Hall element and current sensor

Abstract

The invention provides a Hall element and a current sensor, which can achieve high precision and high sensitivity even under the condition that a high magnetic field is applied, consume low power and restrain reliability variation. A Hall element is provided with: a substrate (11) containing gallium arsenide; an active layer (12) which is formed on the substrate by containing indium arsenide and has a film thickness of 0.63 [mu] m or more and less than 1.45 [mu] m; and an inactive layer (13) formed on the active layer and having a film thickness of 3 nm or more and less than 100 nm, the film thickness ratio of the inactive layer to the active layer being 0.005 or more and less than 0.067. As a result, it is possible to provide a Hall element and a current sensor which can achieve both high accuracy and high sensitivity even when a high magnetic field is applied, consume low power, and suppress variation in reliability.

Description

Technical Field

[0001] The present invention relates to a Hall element and a current sensor. Background Art

[0002] A current sensor is known which includes a Hall element, and applies a magnetic field generated by a current flowing through a measurement conductor to the Hall element, and measures the current based on the output Hall voltage. As such a Hall element, a Hall element having an active layer formed on a substrate, an inactive layer formed on the active layer, and a protective layer formed on the inactive layer is known (for example, refer to Patent Document 1). By setting the film thickness to 0.6 μm or less, this Hall element can improve sensitivity, and can protect the active layer from mechanical damage caused by the formation of the protective layer, but it may not be possible to suppress crystal defects of the active layer generated at the interface between the substrate and the active layer and at the interface between the active layer and the inactive layer.

[0003] Patent Document 1: Japanese Patent Publication No. 4855189 Summary of the Invention

[0004] [Means for Solving the Problem]

[0005] In a first aspect of the present invention, there is provided a Hall element, wherein the Hall element includes: a substrate containing gallium arsenide; an active layer containing indium arsenide and formed on the substrate, and having a film thickness of 0.63 μm or more and less than 1.45 μm; and an inactive layer formed on the active layer, and having a film thickness of 3 nm or more and less than 100 nm, and a film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067.

[0006] In a second aspect of the present invention, there is provided a Hall element, wherein the Hall element includes: a substrate containing gallium arsenide; an active layer containing indium arsenide and formed on the substrate, and having a film thickness of 0.63 μm or more and less than 1.35 μm; and an inactive layer formed on the active layer, and having a film thickness of 3 nm or more and less than 100 nm, and a film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067.

[0007] In a third aspect of the present invention, there is provided a current sensor including the Hall element of the first aspect, the Hall element including an electrode in contact with the active layer.

[0008] In addition, the above summary of the invention does not enumerate all features of the present invention. In addition, sub-combinations of these feature groups can also form an invention. Brief Description of the Drawings

[0009] Figure 1Shows the structure of the Hall element of this embodiment.

[0010] Figure 2 Shows the correlation between the magnetic field applied to the Hall element and the Hall voltage.

[0011] Figure 3 Shows the correlation between the mobility of electrons and the non-linearity coefficient.

[0012] Figure 4 Shows a scanning electron microscope image of the cross section of the substrate, active layer, and inactive layer.

[0013] Figure 5A Shows the correlation between the film thickness and the consumption current of the Hall element to which a drive voltage of 3 V is applied.

[0014] Figure 5B Shows the correlation between the film thickness and the consumption current of the Hall element to which a drive voltage of 2.8 V is applied.

[0015] Figure 6 Shows the correlation between the film thickness of the active layer and the linearity error.

[0016] Figure 7 Shows the correlation between the film thickness of the active layer and the mobility of electrons.

[0017] Figure 8 Shows the correlation between the film thickness of the inactive layer and the mobility of electrons.

[0018] Figure 9 Shows the correlation between the film thickness ratio of the inactive layer to the active layer and the improvement amount of the electron mobility.

[0019] [Description of Reference Numerals]

[0020] 1... Hall element, 11... Substrate, 12... Active layer, 13... Inactive layer, 14... Protective layer, 15a, 15b... Electrodes. Detailed Embodiment

[0021] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention described in the claims. In addition, the combinations of features described in the embodiments are not necessarily all essential for the solution means of the invention.

[0022] Figure 1 Shows the structure of the Hall element 1 of this embodiment. The Hall element 1 is an element that outputs a Hall electromotive force (also referred to as a Hall voltage) when a magnetic field is applied. The Hall element 1 of this embodiment is particularly an element that realizes high precision, in other words, a wide dynamic range, by improving the linearity of the Hall voltage with respect to the applied magnetic field.

[0023] Figure 2 It represents the correlation between the magnetic field strength B applied to the Hall element 1 and the Hall voltage V. Here, the solid line represents the experimental data, and the dash-dotted line represents the approximate straight line of the experimental data. The greater the applied magnetic field, the greater the error (referred to as the linearity error) between the Hall voltage and the approximate straight line, and the lower the linearity. The linearity error ρ (%) can be expressed by the following formula.

[0024] [Equation 1]

[0025]

[0026] Among them, Vdmax is the maximum value of the difference between the Hall output and the approximate straight line, and F.S. is the output range of the Hall voltage. The smaller the linearity error, the more the linearity of the Hall voltage can be ensured even when a high magnetic field is applied, and the Hall element 1 with a wide dynamic range is obtained.

[0027] The magnetic sensitivity Vhi of the Hall element 1 during constant current drive is obtained by the following formula. In addition, β is an experimental value, for example, 0.1.

[0028] [Equation 2]

[0029]

[0030] Among them, Vhi0 is the ideal magnetic sensitivity without a magnetic field, μ is the mobility of electrons in the active layer 12, B is the magnetic field applied to the active layer 12, α is the non-linearity coefficient, and β is the experimental value (0.1). It can be seen from this formula that the magnetic sensitivity Vhi of the Hall element 1 can be improved by reducing the mobility μ. In addition, since the non-linearity coefficient α is usually greater than β, the magnetic sensitivity Vhi can also be improved by reducing the non-linearity coefficient α. However, the reduction of the mobility μ will increase the magnetic sensitivity and decrease the Hall voltage, so the S / N ratio deteriorates and the accuracy of the Hall element 1 may be reduced. Therefore, it is necessary to improve the magnetic sensitivity of the Hall element 1 by reducing the non-linearity coefficient α.

[0031] Figure 3The correlation between the electron mobility μ and the nonlinear coefficient β - α is shown. If the mobility μ is large, in other words, there are few defects and high crystallinity in the crystal structure of the active layer 12, the scattering mechanism becomes polar optical phonon scattering, and the nonlinear coefficient α is small, for example, about 0.09. If the mobility μ is small, in other words, there are many defects and low crystallinity in the crystal structure of the active layer 12, the scattering mechanism becomes transfer scattering, and the nonlinear coefficient α is large, for example, about 1.37. The improvement of crystallinity can reduce the magnetic sensitivity of the Hall element 1 through the increase of the mobility μ. However, the more the reduction of the nonlinear coefficient α caused by the improvement of crystallinity exceeds the reduction of sensitivity caused by the increase of the mobility μ, the more the sensitivity of the Hall element 1 increases. Furthermore, the increase of the mobility μ increases the Hall voltage and improves the S / N ratio, improving the accuracy of the Hall element 1. Therefore, in the present embodiment, the crystallinity of the active layer 12 is improved, and the mobility μ is increased to improve the magnetic sensitivity of the Hall element 1.

[0032] The Hall element 1 includes a substrate 11, an active layer 12, an inactive layer 13, a protective layer 14, and electrodes 15a and 15b.

[0033] The substrate 11 is a base material for forming the active layer 12 as the element main body, and is a semiconductor substrate including gallium arsenide (GaAs) as a compound semiconductor. In addition to gallium arsenide, the substrate 11 can also use silicon (Si), indium phosphide (InP), gallium nitride (GaN), aluminum nitride (AlN), sapphire (Al2O3), silicon carbide (SiC), and diamond. The surface of the substrate 11 is highly active due to the presence of dangling bonds, that is, the state where the bonding bonds of the single crystal of the compound semiconductor are broken. If the active layer 12 is heteroepitaxially grown on the surface of the substrate 11, strong covalent bonds are generated at the interface between the substrate 11 and the active layer 12. Thus, when there are defects in the crystal structure of the substrate 11, the crystal of the active layer 12 covalently bonded to the crystal of the substrate 11 also has defects. Therefore, by using a high-quality substrate 11 with few crystal defects, the generation of crystal defects in the active layer 12 can be suppressed, and the etch pit density of the substrate 11 is preferably 1×104 / cm2 or less. Such a substrate 11 can grow the crystal of the compound semiconductor of the substrate 11 by the vertical Bridgman method, for example. Thereby, the crystal defects of the active layer 12 grown on the substrate 11 can be suppressed, and a high-precision and high-sensitivity Hall element 1 can be realized even under the application of a high magnetic field.

[0034] The active layer 12 (also referred to as the magnetic induction portion) is a layer disposed on the substrate 11 that generates a Hall electromotive force, contains indium arsenide (InAs) as a compound semiconductor, and is formed on the substrate 11 with a film thickness of, for example, 0.63 μm or more and less than 1.35 μm, or 0.63 μm or more and less than 1.45 μm. In addition to indium arsenide, indium antimonide (InSb), gallium arsenide (GaAs), and InaAlbGa ( 1 - a - b ) AsxSb ( 1 - x ) can also be used for the active layer 12. Here, the non - linear coefficient α varies according to the scattering mechanism of carriers in the active layer 12. The scattering mechanism of carriers varies according to the crystallinity of the active layer 12. The crystallinity is related to the electron mobility μ. If the crystallinity is high, the mobility μ increases, and if the crystallinity is low, the mobility μ decreases.

[0035] Figure 4 Scanning electron microscope (SEM) images of the substrate 11, the active layer 12, and the non - active layer 13 are shown. It can be seen that at the interface between the active layer 12 and the substrate 11, a large number of crystal defects are generated in the active layer 12. The lattice constants of the semiconductor compound contained in the substrate 11 and the semiconductor compound contained in the active layer 12 are different. When the active layer 12 grows on the substrate 11, strong covalent bonds generated by the dangling bonds on the surface of the substrate 11 are formed between the active layer 12 and the substrate 11, and the crystal structure of the active layer 12 is distorted in a manner consistent with the crystal structure of the substrate 11, and defects called lattice - misfit dislocations are generated in the crystal structure of the active layer 12. The crystal structure of the compound semiconductor contained in the active layer 12 is more approximate to the original structure of the compound semiconductor as it is farther from the interface with the substrate 11. Therefore, as the crystal growth of the active layer 12 and the film thickness of the active layer 12 increase, the original crystal structure of the compound semiconductor becomes more dominant, and the crystal defect density of the active layer 12 decreases. Therefore, in the present embodiment, the film thickness of the active layer 12 is 0.63 μm or more, preferably 0.788 μm or more, and more preferably 1.05 μm or more.

[0036] Figure 5A Shows the correlation between the film thickness of the Hall element 1 to which a driving voltage of 3V is applied and the consumption current. It can be seen that the power consumption of the Hall element 1 and the film thickness of the Hall element 1 are in a linear relationship. By increasing the film thickness of the active layer 12, the crystallinity is improved. On the other hand, the resistance value of the Hall element 1 decreases, and the consumption current increases. In view of applying the Hall element 1 to a current sensor, the consumption current of the Hall element 1 is preferably 22 mA or less when a driving voltage of 3V is applied. By making the film thickness of the active layer 12 less than 1.35 μm, the consumption current of the Hall element 1 can be made 22 mA or less.

[0037] Figure 5B It shows the correlation between the film thickness and the consumption current of the Hall element 1 with a driving voltage of 2.8 V applied. The magnitude of the driving voltage is appropriately changed according to the application. However, when driving the Hall element under a regulator, the driving voltage is generally suppressed. Similarly to the Figure 5A shown correlation, it can be known that the power consumption of the Hall element 1 and the film thickness of the Hall element 1 are in a linear relationship. By increasing the film thickness of the active layer 12, the crystallinity is improved. On the other hand, the resistance value of the Hall element 1 decreases, and the consumption current increases. Considering the application of the Hall element 1 to a current sensor, the consumption current of the Hall element 1 is preferably 22 mA or less when a driving voltage of 2.8 V is applied. By making the film thickness of the active layer 12 less than 1.45 μm, the consumption current of the Hall element 1 can be made 22 mA or less.

[0038] The active layer 12 is preferably doped with an n-type dopant, and the electron density at room temperature (for example, 27 degrees) is 5×1016 to 5×1017 / cm3. As the n-type dopant, for example, general dopants such as phosphorus (P), nitrogen (N), silicon (Si), tin (Sn), sulfur (S), selenium (Se), tellurium (Te), germanium (Ge), and carbon (C) can be used. The formation of the active layer containing the n-type dopant can use the molecular beam epitaxy (MBE) method, or the metalorganic chemical vapor deposition (MOCVD) method can also be used. In addition, as a method of doping the n-type dopant after forming the substrate, general methods such as a diffusion method of thermally diffusing the n-type dopant in the active layer 12 and an ion implantation method of injecting the accelerated n-type dopant into the active layer 12 and then heating it to activate it can be used. By doping the active layer 12 with the n-type dopant to make the electron density at room temperature 5×1016 or more, the electron mobility can be increased, the SN ratio of the Hall element 1 can be increased, and the accuracy can be improved. In addition, by doping the n-type dopant to such an extent that the electron density at room temperature becomes 5×1017 / cm3 or less, it is possible to prevent the excess n-type dopant from reducing the crystallinity of the active layer 12.

[0039] The inactive layer 13 is an electrically inert layer disposed on the active layer 12 to protect the active layer 12. For example, it contains a compound semiconductor such as gallium arsenide (GaAs), and is formed on the active layer 12 with a film thickness of 3 nm or more and less than 100 nm, preferably 3.15 nm or more and less than 90.45 nm, more preferably 3.15 nm or more and less than 67.50 nm. By setting the film thickness of the inactive layer 13 to 3 nm or more, preferably 3.15 nm or more, the active layer 12 can be protected from mechanical damage caused by the formation of the protective layer 14, and reliability variations can be suppressed. The electrically inert inactive layer 13 does not change the electrical characteristics of the active layer 12 when damaged, so that deterioration of the electrical characteristics of the Hall element 1 can be prevented. By forming such an inactive layer 13 by film formation containing gallium arsenide that is difficult to oxidize, has a large bandgap, and has a high resistance, oxidation of the active layer 12 can be prevented, high-temperature resistance can be improved, and the SN ratio can be increased.

[0040] At the interface between the inactive layer 13 and the active layer 12, a large number of crystal defects are also generated in the active layer 12 (see Figure 4 ). The semiconductor compound contained in the inactive layer 13 and the semiconductor compound contained in the active layer 12 have different lattice constants. For example, the lattice constant difference between the inactive layer 13 and the active layer 12 may be 0.6% or more, preferably 3% or more, compared with the lattice constant of the layer having the larger lattice constant among the two. In addition, the lattice constant difference between the inactive layer 13 and the active layer 12 may be 15% or less compared with the lattice constant of the layer having the larger lattice constant among the two. When the inactive layer 13 is grown on the active layer 12, strong covalent bonds generated by dangling bonds on the surface of the inactive layer 13 are formed between the active layer 12 and the inactive layer 13, and the crystal structure of the active layer 12 is distorted in a manner consistent with the crystal structure of the inactive layer 13, and defects called lattice misfit dislocations are generated in the crystal structure of the active layer 12. The more the inactive layer 13 grows, in other words, the thicker the film thickness, the greater the distortion, and the worse the crystallinity of the active layer 12. Therefore, the film thickness of the inactive layer 13 is less than 100 nm, preferably less than 90.45 nm, more preferably less than 67.50 nm. Thereby, the crystallinity of the active layer 12 can be improved, and the sensitivity of the Hall element 1 can be increased.

[0041] The film thickness ratio of the inactive layer 13 to the active layer 12 is 0.005 or more and less than 0.067, preferably 0.005 or more and less than 0.050. By making the film thickness ratio of the inactive layer 13 to the active layer 12 0.005 or more, the active layer 12 can be protected from mechanical damage and the like caused by the formation of the protective layer 14. In addition, crystal defects generated at the interface between the inactive layer 13 and the active layer 12 are suppressed by the small film thickness of the inactive layer 13 and relatively reduced within the active layer 12 due to the large film thickness of the active layer 12. By making the film thickness ratio of the inactive layer 13 to the active layer 12 less than 0.067, preferably less than 0.050, the crystallinity of the active layer 12 can be improved and the sensitivity of the Hall element 1 can be enhanced.

[0042] The protective layer 14 is a layer disposed on the inactive layer 13 to protect the active layer 12 and the inactive layer 13 from external damage, and is formed on the inactive layer 13 and contains, for example, silicon nitride (SiN), silicon oxynitride (SiON), silicon dioxide (SiO2), etc. The protective layer 14 preferably has a density of 2.29 g / cm3 or more and 2.90 g / cm3 or less, and a tensile stress of 160 MPa or more and 274 MPa or less. The film formation method is not particularly limited, and for example, sputtering, plasma CVD, or the like can be used. By providing the protective layer 14 having a density of 2.29 g / cm3 or more and 2.90 g / cm3 or less and a tensile stress of 160 MPa or more and 274 MPa or less on the inactive layer 13, the active layer 12 and the inactive layer 13 can be protected from external damage, the transfer scattering of carriers within the active layer 12 can be suppressed, and the accuracy and sensitivity of the Hall element 1 can be maintained.

[0043] The electrodes 15a and 15b are conductive members for outputting the Hall voltage output from the element main body, and are formed of, for example, gold (Au), platinum (Pt), or titanium (Ti) to make an ohmic contact with the active layer 12.

[0044] The current sensor including the Hall element 1 applies the magnetic field generated by the current flowing through the measurement object to the Hall element 1, and measures the current flowing through the measurement conductor based on the Hall voltage output from the Hall element 1 by the magnetic field.

[0045] The current sensor including the Hall element 1 can, for example, include the Hall element 1, a signal processing IC that processes the output signal based on the Hall voltage output from the Hall element 1, and an output terminal that outputs the output signal. The current sensor can also include a current conductor through which the current to be measured flows. In addition, the Hall element 1 and the signal processing IC can be electrically connected via a wire.

[0046] [Example 1]

[0047] In order to verify the correlation between the film thickness of the active layer 12 and the linearity error, for the Hall elements of Comparative Example 1 and Examples 1 and 2 shown in Table 1, a magnetic field in the range of -200 to +200 mT was applied in a room at 23°C, and the linearity error was obtained.

[0048] (Example 1)

[0049] On a GaAs substrate (substrate 11) with an etch pit density of 1×104 / cm2 or less, an InAs layer (active layer 12) was formed to have an electron density of 1.9×10-17 / cm3 and a film thickness of 0.630 μm. A GaAs layer (inactive layer 13) with a film thickness of 20 nm and electrodes (15a, b) were formed on the InAs layer, and a SiN layer (protective layer 14) with a density of 2.34 g / cm3 and a tensile stress of 235 MPa was formed on the GaAs layer to fabricate the Hall element of Example 1.

[0050] (Example 2)

[0051] Except that the InAs layer (active layer 12) was set to have an electron density of 1.8×10-17 / cm3 and a film thickness of 1.050 μm, the Hall element of Example 2 was fabricated in the same manner as in Example 1.

[0052] (Comparative Example 1)

[0053] Except that the InAs layer (active layer 12) was set to have an electron density of 1.0×10-17 / cm3 and a film thickness of 0.525 μm, the Hall element of Example 2 was fabricated in the same manner as in Example 1.

[0054] [Table 1]

[0055]

[0056] Figure 6 Indicates the correlation between the film thickness of the active layer 12 and the linearity error. As the film thickness increases, the linearity error decreases, and when the film thickness of the active layer 12 is 0.63 μm or more, the linearity error is 0.05% or less.

[0057] In order to verify the correlation between the film thickness of the active layer 12 and the crystallinity exhibited by the electron mobility, for the semiconductor films of Comparative Example 2 and Examples 3 to 5 shown in Table 2, the mobility was measured using the van der Waals method in a room at 23°C.

[0058] (Example 3)

[0059] On a GaAs substrate (substrate 11) with an etch pit density of 1×104 / cm2 or less, an InAs layer (active layer 12) was formed with an electron density of 1.9×10-17 / cm3 and a film thickness of 0.630 μm. A GaAs layer (inactive layer 13) with a film thickness of 20 nm was formed on the InAs layer to fabricate the semiconductor film of Example 3.

[0060] (Example 4)

[0061] The semiconductor film of Example 4 was fabricated in the same manner as in Example 3, except that the InAs layer (active layer 12) had an electron density of 1.9×10-17 / cm3 and a film thickness of 0.788 μm.

[0062] (Example 5)

[0063] The semiconductor film of Example 5 was fabricated in the same manner as in Example 3, except that the InAs layer (active layer 12) had an electron density of 1.8×10-17 / cm3 and a film thickness of 1.050 μm.

[0064] (Comparative Example 2)

[0065] The semiconductor film of Comparative Example 1 was fabricated in the same manner as in Example 3, except that the InAs layer (active layer 12) had an electron density of 1.0×10-17 / cm3 and a film thickness of 0.525 μm.

[0066] [Table 2]

[0067]

[0068] Figure 7 The correlation between the film thickness of the InAs layer (active layer 12) and the electron mobility is shown. It can be seen that in the semiconductor film with a film thickness of the active layer 12 of 0.63 μm or more, the mobility exceeds 14000 cm2 / Vs and the crystallinity is significantly improved.

[0069] To verify the correlation between the film thickness of the inactive layer 13 and the crystallinity in the electron mobility, the van der Waals method was applied to the semiconductor films of Comparative Examples 3 to 6 shown in Table 3 at room temperature of 23°C to measure the mobility.

[0070] (Comparative Example 3)

[0071] On a GaAs substrate (substrate 11) with an etch pit density of 1×104 / cm2 or less, an InAs layer (active layer 12) with an electron density of 0.92×10-17 / cm3 and a film thickness of 0.525 nm was formed. A GaAs layer with a film thickness of 4.5 nm was formed on the InAs layer to fabricate the semiconductor film of Comparative Example 3.

[0072] (Comparative Example 4)

[0073] A semiconductor film of Comparative Example 4 was fabricated in the same manner as Comparative Example 3, except that the electron density of the InAs layer was set to 0.96×10-17 / cm3 and the film thickness of the GaAs layer was set to 20 nm.

[0074] (Comparative Example 5)

[0075] A semiconductor film of Comparative Example 4 was fabricated in the same manner as Comparative Example 3, except that the electron density of the InAs layer was set to 0.99×10-17 / cm3 and the film thickness of the GaAs layer was set to 25 nm.

[0076] (Comparative Example 6)

[0077] A semiconductor film of Comparative Example 4 was fabricated in the same manner as Comparative Example 3, except that the electron density of the InAs layer was set to 0.95×10-17 / cm3 and the film thickness of the GaAs layer was set to 50 nm.

[0078] [Table 3]

[0079]

[0080] Figure 8 The correlation between the crystallinity of the active layer 12 and the film thickness of the GaAs-cap (inactive layer 13) and the electron mobility is shown. It can be seen that as the film thickness of the inactive layer 13 increases, the electron mobility decreases, in other words, the crystallinity of the active layer 12 decreases.

[0081] Figure 9 The correlation between the film thickness ratio of the inactive layer 13 to the active layer 12 and the improvement amount of the electron mobility is shown. Here, the improvement amount of the mobility refers to the relative mobility when the electron mobility of 12000 cm2 / Vs in a semiconductor film where the active layer 12 is an InAs layer with a film thickness of 520 nm and the inactive layer 13 is a GaAs layer with a film thickness of 20 nm (see Figure 8 and Comparative Example 4 in Table 3) is taken as 100%. The solid line represents the data of a semiconductor film with an InAs layer with a film thickness of 630 nm as the active layer 12, the dashed line represents the data of a semiconductor film with an InAs layer with a film thickness of 1050 nm as the active layer 12, and the dotted line represents the data of a semiconductor film with an InAs layer with a film thickness of 1350 nm as the active layer 12.

[0082] It can be seen that in the semiconductor film with a thickness of 630 nm of the active layer 12, if the film thickness ratio of the inactive layer 13 to the active layer 12 is less than 0.067, the mobility improvement amount exceeds 100%. In addition, if the film thickness ratio of the inactive layer 13 to the active layer 12 is less than 0.050, it can be seen that in any case where the film thickness of the active layer 12 is 630 nm, 1050 nm, or 1350 nm, the mobility improvement amount exceeds 105%. By making the mobility improvement amount 100% or more, preferably 105% or more, in other words, making the mobility 12000 cm2 / Vs or more, preferably 12000 cm2 / Vs or more, the crystallinity of the active layer 12 can be improved to increase the sensitivity, and further the SN ratio can be increased to realize a high-precision Hall element.

[0083] According to the Hall element according to the present embodiment, by including a substrate 11 containing gallium arsenide, an active layer 12 containing indium arsenide and formed on the substrate 11 and having a film thickness of 0.63 μm or more and less than 1.45 μm or 0.63 μm or more and less than 1.35 μm, and an inactive layer 13 formed on the active layer 12 and having a film thickness of 3 nm or more and less than 100 nm, and the film thickness ratio of the inactive layer 13 to the active layer 12 is 0.005 or more and less than 0.067, it is possible to provide a Hall element and a current sensor that can achieve both high precision and high sensitivity even when a high magnetic field is applied, have low power consumption, and suppress reliability variations.

[0084] According to the current sensor according to the present embodiment, by including a Hall element 1, and the Hall element 1 includes electrodes 15a and 15b in contact with the active layer 12, it is possible to provide a current sensor that can achieve both high precision and high sensitivity even when a high magnetic field is applied, has low power consumption, and suppresses reliability variations.

[0085] As described above, the present invention has been described using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. For those skilled in the art, it is obvious that various changes or improvements can be made to the above embodiments. According to the description in the claims, the embodiments to which such changes or improvements are applied are also included in the technical scope of the present invention.

[0086] It should be noted that, as long as the execution order of each process such as actions, steps, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is not specifically indicated as "before", "prior to", etc., and as long as the output of the previous process is not used in the subsequent process, it can be implemented in any order. Regarding the action flow in the claims, the specification, and the drawings, even if it is described using "first", "next", etc. for convenience, it does not mean that it must be implemented in that order.

Claims

1. A Hall element, wherein: The Hall element has: a substrate comprising gallium arsenide; an active layer comprising indium arsenide, formed on the substrate, and having a film thickness of not less than 0.63 μm and less than 1.45 μm; and an inactive layer formed on the active layer and having a film thickness of 3 nm or more and less than 100 nm, A film thickness ratio of the inactive layer to the active layer is greater than or equal to 0.005 and less than 0.

067.

2. A Hall element, wherein: The Hall element has: a substrate comprising gallium arsenide; an active layer comprising indium arsenide, formed on the substrate, and having a film thickness of not less than 0.63 μm and less than 1.35 μm; and an inactive layer formed on the active layer and having a film thickness of 3 nm or more and less than 100 nm, A film thickness ratio of the inactive layer to the active layer is greater than or equal to 0.005 and less than 0.

067.

3. The Hall element according to claim 1 or 2, wherein: A film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.

050.

4. The Hall element according to claim 1 or 2, wherein: The difference in lattice constant between the inactive layer and the active layer is 0.6% or more and 15% or less compared to the lattice constant of the layer having a larger lattice constant.

5. The Hall element according to claim 1 or 2, wherein: The inactive layer includes gallium arsenide.

6. The Hall element according to claim 1 or 2, wherein: The active layer is doped with N-type dopants and has an electron density of 5×10 16 ~5×10 17 / cm 3 .

7. The Hall element according to claim 1 or 2, wherein: The electron mobility is 12000cm 2 / Vs or above.

8. The Hall element according to claim 1 or 2, wherein: The Hall element further comprises a protective layer formed on the inactive layer. The density of the protective layer is 2.29 g / cm 3 Above and 2.90g / cm 3 Below, the tensile stress is 160 MPa or more and 274 MPa or less.

9. The Hall element according to claim 1 or 2, wherein: The etch pit density of the substrate is 1×10 4 / cm 2 the following.

10. A current sensor, wherein: The current sensor comprises the Hall element according to claim 1 or 2, The Hall element includes an electrode in contact with the active layer.

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