Hall element and current sensor

Abstract

To provide a Hall element and a current sensor in each of which high accuracy and high sensitivity can be made compatible with each other even when a high magnetic field is applied to the Hall element and the current sensor, the Hall element and the current sensor consuming low power and being suppressed in reliability variation.SOLUTION: The Hall element comprises a substrate 11 including gallium arsenide, an active layer 12 including indium arsenide, formed on the substrate, 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. The film thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067. This enables the provision of the Hall element and a current sensor which can achieve both high precision and high sensitivity even under high magnetic fields, have low power consumption, and suppress reliability variations.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There is known a current sensor that includes a Hall element, applies a magnetic field generated by a current flowing through a measurement conductor to the Hall element, and measures a current based on an output Hall voltage. As such a Hall element, a Hall element that includes 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 (see, for example, Patent Document 1). Such a Hall element can improve sensitivity by making the film thickness 0.6 μm or less, while protecting the active layer from mechanical damage caused by the formation of the protective layer by the inactive layer, but there is a concern that crystal defects in the active layer generated at the interface between the substrate and the active layer and the interface between the active layer and the inactive layer cannot be suppressed. Patent Document 1 Patent No. 4855189 Summary of the Invention [Means for solving the problem]

[0003] 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 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 thickness of 3 nm or more and less than 100 nm, wherein a thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067.

[0004] 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 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 thickness of 3 nm or more and less than 100 nm, wherein a thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067.

[0005] In a third aspect of the present invention, there is provided a current sensor comprising the Hall element of the first aspect, the Hall element including an electrode in contact with the active layer.

[0006] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0007] [Figure 1] 2 shows the configuration of a Hall element according to the present embodiment. [Diagram 2] 1 shows the correlation between the magnetic field applied to the Hall element and the Hall voltage. [Diagram 3] The correlation between the electron mobility and the nonlinear coefficient is shown. [Figure 4] 1 shows a scanning electron microscope image of a cross section of the substrate, active layer, and passive layer. [Figure 5A] The figure shows the correlation between the film thickness and current consumption of a Hall element when a drive voltage of 3 V is applied. [Figure 5B] The figure shows the correlation between the film thickness and current consumption of a Hall element when a drive voltage of 2.8 V is applied. [Figure 6] 4 shows the correlation between the thickness of the active layer and the linearity error. [Figure 7] 4 shows the correlation between the thickness of the active layer and the mobility of electrons. [Figure 8] 1 shows the correlation between the thickness of the inactive layer and the mobility of electrons. [Figure 9] 1 shows the correlation between the thickness ratio of the inactive layer to the active layer and the improvement in electron mobility. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0009] 1 shows the configuration of a Hall element 1 according to this embodiment. The Hall element 1 is an element that outputs a Hall electromotive force (also called a Hall voltage) when a magnetic field is applied. The Hall element 1 according to this embodiment realizes an element with high accuracy, in other words, a wide dynamic range, even when a strong magnetic field is applied, by particularly improving the linearity of the Hall voltage with respect to the applied magnetic field.

[0010] Figure 2 shows the correlation between the magnetic field strength B applied to the Hall element 1 and the Hall voltage V. Here, the solid line indicates the experimental data, and the dashed line indicates the linear approximation of the experimental data. The stronger the applied magnetic field, the larger the error (called linearity error) of the Hall voltage from the linear approximation, and the lower the linearity. The linearity error ρ (%) can be expressed by the following formula.

number

[0011] Magnetic sensitivity V of Hall element 1 when driven by constant current hi is calculated by the following formula: where β is an experimental value, for example 0.1.

number

[0012] FIG. 3 shows the correlation between the mobility μ of electrons and the nonlinear coefficient β-α. If the mobility μ is large, in other words, if the crystal structure of the active layer 12 has few defects and is highly crystalline, the scattering mechanism becomes polar optical phonon scattering, and the nonlinear coefficient α becomes small, for example, about 0.09. If the mobility μ is small, in other words, if the crystal structure of the active layer 12 has many defects and is low in crystallinity, the scattering mechanism becomes transition scattering, and the nonlinear coefficient α becomes large, for example, about 1.37. Although the improvement of the crystallinity can reduce the magnetic sensitivity of the Hall element 1 by increasing the mobility μ, the reduction of the nonlinear coefficient α due to the improvement of the crystallinity increases the sensitivity of the Hall element 1 so much that it exceeds the reduction in sensitivity due to the increase in the mobility μ. Furthermore, the increase in the mobility μ increases the Hall voltage, improving the S / N ratio, and increasing the accuracy of the Hall element 1. Therefore, in this embodiment, the crystallinity of the active layer 12 is improved, and the mobility μ is increased, thereby improving the magnetic sensitivity of the Hall element 1.

[0013] 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.

[0014] The substrate 11 is a base material for forming the active layer 12, which is the main body of the element, and is a semiconductor substrate containing gallium arsenide (GaAs), which is a compound semiconductor. In addition to gallium arsenide, the substrate 11 may also contain silicon (Si), indium phosphide (InP), gallium nitride (GaN), aluminum nitride (AlN), sapphire (Al 2 O 3), silicon carbide (SiC), and diamond can also be used. The surface of the substrate 11 is highly active due to the presence of dangling bonds, i.e., the bonds of the compound semiconductor single crystal are broken and left vacant, and when the active layer 12 is hetero-grown on the surface of the substrate 11, strong covalent bonds are formed at the interface between the substrate 11 and the active layer 12. As a result, if there is a defect in the crystal structure of the substrate 11, the crystal of the active layer 12 covalently bonded to the crystal of the substrate 11 will also have a defect. Therefore, by using a high-quality substrate 11 with few crystal defects, it is possible to suppress the occurrence of crystal defects in the active layer 12, and the etch pit density of the substrate 11 is reduced to 1×10 4 / cm 2 It is preferable that the thickness of the substrate 11 is equal to or less than 100 nm. Such a substrate 11 can be obtained by growing crystals of the compound semiconductor of the substrate 11 using, for example, the vertical Bridgman method. This makes it possible to suppress crystal defects in the active layer 12 grown on the substrate 11, and to realize a Hall element 1 that is highly accurate and sensitive even when a high magnetic field is applied.

[0015] The active layer 12 (also called a magnetic sensing portion) is a layer disposed on the substrate 11 to generate a Hall electromotive force, and contains indium arsenide (InAs), which is a compound semiconductor, and is formed on the substrate 11 with a 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, the active layer 12 may contain indium antimony (InSb), gallium arsenide (GaAs), In a Al b Ga (1-a-b) As x Sb (1-x) can also be used. Here, the nonlinearity coefficient α changes depending on the scattering mechanism of carriers in the active layer 12. The scattering mechanism of carriers changes depending on the crystallinity of the active layer 12. Crystallinity and electron mobility μ are correlated, and the higher the crystallinity, the higher the mobility μ, and the lower the mobility μ.

[0016] FIG. 4 shows scanning electron microscope (SEM) images of the substrate 11, the active layer 12, and the inactive layer 13. It can be seen that many crystal defects occur in the active layer 12 at the interface between the active layer 12 and the substrate 11. The semiconductor compound contained in the substrate 11 and the semiconductor compound contained in the active layer 12 have different lattice constants. When the active layer 12 grows on the substrate 11, a strong covalent bond is formed between the active layer 12 and the substrate 11 by the dangling bonds on the surface of the substrate 11, and the crystal structure of the active layer 12 is distorted to match 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 becomes closer to the original structure of the compound semiconductor as it moves away from the interface with the substrate 11. Therefore, as the crystals constituting the active layer 12 grow and the film thickness of the active layer 12 increases, the original crystal structure of the compound semiconductor becomes dominant, and the crystal defect density of the active layer 12 decreases. Therefore, in this embodiment, the thickness of the active layer 12 is set to 0.63 μm or more, preferably 0.788 μm or more, and more preferably 1.05 μm or more.

[0017] FIG. 5A shows the correlation between the film thickness and current consumption of the Hall element 1 when a drive voltage of 3V is applied. It can be seen that there is a linear relationship between the power consumption of the Hall element 1 and the film thickness of the Hall element 1. Increasing the film thickness of the active layer 12 improves the crystallinity, while decreasing the resistance value of the Hall element 1 and increasing the current consumption. In consideration of applying the Hall element 1 to a current sensor, it is preferable that the current consumption of the Hall element 1 is 22 mA or less when a drive voltage of 3V is applied. By making the film thickness of the active layer 12 less than 1.35 μm, the current consumption of the Hall element 1 can be made 22 mA or less.

[0018] FIG. 5B shows the correlation between the film thickness and current consumption of the Hall element 1 when a drive voltage of 2.8V is applied. The magnitude of the drive voltage is appropriately changed depending on the application, but when the Hall element is driven under a regulator, the drive voltage is generally suppressed. As with the correlation shown in FIG. 5A, it can be seen that the power consumption of the Hall element 1 and the film thickness of the Hall element 1 are linearly related. While the crystallinity improves as the film thickness of the active layer 12 increases, the resistance value of the Hall element 1 decreases and the current consumption increases. In consideration of applying the Hall element 1 to a current sensor, it is preferable that the current consumption of the Hall element 1 is 22 mA or less when a drive voltage of 2.8V is applied. By making the film thickness of the active layer 12 less than 1.45 μm, the current consumption of the Hall element 1 can be made 22 mA or less.

[0019] The active layer 12 is 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 It is preferable that the n-type dopant is a general dopant such as phosphorus (P), nitrogen (N), silicon (Si), tin (Sn), sulfur (S), selenium (Se), tellurium (Te), germanium (Ge), or carbon (C). The active layer containing the n-type dopant can be formed by molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD). As a method for doping the n-type dopant after forming the substrate, a general method such as a diffusion method in which the n-type dopant is thermally diffused into the active layer 12 or an ion implantation method in which accelerated n-type dopant is implanted into the active layer 12 and then heated to activate it can be used. The active layer 12 is doped with the n-type dopant to increase the electron density at room temperature to 5×10 16 By setting the value to 5×10 or more, the mobility of electrons can be increased, the signal-to-noise ratio of the Hall element 1 can be increased, and the accuracy can be improved. 17 / cm 3 By doping the n-type dopant to the extent described below, it is possible to prevent the crystallinity of the active layer 12 from being reduced by an excess of the n-type dopant.

[0020] The inactive layer 13 is an electrically inactive layer disposed on the active layer 12 to protect the active layer 12, and contains a compound semiconductor such as gallium arsenide (GaAs) and is formed on the active layer 12 with a thickness of, for example, 3 nm or more and less than 100 nm, preferably 3.15 nm or more and less than 90.45 nm, and more preferably 3.15 nm or more and less than 67.50 nm. By making the thickness of the inactive layer 13 3 nm or more, preferably 3.15 nm or more, it is possible to protect the active layer 12 from mechanical damage caused by the formation of the protective layer 14 and suppress reliability fluctuations. The electrically inactive inactive layer 13 does not change the electrical characteristics of the active layer 12 when damaged, and therefore it is possible to prevent deterioration of the electrical characteristics of the Hall element 1. By forming such an inactive layer 13 to contain gallium arsenide, which is difficult to oxidize, has a large forbidden band width, and has high resistance, it is possible to prevent oxidation of the active layer 12, improve high temperature resistance, and improve the signal-to-noise ratio.

[0021] Many crystal defects occur in the active layer 12 even at the interface between the inactive layer 13 and the active layer 12 (see FIG. 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 difference in lattice constant between the inactive layer 13 and the active layer 12 may be 0.6% or more, preferably 3% or more, compared to the lattice constant of the layer with the larger lattice constant. Also, the difference in lattice constant between the inactive layer 13 and the active layer 12 may be 15% or less, compared to the lattice constant of the layer with the larger lattice constant. When the inactive layer 13 grows on the active layer 12, a strong covalent bond is formed between the active layer 12 and the inactive layer 13 by the dangling bonds on the surface of the inactive layer 13, and the crystal structure of the active layer 12 is distorted to match the crystal structure of the inactive layer 13, and defects called lattice mismatch dislocations are generated in the crystal structure of the active layer 12. The more the inactive layer 13 grows, in other words, the greater the film thickness, the greater the distortion, and the worse the crystallinity of the active layer 12. Therefore, the thickness of the inactive layer 13 is set to less than 100 nm, preferably less than 90.45 nm, and more preferably less than 67.50 nm, so that the crystallinity of the active layer 12 can be improved and the sensitivity of the Hall element 1 can be improved.

[0022] The 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 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 caused by the formation of the protective layer 14. In addition, crystal defects occurring at the interface between the inactive layer 13 and the active layer 12 are suppressed by the small thickness of the inactive layer 13, and become relatively small within the active layer 12 by the large thickness of the active layer 12. By making the 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 improved.

[0023] 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 made of, for example, silicon nitride (SiN), silicon oxynitride (SiON), silicon dioxide (SiO 2 ) and is deposited on the inactive layer 13. The protective layer 14 has a density of 2.29 g / cm 3 More than 2.90g / cm 3 The density of the inactive layer 13 is preferably 2.29 g / cm or less, and the tensile stress is preferably 160 MPa or more and 274 MPa or less. The method of film formation is not particularly limited, but methods such as sputtering and plasma CVD can be used. 3 More than 2.90g / cm 3 By providing the protective layer 14 having a tensile stress of 160 MPa or more and 274 MPa or less, the active layer 12 and the inactive layer 13 are protected from external damage, and transfer scattering of carriers in the active layer 12 is suppressed, thereby making it possible to maintain the accuracy and sensitivity of the Hall element 1.

[0024] The electrodes 15a and 15b are conductive members for outputting the Hall voltage outputted by the element body, and are formed to be in ohmic contact with the active layer 12 and contain gold (Au), platinum (Pt), titanium (Ti), or the like.

[0025] A current sensor equipped with the Hall element 1 applies a magnetic field generated by a current flowing through an object to be measured to the Hall element 1, and measures the current flowing through a conductor to be measured based on a Hall voltage output from the Hall element 1 by the magnetic field.

[0026] A current sensor including the Hall element 1 may include, for example, the Hall element 1, a signal processing IC that processes an 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 may further include a current conductor through which a current to be measured flows. The Hall element 1 and the signal processing IC may be electrically connected via a wire. EXAMPLES

[0027] In order to verify the correlation between the film thickness of the active layer 12 and the linearity error, a magnetic field in the range of -200 to +200 mT was applied to the Hall elements of Comparative Example 1 and Examples 1 and 2 shown in Table 1 in a room at 23°C, and the linearity error was calculated.

[0028] Example 1 Etch pit density 1×10 4 / cm 2 An InAs layer (active layer 12) with an electron density of 1.9×10 -17 / cm 3 A GaAs layer (inactive layer 13) having a thickness of 20 nm and electrodes (15a, b) are formed on the InAs layer, and a GaAs layer having a density of 2.34 g / cm 3 In addition, a SiN layer (protective layer 14) having a tensile stress of 235 MPa was formed to fabricate the Hall element of Example 1.

[0029] Example 2 The InAs layer (active layer 12) has an electron density of 1.8×10 ―17 / cm 3 A Hall element of Example 2 was produced in the same manner as in Example 1, except that the film thickness was 1.050 μm.

[0030] Comparative Example 1 The InAs layer (active layer 12) has an electron density of 1.0×10―17 / cm 3 A Hall element of Example 2 was produced in the same manner as in Example 1, except that the film thickness was 0.525 μm.

[0031] [Table 1]

[0032] 6 shows the correlation between the linearity error and the film thickness of the active layer 12. 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.

[0033] In order to verify the correlation between the film thickness of the active layer 12 and the crystallinity expressed in the electron mobility, the mobility was measured for the semiconductor films of Comparative Example 2 and Examples 3 to 5 shown in Table 2 in a room at 23°C by applying the Van del Pauw method.

[0034] Example 3 Etch pit density 1×10 4 / cm 2 The electron density on the GaAs substrate (substrate 11) is 1.9×10 -17 / cm 3 An InAs layer (active layer 12) was formed to a thickness of 0.630 μm, and a GaAs layer (inactive layer 13) was formed to a thickness of 20 nm on the InAs layer, thereby completing the semiconductor film of Example 3.

[0035] Example 4 The InAs layer (active layer 12) has an electron density of 1.9×10 -17 / cm 3 The semiconductor film of Example 4 was produced in the same manner as in Example 3, except that the film thickness was 0.788 μm.

[0036] Example 5 The InAs layer (active layer 12) has an electron density of 1.8×10 -17 / cm 3 The semiconductor film of Example 5 was produced in the same manner as in Example 3, except that the film thickness was 1.050 μm.

[0037] Comparative Example 2 The InAs layer (active layer 12) has an electron density of 1.0×10 -17 / cm 3 The semiconductor film of Comparative Example 1 was produced in the same manner as in Example 3, except that the film thickness was 0.525 μm.

[0038] [Table 2]

[0039] FIG. 7 shows the correlation between the thickness of the InAs layer (active layer 12) and the electron mobility. In a semiconductor film in which the thickness of the active layer 12 is 0.63 μm or more, the mobility is 14000 cm 2 / Vs, and it is clear that the crystallinity is significantly improved.

[0040] In order to verify the correlation between the film thickness of the inactive layer 13 and the crystallinity expressed by the electron mobility, the mobility was measured for the semiconductor films of Comparative Examples 3 to 6 shown in Table 3 by applying the Van del Pauw method in a room at 23°C.

[0041] Comparative Example 3 Etch pit density 1×10 4 / cm 2 The electron density on the GaAs substrate (substrate 11) is 0.92×10 ―17 / cm 3 In addition, a 0.525 nm-thick InAs layer (active layer 12) was formed, and a 4.5 nm-thick GaAs layer was formed on the InAs layer to form a semiconductor film of Comparative Example 3.

[0042] Comparative Example 4 The electron density of the InAs layer is 0.96×10 ―17 / cm 3 A semiconductor film of Comparative Example 4 was prepared in the same manner as in Comparative Example 3, except that the thickness of the GaAs layer was 20 nm.

[0043] Comparative Example 5 The electron density of the InAs layer is set to 0.99×10 ―17 / cm 3A semiconductor film of Comparative Example 4 was prepared in the same manner as in Comparative Example 3, except that the thickness of the GaAs layer was 25 nm.

[0044] Comparative Example 6 The electron density of the InAs layer is set to 0.95×10 ―17 / cm 3 A semiconductor film of Comparative Example 4 was prepared in the same manner as in Comparative Example 3, except that the thickness of the GaAs layer was 50 nm. [Table 3]

[0045] 8 shows the correlation between the thickness of the GaAs-cap (inactive layer 13) and the crystallinity of the active layer 12 as expressed by the electron mobility. It can be seen that as the thickness of the inactive layer 13 increases, the electron mobility decreases, in other words, the crystallinity of the active layer 12 decreases.

[0046] 9 shows the correlation between the thickness ratio of the inactive layer 13 to the active layer 12 and the improvement in electron mobility. Note that the improvement in mobility referred to here is the improvement in electron mobility of 12,000 cm in a semiconductor film in which the active layer 12 is an InAs layer with a thickness of 520 nm and the inactive layer 13 is a GaAs layer with a thickness of 20 nm (see FIG. 8 and Comparative Example 4 in Table 3). 2 / Vs is taken as 100%. The solid line shows data for a semiconductor film having an InAs layer with a thickness of 630 nm as the active layer 12, the dashed line shows data for a semiconductor film having an InAs layer with a thickness of 1050 nm as the active layer 12, and the dashed dotted line shows data for a semiconductor film having an InAs layer with a thickness of 1350 nm as the active layer 12.

[0047] It can be seen that in a semiconductor film having an active layer 12 with a thickness of 630 nm, when the thickness ratio of the inactive layer 13 to the active layer 12 is less than 0.067, the mobility improvement exceeds 100%. It can also be seen that when the thickness ratio of the inactive layer 13 to the active layer 12 is less than 0.050, the mobility improvement exceeds 105% regardless of whether the active layer 12 has a thickness of 630 nm, 1050 nm, or 1350 nm. It is preferable to increase the mobility improvement by 100% or more, preferably 105% or more, in other words, to increase the mobility to 12000 cm. 2 / Vs or higher, preferably 12000cm 2 By setting the potential at or above / Vs, the crystallinity of the active layer 12 can be improved to improve the sensitivity, and the S / N ratio can be further improved to realize a highly accurate Hall element.

[0048] The Hall element according to the present embodiment includes a substrate 11 containing gallium arsenide, an active layer 12 containing indium arsenide formed on the substrate 11 and having a 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 thickness of 3 nm or more and less than 100 nm, where the thickness ratio of the inactive layer 13 to the active layer 12 is 0.005 or more and less than 0.067. This makes it possible to provide a Hall element and current sensor that has low power consumption and suppresses reliability fluctuations, and that can achieve both high accuracy and high sensitivity even when a high magnetic field is applied.

[0049] The current sensor according to this embodiment includes the Hall element 1, and the Hall element 1 includes electrodes 15a, 15b in contact with the active layer 12. This makes it possible to provide a current sensor that has both high accuracy and high sensitivity even when a strong magnetic field is applied, has low power consumption, and suppresses reliability fluctuations.

[0050] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0051] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0052] Reference Signs List 1: Hall element, 11: substrate, 12: active layer, 13: inactive layer, 14: protective layer, 15a, 15b: electrodes.

Claims

1. a substrate comprising gallium arsenide; an active layer containing indium arsenide formed on the substrate and having a thickness of 0.63 μm or more and less than 1.45 μm; an inactive layer having a thickness of 3 nm or more and less than 100 nm formed on the active layer; a thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067; Hall element.

2. a substrate comprising gallium arsenide; an active layer containing indium arsenide formed on the substrate and having a thickness of 0.63 μm or more and less than 1.35 μm; an inactive layer having a thickness of 3 nm or more and less than 100 nm formed on the active layer; a thickness ratio of the inactive layer to the active layer is 0.005 or more and less than 0.067; Hall element.

3. 3. The Hall element according to claim 1, wherein a thickness ratio of the inactive layer to the active layer is equal to or greater than 0.005 and less than 0.

050.

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

5. 3. The Hall element according to claim 1, wherein the inactive layer comprises gallium arsenide.

6. The active layer is doped with an N-type dopant, and the electron density at room temperature is 5×10 １６ ~5×10 １７ / cm ３ 3. The Hall element according to claim 1, wherein:

7. Electron mobility is 12000 cm ２ 3. The Hall element according to claim 1, wherein the Vref is greater than or equal to 1Vs.

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

9. The etch pit density of the substrate is 1×10 ４ / cm ２ 3. The Hall element according to claim 1, wherein:

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

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