Magnetoelectric conversion element and manufacturing method of the same

Abstract

To reduce a contact resistance between a magnetic sensitive layer and a metal electrode layer.SOLUTION: A Hall element 10 includes: a substrate 11 including a compound semiconductor; a magnetic sensitive layer 12 formed in a substantially cross-shaped pattern on a top surface of the substrate 11 in plan view; a selective growth mask layer 13 formed on the top surface to cover the magnetic sensitive layer 12 such that a predetermined area at an end portion of the substantially cross-shaped pattern of the magnetic sensitive layer 12 is exposed; a contact layer 14 formed on the magnetic sensitive layer 12 exposed from the selective growth mask layer 13, a contact resistance to metal of the contact layer being lower than a contact resistance to metal of the magnetic sensitive layer 12; and a metal electrode layer 15 formed, on the selective growth mask layer 13 and the contact layer 14, in a predetermined pattern so as to cover at least the contact layer 14. Each of the magnetic sensitive layer 12 and the contact layer 14 includes the compound semiconductor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a magnetoelectric transducer and a manufacturing method thereof. [Background technology]

[0002] Hall elements are known as an example of magnetoelectric conversion elements. Hall elements convert magnetic signals into electric signals for detection, and are used in a wide range of fields, such as current sensors and motor rotation angle detection sensors. The configuration of a conventional Hall element is disclosed, for example, in Patent Document 1. Patent Document 1 discloses a Hall element in which a magnetosensitive layer made of an n-type semiconductor in which GaAs (gallium arsenide) is doped with the impurity Si (silicon) is formed on a substrate in a cross shape in a plan view. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-50394 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a magneto-sensitive layer made of n-type GaAs doped with Si, it is necessary to increase the carrier mobility in order to increase the magnetic detection sensitivity, which requires a low concentration of Si. This tends to increase the contact resistance at the metal-semiconductor junction between the magneto-sensitive layer and the metal electrode layer. This high contact resistance reduces the sensitivity of a Hall element driven by a constant voltage, and increases the element resistance of a Hall element driven by a constant current. In order to reduce the contact resistance, a so-called contact layer, in which a high concentration of impurities is added, is sometimes inserted at the interface of the semiconductor in contact with the metal, but as an n-type impurity, Si has a high diffusion coefficient, and it diffuses into the magneto-sensitive layer, reducing the sensitivity, making it difficult to use Si.

[0005] The present invention has been proposed in view of the above-mentioned circumstances, and aims to reduce the contact resistance at the metal-semiconductor junction between the magnetosensitive layer and the metal electrode layer in a magnetoelectric conversion element having a magnetosensitive layer made of an n-type semiconductor in which GaAs is doped with Si as an impurity. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present disclosure includes a substrate including a compound semiconductor, a magnetosensitive layer formed in a predetermined pattern on a top surface of the substrate, a selective growth mask layer formed on the top surface to cover the magnetosensitive layer so that the magnetosensitive layer is exposed in the predetermined pattern, a contact layer having a lower contact resistance with metal than the magnetosensitive layer formed on the magnetosensitive layer exposed from the selective growth mask layer, and a metal electrode layer formed on the selective growth mask layer and the contact layer in a predetermined pattern so as to cover at least the contact layer, wherein the magnetosensitive layer and the contact layer include compound semiconductors. Effect of the Invention

[0007] According to the present disclosure, the contact resistance between the magnetosensitive layer and the metal electrode layer can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a Hall element according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the Hall element according to the first embodiment. [Figure 3A] FIG. 3A is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3B] FIG. 3B is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3C] FIG. 3C is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3D] FIG. 3D is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3E]FIG. 3E is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3F] 3A to 3F are cross-sectional views illustrating a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 3G] FIG. 3G is a cross-sectional view showing a series of steps in the method for manufacturing the Hall element according to the first embodiment. [Figure 4A] FIG. 4 is a partially enlarged cross-sectional view of a Hall element according to a first modified example. [Figure 4B] FIG. 11 is a partially enlarged cross-sectional view of a Hall element according to a second modified example. [Diagram 5] FIG. 5 is a cross-sectional view of a Hall element according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a Hall element according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a magnetoelectric conversion element and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. In the present embodiment, a Hall element will be described as an example of a magnetoelectric conversion element.

[0010] (First embodiment) Fig. 1 is a plan view showing a Hall element 10 according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view of the Hall element 10 taken along line II-II in Fig. 1.

[0011] The Hall element 10 includes a substrate 11, a magnetosensitive layer 12, a selective growth mask layer 13, a contact layer 14, and a metal electrode layer 15, which are laminated in this order on the top surface of the substrate 11. The selective growth mask layer 13 and the contact layer 14 are disposed in the same layer and form a single layer.

[0012] On the top surface of the substrate 11 having a substantially rectangular shape in plan view, the magnetosensitive layer 12 is formed so as to form a substantially cross-shaped pattern in plan view extending in the two diagonal directions of the substantially rectangular shape. Furthermore, on the top surface of the substrate 11, a selective growth mask layer 13 and a contact layer 14 are formed to form one layer so as to cover the magnetosensitive layer 12. In this layer, a predetermined region covering the end of the magnetosensitive layer 12 forming the substantially cross-shaped pattern is formed by the contact layer 14, and the rest is formed by the selective growth mask layer 13. The contact layer 14 is formed directly under the electrically isolated metal electrode layer 15 and is covered by the metal electrode layer 15. The metal electrode layer 15 is further extended to a region adjacent to the contact layer 14 on the selective growth mask layer 13 and is formed in a predetermined pattern.

[0013] The metal electrode layer 15 is composed of four layers, namely, the first metal electrode layer 151 to the fourth metal electrode layer 154. Of these, for example, the first metal electrode layer 151 and the third metal electrode layer 153, which face each other in one diagonal direction, constitute an input terminal, and for example, the second metal electrode layer 152 and the fourth metal electrode layer 154, which face each other in the other diagonal direction, constitute an output terminal. In the magnetosensitive layer 12, a Lorentz force is exerted on carriers moving along a path between a pair of input terminals, such as the first metal electrode layer 151 and the third metal electrode layer 153, in a direction perpendicular to the moving direction by the magnetic field penetrating the magnetosensitive layer 12, and an electromotive force according to the strength of the magnetic field is detected in output terminals, such as the second metal electrode layer 152 and the fourth metal electrode layer 154, which face each other in a direction substantially perpendicular to the moving direction.

[0014] In the Hall element 10 of the first embodiment, the substrate 11 is made of a compound semiconductor of GaAs (gallium arsenide) of the III-V group. The magnetosensitive layer 12 is made of an n-type compound semiconductor of GaAs doped with at least one of Si (silicon) and Te (tellurium) as an impurity. The magnetosensitive layer 12 is doped with a low concentration of impurities to increase carrier mobility in order to ensure sensitivity in detecting magnetism.

[0015] The selective growth mask layer 13 is made of SiO2 (silicon dioxide). The selective growth mask layer 13 prevents crystal growth on its surface and enables selective crystal growth in uncovered areas. The contact layer 14 is formed by selective growth in areas not covered by the selective growth mask layer 13. The formation of the contact layer 14 by selective growth will be described further below.

[0016] The contact layer 14 is made of an n-type compound semiconductor of GaAs doped with Te as an impurity. The contact layer 14 is interposed between the magnetosensitive layer 12, which has a low carrier concentration, and the metal electrode layer 15, and is doped with a high concentration of Te to give the contact layer 14 a high carrier concentration so as to reduce the contact resistance with the metal electrode layer 15. The contact layer 14 is in contact with the magnetosensitive layer 12, but the high concentration of Te contained in the contact layer 14 has a property that it is difficult to diffuse. Therefore, deterioration of the magnetosensitive layer 12, such as a decrease in mobility due to diffusion of Te into the magnetosensitive layer 12, does not occur, and the sensitivity of the Hall element 10 is ensured.

[0017] The metal electrode layer 15 may be a laminate in which, for example, AuGe (gold germanium), Ni (nickel), and Au (gold) are laminated in this order. In the Hall element 10 of the first embodiment, the compound semiconductor contained in the substrate 11, the magnetosensitive layer 12, and the contact layer 14 is GaAs of the III-V group, but this is not limiting and other types of compound semiconductors such as InSb (indium antimonide) and InAs (indium arsenide) may also be used.

[0018] In the Hall element 10 of the first embodiment, Te is used as the impurity doped in the contact layer 14 at a high concentration. Therefore, in the first embodiment, the high concentration of Te doped in the contact layer 14 provides a high concentration of carriers, thereby reducing the contact resistance with the metal electrode layer 15. By reducing such contact resistance, the sensitivity or efficiency of the Hall element 10 can be improved. Furthermore, since Te has a property of being difficult to diffuse, even if the contact layer 14 doped with a high concentration of Te is in contact with the magnetosensitive layer 12, the sensitivity will not decrease due to deterioration of the magnetosensitive layer 12 caused by diffusion of Te.

[0019] 3A to 3G are cross-sectional views showing a series of steps for manufacturing the Hall element 10. The manufacturing method of the Hall element 10 will be described with reference to these drawings.

[0020] As shown in Fig. 3A, a substrate 11 made of GaAs is prepared. As shown in Fig. 3B, an n-type compound semiconductor made of GaAs doped with at least one of Si and Te as an impurity is deposited on the top surface of the substrate 11 to form a magnetosensitive layer 12 of a predetermined thickness. In order to ensure sensitivity in detecting magnetism, the magnetosensitive layer 12 is doped with a low concentration of impurities so as to increase carrier mobility. Following the formation of the magnetosensitive layer 12, unnecessary portions are removed from the magnetosensitive layer 12 by etching or the like so that the magnetosensitive layer 12 forms a substantially cross-shaped pattern in a planar view on the top surface of the substrate 11.

[0021] 3C, SiO2 is deposited on the top surface of the substrate 11 so as to cover the magnetosensitive layer 12 formed in the approximately cross-shaped pattern, and a selective growth mask layer 13 is formed to a predetermined thickness. The selective growth mask layer 13 prevents crystal growth on its surface and enables selective crystal growth in areas not covered by the selective growth mask layer 13. Following the formation of the selective growth mask layer 13, unnecessary portions are removed from the selective growth mask layer 13 by etching or the like so that the selective growth mask layer 13 opens in predetermined areas at the ends of the magnetosensitive layer 12 formed in the approximately cross-shaped pattern, exposing the magnetosensitive layer 12.

[0022] As shown in FIG. 3D, in an opening in the selective growth mask layer 13 formed in a predetermined region at the end of the magnetosensitive layer 12 having a substantially cross-shaped pattern, a contact layer 14 made of an n-type compound semiconductor of GaAs doped with Te as an impurity is crystal-grown on the exposed surface of the magnetosensitive layer 12. The contact layer 14 is doped with a high concentration of Te to increase the carrier concentration so as to reduce the contact resistance with the metal electrode layer 15. The crystal growth of the contact layer 14 continues from the magnetosensitive layer 12 exposed in the opening until it reaches the height of the selective growth mask layer 13 surrounding the opening. As a result of such selective growth, the contact layer 14 is fitted into the predetermined open region of the selective growth mask layer 13, and one layer is formed in which the selective growth mask layer 13 and the contact layer 14 are arranged in the same layer.

[0023] As shown in FIG. 3F, a metal electrode layer 15 is formed by, for example, a laminate of AuGe, Ni, and Au in order so as to cover one layer composed of the selective growth mask layer 13 and the contact layer 14. Then, as shown in FIG. G, unnecessary parts are removed from the metal electrode layer 15 by etching, lift-off, or the like. As a result, as shown in FIG. 1, the metal electrode layer 15 is formed in a predetermined pattern so as to cover the contact layer 14 exposed from the selective growth mask layer 13 in predetermined regions at each end of the magnetosensitive layer 12 having an approximately cross shape, and further extend to a region adjacent to the contact layer 14 on the selective growth mask layer 13. In this way, through a series of steps from FIG. 3A to FIG. 3G, the magnetosensitive layer 12, the selective growth mask layer 13, the contact layer 14, and the metal electrode layer 15 in the Hall element 10 shown in FIG. 1 and FIG. 2 are formed, and the Hall element 10 shown in FIG. 1 and FIG. 2 is obtained.

[0024] In the manufacturing method of the Hall element 10 of the first embodiment, etching is used to form the substantially cross-shaped pattern of the magnetosensitive layer 12 in the step shown in Fig. 3B, to form the opening in the selective growth mask layer 13 in the step shown in Fig. 3C, and to form the metal electrode layer 15 into a predetermined pattern in the step shown in Fig. 3G, but this is not limiting and other methods such as lift-off may also be used. In addition, in the manufacturing method of the Hall element 10 of the first embodiment, GaAs of the III-V group is used as the compound semiconductor contained in the substrate 11, the magnetosensitive layer 12, and the contact layer 14, but this is not limiting and other types of compound semiconductors such as InSb and InAs may also be used.

[0025] In the manufacturing method of the first embodiment, a selective growth mask layer 13 having a predetermined pattern is formed on the top surface of the substrate 11 so as to cover the magnetosensitive layer 12 having a substantially cross-shaped pattern, and the contact layer 14 can be formed by selectively growing crystals on the magnetosensitive layer 12 exposed in an opening formed in the selective growth mask layer 13. The selective growth mask layer 13 makes it possible to easily form the contact layer 14 of a desired pattern and a desired thickness on the magnetosensitive layer 12 so as to be located directly below the metal electrode layer 15. In addition, since the selective growth mask layer 13 is made of SiO2, the selective growth mask layer 13 plays a role of protecting the top surface of the substrate 11 and the magnetosensitive layer 12 that it covers.

[0026] In the Hall element 10 manufactured by the manufacturing method of the first embodiment, Te is used as the impurity added at a high concentration to the contact layer 14, and therefore the high concentration of Te provides a high concentration of carriers, thereby reducing the contact resistance with the metal electrode layer 15. By reducing such contact resistance, the sensitivity or efficiency of the Hall element 10 can be improved. In addition, although the contact layer 14 is in contact with the magnetosensitive layer 12, the high concentration of Te contained in the contact layer 14 has a property of being difficult to diffuse. Therefore, deterioration of the magnetosensitive layer 12, such as a decrease in mobility due to diffusion of Te into the magnetosensitive layer 12, does not occur, and the sensitivity of the Hall element 10 is ensured.

[0027] In the Hall element 10 of the first embodiment, the selective growth mask layer 17 is made of SiO2, which has better adhesion to GaAs than SiN, which will be described later. This ensures adhesion between the selective growth mask layer 17 and the magnetosensitive layer 12 made of n-type GaAs.

[0028] (Modification) 4A and 4B are partially enlarged cross-sectional views of the Hall element 10 of the modified example. FIG. 4A and FIG. 4B are enlarged views of the portion indicated by the arrow A in the cross-sectional view of FIG. 2. The Hall element 10 of the first modified example shown in FIG. 4A has a contact layer 14 that is thinner than the selective growth mask layer 13, and the Hall element 10 of the second modified example shown in FIG. 4B has a contact layer 14 that is thicker than the selective growth mask layer 13, which is different from the Hall element 10 of the first embodiment in that the contact layer 14 has the same thickness as the selective growth mask layer 13. Since the other configurations of the Hall element 10 of the first and second modified examples are similar to those of the Hall element 10 of the first embodiment, the corresponding components are indicated by the same reference numerals. The thicknesses of the contact layer 14 and the selective growth mask layer 13 can be easily adjusted in the process of crystal growth of the contact layer 14 shown in FIG. 3D and the process of forming the selective growth mask layer 13 shown in FIG. 3C in the manufacturing method of the first embodiment.

[0029] In the Hall element 10 of the first modification shown in FIG. 4A, the contact layer 14 is thinner than the selective growth mask layer 13. Therefore, at the boundary between the contact layer 14 and the selective growth mask layer 13, the surface of the contact layer 14 forms an inclined surface that slopes toward the surface of the selective growth mask layer 13. In other words, the outer periphery of the contact layer 14 rises toward the side opposite the substrate 11 in the plan view shown in FIG. 1. Since the contact layer 14 of the first modification is thin, the time required to form the contact layer 14 by crystal growth can be shortened. In addition, the number of crystal defects is reduced, and the life of the contact layer 14 can be extended.

[0030] In the Hall element 10 of the second modification shown in Fig. 4B, the contact layer 14 is thicker than the selective growth mask layer 13. Therefore, the contact layer 14 protrudes upward from an opening formed in the selective growth mask layer 13 along the surface of the selective growth mask layer 13, and the portion extending outward from the opening is inclined toward the surface of the selective growth mask layer 13. In other words, the outer periphery of the contact layer 14 slopes down toward the substrate 11 in the plan view shown in Fig. 1. Since the contact area between the contact layer 14 of the second modification and the metal electrode layer 15 is increased, the contact resistance between the contact layer 14 and the metal electrode layer 15 can be reduced.

[0031] In the first modified example, an example is shown in which the contact layer 14 is thinner than the selective growth mask layer 13, and in the second modified example, an example is shown in which the contact layer 14 is thicker than the selective growth mask layer 13, but in these examples, whether the contact layer 14 is thin or thick may be determined based on the selective growth mask layer 13 having a predetermined thickness. In this case, in the first modified example, the contact layer 14 is thinner than the selective growth mask layer 13 having a predetermined thickness, in the second modified example, the contact layer 14 is thicker than the selective growth mask layer 13, and the contact layer 14 of the first modified example is thinner than the contact layer 14 of the second modified example.

[0032] (Second embodiment) 5 is a cross-sectional view showing a Hall element 20 of the second embodiment. The Hall element 20 of the second embodiment differs from the Hall element 10 of the first embodiment in that the selective growth mask layer 13 of the Hall element 10 of the first embodiment is made of SiO2 (silicon dioxide), but the selective growth mask layer 16 of the Hall element 20 of the second embodiment is made of SiN (silicon nitride). Since the other configurations are similar to those of the Hall element 10 of the first embodiment, the same reference numerals are used to designate the components common to the Hall element 10 of the first embodiment to clarify the correspondence.

[0033] The Hall element 20 of the second embodiment is also manufactured by a series of steps of the manufacturing method shown in Figures 3A to 3G, similarly to the Hall element 10 of the first embodiment. In detail, in the step shown in Figure 3C, SiN is deposited as the selective growth mask layer 16 on the top surface of the substrate 11 in place of SiO2 of the selective growth mask layer 13, and after the selective growth mask layer 16 made of SiN is etched in the step shown in Figure 3D, the contact layer 14 is selectively grown in the opening of the selective growth mask layer 16 in the step shown in Figure 3E.

[0034] In the Hall element 20 of the second embodiment, similarly to the Hall element 10 of the first embodiment, the contact layer 14 is formed by selectively growing crystals on the magnetosensitive layer 12 exposed in an opening formed in the selective growth mask layer 16. The selective growth mask layer 16 makes it possible to easily form the contact layer 14 of a desired thickness in a desired pattern on the magnetosensitive layer 12 so as to be located directly below the metal electrode layer 15. In addition, since the selective growth mask layer 16 is made of SiN, the selective growth mask layer 16 plays a role of protecting the top surface of the substrate 11 and the magnetosensitive layer 12 that it covers.

[0035] In the Hall element 20 of the second embodiment, Te is also used as the impurity added to the contact layer 14 at a high concentration, and the high concentration of Te provides a high concentration of carriers, thereby reducing the contact resistance with the metal electrode layer 15. By reducing such contact resistance, the sensitivity or efficiency of the Hall element 20 can be improved. In addition, although the contact layer 14 is in contact with the magnetosensitive layer 12, the high concentration of Te contained in the contact layer 14 has a property of being difficult to diffuse. Therefore, deterioration of the magnetosensitive layer 12, such as a decrease in mobility due to diffusion of Te into the magnetosensitive layer 12, does not occur, and the sensitivity of the Hall element 20 is ensured.

[0036] In the Hall element 20 of the second embodiment, the selective growth mask layer 16 is made of SiN, which serves as an excellent barrier against impurity diffusion, and therefore the Hall element 20 of the second embodiment is resistant to moisture and metal contamination.

[0037] In the second embodiment, the contact layer 14 can be made thinner than the selective growth mask layer 16 as shown in the first modification of FIG. 4A, or can be made thicker than the selective growth mask layer 16 as shown in the second modification of FIG. 4B. When the contact layer 14 is made thinner than the selective growth mask layer 16 as shown in FIG. 4A, the time required to form the contact layer 14 by crystal growth can be shortened, the number of crystal defects can be reduced, and the life of the contact layer 14 can be extended, as in the first embodiment. When the contact layer 14 is made thicker than the selective growth mask layer 16 as shown in FIG. 4B, the contact area with the metal electrode layer 15 increases, and therefore the contact resistance between the contact layer 14 and the metal electrode layer 15 can be reduced, as in the first embodiment.

[0038] (Third embodiment) 6 is a cross-sectional view showing a Hall element 30 of the third embodiment. The Hall element 30 of the third embodiment differs from the Hall element 10 of the first embodiment in that the selective growth mask layer 17 is a laminate consisting of a first layer 17a made of SiO2 and a second layer 17b made of SiN (silicon nitride) instead of the selective growth mask layer 13 made of a single layer of SiO2 (silicon dioxide) in the Hall element 10 of the first embodiment. Since the other configurations are the same as those of the Hall element 10 of the first embodiment, the same reference numbers are used for components common to the Hall element 10 of the first embodiment to clarify the correspondence.

[0039] The Hall element 30 of the third embodiment is also manufactured by a series of steps of the manufacturing method shown in Figures 3A to 3G, similarly to the Hall element 10 of the first embodiment. In detail, in the step shown in Figure 3C, a laminate consisting of a first layer 17a of SiO2 and a second layer 17b of SiN is deposited as the selective growth mask layer 17 on the top surface of the substrate 11 in place of the SiO2 of the selective growth mask layer 13, and after the selective growth mask layer 17 made of the laminate is etched in the step shown in Figure 3D, the contact layer 14 is selectively grown in the opening of the selective growth mask layer 17 in the step shown in Figure 3E.

[0040] In the Hall element 23 of the third embodiment, similarly to the Hall element 10 of the first embodiment, the contact layer 14 is formed by selectively growing crystals on the magnetosensitive layer 12 exposed in the opening formed in the selective growth mask layer 17. The selective growth mask layer 17 makes it possible to easily form the contact layer 14 of a desired thickness in a desired pattern on the magnetosensitive layer 12 so as to be located directly below the metal electrode layer 15. In addition, since the selective growth mask layer 17 is composed of a laminated body consisting of a first layer 17a of SiO2 and a second layer 17b of SiN, the selective growth mask layer 17 plays a role of protecting the top surface of the substrate 11 and the magnetosensitive layer 12 that it covers.

[0041] In the Hall element 30 of the third embodiment, Te is also used as the impurity added to the contact layer 14 at a high concentration, and the high concentration of Te provides a high concentration of carriers, thereby reducing the contact resistance with the metal electrode layer 15. By reducing such contact resistance, the sensitivity or efficiency of the Hall element 30 can be improved. In addition, although the contact layer 14 is in contact with the magnetosensitive layer 12, the high concentration of Te contained in the contact layer 14 has a property of being difficult to diffuse. Therefore, deterioration of the magnetosensitive layer 12, such as a decrease in mobility due to diffusion of Te into the magnetosensitive layer 12, does not occur, and the sensitivity of the Hall element 30 is ensured.

[0042] In the Hall element 30 of the third embodiment, the first layer 17a of the selective growth mask layer 17 is made of SiO2, which has better adhesion to GaAs than SiN, and the outermost second layer 17b is made of SiN, which acts as an excellent barrier against impurity diffusion. Therefore, in the Hall element 30 of the third embodiment, adhesion between the selective growth mask layer 17 and the magnetosensitive layer 12 made of n-type GaAs is ensured, and resistance to moisture and metal contamination is also ensured.

[0043] In the third embodiment, the contact layer 14 can be made thinner than the selective growth mask layer 17 as shown in the first modification of FIG. 4A, or can be made thicker than the selective growth mask layer 17 as shown in the second modification of FIG. 4B. When the contact layer 14 is made thinner than the selective growth mask layer 17 as shown in FIG. 4A, the time required to form the contact layer 14 by crystal growth can be shortened, the number of crystal defects can be reduced, and the life of the contact layer 14 can be extended, as in the first embodiment. When the contact layer 14 is made thicker than the selective growth mask layer 17 as shown in FIG. 4B, the contact area with the metal electrode layer 15 increases, and therefore the contact resistance between the contact layer 14 and the metal electrode layer 15 can be reduced, as in the first embodiment.

[0044] In the third embodiment, the selective growth mask layer 17 is a laminated body consisting of the first layer 17a made of SiO2 and the second layer 17b made of SiN, but the order of the laminated body is not limited to this. The selective growth mask layer 17 can also be composed of a laminated body in which the first layer is SiN and the second layer is SiO2.

[0045] (Appendix 1) The Hall element 10 includes a substrate 11 containing a compound semiconductor, a magnetosensitive layer 12 formed on the top surface of the substrate 11 in a substantially cross-shaped pattern in a plan view, a selective growth mask layer 13 formed on the top surface to cover the magnetosensitive layer 12 so that a predetermined region at the end of the substantially cross-shaped pattern of the magnetosensitive layer 12 is exposed, a contact layer 14 formed on the magnetosensitive layer 12 exposed from the selective growth mask layer 13 and having a lower contact resistance with metal than the magnetosensitive layer 12, and a metal electrode layer 15 formed on the selective growth mask layer 13 and the contact layer 14 in a predetermined pattern to cover at least the contact layer 14, and both the magnetosensitive layer 12 and the contact layer 14 are made of a compound semiconductor. The contact layer 14 reduces the contact resistance with the metal electrode layer 15, thereby improving the sensitivity or efficiency of the Hall element. The selective growth mask layer 13 can cover and protect the magnetosensitive layer 12 and the top surface of the substrate 11.

[0046] (Appendix 2) The compound semiconductor described in Appendix 1 may include a III-V group semiconductor. The compound semiconductor may be appropriately selected from III-V group semiconductors.

[0047] (Appendix 3) The III-V semiconductor described in Appendix 2 may include at least one of GaAs, InSb, and InAs. The III-V semiconductor may be appropriately selected from GaAs, InSb, and InAs.

[0048] (Appendix 4) At least one of Si and Te may be added to the magnetosensitive layer 12 described in any one of Supplementary Notes 1 to 3. By adding at least one of Si and Te, an n-type semiconductor can be formed. Furthermore, since Te has a property of being difficult to diffuse, it does not diffuse into the magnetosensitive layer 12 and thereby does not reduce the sensitivity of the Hall element 10.

[0049] (Appendix 5) The selective growth mask layer 13 described in any one of Supplementary Notes 1 to 4 may contain SiO2. Since the selective growth mask layer 13 contains SiO2, crystal growth on the selective growth mask layer 13 is prevented, and crystal growth can be selectively performed in areas not covered by the selective growth mask layer 13. Furthermore, since the selective growth mask layer 13 contains SiO2, the selective growth mask layer 13 can protect the top surfaces of the magnetosensitive layer 12 and the substrate 11 covered by the selective growth mask layer 13.

[0050] (Appendix 6) The selective growth mask layer 16 described in any one of Supplementary Notes 1 to 4 may contain SiN. Since the selective growth mask layer 16 contains SiN, crystal growth on the selective growth mask layer 16 is prevented, and crystal growth can be selectively performed in areas not covered by the selective growth mask layer 16. Furthermore, since the selective growth mask layer 16 contains SiN, the selective growth mask layer 16 can protect the magnetosensitive layer 12 and the top surface of the substrate 11 covered by the selective growth mask layer 16.

[0051] (Appendix 7) The selective growth mask layer 17 described in any one of Supplementary Notes 1 to 4 may include a laminate in which SiO2 and SiN are laminated in order. Since the selective growth mask layer 17 includes a laminate of SiO2 and SiN, crystal growth on the selective growth mask layer 17 is prevented, and crystal growth can be selectively performed in the area not covered by the selective growth mask layer 17. Furthermore, since the selective growth mask layer 17 includes a laminate of SiO2 and SiN, the magnetosensitive layer 12 and the top surface of the substrate 11 covered by the selective growth mask layer 17 can be protected.

[0052] (Appendix 8) The contact layer described in any one of Supplementary Notes 1 to 7 may be doped with Te. Doping of Te allows an n-type semiconductor to be formed. Furthermore, since Te has a property of being difficult to diffuse, it does not diffuse into the magnetosensitive layer 12 and thereby does not reduce the sensitivity of the Hall element 10.

[0053] (Appendix 9) The contact layer 14 according to any one of Supplementary Notes 1 to 8 may be thinner than the selective growth mask layer 13. The time required to form the contact layer 14 is shortened, and the number of crystal defects is reduced.

[0054] (Appendix 10) The contact layer 14 described in any one of Supplementary Notes 1 to 8 may be thicker than the selective growth mask layer 13. This increases the contact area between the metal electrode layer 15 and the contact layer 14, thereby reducing the contact resistance.

[0055] (Appendix 11) The manufacturing method of the Hall element 10 includes the steps of forming the magnetosensitive layer 12 in a substantially cross-shaped pattern in a plan view on the top surface of the substrate 11 made of a compound semiconductor, forming a selective growth mask layer 13 on the top surface so as to cover the magnetosensitive layer 12 so that a predetermined region of the end of the substantially cross-shaped pattern of the magnetosensitive layer 12 is exposed, selectively growing a contact layer 14 having a lower contact resistance with metal than the magnetosensitive layer 12 on the magnetosensitive layer 12 exposed from the selective growth mask layer 13, and forming a metal electrode layer 15 on the selective growth mask layer 13 and the contact layer 14 in a predetermined pattern so as to cover at least the contact layer 14, both of which are made of a compound semiconductor. The contact layer 14 reduces the contact resistance with the metal electrode layer 15, thereby improving the sensitivity or efficiency of the Hall element. The selective growth mask layer 13 makes it easy to form the contact layer 14 in a desired pattern and with a desired thickness on the magnetosensitive layer 12.

[0056] (Appendix 12) The compound semiconductor described in Appendix 11 may include a III-V group semiconductor. The compound semiconductor may be appropriately selected from III-V group semiconductors.

[0057] (Appendix 13) The III-V semiconductor described in Supplementary Note 12 may include at least one of GaAs, InSb, and InAs. The III-V semiconductor may be appropriately selected from GaAs, InSb, and InAs.

[0058] (Appendix 14) At least one of Si and Te may be added to the magnetosensitive layer 12 described in any one of Supplementary Notes 11 to 13. By adding at least one of Si and Te, an n-type semiconductor can be formed. Furthermore, since Te has a property of being difficult to diffuse, it does not diffuse into the magnetosensitive layer 12 and does not reduce the sensitivity of the Hall element 10.

[0059] (Appendix 15) The contact layer 14 described in any one of Supplementary Notes 11 to 14 may be doped with Te. Doping of Te allows an n-type semiconductor to be formed. Furthermore, since Te is difficult to diffuse, it does not diffuse into the magnetosensitive layer 12 and thereby does not reduce the sensitivity of the Hall element 10.

[0060] (Appendix 16) The selective growth mask layer 13 described in any one of Appendices 11 to 15 may contain SiO2. The selective growth mask layer 13 prevents crystal growth on the selective growth mask layer 13, and allows crystal growth selectively in areas not covered by the selective growth mask layer 13. The selective growth mask layer 13 can also protect the top surfaces of the magnetosensitive layer 12 and the substrate 11 that are covered by the selective growth mask layer 13.

[0061] (Appendix 17) The selective growth mask layer 16 described in any one of Appendices 11 to 15 may contain SiN. The selective growth mask layer 16 prevents crystal growth on the selective growth mask layer 16, and allows crystal growth selectively in areas not covered by the selective growth mask layer 16. The selective growth mask layer 16 can also protect the top surfaces of the magnetosensitive layer 12 and the substrate 11 that are covered by the selective growth mask layer 16.

[0062] (Appendix 18) The selective growth mask layer 17 described in any one of Appendices 11 to 15 may include a laminate in which SiO2 and SiN are laminated in order. The selective growth mask layer 17 prevents crystal growth on the selective growth mask layer 17, and allows crystal growth selectively in areas not covered by the selective growth mask layer 17. The selective growth mask layer 17 can also protect the top surfaces of the magnetosensitive layer 12 and the substrate 11 that are covered by the selective growth mask layer 17.

[0063] (Appendix 19) The step of forming the magnetosensitive layer 12 described in any one of Supplementary Notes 11 to 18 may further include a step of forming the magnetosensitive layer 12 so as to cover the top surface of the substrate 11, and a step of forming the magnetosensitive layer 12 into a substantially cross-shaped pattern in a plan view. The magnetosensitive layer 12 is formed into a pattern suitable for a Hall element.

[0064] (Appendix 20) The step of forming the selective growth mask layer 13 described in any one of Supplementary Notes 11 to 19 may further include a step of forming the selective growth mask layer 13 so as to cover the magnetosensitive layer 12, and a step of forming the selective growth mask layer 13 in a predetermined pattern. The selective growth mask layer 13 is removed in an area where crystal growth can be selectively performed, to form an opening.

[0065] (Appendix 21) The step of forming the metal electrode layer 15 described in any one of Supplementary Notes 11 to 20 may further include a step of forming the metal electrode layer 15 so as to cover the selective growth mask layer 13 and the contact layer 14, and a step of forming the metal electrode layer 15 into a predetermined pattern. The metal electrode layer 15 is formed so as to be connected to each contact layer 14 and to constitute an electrically independent electrode. [Explanation of symbols]

[0066] 10 Hall element 11 Substrate 12 Magnetically sensitive layer 13 Selective growth mask layer 14 Contact layer 15 Metal electrode layer 16 Selective growth mask layer 17 Mask layer for selective growth 20 Hall element 30 Hall element

Claims

1. A substrate including a compound semiconductor; a magnetosensitive layer formed in a predetermined pattern on the top surface of the substrate; a selective growth mask layer formed on the top surface so as to cover the magnetosensitive layer and expose the magnetosensitive layer in a predetermined pattern; a contact layer having a lower contact resistance with metal than that of the magnetosensitive layer, the contact layer being formed on the magnetosensitive layer exposed from the selective growth mask layer; a metal electrode layer formed on the selective growth mask layer and the contact layer in a predetermined pattern so as to cover at least the contact layer; Including, The magnetoelectric conversion element includes the magnetosensitive layer and the contact layer, each of which contains the compound semiconductor.

2. 2. The magnetoelectric transducer according to claim 1, wherein the compound semiconductor includes a III-V group semiconductor.

3. 3. The magnetoelectric transducer according to claim 2, wherein the III-V group semiconductor includes at least one of GaAs, InSb, and InAs.

4. 2. The magnetoelectric transducer according to claim 1, wherein at least one of Si and Te is added to the magnetosensitive layer.

5. The selective growth mask layer is made of SiO ２ The magnetoelectric transducer according to claim 1 .

6. 2. The magnetoelectric transducer according to claim 1, wherein the selective growth mask layer contains SiN.

7. The selective growth mask layer is made of SiO ２ 2. The magnetoelectric transducer according to claim 1, comprising a laminate in which a layer of a ferromagnetic material and a layer of SiN are laminated in this order.

8. 2. The magnetoelectric transducer according to claim 1, wherein the contact layer is doped with Te.

9. 2. The magnetoelectric transducer according to claim 1, wherein the contact layer is thinner than the selective growth mask layer.

10. 2. The magnetoelectric transducer according to claim 1, wherein the contact layer is thicker than the selective growth mask layer.

11. forming a magnetosensitive layer in a predetermined pattern on a top surface of a substrate including a compound semiconductor; forming a selective growth mask layer on the top surface so as to cover the magneto-sensitive layer and expose the magneto-sensitive layer in a predetermined pattern; selectively growing a contact layer on the magnetosensitive layer exposed through the selective growth mask layer, the contact layer having a lower contact resistance with a metal than the magnetosensitive layer; forming a metal electrode layer on the selective growth mask layer and the contact layer in a predetermined pattern so as to cover at least the contact layer; Including, A method for manufacturing a magnetoelectric conversion element, wherein the magnetosensitive layer and the contact layer both contain the compound semiconductor.

12. 12. The method for producing a magnetoelectric conversion element according to claim 11, wherein the compound semiconductor includes a III-V group semiconductor.

13. 13. The method for producing a magnetoelectric transducer according to claim 12, wherein the III-V group semiconductor includes at least one of GaAs, InSb, and InAs.

14. The method for producing a magnetoelectric transducer according to claim 11, wherein at least one of Si and Te is added to the magneto-sensitive layer.

15. The method for manufacturing a magnetoelectric transducer according to claim 11, wherein the contact layer is doped with Te.

16. The selective growth mask layer is made of SiO ２ The method for manufacturing the magnetoelectric transducer according to claim 11, comprising:

17. The method for manufacturing a magnetoelectric transducer according to claim 11 , wherein the selective growth mask layer contains SiN.

18. The selective growth mask layer is made of SiO ２ The method for manufacturing a magnetoelectric transducer according to claim 11 , further comprising laminating a layered body in which a layer of a ferromagnetic material and a layer of SiN are laminated in this order.

19. The step of forming the magnetosensitive layer includes: forming the magnetosensitive layer so as to cover the top surface; forming the magnetosensitive layer into a predetermined pattern; The method for manufacturing a magnetoelectric transducer according to claim 11, further comprising:

20. The step of forming a selective growth mask layer includes: forming a selective growth mask layer so as to cover the magnetosensitive layer; forming the selective growth mask layer into a predetermined pattern; The method for manufacturing a magnetoelectric transducer according to claim 11, further comprising:

21. The step of forming the metal electrode layer includes: forming the metal electrode layer so as to cover the selective growth mask layer and the contact layer; forming the metal electrode layer into a predetermined pattern; The method for manufacturing a magnetoelectric transducer according to claim 11, further comprising:

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