Photodetection element, receiving device, and photo sensor device

Abstract

To provide a light detection element, a receiver, and a light sensor device with excellent heat dissipation.SOLUTION: This light detection element has a magnetic element with a first ferromagnetic layer to which light is radiated, a second ferromagnetic layer, a spacer layer sandwiched between the first and second ferromagnetic layers, a first electrode that contacts a first side of the first ferromagnetic layer in a stacking direction of the magnetic element, a second electrode that contacts a second side opposite the first side, and a first high thermal conductivity layer that is outside the first ferromagnetic layer and has higher thermal conductivity than the first electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light detection element, a receiving device, and a light sensor device. [Background technology]

[0002] Photoelectric conversion elements are used for a variety of purposes.

[0003] For example, Patent Document 1 describes a receiving device that receives an optical signal using a photodiode. The photodiode is, for example, a pn junction diode that uses a semiconductor pn junction, and converts light into an electrical signal.

[0004] Furthermore, for example, Patent Document 2 describes an optical sensor using a semiconductor pn junction and an image sensor using this optical sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-292107 [Patent Document 2] U.S. Patent No. 9,842,874 Summary of the Invention [Problem to be solved by the invention]

[0006] Photodetectors using semiconductor pn junctions are widely used, but new photodetectors are needed for further development. Furthermore, photodetectors often generate heat when exposed to light, which adversely affects the element and circuitry, so improvements in heat dissipation are needed.

[0007] The present invention has been made in view of the above problems, and has an object to provide a light detecting element, a receiving device, and a light sensor device that have excellent heat dissipation properties. [Means for solving the problem]

[0008] In order to solve the above problems, the following means are provided.

[0009] (1) A light detection element according to a first aspect includes a magnetic element including a first ferromagnetic layer to which light is irradiated, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer; a first electrode in contact with a first surface of the magnetic element on the side of the first ferromagnetic layer in the stacking direction; a second electrode in contact with a second surface opposite the first surface; and a first high thermal conductivity layer located outside the first ferromagnetic layer and having a higher thermal conductivity than the first electrode.

[0010] (2) In the light-detecting element according to the above aspect, the first electrode may include an oxide that is transparent to the light.

[0011] (3) In the light-detecting element according to the above aspect, the first highly thermally conductive layer may be made of a non-magnetic material.

[0012] (4) In the light-detecting element according to the above aspect, the first highly thermally conductive layer may be in contact with the first ferromagnetic layer.

[0013] (5) In the light-detecting element according to the above aspect, the first highly thermally conductive layer may be in contact with the first electrode.

[0014] (6) The light detection element according to the above aspect may further include a second highly thermally conductive layer, the second highly thermally conductive layer being in contact with a side wall of the first electrode, and the second highly thermally conductive layer having a higher thermal conductivity than the first electrode.

[0015] (7) In the light-detecting element according to the above aspect, the first high thermal conductivity layer may be in contact with the second high thermal conductivity layer.

[0016] (8) In the light-detecting element according to the above aspect, the first high thermal conductivity layer may be made of metal.

[0017] (9) In the light-detecting element according to the above aspect, the first high thermal conductivity layer may contain copper, gold, or silver.

[0018] (10) The light-detecting element according to the above aspect may further include an insulating layer, which may cover at least a portion of the sidewall of the magnetic element below a lower end of the spacer layer on the second ferromagnetic layer side.

[0019] (11) In the light-detecting element according to the above aspect, the first high thermal conductive layer may be an insulator.

[0020] (12) In the light-detecting element according to the above aspect, the first high-thermal-conductivity layer may have a thermal conductivity of more than 40 W / m·K.

[0021] (13) In the light-detecting element according to the above aspect, the first high thermal conductivity layer may contain silicon carbide, aluminum nitride, or boron nitride.

[0022] (14) The light-detecting element according to the above aspect may further include a high resistivity layer between the first high thermal conductivity layer and the second electrode, and the high resistivity layer may have a higher resistivity than the first high thermal conductivity layer.

[0023] (15) The light-detecting element according to the above aspect may further include a low-dielectric layer between the first high-thermal-conductivity layer and the second electrode, and the low-dielectric layer may have a lower dielectric constant than the first high-thermal-conductivity layer.

[0024] (16) A second aspect of the light detection element includes a magnetic element including a first ferromagnetic layer to which light is irradiated, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, and a first high thermal conductivity layer located outside the first ferromagnetic layer and made of a non-magnetic metal.

[0025] (17) In the light-detecting element according to the above aspect, the first high thermal conductivity layer may contain copper, gold, or silver.

[0026] (18) A receiving device according to a third aspect includes the photodetector element according to the above aspect.

[0027] (19) An optical sensor device according to a fourth aspect includes the optical detection element according to the above aspect. [Effects of the Invention]

[0028] The light detecting element, the receiving device, and the light sensor device according to the above aspects have excellent heat dissipation properties. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is a cross-sectional view of the photodetector according to the first embodiment. [Figure 2] 5A and 5B are diagrams illustrating a first mechanism of a first operation example of the photodetector according to the first embodiment. [Figure 3] 5A and 5B are diagrams illustrating a second mechanism of the first operation example of the photodetector according to the first embodiment. [Figure 4] 5A and 5B are diagrams illustrating a first mechanism of a second operation example of the light-detecting element according to the first embodiment. [Figure 5] 10A and 10B are diagrams illustrating a second mechanism of a second operation example of the light-detecting element according to the first embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a light-detecting element according to a first modified example. [Figure 7] FIG. 10 is a cross-sectional view of a light-detecting element according to a second modified example. [Figure 8] FIG. 10 is a cross-sectional view of a light-detecting element according to a third modified example. [Figure 9] FIG. 10 is a cross-sectional view of a light-detecting element according to a fourth modified example. [Figure 10] FIG. 11 is a cross-sectional view of a light-detecting element according to a fifth modified example. [Figure 11] FIG. 13 is a cross-sectional view of a light-detecting element according to a sixth modified example. [Figure 12] FIG. 13 is a cross-sectional view of a light-detecting element according to a seventh modified example. [Figure 13] FIG. 10 is a block diagram of a transmitting / receiving device according to a first application example. [Figure 14] FIG. 1 is a conceptual diagram of an example of a communication system. [Figure 15] FIG. 10 is a conceptual diagram of a cross section of an optical sensor device according to a second application example. [Figure 16] FIG. 2 is a schematic diagram of an example of a terminal device. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for convenience in order to make the features easier to understand, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate changes can be made within the scope of the effects of the present invention.

[0031] The directions are defined as follows. The stacking direction of the magnetic element 10 is the z direction, one direction in a plane perpendicular to the z direction is the x direction, and the direction perpendicular to the x and z directions is the y direction. The z direction is an example of a stacking direction. Hereinafter, the +z direction may be expressed as "up" and the -z direction as "down". The +z direction is the direction from the second ferromagnetic layer 2 to the first ferromagnetic layer 1. Up and down do not necessarily coincide with the direction in which gravity is applied.

[0032] FIG. 1 is a cross-sectional view of a photodetector 100 according to the first embodiment. The photodetector 100 converts changes in the state of irradiated light into an electrical signal. The resistance value of the photodetector 100 in the z-direction changes depending on the state of irradiated light. The output voltage from the photodetector 100 changes depending on the state of irradiated light. In this specification, light is not limited to visible light but also includes infrared light, which has a longer wavelength than visible light, and ultraviolet light, which has a shorter wavelength than visible light. The wavelength of visible light is, for example, 380 nm or more and less than 800 nm. The wavelength of infrared light is, for example, 800 nm or more and 1 mm or less. The wavelength of ultraviolet light is, for example, 200 nm or more and less than 380 nm.

[0033] The light-detecting element 100 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first highly thermally conductive layer 20, an insulating layer 30, and a substrate 40.

[0034] The magnetic element 10 has, for example, a first ferromagnetic layer 1, a second ferromagnetic layer 2, a spacer layer 3, and a cap layer 4. The spacer layer 3 is located between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The cap layer 4 covers the top surface of the magnetic element 10 in the stacking direction. The cap layer 4 is located on, for example, the first ferromagnetic layer 1. The magnetic element 10 may have other layers in addition to these.

[0035] The magnetic element 10 is, for example, an MTJ (Magnetic Tunnel Junction) element in which the spacer layer 3 is made of an insulating material. In this case, the resistance value in the z direction (the resistance value when a current flows in the z direction) of the magnetic element 10 changes according to the relative change between the magnetization state of the first ferromagnetic layer 1 and the magnetization state of the second ferromagnetic layer 2. Such an element is also called a magnetoresistance effect element.

[0036] The first ferromagnetic layer 1 is a light detection layer whose magnetization state changes when irradiated with light from the outside. The first ferromagnetic layer 1 is also called a magnetization free layer. The magnetization free layer is a layer containing a magnetic material whose magnetization state changes when a predetermined external force is applied. The predetermined external force is, for example, light irradiated from the outside, a current flowing in the z direction of the magnetic element 10, or an external magnetic field. The magnetization state of the first ferromagnetic layer 1 changes depending on the intensity of the light irradiated onto the first ferromagnetic layer 1.

[0037] The first ferromagnetic layer 1 includes a ferromagnetic material. The first ferromagnetic layer 1 includes at least one of magnetic elements such as Co, Fe, or Ni. The first ferromagnetic layer 1 may include a non-magnetic element such as B, Mg, Hf, or Gd in addition to the magnetic elements described above. The first ferromagnetic layer 1 may be, for example, an alloy including a magnetic element and a non-magnetic element. The first ferromagnetic layer 1 may be composed of multiple layers. The first ferromagnetic layer 1 may be, for example, a CoFeB alloy, a stacked body in which a CoFeB alloy layer is sandwiched between Fe layers, or a stacked body in which a CoFeB alloy layer is sandwiched between CoFe layers.

[0038] The first ferromagnetic layer 1 may be an in-plane magnetization film having an axis of easy magnetization in the in-plane direction (any direction in the xy plane) or a perpendicular magnetization film having an axis of easy magnetization in the direction perpendicular to the film plane (z direction).

[0039] The thickness of the first ferromagnetic layer 1 is, for example, 1 nm or more and 5 nm or less. The thickness of the first ferromagnetic layer 1 is preferably, for example, 1 nm or more and 2 nm or less. When the first ferromagnetic layer 1 is a perpendicular magnetization film, if the thickness of the first ferromagnetic layer 1 is thin, the effect of perpendicular magnetic anisotropy applied from the layers above and below the first ferromagnetic layer 1 is strengthened, and the perpendicular magnetic anisotropy of the first ferromagnetic layer 1 is increased. In other words, if the perpendicular magnetic anisotropy of the first ferromagnetic layer 1 is high, the force that causes the magnetization M1 to return to the z-direction is strengthened. On the other hand, if the thickness of the first ferromagnetic layer 1 is thick, the effect of perpendicular magnetic anisotropy applied from the layers above and below the first ferromagnetic layer 1 is relatively weakened, and the perpendicular magnetic anisotropy of the first ferromagnetic layer 1 is weakened.

[0040] As the thickness of the first ferromagnetic layer 1 decreases, its volume as a ferromagnetic material decreases, and as it increases, its volume as a ferromagnetic material increases. The responsiveness of the magnetization of the first ferromagnetic layer 1 when external energy is applied is inversely proportional to the product (KuV) of the magnetic anisotropy (Ku) and volume (V) of the first ferromagnetic layer 1. In other words, as the product of the magnetic anisotropy and volume of the first ferromagnetic layer 1 decreases, its responsiveness to light increases. From this perspective, in order to enhance its responsiveness to light, it is preferable to reduce the volume of the first ferromagnetic layer 1 after appropriately designing the magnetic anisotropy of the first ferromagnetic layer 1.

[0041] If the thickness of the first ferromagnetic layer 1 is greater than 2 nm, an insertion layer made of, for example, Mo or W may be provided within the first ferromagnetic layer 1. That is, the first ferromagnetic layer 1 may be a stack in which a ferromagnetic layer, an insertion layer, and a ferromagnetic layer are stacked in this order in the z direction. The interfacial magnetic anisotropy at the interface between the insertion layer and the ferromagnetic layer enhances the perpendicular magnetic anisotropy of the entire first ferromagnetic layer 1. The thickness of the insertion layer is, for example, 0.1 nm to 0.6 nm.

[0042] The second ferromagnetic layer 2 is a magnetization fixed layer. The magnetization fixed layer is a layer made of a magnetic material whose magnetization state is less likely to change when a predetermined external energy is applied than the magnetization free layer. For example, the magnetization direction of the magnetization fixed layer is less likely to change when a predetermined external energy is applied than the magnetization free layer. Also, for example, the magnitude of the magnetization of the magnetization fixed layer is less likely to change when a predetermined external energy is applied than the magnetization free layer. The coercive force of the second ferromagnetic layer 2 is, for example, greater than the coercive force of the first ferromagnetic layer 1. The second ferromagnetic layer 2 has an easy axis of magnetization in the same direction as the first ferromagnetic layer 1. The second ferromagnetic layer 2 may be an in-plane magnetization film or a perpendicular magnetization film.

[0043] The material constituting the second ferromagnetic layer 2 is, for example, the same as that of the first ferromagnetic layer 1. The second ferromagnetic layer 2 may be, for example, a laminate in which Co is 0.4 nm to 1.0 nm thick, Mo is 0.1 nm to 0.5 nm thick, a CoFeB alloy is 0.3 nm to 1.0 nm thick, and Fe is 0.3 nm to 1.0 nm thick are laminated in this order.

[0044] The magnetization of the second ferromagnetic layer 2 may be fixed by magnetic coupling with a third ferromagnetic layer via a magnetic coupling layer, for example. In this case, the combination of the second ferromagnetic layer 2, the magnetic coupling layer, and the third ferromagnetic layer may be referred to as a magnetization fixed layer.

[0045] The third ferromagnetic layer is magnetically coupled to the second ferromagnetic layer 2, for example. The magnetic coupling is, for example, an antiferromagnetic coupling caused by RKKY interaction. The material constituting the third ferromagnetic layer is, for example, the same as that of the first ferromagnetic layer 1. The magnetic coupling layer is, for example, Ru, Ir, or the like.

[0046] The spacer layer 3 is a non-magnetic layer disposed between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. The spacer layer 3 is composed of a layer made of a conductor, an insulator, or a semiconductor, or a layer containing current-carrying points made of a conductor in an insulator. The thickness of the spacer layer 3 can be adjusted depending on the orientation directions of the magnetizations of the first ferromagnetic layer 1 and the second ferromagnetic layer 2 in the initial state, which will be described later.

[0047] For example, when the spacer layer 3 is made of an insulator, the magnetic element 10 has a magnetic tunnel junction (MTJ) consisting of the first ferromagnetic layer 1, the spacer layer 3, and the second ferromagnetic layer 2. Such an element is called an MTJ element. In this case, the magnetic element 10 can exhibit a tunnel magnetoresistance (TMR) effect. For example, when the spacer layer 3 is made of a metal, the magnetic element 10 can exhibit a giant magnetoresistance (GMR) effect. Such an element is called a GMR element. The magnetic element 30 may be called an MTJ element, a GMR element, or other names depending on the material of the spacer layer 3, but is also collectively called a magnetoresistance effect element.

[0048] When the spacer layer 3 is made of an insulating material, a material containing aluminum oxide, magnesium oxide, titanium oxide, silicon oxide, or the like can be used. These insulating materials may also contain elements such as Al, B, Si, and Mg, or magnetic elements such as Co, Fe, and Ni. A high magnetoresistance ratio can be obtained by adjusting the thickness of the spacer layer 3 so that a high TMR effect is exhibited between the first ferromagnetic layer 1 and the second ferromagnetic layer 2. To efficiently utilize the TMR effect, the thickness of the spacer layer 3 may be approximately 0.5 to 5.0 nm, or approximately 1.0 to 2.5 nm.

[0049] When the spacer layer 3 is made of a nonmagnetic conductive material, conductive materials such as Cu, Ag, Au, or Ru can be used. To efficiently utilize the GMR effect, the thickness of the spacer layer 3 may be about 0.5 to 5.0 nm, or about 2.0 to 3.0 nm.

[0050] When the spacer layer 3 is made of a non-magnetic semiconductor material, it can be made of zinc oxide, indium oxide, tin oxide, germanium oxide, gallium oxide, ITO, etc. In this case, the thickness of the spacer layer 3 may be about 1.0 to 4.0 nm.

[0051] When a layer including current-carrying points formed by a conductor in a nonmagnetic insulator is used as the spacer layer 3, the current-carrying points may be formed by a nonmagnetic conductor such as Cu, Au, or Al in a nonmagnetic insulator made of aluminum oxide or magnesium oxide. The conductor may also be made of a magnetic element such as Co, Fe, or Ni. In this case, the thickness of the spacer layer 3 may be approximately 1.0 to 2.5 nm. The current-carrying points are, for example, columnar bodies with a diameter of 1 nm to 5 nm when viewed perpendicular to the film surface.

[0052] The cap layer 4 is located between the first ferromagnetic layer 1 and the first electrode 11. The cap layer 4 prevents damage to the lower layer during the process and improves the crystallinity of the lower layer during annealing. The thickness of the cap layer 4 is, for example, 3 nm or less so that the first ferromagnetic layer 1 is irradiated with sufficient light. The cap layer 4 is made of, for example, MgO, W, Mo, Ru, Ta, Cu, Cr, or a laminated film of these materials.

[0053] The magnetic element 10 may also have an underlayer, a perpendicular magnetization induction layer, etc. The underlayer is located between the second ferromagnetic layer 2 and the second electrode 12. The underlayer is a seed layer or a buffer layer. The seed layer improves the crystallinity of the layer stacked on the seed layer. The seed layer is, for example, Pt, Ru, Hf, Zr, or NiFeCr. The seed layer has a thickness of, for example, 1 nm or more and 5 nm or less. The buffer layer is a layer that alleviates lattice mismatch between different crystals. The buffer layer is, for example, Ta, Ti, W, Zr, Hf, or nitrides of these elements. The buffer layer has a thickness of, for example, 1 nm or more and 5 nm or less.

[0054] The perpendicular magnetization induction layer is formed when the first ferromagnetic layer 1 is a perpendicular magnetization film. The perpendicular magnetization induction layer is stacked on the first ferromagnetic layer 1. The perpendicular magnetization induction layer induces perpendicular magnetic anisotropy in the first ferromagnetic layer 1. The perpendicular magnetization induction layer is made of, for example, magnesium oxide, W, Ta, Mo, etc. When the perpendicular magnetization induction layer is made of magnesium oxide, it is preferable that the magnesium oxide has oxygen deficiency to increase conductivity. The film thickness of the perpendicular magnetization induction layer is, for example, 0.5 nm or more and 2.0 nm or less.

[0055] The first electrode 11 is in contact with a first surface of the magnetic element 10. The first surface is the surface of the magnetic element 10 on the first ferromagnetic layer 1 side in the z direction. The first electrode 11 is transparent to, for example, the wavelength range of light irradiated onto the magnetic element 10.

[0056] The first electrode 11 includes, for example, an oxide that is transparent to the wavelength region of light irradiated onto the magnetic element 10. The first electrode 11 is a transparent electrode including, for example, an oxide transparent electrode material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium gallium zinc oxide (IGZO). The first electrode 11 may be configured to include a plurality of metal columns in the transparent electrode material. In this case, the film thickness of the first electrode 11 is, for example, 10 nm to 300 nm. It is not essential to use the above-mentioned transparent electrode material for the first electrode 11. A thin metal material such as Au, Cu, or Al may be used to allow external light to reach the first ferromagnetic layer 1. When a metal is used as the material for the first electrode 11, the film thickness of the first electrode 11 is, for example, 3 to 10 nm. In particular, Au has a higher transmittance for light with wavelengths near blue than other metal materials. The first electrode 11 may also have an anti-reflection film on the irradiation surface onto which light is irradiated.

[0057] The second electrode 12 is made of a conductive material. The second electrode 12 is made of, for example, a metal such as Cu, Al, or Au. Ta or Ti may be laminated above and below these metals. Alternatively, a laminated film of Cu and Ta, a laminated film of Ta, Cu, and Ti, or a laminated film of Ta, Cu, and TaN may be used. Alternatively, TiN or TaN may be used as the second electrode 12. The film thickness of the second electrode 12 is, for example, 200 nm to 800 nm.

[0058] The second electrode 12 may be transparent to light irradiated onto the magnetic element 10. As with the first electrode 11, the second electrode 12 may be made of a transparent oxide electrode material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium gallium zinc oxide (IGZO). Even when light is irradiated from the first electrode 11, the light may reach the second electrode 12 depending on the intensity of the light. In this case, since the second electrode 12 is made of a transparent oxide electrode material, light reflection at the interface between the second electrode 12 and a layer adjacent to it can be suppressed compared to when the second electrode 12 is made of a metal.

[0059] The first highly thermally conductive layer 20 is located outside the first ferromagnetic layer 1 when viewed from the z direction. The first highly thermally conductive layer 20 is located, for example, outside the in-plane direction of the magnetic element 10 and covers at least a portion of the sidewall of the magnetic element 10. The first highly thermally conductive layer 20 is connected to the magnetic element 10, for example, via an insulating layer 30. The first highly thermally conductive layer 20 surrounds, for example, at least a portion of the magnetic element 10. For example, the first highly thermally conductive layer 20 surrounds the first ferromagnetic layer 1 of the magnetic element 10. The first highly thermally conductive layer 20 is in contact with, for example, the first electrode 11. When the first highly thermally conductive layer 20 and the first electrode 11 are in contact with each other, a heat path is formed from the first highly thermally conductive layer 20 to the wiring via the first electrode 11, allowing heat to be efficiently dissipated from the magnetic element 10.

[0060] The first high thermal conductive layer 20 has a higher thermal conductivity than the first electrode 11. The first high thermal conductive layer 20 has a higher thermal conductivity than, for example, the insulating layer 30. The thermal conductivity of the first high thermal conductive layer 20 is greater than, for example, 40 W / m·K. A portion of the heat generated in the magnetic element 10 is released through the first high thermal conductive layer 20.

[0061] The first high thermal conductive layer 20 is, for example, a metal. The first high thermal conductive layer 20 is, for example, a non-magnetic material. If the first high thermal conductive layer 20 is a non-magnetic material, no leakage magnetic field is generated from the first high thermal conductive layer 20, and deterioration of the magnetic properties of the magnetic element 10 can be suppressed. If the first high thermal conductive layer 20 is a non-magnetic metal, for example, even if the first electrode 11 is a metal and has a higher thermal conductivity than the first high thermal conductive layer 20, the first high thermal conductive layer 20 has a high thermal conductivity. Therefore, even if the first electrode 11 has a higher thermal conductivity than the first high thermal conductive layer 20, heat can be efficiently released from the magnetic element 10. The first high thermal conductive layer 20 includes, for example, copper, gold, or silver.

[0062] The first high thermal conductive layer 20 may be an insulator. When the first high thermal conductive layer 20 is made of an insulator, the first high thermal conductive layer 20 contains, for example, silicon carbide, aluminum nitride, or boron nitride.

[0063] The insulating layer 30 is located between the magnetic element 10 and the first high thermal conductive layer 20. The insulating layer 30 covers, for example, the periphery of the magnetic element 10. The insulating layer 30 is, for example, an oxide, nitride, or oxynitride of Si, Al, or Mg. The insulating layer 30 is, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride, silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO x ) etc.

[0064] The photodetector element 100 is fabricated through a process of stacking each layer, an annealing process, and a processing process. First, the second electrode 12, the second ferromagnetic layer 2, the spacer layer 3, the first ferromagnetic layer 1, and the cap layer 4 are stacked in this order on a substrate. Each layer is formed by, for example, sputtering.

[0065] Next, the laminated film is annealed. The annealing temperature is, for example, 250°C to 450°C. When the substrate is a circuit board, it is preferable to anneal at 400°C or higher. Thereafter, the laminated film is processed into a predetermined columnar shape by photolithography and etching. The columnar shape may be a cylindrical or rectangular columnar shape. For example, the minimum width of the columnar shape when viewed from the z direction may be 10 nm to 2000 nm, or 30 nm to 500 nm.

[0066] Next, an insulating layer 30 is formed to cover the side surfaces of the pillars. The insulating layer 30 may be laminated multiple times. Next, a first high thermal conductive layer 20 is formed on the insulating layer 30. Next, the upper surface of the cap layer 4 is exposed from the insulating layer 30 and the first high thermal conductive layer 20 by chemical mechanical polishing (CMP), and a first electrode 11 is formed on the cap layer 4. Through the above steps, a light-detecting element 100 is obtained.

[0067] Next, several examples of the operation of the photodetector 100 will be described. The first ferromagnetic layer 1 is irradiated with light whose intensity varies. The output voltage from the photodetector 100 varies as the first ferromagnetic layer 1 is irradiated with light. In the first operation example, a case will be described in which the intensity of the light irradiated to the first ferromagnetic layer 1 has two levels: a first intensity and a second intensity. The intensity of the light with the second intensity is greater than the intensity of the light with the first intensity. The first intensity may also be zero when the intensity of the light irradiated to the first ferromagnetic layer 1 is zero.

[0068] 2 and 3 are diagrams illustrating a first operation example of the photodetector element 100 according to the first embodiment. FIG. 2 is a diagram illustrating a first mechanism of the first operation example, and FIG. 3 is a diagram illustrating a second mechanism of the first operation example. In the upper graphs of FIGS. 2 and 3, the vertical axis represents the intensity of light irradiated onto the first ferromagnetic layer 1, and the horizontal axis represents time. In the lower graphs of FIGS. 2 and 3, the vertical axis represents the resistance value of the magnetic element 10 in the z direction, and the horizontal axis represents time.

[0069] First, in a state where the first ferromagnetic layer 1 is irradiated with light of a first intensity (hereinafter referred to as the initial state), the magnetization M1 of the first ferromagnetic layer 1 and the magnetization M2 of the second ferromagnetic layer 2 are parallel, the resistance value of the magnetic element 10 in the z direction exhibits a first resistance value R1, and the magnitude of the output voltage from the magnetic element 10 exhibits a first value. The resistance value of the magnetic element 10 in the z direction is determined by Ohm's law from the voltage value generated across both ends of the magnetic element 10 in the z direction by passing a sense current Is through the magnetic element 10 in the z direction. The output voltage from the magnetic element 10 is generated between the first electrode 11 and the second electrode 12. In the example shown in FIG. 2, the sense current Is is passed from the first ferromagnetic layer 1 to the second ferromagnetic layer 2. By passing the sense current Is in this direction, a spin transfer torque acts on the magnetization M1 of the first ferromagnetic layer 1 in the same direction as the magnetization M2 of the second ferromagnetic layer 2, and the magnetizations M1 and M2 become parallel in the initial state. Also, by passing the sense current Is in this direction, it is possible to prevent the magnetization M1 of the first ferromagnetic layer 1 from reversing during operation.

[0070] Next, the intensity of the light irradiated to the first ferromagnetic layer 1 changes from the first intensity to a second intensity. The second intensity is greater than the first intensity, and the magnetization M1 of the first ferromagnetic layer 1 changes from its initial state. The state of the magnetization M1 of the first ferromagnetic layer 1 when no light is irradiated to the first ferromagnetic layer 1 is different from the state of the magnetization M1 of the first ferromagnetic layer 1 at the second intensity. The state of the magnetization M1 refers to, for example, the tilt angle or magnitude with respect to the z direction.

[0071] For example, as shown in Fig. 2, when the intensity of light irradiated to the first ferromagnetic layer 1 changes from a first intensity to a second intensity, the magnetization M1 tilts with respect to the z direction. Furthermore, as shown in Fig. 3, when the intensity of light irradiated to the first ferromagnetic layer 1 changes from the first intensity to a second intensity, the magnitude of the magnetization M1 decreases. For example, when the magnetization M1 of the first ferromagnetic layer 1 tilts with respect to the z direction due to the intensity of light irradiation, the tilt angle is greater than 0° and less than 90°.

[0072] When the magnetization M1 of the first ferromagnetic layer 1 changes from its initial state, the resistance value in the z direction of the magnetoresistive element 10 exhibits a second resistance value R2, and the magnitude of the output voltage from the magnetic element 10 exhibits a second value. The second resistance value R2 is greater than the first resistance value R1, and the second value of the output voltage is greater than the first value. The second resistance value R2 is between the resistance value (first resistance value R1) when the magnetization M1 and the magnetization M2 are parallel and the resistance value when the magnetization M1 and the magnetization M2 are antiparallel.

[0073] In the case shown in FIG. 2, a spin transfer torque acts on the magnetization M1 of the first ferromagnetic layer 1 in the same direction as the magnetization M2 of the second ferromagnetic layer 2. Therefore, the magnetization M1 attempts to return to a state parallel to the magnetization M2, and when the intensity of the light irradiated to the first ferromagnetic layer 1 changes from the second intensity to the first intensity, the magnetic element 10 returns to its initial state. In the case shown in FIG. 3, when the intensity of the light irradiated to the first ferromagnetic layer 1 returns to the first intensity, the magnitude of the magnetization M1 of the first ferromagnetic layer 1 returns to its original value, and the magnetic element 10 returns to its initial state. In either case, the resistance value in the z direction of the magnetic element 10 returns to the first resistance value R1. In other words, when the intensity of the light irradiated to the first ferromagnetic layer 1 changes from the second intensity to the first intensity, the resistance value in the z direction of the photodetector element 100 changes from the second resistance value R2 to the first resistance value R1.

[0074] The output voltage from the photodetector element 100 changes in response to changes in the intensity of light irradiated onto the first ferromagnetic layer 1, and the change in the intensity of the irradiated light can be converted into a change in the output voltage from the photodetector element 100. In other words, the photodetector element 100 can convert light into an electrical signal. For example, if the output voltage from the photodetector element 100 is equal to or greater than a threshold, it is processed as a first signal (e.g., "1"), and if it is less than the threshold, it is processed as a second signal (e.g., "0").

[0075] Here, the case where the magnetization M1 and the magnetization M2 are parallel in the initial state has been described as an example, but the magnetization M1 and the magnetization M2 may be antiparallel in the initial state. In this case, the resistance value in the z direction of the magnetic element 10 decreases as the state of the magnetization M1 changes (for example, as the angle change of the magnetization M1 from the initial state increases). If the initial state is one in which the magnetization M1 and the magnetization M2 are antiparallel, it is preferable to flow the sense current from the second ferromagnetic layer 2 toward the first ferromagnetic layer 1. By flowing the sense current in this direction, a spin transfer torque acts on the magnetization M1 of the first ferromagnetic layer 1 in the opposite direction to the magnetization M2 of the second ferromagnetic layer 2, and the magnetization M1 and the magnetization M2 become antiparallel in the initial state.

[0076] In the first operating example, the case where the light irradiated to the first ferromagnetic layer 1 has two levels of intensity, a first intensity and a second intensity, is described, but in the second operating example, the case where the intensity of the light irradiated to the first ferromagnetic layer 1 changes in multiple levels or in an analog manner is described.

[0077] 4 and 5 are diagrams illustrating a second operation example of the photodetector element 100 according to the first embodiment. FIG. 4 is a diagram illustrating a first mechanism of the first operation example, and FIG. 5 is a diagram illustrating a second mechanism of the first operation example. In the upper graphs of FIGS. 4 and 5, the vertical axis represents the intensity of light irradiated onto the first ferromagnetic layer 1, and the horizontal axis represents time. In the lower graphs of FIGS. 4 and 5, the vertical axis represents the resistance value of the magnetic element 10 in the z direction, and the horizontal axis represents time.

[0078] 4, when the intensity of light irradiated onto the first ferromagnetic layer 1 changes, the external energy caused by the light irradiation tilts the magnetization M1 of the first ferromagnetic layer 1 from its initial state. The angle between the direction of the magnetization M1 of the first ferromagnetic layer 1 when no light is irradiated onto the first ferromagnetic layer 1 and the direction of the magnetization M1 when light is irradiated onto the first ferromagnetic layer 1 is both greater than 0° and smaller than 90°.

[0079] When the magnetization M1 of the first ferromagnetic layer 1 tilts from its initial state, the resistance value in the z direction of the magnetoresistive element 10 changes. Consequently, the output voltage from the magnetic element 10 changes. For example, depending on the tilt of the magnetization M1 of the first ferromagnetic layer 1, the resistance value in the z direction of the magnetic element 10 changes from a second resistance value R2 to a third resistance value R3 to a fourth resistance value R4, and the output voltage from the magnetic element 30 changes from a second value to a third value to a fourth value. The resistance values ​​increase in the order of the first resistance value R1, the second resistance value R2, the third resistance value R3, and the fourth resistance value R4. The output voltage from the magnetic element 30 increases in the order of the first value, the second value, the third value, and the fourth value.

[0080] When the intensity of light irradiated onto the first ferromagnetic layer 1 changes, the output voltage from the magnetic element 10 (the resistance value of the magnetic element 10 in the z-direction) changes. For example, if the first value (first resistance value R1) is defined as "0," the second value (second resistance value R2) as "1," the third value (third resistance value R3) as "2," and the fourth value (fourth resistance value R4) as "3," the photodetector element 100 can output four values. While the example shown here shows a case where four values ​​are read, the number of values ​​to be read can be freely designed by setting the threshold value of the output voltage from the magnetic element 10 (the resistance value of the magnetic element 10). The photodetector element 100 may also output analog values ​​as they are.

[0081] Similarly, in the case of FIG. 5, when the intensity of light irradiated onto the first ferromagnetic layer 1 changes, the magnitude of the magnetization M1 of the first ferromagnetic layer 1 decreases from its initial state due to external energy from the light irradiation. When the magnetization M1 of the first ferromagnetic layer 1 decreases from its initial state, the resistance value in the z direction of the magnetoresistive element 10 changes. Consequently, the output voltage from the magnetic element 10 changes. For example, depending on the magnitude of the magnetization M1 of the first ferromagnetic layer 1, the resistance value in the z direction of the magnetic element 10 changes from a second resistance value R2 to a third resistance value R3 to a fourth resistance value R4, and the output voltage from the magnetic element 10 changes from a second value to a third value to a fourth value. Therefore, similar to the case of FIG. 4, the light-detecting element 100 can output the difference in these output voltages (resistance values) as multi-value or analog data.

[0082] Also, in the second operating example, as in the first operating example, when the intensity of the light irradiated to the first ferromagnetic layer 1 returns to the first intensity, the state of the magnetization M1 of the first ferromagnetic layer 1 returns to its original state, and the magnetic element 10 returns to its initial state.

[0083] Here, the case where the magnetization M1 and the magnetization M2 are parallel in the initial state has been described as an example, but also in the second operation example, the magnetization M1 and the magnetization M2 may be antiparallel in the initial state.

[0084] As described above, the photodetector 100 according to the first embodiment can convert light irradiated onto the magnetic element 10 into an output voltage from the magnetic element 10, thereby converting the light into an electrical signal. Furthermore, the presence of the first highly thermally conductive layer 20, which has high thermal conductivity, on the outside of the magnetic element 10, which generates heat in response to light irradiation, can promote heat dissipation from the magnetic element 10. In other words, when the irradiation of the first ferromagnetic layer 1 with light is stopped, the magnetic element 10 is quickly cooled, and the magnetization M1 quickly returns to its initial state. The faster the magnetization M1 of the first ferromagnetic layer 1 returns to its initial state, the faster the response characteristics of the photodetector 100 to light. In other words, the response characteristics of the photodetector 100 to light are increased.

[0085] Although the first embodiment has been described in detail above with reference to the drawings, the first embodiment is not limited to this example.

[0086] (First Modification) 6 is a cross-sectional view of a light-detecting element 101 according to a first modified example. The light-detecting element 101 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 21, insulating layers 30 and 31, and a substrate 40. In the first modified example, the same components as those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

[0087] The first highly thermally conductive layer 21 is located outside the first ferromagnetic layer 1 when viewed in the z direction. The first highly thermally conductive layer 21 is connected to the magnetic element 10, for example, via an insulating layer 30. The first highly thermally conductive layer 21, for example, surrounds at least a portion of the magnetic element 10. For example, the first highly thermally conductive layer 21 surrounds the first ferromagnetic layer 1 of the magnetic element 10. The first highly thermally conductive layer 21, for example, is in contact with the first electrode 11. The first highly thermally conductive layer 21 is sandwiched between the insulating layer 30 and the insulating layer 31.

[0088] The first highly thermally conductive layer 21 has a higher thermal conductivity than the first electrode 11. The first highly thermally conductive layer 21 is made of the same material as the first highly thermally conductive layer 20.

[0089] The insulating layer 31 covers the upper surface of the first high thermal conductive layer 21. The insulating layer 31 sandwiches the insulating layer 30 and the first high thermal conductive layer 21. The insulating layer 31 is made of the same material as the insulating layer 30.

[0090] The light-detecting element 101 according to the first modification has the first high thermal conductive layer 21, and therefore has the same effects as the light-detecting element 100.

[0091] (Second Modification) 7 is a cross-sectional view of a photodetector element 102 according to a second modified example. The photodetector element 102 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 22, insulating layers 30 and 31, and a substrate 40. In the second modified example, the same components as those in the first modified example are denoted by the same reference numerals, and a description thereof will be omitted.

[0092] When viewed from the z direction, the first highly thermal conductive layer 22 is located outside the first ferromagnetic layer 1. The first highly thermal conductive layer 22 differs from the first highly thermal conductive layer 21 according to the first modified example in that the first highly thermal conductive layer 22 is not in contact with the first electrode 11.

[0093] The light-detecting element 102 according to the second modification has the first high thermal conductive layer 22, and therefore has the same effects as the light-detecting element 100.

[0094] (Third Modification) 8 is a cross-sectional view of a photodetector element 103 according to a third modified example. The photodetector element 103 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 20, an insulating layer 30, a substrate 40, and a second high thermal conductive layer 50. In the third modified example, the same components as those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

[0095] The second highly thermally conductive layer 50 is in contact with the sidewall of the first electrode 11. The second highly thermally conductive layer 50, for example, surrounds the periphery of the first electrode 11. The second highly thermally conductive layer 50 has a higher thermal conductivity than the first electrode 11. The second highly thermally conductive layer 50 is in contact with, for example, the first highly thermally conductive layer 20. When the second highly thermally conductive layer 50 and the first highly thermally conductive layer 20 are in contact, heat is discharged from the first highly thermally conductive layer 20 toward the second highly thermally conductive layer 50, allowing heat to be efficiently dissipated from the magnetic element 10. The same material as the first highly thermally conductive layer 20 can be used for the second highly thermally conductive layer 50. The first highly thermally conductive layer 20 and the second highly thermally conductive layer 50 may be made of the same material or different materials.

[0096] The light-detecting element 103 according to the third modification has the first high thermal conductive layer 20, and therefore has the same effects as the light-detecting element 100. Furthermore, the light-detecting element 103 has the second high thermal conductive layer 50, and therefore has better heat dissipation properties.

[0097] (Fourth Modification) 9 is a cross-sectional view of a photodetector element 104 according to a fourth modified example. The photodetector element 104 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 23, an insulating layer 32, and a substrate 40. In the fourth modified example, the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0098] The first highly thermal conductive layer 23 is located outside the first ferromagnetic layer 1 when viewed in the z direction. The first highly thermal conductive layer 23 is in direct contact with the magnetic element 10. For example, the first highly thermal conductive layer 23 is in direct contact with at least a portion of the side surface of the first ferromagnetic layer 1. The first highly thermal conductive layer 23 surrounds the periphery of at least a portion of the magnetic element 10. For example, the first highly thermal conductive layer 23 surrounds the periphery of the first ferromagnetic layer 1 of the magnetic element 10.

[0099] The first highly thermally conductive layer 23 has a higher thermal conductivity than the first electrode 11. The first highly thermally conductive layer 23 is made of the same material as the first highly thermally conductive layer 20.

[0100] A portion of the insulating layer 32 is located between the magnetic element 10 and the first high thermal conductivity layer 23. The insulating layer 32 is made of the same material as the insulating layer 30. The insulating layer 32 covers at least a portion of the sidewall of the magnetic element 10 below the lower end 3U of the spacer layer 3. By having the insulating layer 32 cover the portion below the lower end 3U of the spacer layer 3, it is possible to prevent a short circuit between the first high thermal conductivity layer 23 and the second ferromagnetic layer 2 even if the first high thermal conductivity layer 23 is a conductor.

[0101] The photodetector element 104 according to the fourth modification has the first high thermal conductive layer 23, and therefore has the same effects as the photodetector element 100. Furthermore, the first high thermal conductive layer 23 is in direct contact with the first ferromagnetic layer 1, so that heat generated in the first ferromagnetic layer 1 can be dissipated more efficiently. Furthermore, when the first high thermal conductive layer 23 is a conductor, the insulating layer 32 prevents a short circuit between the first high thermal conductive layer 23 and the second ferromagnetic layer 2, thereby suppressing a deterioration in the magnetic properties of the magnetic element 10.

[0102] (Fifth Modification) 10 is a cross-sectional view of a light-detecting element 105 according to a fifth modified example. The light-detecting element 105 has, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 25, and a substrate 40. In the fifth modified example, the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0103] The first highly thermally conductive layer 25 is located outside the first ferromagnetic layer 1 when viewed in the z direction. The first highly thermally conductive layer 25 is in direct contact with the magnetic element 10. The first highly thermally conductive layer 25 surrounds the periphery of the magnetic element 10.

[0104] The first high thermal conductive layer 25 has a higher thermal conductivity than the first electrode 11. The first high thermal conductive layer 25 is an insulator. The thermal conductivity of the first high thermal conductive layer 25 is, for example, greater than 40 W / m·K. The first high thermal conductive layer 25 includes, for example, silicon carbide, aluminum nitride, or boron nitride.

[0105] The photodetector element 105 according to the fifth modification has the first high thermal conductivity layer 25, and therefore has the same effects as the photodetector element 100. Furthermore, the first high thermal conductivity layer 25 is insulating, and therefore can be in direct contact with the entire side surface of the magnetic element 10. As a result, the photodetector element 105 can efficiently dissipate heat from the magnetic element 10.

[0106] (Sixth Modification) 11 is a cross-sectional view of a photodetector 106 according to a sixth modified example. The photodetector 106 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductivity layer 26, a substrate 40, and a high resistivity layer 60. In the sixth modified example, the same components as those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

[0107] The first high thermal conductivity layer 26 is located outside the first ferromagnetic layer 1 when viewed in the z direction. The first high thermal conductivity layer 26 is in direct contact with the first ferromagnetic layer 1, for example. A high resistivity layer 60 may be present between the first high thermal conductivity layer 26 and the first ferromagnetic layer 1. The first high thermal conductivity layer 26 surrounds the periphery of the first ferromagnetic layer 1, for example.

[0108] The first high thermal conductive layer 26 has a higher thermal conductivity than the first electrode 11. The first high thermal conductive layer 26 is an insulator. The thermal conductivity of the first high thermal conductive layer 26 is, for example, greater than 40 W / m·K. The first high thermal conductive layer 26 includes, for example, silicon carbide, aluminum nitride, or boron nitride.

[0109] The high resistivity layer 60 is between the first high thermal conductivity layer 26 and the second electrode 12. A portion of the high resistivity layer 60 may be between the magnetic element 10 and the first high thermal conductivity layer 26. The high resistivity layer 60 has a higher resistivity than the first high thermal conductivity layer 26.

[0110] The high resistivity layer 60 is, for example, an insulator. The high resistivity layer 60 may be, for example, aluminum oxide (Al2O3), zirconium oxide (ZrO2), silicon oxide (SiO2), silicon nitride (Si3N4), forsterite (2MgO SiO2), yttrium oxide (Y2O3), aluminum nitride (AlN), or boron nitride (BN), although the material may vary depending on the material constituting the first high thermal conductivity layer 26.

[0111] For example, when the first high thermal conductivity layer 26 is silicon carbide (SiC), the high resistivity layer 60 is preferably aluminum oxide (Al2O3), zirconium oxide (ZrO2), silicon oxide (SiO2), silicon nitride (Si3N4), forsterite (2MgO·SiO2), yttrium oxide (YO3), aluminum nitride (AlN), or boron nitride (BN). For example, when the first high thermal conductivity layer 26 is aluminum nitride (AlN) or boron nitride (BN), the high resistivity layer 60 is preferably silicon oxide (SiO2).

[0112] The photodetector element 106 according to the sixth modification has the first high thermal conductivity layer 26, and therefore has the same effects as the photodetector element 100. Furthermore, by providing the high resistivity layer 60 between the first electrode 11 and the second electrode 12, the insulation between the first electrode 11 and the second electrode 12 can be improved.

[0113] (Seventh Modification) 12 is a cross-sectional view of a photodetector element 107 according to the seventh modification. The photodetector element 107 includes, for example, a magnetic element 10, a first electrode 11, a second electrode 12, a first high thermal conductive layer 26, a substrate 40, and a low dielectric constant layer 70. In the seventh modification, the same components as those in the sixth modification are denoted by the same reference numerals, and a description thereof will be omitted.

[0114] The low dielectric constant layer 70 is located between the first high thermal conductive layer 26 and the second electrode 12. A portion of the low dielectric constant layer 70 may be located between the magnetic element 10 and the first high thermal conductive layer 26. The low dielectric constant layer 70 has a lower dielectric constant than the first high thermal conductive layer 26.

[0115] The low dielectric constant layer 70 is, for example, an insulator. The low dielectric constant layer 70 may be, for example, silicon oxide (SiO), silicon nitride (SiN), forsterite (2MgO SiO), aluminum nitride (AlN), or boron nitride (BN), although this may vary depending on the material constituting the first high thermal conductive layer 26.

[0116] For example, when the first high thermal conductivity layer 26 is silicon carbide (SiC), the low dielectric constant layer 70 is preferably silicon oxide (SiO), silicon nitride (SiN), forsterite (2MgO·SiO), aluminum nitride (AlN), or boron nitride (BN). For example, when the first high thermal conductivity layer 26 is aluminum nitride (AlN), the low dielectric constant layer 70 is preferably silicon oxide (SiO), forsterite (2MgO·SiO), or boron nitride (BN). For example, when the first high thermal conductivity layer 26 is boron nitride (BN), the low dielectric constant layer 70 is preferably silicon oxide (SiO).

[0117] The photodetector 107 according to the seventh modification has the first high thermal conductivity layer 26, and therefore has the same effects as the photodetector 100. Furthermore, by providing the low dielectric constant layer 70 between the first electrode 11 and the second electrode 12, the capacitance between the first electrode 11 and the second electrode 12 can be reduced.

[0118] As described above, the present invention is not limited to the above-described embodiment and modifications, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims. For example, the characteristic features of the above-described embodiment and modifications may be combined.

[0119] The light-detecting elements according to the above-described embodiments and modifications can be applied to light sensor devices such as image sensors, transmitters and receivers in communication systems, and the like.

[0120] 13 is a block diagram of a transceiver 1000 according to the first application example. The transceiver 1000 includes a receiver 300 and a transmitter 400. The receiver 300 receives an optical signal L1, and the transmitter 400 transmits an optical signal L2.

[0121] The receiving device 300 includes, for example, a photodetector element 301 and a signal processing unit 302. The photodetector element 301 is any of the photodetector elements 100 to 107 according to the above-described embodiments or modifications. The photodetector element 301 converts an optical signal L1 into an electrical signal. The operation of the photodetector element 301 may be either the first operation example or the second operation example. The first ferromagnetic layer 1 of the photodetector element 301 is irradiated with light containing an optical signal L1 having a light intensity variation. A lens may be disposed on the first ferromagnetic layer 1 side in the stacking direction of the photodetector element 301, so that light that passes through the lens and is condensed is irradiated onto the first ferromagnetic layer 1. The lens may be formed during a wafer process for forming the photodetector element 301. Alternatively, light that passes through a waveguide may be irradiated onto the first ferromagnetic layer 1 of the photodetector element 301. The light irradiated onto the first ferromagnetic layer 1 of the photodetector element 301 is, for example, laser light. The signal processing unit 302 processes the electrical signal converted by the photodetector element 301. The signal processing unit 302 processes the electrical signal generated by the photodetector element 301 to receive the signal contained in the optical signal L1.

[0122] The transmitting device 400 includes, for example, a light source 401, an electric signal generating element 402, and an optical modulation element 403. The light source 401 is, for example, a laser element. The light source 401 may be external to the transmitting device 400. The electric signal generating element 402 generates an electric signal based on transmission information. The electric signal generating element 402 may be integrated with a signal conversion element of the signal processing unit 302. The optical modulation element 403 modulates the light output from the light source 401 based on the electric signal generated by the electric signal generating element 402, and outputs an optical signal L2.

[0123] Fig. 14 is a conceptual diagram of an example of a communication system. The communication system shown in Fig. 14 has two terminal devices 500. The terminal devices 500 are, for example, smartphones, tablets, personal computers, or the like.

[0124] Each of the terminal devices 500 includes a receiving device 300 and a transmitting device 400. An optical signal transmitted from the transmitting device 400 of one terminal device 500 is received by the receiving device 300 of the other terminal device 500. The light used for transmission and reception between the terminal devices 500 is, for example, visible light. The receiving device 300 has the above-mentioned photodetecting elements 100 to 107 as the photodetecting element 301. The above-mentioned photodetecting elements 100 to 107 have excellent heat dissipation properties, so the communication system shown in FIG. 14 is capable of high-speed communication.

[0125] 15 is a conceptual diagram of a cross section of an optical sensor device 2000 according to a second application example. The optical sensor device 2000 includes, for example, a circuit board 110, a wiring layer 120, and a plurality of optical sensors S. The wiring layer 120 and the plurality of optical sensors S are each formed on the circuit board 110.

[0126] Each of the multiple optical sensors S has, for example, a photodetector element 100, a wavelength filter F, and a lens R. While FIG. 15 shows an example in which the photodetector element 100 is used, photodetectors 101 to 106 may be used instead of the photodetector element 100. The photodetector element 100 is irradiated with light that has passed through the wavelength filter F. As described above, the photodetector element 100 converts the light irradiated onto the magnetic element 10 into an electrical signal. It is preferable that the photodetector element 100 operates in the second operation example.

[0127] The wavelength filter F selects light of a specific wavelength and transmits light of a specific wavelength range. The wavelength range of light transmitted by each wavelength filter F may be the same or different. For example, the optical sensor device 2000 may include an optical sensor S (hereinafter referred to as a blue sensor) having a wavelength filter F that transmits blue light (a wavelength range of 380 nm or more and less than 490 nm), an optical sensor S (hereinafter referred to as a green sensor) having a wavelength filter F that transmits green light (a wavelength range of 490 nm or more and less than 590 nm), and an optical sensor S (hereinafter referred to as a red sensor) having a wavelength filter F that transmits red light (a wavelength range of 590 nm or more and less than 800 nm). The blue sensor, the green sensor, and the red sensor form one pixel, and by arranging these pixels, the optical sensor device 2000 can be used as an image sensor.

[0128] The lens R focuses the light toward the magnetic element 10. In the optical sensor S shown in FIG. 15, one photodetector element 100 is arranged below one wavelength filter F, but multiple photodetector elements 100 may be arranged below one wavelength filter F.

[0129] The circuit board 110 has, for example, an analog-to-digital converter 111 and an output terminal 112. The electrical signal sent from the optical sensor S is converted into digital data by the analog-to-digital converter 111 and output from the output terminal 112.

[0130] The wiring layer 120 has a plurality of wirings 121. Interlayer insulating films 122 are present between the plurality of wirings 121. The wirings 121 electrically connect each of the optical sensors S to the circuit board 110 and between each of the arithmetic circuits formed on the circuit board 110. Each of the optical sensors S and the circuit board 110 are connected via, for example, through-wiring that penetrates the interlayer insulating film 122 in the z direction. Noise can be reduced by shortening the distance between the wirings between each of the optical sensors S and the circuit board 110.

[0131] The wiring 121 is conductive. The wiring 121 is made of, for example, Al, Cu, or the like. The interlayer insulating film 122 is an insulator that insulates between wirings in a multilayer wiring or between elements. The interlayer insulating film 122 is made of, for example, an oxide, nitride, or oxynitride of Si, Al, or Mg. The interlayer insulating film 122 is made of, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride, silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO x ) etc.

[0132] The optical sensor device 2000 described above can be used in, for example, a terminal device. FIG. 16 is a schematic diagram of an example of a terminal device 600. The left side of FIG. 16 is the front side of the terminal device 600, and the right side of FIG. 16 is the back side of the terminal device 600. The terminal device 600 has a camera CA. The optical sensor device 2000 described above can be used as an imaging element of this camera CA. In FIG. 16, a smartphone is shown as an example of the terminal device 600, but this is not limiting. The terminal device 600 can be, for example, a tablet, a personal computer, a digital camera, etc., in addition to a smartphone. [Explanation of symbols]

[0133] 1...first ferromagnetic layer, 2...second ferromagnetic layer, 3...spacer layer, 3U...lower end, 4...cap layer, 10...magnetic element, 11...first electrode, 12...second electrode, 20, 21, 22, 23, 25, 26...first high thermal conductive layer, 30, 31, 32...insulating layer, 40...substrate, 50...second high thermal conductive layer, 60...high resistivity layer, 70...low dielectric constant layer, 100, 101, 102, 103, 104, 105, 106, 107...photodetector element, 110...circuit board, 111...analog-to-digital converter, 112...output terminal, 120...wiring layer, 121...wiring, 122...interlayer insulating layer, 300...receiving device, 301...photodetecting element, 302...signal processing unit, 400...transmitting device, 401...light source, 402...electrical signal generating element, 403...light modulation element, 500, 600...terminal device, 1000...transmitting / receiving device, 2000...optical sensor device, CA...camera, F...wavelength filter, R...lens, S...optical sensor

Claims

1. a magnetic element including a first ferromagnetic layer irradiated with light, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer; a first electrode in contact with a first surface on the side of the first ferromagnetic layer in the stacking direction of the magnetic element, and a second electrode in contact with a second surface on the opposite side to the first surface; a first high thermal conductive layer surrounding the first ferromagnetic layer and having a thermal conductivity higher than that of the first electrode.

2. The light-sensing element according to claim 1 , wherein the first electrode comprises an oxide that is transparent to the light.

3. The light-detecting element according to claim 1 , wherein the first high-thermal-conductivity layer is made of a non-magnetic material.

4. 4. The light-detecting element according to claim 1, wherein the first highly thermally conductive layer is in contact with the first ferromagnetic layer.

5. 5. The light-detecting element according to claim 1, wherein the first highly thermally conductive layer is in contact with the first electrode.

6. Further comprising a second high thermal conductive layer; the second high thermal conductive layer is in contact with a side wall of the first electrode, 6. The light-detecting element according to claim 1, wherein the second highly thermally conductive layer has a thermal conductivity higher than that of the first electrode.

7. The light-sensing element of claim 6 , wherein the first high thermal conductivity layer is in contact with the second high thermal conductivity layer.

8. The photodetector element according to any one of claims 1 to 7, wherein the first high thermal conductivity layer is a metal.

9. The light-sensing element of claim 8 , wherein the first high thermal conductivity layer comprises copper, gold, or silver.

10. further comprising an insulating layer; 10. The light-detecting element according to claim 1, wherein the insulating layer covers at least a portion of the sidewall of the magnetic element below a lower end of the spacer layer on the second ferromagnetic layer side.

11. The light-detecting element according to any one of claims 1 to 7, wherein the first highly thermally conductive layer is an insulator.

12. The light-sensing element of claim 11 , wherein the thermal conductivity of the first high-thermal-conductivity layer is greater than 40 W / m·K.

13. 13. The photo-sensing element according to claim 11 or 12, wherein the first high thermal conductivity layer comprises silicon carbide, aluminum nitride or boron nitride.

14. a high resistivity layer between the first high thermal conductivity layer and the second electrode; The light-sensing element according to any one of claims 11 to 13, wherein the high resistivity layer has a resistivity higher than that of the first high thermal conductivity layer.

15. a low dielectric constant layer between the first high thermal conductive layer and the second electrode; The light-detecting element according to any one of claims 11 to 14, wherein the low-dielectric-constant layer has a lower dielectric constant than the first high-thermal-conductivity layer.

16. A receiving device comprising a photodetector element according to any one of claims 1 to 15.

17. An optical sensor device comprising a photodetector element according to any one of claims 1 to 15.

Images