Hall element and current sensor

Abstract

The present invention provides a Hall element and a current sensor that can achieve both high precision and high sensitivity, have low power consumption, and suppress reliability variations even when a high magnetic field is applied. The Hall element includes: a substrate (11) containing gallium arsenide; an active layer (12) formed on the substrate and containing indium arsenide, having a film thickness of 0.63 μm or more and less than 1.45 μm; and an inactive layer (13) formed on the active layer, having a film thickness of 3 nm or more and less than 100 nm, and the film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067. Thereby, it is possible to provide a Hall element and a current sensor that can achieve both high precision and high sensitivity, have low power consumption, and suppress reliability variations even when a high magnetic field is applied.

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, see 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 Problems]

[0005] In a first aspect of the present invention, there is provided a Hall element, comprising: a substrate containing gallium arsenide; an active layer containing indium arsenide 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, the film thickness ratio of the inactive layer to the active layer being 0.005 or more and less than 0.067.

[0006] In a second aspect of the present invention, there is provided a Hall element, comprising: a substrate containing gallium arsenide; an active layer containing indium arsenide 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, the film thickness ratio of the inactive layer to the active layer being 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 inventions. 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-linear coefficient.

[0012] Figure 4 Shows the scanning electron microscope images of the cross-sections of the substrate, the active layer, and the inactive layer.

[0013] Figure 5A Shows the correlation between the film thickness and the consumption current of the Hall element to which a driving 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 driving 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 mobility of electrons.

[0019] [Explanation of reference numerals]

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

[0021] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention recited 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 Indicates 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, V dmax 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 guaranteed even when a high magnetic field is applied, and the Hall element 1 with a wide dynamic range is obtained.

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

[0028] [Equation 2]

[0029]

[0030] Among them, V hi0 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 an experimental value (0.1). It can be seen from this formula that the magnetic sensitivity V of the Hall element 1 hi can be improved by reducing the mobility μ. In addition, since the non-linearity coefficient α is usually greater than β, the magnetic sensitivity V can also be improved by reducing the non-linearity coefficient α hi . 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 by increasing the mobility μ, but the more the decrease of the nonlinear coefficient α caused by the improvement of crystallinity exceeds the decrease of the 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, the mobility μ is increased, and the magnetic sensitivity of the Hall element 1 is improved.

[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), 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. Therefore, 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 1×10 4 / cm 2 Below. Such a substrate 11 can be used, for example, to grow the crystal of the compound semiconductor of the substrate 11 by the vertical Bridgman method. Thereby, the crystal defects of the active layer 12 grown on the substrate 11 can be suppressed, and a Hall element 1 with high precision and high sensitivity can be realized even under the application of a high magnetic field.

[0034] The active layer 12 (also referred to as the magnetic induction part) is a layer disposed on the substrate 11 that generates a Hall electromotive force. It 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 In a Al b Ga (1-a-b) As x Sb (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 a large number of crystal defects are generated in the active layer 12 at the interface between the active layer 12 and the substrate 11. 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 mismatch 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 closer to the original structure of the compound semiconductor the farther it is 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 and the consumption current of the Hall element 1 to which a driving voltage of 3V is applied. It can be seen that the power consumption of the Hall element 1 is in a linear relationship with the film thickness of the Hall element 1. 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 5BShows the correlation between the film thickness and the consumption current of the Hall element 1 to which a driving voltage of 2.8 V is applied. The magnitude of the driving voltage is appropriately changed according to the application, but when driving the Hall element under a regulator, the driving voltage is generally suppressed. Similarly to the Figure 5A shown correlation, 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 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 (e.g., 27 degrees) is 5×10 16 ~5×10 17 / cm 3 . 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), carbon (C), etc. can be used. The formation of the active layer containing the n-type dopant can use the molecular beam epitaxy (MBE) method, and 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, for example, a diffusion method in which the n-type dopant is thermally diffused in the active layer 12, an ion implantation method in which the accelerated n-type dopant is implanted into the active layer 12 and then heated to activate it, and other general methods can be used. By doping the n-type dopant in the active layer 12 so that the electron density at room temperature is 5×10 16 or more, the electron mobility can be increased, the signal-to-noise 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 5×10 17 / cm 3 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 depositing a film 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 S / N 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 of 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 of the two. When the inactive layer 13 is grown on the active layer 12, strong covalent bonds are formed due to the dangling bonds on the surface of the inactive layer 13 at the interface between the active layer 12 and the inactive layer 13, and the crystal structure of the active layer 12 is distorted to be 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 this distortion becomes, and the crystallinity of the active layer 12 deteriorates. 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 increased.

[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 / cm 3 or more and 2.90 g / cm 3 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 / cm 3 or more and 2.90 g / cm 3 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, 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 body, and are formed of gold (Au), platinum (Pt), titanium (Ti), or the like 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 due to 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] 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 determined.

[0048] (Example 1)

[0049] On a GaAs substrate (substrate 11) with an etch pit density of 1×10 4 / cm 2 or less, an InAs layer (active layer 12) was formed to have an electron density of 1.9×10 -17 / cm 3 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. A SiN layer (protective layer 14) with a density of 2.34 g / cm 3 and a tensile stress of 235 MPa was formed on the GaAs layer, and the Hall element of Example 1 was fabricated.

[0050] (Example 2)

[0051] Except that the InAs layer (active layer 12) was set to have an electron density of 1.8×10 -17 / cm 3 and a film thickness of 1.050 μm, the Hall element of Example 2 was fabricated in the same manner as 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 / cm 3 and a film thickness of 0.525 μm, the Hall element of Example 2 was fabricated in the same manner as 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. When the film thickness of the active layer 12 is 0.63 μm or more, the linearity error is 0.05% or less.

[0057] 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 1×10 4 / cm 2 or less, an InAs layer (active layer 12) is formed with an electron density of 1.9×10 -17 / cm 3 and a film thickness of 0.630 μm. A GaAs layer (inactive layer 13) with a film thickness of 20 nm is formed on the InAs layer to fabricate the semiconductor film of Example 3.

[0060] (Example 4)

[0061] Except that the InAs layer (active layer 12) is set to have an electron density of 1.9×10 -17 / cm 3 and a film thickness of 0.788 μm, the semiconductor film of Example 4 is fabricated in the same manner as in Example 3.

[0062] (Example 5)

[0063] Except that the InAs layer (active layer 12) is set to have an electron density of 1.8×10 -17 / cm 3 and a film thickness of 1.050 μm, the semiconductor film of Example 5 is fabricated in the same manner as in Example 3.

[0064] (Comparative Example 2)

[0065] Except that the InAs layer (active layer 12) is set to have an electron density of 1.0×10 -17 / cm 3 and a film thickness of 0.525 μm, the semiconductor film of Comparative Example 1 is fabricated in the same manner as in Example 3.

[0066] [Table 2]

[0067]

[0068] Figure 7 Shows the correlation between the film thickness of the InAs layer (active layer 12) and the electron mobility. 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 cm 2 / 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 is applied to the semiconductor films of Comparative Examples 3 to 6 shown in Table 3 in a room at 23°C to measure the mobility.

[0070] (Comparative Example 3)

[0071] On a GaAs substrate (substrate 11) with an etch pit density of 1×10 4 / cm 2 or less, an InAs layer (active layer 12) with an electron density of 0.92×10 -17 / cm 3 and a film thickness of 0.525 nm is formed. A GaAs layer with a film thickness of 4.5 nm is formed on the InAs layer to fabricate the semiconductor film of Comparative Example 3.

[0072] (Comparative Example 4)

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

[0074] (Comparative Example 5)

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

[0076] (Comparative Example 6)

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

[0078] [Table 3]

[0079]

[0080] Figure 8 Shows the correlation between the film thickness of the GaAs - cap (inactive layer 13) and the crystallinity of the active layer 12 as manifested in the electron mobility. 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 Represents 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. Here, the mobility improvement amount refers to the electron mobility of 12000 cm Figure 8 and in the 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 2The relative mobility when / Vs is 100%. The solid line represents the data of the semiconductor film with the InAs layer having a film thickness of 630 nm as the active layer 12, the dashed line represents the data of the semiconductor film with the InAs layer having a film thickness of 1050 nm as the active layer 12, and the dotted line represents the data of the semiconductor film with the InAs layer having a film thickness of 1350 nm as the active layer 12.

[0082] It can be seen that in the semiconductor film with the active layer 12 having a film thickness of 630 nm, if the film thickness ratio of the non-active 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 non-active 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 cm 2 / Vs or more, preferably 12000 cm 2 / Vs or more, it is possible to improve the crystallinity of the active layer 12 to improve the sensitivity, and further improve the SN ratio 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 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 a non-active 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 non-active 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] 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 with such changes or improvements 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 includes: A substrate containing gallium arsenide; An active layer formed on the substrate and containing indium arsenide, 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, The film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.

067.

2. A Hall element, wherein, The Hall element includes: A substrate containing gallium arsenide; An active layer formed on the substrate and containing indium arsenide, 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, The film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.

067.

3. The Hall element according to claim 1 or 2, wherein, The 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 lattice constant difference 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 with the larger lattice constant of the two.

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

6. The Hall element according to claim 1 or 2, wherein, The active layer is doped with an N-type dopant 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 12000 cm 2 / Vs or higher.

8. The Hall element according to claim 1 or 2, wherein, The Hall element further includes a protective layer formed on the inactive layer, The density of the protective layer is 2.29 g / cm 3 or more and 2.90 g / cm 3 or less, and 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 or less.

10. A current sensor, wherein, The current sensor includes the Hall element according to claim 1 or 2, The Hall element includes an electrode that contacts the active layer.

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