the ferromagnetic material sheet (4) is bonded to the permanent magnet (3) through an adhesive, and the conductor (2) The whole root straddles the magnetoresistive chip (1). 2. The antimony-indium compound semiconductor magnetoresistive current sensor according to claim 1, characterized in that the magnetoresistive chip (1) can be made into various shapes of thin film or single crystal, multi-terminal magnetoresistance chip. 3. The antimony-indium compound semiconductor magnetoresistive current sensor according to claim 1, characterized in that the conductor (2) is entirely across and parallel to the surface or back of the magnetoresistive chip (1), And two or more conductors can be connected in parallel, and only one of the conductors straddles the magnetoresistive chip, and the rest can bypass the magnetoresistive chip. 4. According to the antimony-indium compound semiconductor magnetoresistive current sensor according to claim 1, it is characterized in that the permanent magnet (3) must be installed on the magnetoresistive chip (1) and the substrate (5). Directly below or directly above the resistive element, let the magnetic flux pass through the surface of the magnetic chip vertically.

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