Hall element manufacturing method and magnetic memory element

Abstract

This method for manufacturing a hall element 18 comprises: a step for forming a perovskite-type magnetic layer 14 on a substrate 12 comprising a compound that has a perovskite structure and a lattice constant of 3.90-3.97 Å in pseudo-cubic notation; a step for forming an insulating layer 16 including SrTiO3 on the perovskite-type magnetic layer 14; and a step for forming, on the insulating layer 16, a Hall element 18 including InSb, GaAs, InAs, or a solid solution thereof.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a Hall element and a magnetic memory element. [Background technology]

[0002] Conventionally, InSb, GaAs, or InAs compounds have been used as materials for Hall elements used to read information from magnetic memories. An InSb element is manufactured by, for example, forming an InSb thin film on one side of a mica substrate, and then forming electrodes and a protective film on the mica substrate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-232479 Summary of the Invention [Problem to be solved by the invention]

[0004] When a Hall element is used to read information written in a magnetic memory, it is necessary to manufacture a Hall element suitable for reading information written in the magnetic memory.

[0005] The present invention has been made in view of the above circumstances, and one of its objects is to provide a technique for manufacturing a Hall element suitable for reading information written in a magnetic memory. [Means for solving the problem]

[0006] In order to solve the above problems, a manufacturing method of a Hall element according to one embodiment of the present invention includes the steps of: forming a perovskite-type magnetic layer on a substrate made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation; forming an insulating layer containing SrTiO3 on the perovskite magnetic layer; forming a Hall element including InSb on the insulator layer; Includes.

[0007] Another aspect of the present invention is a magnetic memory element. The magnetic memory element includes a substrate made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation; a perovskite magnetic layer disposed on a substrate; an insulating layer including SrTiO3 disposed on the perovskite-type magnetic layer; a Hall element including InSb disposed on an insulator layer; Includes. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technique for manufacturing a Hall element suitable for reading information written in a magnetic memory. [Brief explanation of the drawings]

[0009] [Figure 1] 1(a) to 1(d) are cross-sectional views showing an example of a manufacturing process of a Hall element according to an embodiment. [Figure 2] 1 is a schematic diagram showing a configuration of an example of a magnetic memory element according to an embodiment; [Figure 3] FIG. 1 is a diagram showing the results of X-ray diffraction measurements of Examples and Comparative Examples. [Figure 4] FIG. 10 is a diagram showing the results of measuring the Hall effect of the Hall element of the example. [Figure 5] FIG. 10 is a diagram showing the results of measuring the Hall effect of the Hall element of the example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. Identical or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and should not be interpreted as limiting unless otherwise specified.

[0011] (Hall element manufacturing method) 1(a) to 1(d) are cross-sectional views showing an example of a manufacturing process of a Hall element according to an embodiment.

[0012] In the manufacturing method according to the embodiment, first, a substrate 12 is prepared as shown in Fig. 1(a). The substrate 12 has a perovskite structure and is made of a compound having a lattice constant of 3.90 to 3.97 Å in pseudocubic notation. Specific examples of the substrate 12 include a 110-oriented GdScO3 substrate, a 110-oriented DyScO3 substrate, a 110-oriented SrTiO3 substrate, a 111-oriented SrTiO3 substrate, and a 001-oriented SrTiO3 substrate.

[0013] 1(b), a perovskite-type magnetic layer (hereinafter also simply referred to as a magnetic layer) 14 is formed on the substrate 12. Examples of perovskite-type magnetic materials that form the magnetic layer 14 include La2NiMnO6, CeCu3Mn4O 12 , La 0.7 Sr 0.3 MnO3, etc. Preferably, the magnetic layer 14 is made of a compound represented by the following formula (1). BiFe 1-x A x O3···(1) In formula (1), A is Co or Mn, and x satisfies 0.05≦x<0.25. When x is 0.05 or more, the magnetic layer 14 can exhibit ferromagnetism and ferroelectricity at room temperature. When x is less than 0.25, changes in the crystal structure of the magnetic layer 14 can be suppressed.

[0014] Next, as shown in FIG. 1(c), an insulating layer 16 is formed on the magnetic layer 14. The insulating layer 16 contains SrTiO3. Then, as shown in FIG. 1(d), a Hall element 18 containing InSb, GaAs, InAs, or a solid solution thereof is formed on the insulating layer 16. By forming the Hall element 18 on the magnetic layer 14 via the insulating layer 16 in this manner, it is possible to prevent a reaction between the magnetic material constituting the magnetic layer 14 and the InSb, GaAs, or InAs constituting the Hall element 18. Therefore, the Hall element 18 can read information written in the magnetic layer 14 as an electrical signal by reversing the magnetic field. In this way, a Hall element 18 suitable for reading information written in a magnetic memory can be manufactured.

[0015] The method for forming the magnetic layer 14, the insulator layer 16, and the Hall element 18 is not particularly limited, and they can be formed by methods known to those skilled in the art, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Specific examples of PVD include pulsed laser deposition (PLD) and electron beam evaporation. Specific examples of CVD include metal organic (MO) CVD and mist CVD.

[0016] The shapes of the substrate 12, the magnetic layer 14, the insulating layer 16, and the Hall element 18 are not limited to those shown in the drawings, and an appropriate shape can be selected depending on the application.

[0017] (magnetic memory element) 2 is a schematic diagram showing an example of the configuration of a magnetic memory element according to an embodiment. The magnetic memory element 100 includes a substrate 12 made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation, a perovskite-type magnetic layer 14 disposed on the substrate 12, an insulator layer 16 disposed on the magnetic layer 14, and a Hall element 18 disposed on the insulator layer 16.

[0018] The substrate 12 is made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation. By forming the magnetic layer 14 on the substrate 12 made of such a compound, the magnetic layer 14 itself can exhibit its inherent magnetization, enabling the magnetization of the magnetic layer 14 to be reversed by applying a magnetic field or electric field. Specific examples of the substrate 12 include a 110-oriented GdScO3 substrate, a 110-oriented DyScO3 substrate, a 110-oriented SrTiO3 substrate, a 111-oriented SrTiO3 substrate, and a 001-oriented SrTiO3 substrate. The thickness of the substrate 12 is not particularly limited, but is preferably 300 μm to 1000 μm, more preferably 400 μm to 600 μm, from the viewpoints of thin film synthesis and ease of handling.

[0019] Preferably, the perovskite magnetic layer 14 is made of a compound represented by the following formula (1). BiFe 1-x A x O3···(1) In formula (1), A is Co or Mn, and x satisfies 0.05≦x<0.25. When x is 0.05 or more, the magnetic layer 14 can exhibit ferromagnetism and ferroelectricity at room temperature. When x is less than 0.25, changes in the crystal structure of the magnetic layer 14 can be suppressed. The magnitude of the spontaneous magnetization of the magnetic layer 14 at room temperature is 1 emu / cm 3 ~10emu / cm 3 The magnitude of spontaneous polarization is about 50-150 μC / cm 2 The magnetization direction of the magnetic layer 14 made of this compound can be reversed by an electric field generated by applying a voltage. This allows information to be written to the magnetic layer 14. Furthermore, the written information can be read by detecting the reversed magnetization with the Hall element 18.

[0020] The thickness of the magnetic layer 14 is, for example, 30 nm to 1000 nm. With such a thickness of the magnetic layer 14, an electric field can be reliably applied to the magnetic layer 14, improving the reliability of the device. From the viewpoint of lattice distortion, the thickness of the magnetic layer 14 is preferably 50 nm to 400 nm.

[0021] The insulating layer 16 contains SrTiO. The thickness of the insulating layer 16 is, for example, 1 nm to 50 nm. From the viewpoint of suppressing reaction with the magnetic layer 14 and suppressing shielding of the magnetic field from the magnetic layer 14 by the insulating layer 16 itself, the thickness of the insulating layer 16 is preferably 2 nm to 30 nm, and more preferably 4 nm to 10 nm.

[0022] The Hall element 18 contains InSb, GaAs, InAs, or a solid solution thereof. The shape of the Hall element 18 shown in FIG. 1 is not particularly limited, and it may have other shapes, such as a cross shape as shown in FIG. 2 or a cylindrical shape. As shown in FIG. 2, by disposing the Hall element 18 on the magnetic layer 14 via the insulating layer 16, it is possible to prevent a reaction between the magnetic material constituting the magnetic layer 14 and the InSb, GaAs, or InAs constituting the Hall element 18. This makes it possible to detect the reversal of the magnetic field of the magnetic layer 14 as an electrical signal. [Example]

[0023] Examples of the present invention will be described below, but these examples are merely illustrative examples for suitably explaining the present invention and do not limit the present invention in any way.

[0024] BiFe was deposited on a SrTiO3 (001) substrate by pulsed laser deposition (PLD) under the conditions shown in Table 1. 1-x Co x A 60-nm thick BFCO (BFCO) layer was then fabricated. A 6.7-nm thick SrTiO (STO) insulator layer was then fabricated on the BFCO layer, and an InSb layer (150 nm) was then fabricated on the insulator layer to fabricate a Hall element according to the example. A comparative example was also fabricated in the same manner as in the example, except that an InSb thin film was fabricated on a BFCO thin film without fabricating an STO insulator layer. Crystallinity was evaluated using X-ray diffraction (XRD) (Rigaku SmartLab). The Hall effect was measured using a physical property measurement system (Quantum Design, USA). Figure 3 shows the X-ray diffraction measurement results for the example and comparative example. Figure 4 shows the Hall effect measurement results for the Hall element according to the example.

[0025] [Table 1]

[0026] As shown in Figure 3, in the comparative example, a reaction between Bi in the BFCO layer and In in the InSb layer was observed. In contrast, in the example, there was no reaction between Bi and In, and each layer was successfully fabricated.

[0027] From FIG. 4, it can be seen that the Hall voltage of the InSb layer is reversed when the external magnetic field is +100 Oe and −100 Oe, and the Hall element of the example can detect the reversal of the external magnetic field as an electric signal.

[0028] Furthermore, the Hall effect of the Hall element according to the example was measured using a physical property measurement system (manufactured by Quantum Design, USA) when the magnetic field was reversed multiple times at room temperature. The results are shown in Figure 5. Figure 5 shows that the sign of the Hall resistance changes when the magnetic field is reversed, and that the Hall element functions as a sensor capable of detecting a magnetic field of 1 Oe.

[0029] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations and substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and order of steps in the embodiments based on the knowledge of a person skilled in the art, and to make modifications to the embodiments such as various design changes, and such modified embodiments are also included in the scope of the present invention. [Industrial Applicability]

[0030] The present invention can be applied to a manufacturing method of a Hall element and a magnetic memory element. [Explanation of symbols]

[0031] 12 substrate, 14 perovskite magnetic layer, 16 insulator layer, 18 Hall element, 100 magnetic memory element.

Claims

1. forming a perovskite-type magnetic layer on a substrate made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation; On the perovskite magnetic layer, SrTiO ３ forming an insulator layer comprising: forming a Hall element containing InSb, GaAs, InAs, or a solid solution thereof on the insulator layer; Including, The method for manufacturing a Hall element is characterized in that the thickness of the insulating layer is 2 nm to 30 nm.

2. a substrate made of a compound having a perovskite structure and a lattice constant of 3.90 to 3.97 Å in pseudocubic notation; a perovskite magnetic layer disposed on the substrate; SrTiO disposed on the perovskite magnetic layer ３ an insulator layer comprising: a Hall element including InSb, GaAs, InAs, or a solid solution thereof, disposed on the insulator layer; Including, The magnetic memory element is characterized in that the thickness of the insulating layer is 2 nm to 30 nm.

3. The substrate is made of GdScO ３ Substrate, 110-oriented DyScO ３ Substrate, 110-oriented SrTiO ３ Substrate, 111-oriented SrTiO ３ Substrate and 001-oriented SrTiO ３ 3. The magnetic memory element according to claim 2, wherein the magnetic memory element is selected from the group consisting of:

4. 4. The magnetic memory element according to claim 3, wherein the perovskite magnetic layer is a thin film made of a compound represented by the following formula (1) and has a thickness of 50 nm to 1000 nm: Bife １－ｘ A ｘ O ３ ・・・(1) [In formula (1), A is Co or Mn, and x satisfies 0.05≦x<0.25.]

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