JP6409457B2 - Semiconductor light emitting element and light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting element and a light emitting device.

  Conventionally, in a group III nitride compound semiconductor light emitting device in which a reflective layer such as aluminum or silver is formed on the back surface of a substrate, a part of the reflective layer is part of a side wall of the light emitting device in view of the problem of the reflective layer peeling off from the substrate. (For example, patent document 1 etc.) is proposed.

JP 2001-332762 A

  However, although silver is a metal having the highest reflectance in the visible wavelength region, the metal state is chemically stable, so that it is difficult to obtain adhesion with a substrate such as an oxide. Even so, there was still room for improvement in the adhesion between the silver reflective layer and the substrate.

  The present invention has been made in view of the above problems, and can obtain light emission characteristics comparable to those of pure silver (however, “pure” is used in a practical sense; the same applies to the following), and has good adhesion to a substrate. Another object of the present invention is to provide a semiconductor light emitting device in which a reflective layer mainly composed of silver is formed on the back surface of a substrate and / or a light emitting device using the same.

The present invention includes the following inventions.
(1) a translucent substrate comprising a first main surface and a second main surface opposite to the first main surface;
A semiconductor light emitting structure formed on the first main surface;
A reflective layer mainly composed of silver formed on the second main surface,
The reflective layer includes one or more metals selected from In, Mn, Al, Cu, Au, Sn, Zn, Ge, and Co in a range of 0.1 mol% to 1 mol%, and the metal is made of the silver. A semiconductor light emitting device segregated at a grain boundary.
(2) the semiconductor light emitting device;
And a conductive member on which the semiconductor light emitting element is mounted.

  According to the present invention, in the reflective layer mainly composed of silver formed on the back surface of the substrate, it is possible to obtain the same light emission characteristics as in the case of pure silver, and to effectively suppress peeling from the substrate. A semiconductor light emitting device that can be obtained is obtained. Thereby, a light emitting device with high luminous flux and high reliability can be obtained.

It is sectional drawing which shows one Embodiment of the semiconductor light-emitting device of this invention. It is sectional drawing which shows one Embodiment of the light-emitting device of this invention. It is a graph which shows the improvement of the luminous efficiency of the light-emitting device of this invention.

  In the present specification, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention to that unless otherwise specified. It is just an illustrative example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Moreover, in the following description, the same name and code | symbol have shown the same or the same member, and detailed description is abbreviate | omitted suitably.

(Semiconductor light emitting device)
A semiconductor light emitting element (hereinafter sometimes simply referred to as “light emitting element”) mainly includes a translucent substrate, a semiconductor light emitting structure, and a reflective layer.
The light-transmitting substrate may be any material that is usually used when manufacturing a semiconductor light emitting device, and includes a material having a refractive index different from that of the semiconductor layer, for example, a material different from the semiconductor layer or a material having a different composition. It is done. The translucent substrate includes a first main surface and a second main surface opposite to the first main surface. Hereinafter, the first main surface may be referred to as the upper surface and the second main surface as the back surface. Specifically, a sapphire (C-plane, A-plane, R-plane), spinel (MgAl ₂ O ₄ ), SiC, NGO (NdGaO ₃ ) substrate suitable as a substrate for a semiconductor light emitting device using a nitride semiconductor, Examples include a LiAlO ₂ substrate, a LiGaO ₃ substrate, and GaN. Of these, a sapphire substrate is preferable. Although the thickness of a translucent board | substrate is not specifically limited, For example, the thickness of about 50-1000 micrometers is mentioned, About 80-500 micrometers is preferable and it is preferable that it is about 100-300 micrometers.
Here, translucency refers to the property of transmitting 50% or more of light emitted from the light emitting element, preferably transmitting 70% or more, more preferably transmitting 80% or more, and transmitting 90% or more. It is even more preferable that

The semiconductor light emitting structure is formed on one surface (first main surface) of the above-described translucent substrate.
Any semiconductor light emitting structure may be used as long as it constitutes an element called a light emitting diode. For example, a laminated structure including an active layer composed of various semiconductors such as nitride semiconductors such as InN, AlN, GaN, InGaN, AlGaN, and InGaAlN, III-V group compound semiconductors, II-VI group compound semiconductors, and the like. It is done. The emission wavelength of the light-emitting element can be changed from the ultraviolet region to the red region depending on the semiconductor material, the mixed crystal ratio, the type of impurities to be doped, and the like.

  The shape of the light-emitting element is determined by the light-transmitting substrate and the semiconductor light-emitting structure, but is not particularly limited. For example, the planar shape viewed from the light extraction side is suitably a polygon or a shape approximating this, and more preferably a quadrangle, rectangle, square or a shape approximating these.

  The light emitting element usually includes an n electrode and a p electrode. A single-sided electrode in which an n-electrode and a p-electrode are formed on the same side with respect to the translucent substrate, or a double-sided electrode in which the n-electrode or p-electrode is formed on the back surface of the translucent substrate It may be. Among these, when the translucent substrate is electrically insulating, a single-sided electrode is preferable, and when the translucent substrate is conductive, a double-sided electrode is preferable.

  Examples of the n electrode and the p electrode include a single layer or a laminated structure of a metal such as W, Pt, or Au and an alloy thereof. Further, a light-transmitting conductive material such as ITO or ZnO may be used. Moreover, it is good also as a laminated structure of what is called an ohmic electrode and a pad electrode. The thickness of these electrodes is not particularly limited.

The reflective layer is formed on a surface (second main surface) opposite to the stacked surface of the semiconductor light emitting structure of the translucent substrate. The reflective layer is a layer for reflecting the light emitted from the semiconductor light emitting structure and transmitted through the translucent substrate to the semiconductor light emitting structure side (upward). Therefore, it is preferable to use a material having a high reflectivity for the light emitted from the semiconductor light emitting structure as the reflective layer. Therefore, silver is used as the main component of the reflective layer.
However, silver is coarsened at the interface with the translucent substrate due to thermal history in the manufacturing process of the light emitting device, stress due to a difference in linear expansion coefficient from the translucent substrate (for example, sapphire substrate), and the like. It is easy, and due to this, the adhesion between the two is reduced. In addition, due to the coarsening of silver, light is absorbed by multiple scattering at the interface with the translucent substrate, leading to a decrease in interface reflectance, resulting in a decrease in luminous efficiency of the light emitting element. .

Therefore, the reflective layer is one or more metals selected from In, Mn, Al, Cu, Au, Sn, Zn, Ge, and Co (hereinafter sometimes referred to as “metal M _SEL ”) in the silver layer. It is preferable to use a metal whose metal is segregated at the grain boundary of silver. The metal M _SEL that segregates at the silver crystal grain boundaries may be at least part of the metal M _SEL included in the reflective layer. From another point of view, the metal _MSEL contained in the silver layer has a large diffusion coefficient into silver, and particularly a metal _MSEL with a larger diffusion coefficient into silver than silver easily segregates at the grain boundaries of silver. ,preferable. For example, the diffusion coefficient into silver is preferably about 1 × 10 ⁻³³ m ² / s or more, and more preferably about 1 × 10 ⁻²⁹ m ² / s or more. Of these, one or more metals selected from In, Mn, Al, Cu, and Au are preferable, and one or more metals selected from In, Mn, and Al are more preferable. In addition, the average particle diameter of silver in the reflective layer is preferably 50 nm or more and 1.0 μm or less, and more preferably 50 nm or more and 0.5 μm or less from the viewpoint of reflectance. The reflective layer is preferably formed on substantially the entire second main surface of the translucent substrate, but a part of the second main surface of the translucent substrate (for example, excluding the peripheral portion of the second main surface). It may be formed over the entire region.

Wherein the amount of metal _{M SEL} contained in the reflective layer include the following about 1 mol%, preferably from 0.1 mol% to 1 mol%, more preferably 0.1mol% ~0.9mol%, 0.1mol% -0.8 mol% is more preferable. As described above, the metal _MSEL contained in the reflective layer is easily segregated at the crystal grain boundaries of silver, and the heat history in the manufacturing process of the light emitting device, or the heat generated when the light emitting element is driven, the stress caused by them, etc. As a result, the segregation of silver to the crystal grain boundaries further proceeds, whereby the coarsening of silver can be effectively suppressed. As a result, it is possible to suppress a decrease in adhesion between the reflective layer and the translucent substrate. Moreover, since the light absorption by the multiple scattering mentioned above can be reduced, the fall of interface reflectance can be suppressed and the fall of the luminous efficiency of a light emitting element can be suppressed effectively. Furthermore, the inclusion of such a small amount of different metals can suppress the influence on the original reflectance of the silver layer to be small, so that the high reflectance inherent in the reflective layer can be maintained.
The thickness of the reflective layer is not particularly limited, but from the viewpoint of light emitting characteristics and mass productivity of the light emitting element, for example, a range of about 20 nm to 1 μm is mentioned, preferably about 50 nm to 500 nm, and preferably about 100 nm to 300 nm. More preferred.

Reflective layer, the metal M _SEL is contained in the silver layer in an amount described above, and if the metal M _SEL is long segregated in the grain boundary of the silver can be formed by methods known in the art.
Specifically, after the silver layer is formed by various methods such as plating, vapor deposition, sputtering, ion beam assisted vapor deposition ALD (atomic layer deposition), the layer containing the metal _MSEL is similarly applied. After laminating and thermally diffusing by the above method, the silver layer is formed by various methods such as plating, vapor deposition, sputtering, ion beam assisted vapor deposition, etc., and then the metal _MSEL itself is diffused by the same method. And a method of simultaneously forming a film by these methods by adjusting the kind and amount of the material so that the composition is within the above-described range.

The light emitting element preferably has an isolation layer on the surface of the reflective layer opposite to the light transmissive substrate. The isolation layer isolates the bonding member for bonding to the conductive member, which will be described later, and the reflective layer, and the elements constituting the bonding member are deposited through the reflective layer at the interface between the reflective layer and the translucent substrate. It is a layer for suppressing it.
The isolation layer is preferably formed of a material having high adhesion to the reflective layer. For example, single layer or laminated structure of Ni, Rh, and these alloys are mentioned.
The thickness of the isolation layer is not particularly limited, and is preferably set to a thickness that can perform the above-described function. For example, the range of about 50 nm-2 micrometers is mentioned, About 100 nm-1 micrometer are preferable, About 200 nm-500 nm are more preferable.

It is preferable that the light emitting element further has an adhesive layer on the surface of the isolation layer opposite to the reflective layer. The adhesive layer is a layer for adhering the light emitting element to a conductive member described later.
As the adhesive layer, it is preferable to use a metal-containing material such as copper, gold, silver, or a low-melting-point metal, for example, Pd—Sn, Au—Sn, etc. having a low melting point and good stability, and more preferably Au—Sn. preferable.
Although the thickness of an adhesive layer is not specifically limited, For example, the range of about 100 nm-10 micrometers is mentioned, About 200 nm-7 micrometers are preferable, About 500 nm-5 micrometers are more preferable.

(Light emitting device)
The light emitting device mainly includes the above-described light emitting element and a conductive member. Further, the light emitting device preferably further includes a resin molded body.

The light emitting element is mounted on the conductive member, and is preferably further electrically connected to the conductive member.
When the light-emitting element has the above-described single-sided electrode structure, face-up (the electrode formation surface is on the light extraction side), flip chip (face-down; the electrode formation surface is opposite to the light extraction side (mounting surface side) It may be mounted in any form.
The light-emitting element can be mounted on the conductive member by a method known in the art. Usually, it is preferable to mount the light emitting element using a bonding member from the viewpoint of productivity.
As the bonding member, in the case of a light-emitting element mounted face-up, a conductive paste such as silver, gold, palladium, etc. can be used in addition to a resin material such as an epoxy resin or a silicone resin.
In the case of a light emitting device having a double-sided electrode structure, in addition to the above conductive paste, Sn—Bi, Sn—Pb, Pd—Sn, Sn—Ag—Cu, Au—Sn, Sn—Zn Su-Cu solder or the like may be used.
In the case of a light emitting element mounted on a flip chip, the above solder can be used.
In addition, the silver of the reflective layer or the adhesive layer of the light-emitting element and the silver on the conductive member side can be directly bonded.

  In particular, the light emitting element preferably has a single-sided electrode configuration, and the light emitting element is preferably mounted face up on the conductive member.

  The conductive member mounts the semiconductor light emitting element, and is preferably further electrically connected to the semiconductor light emitting element. Therefore, the conductive member may have any material and structure as long as it has conductivity. The conductive member may be made of, for example, a conductive material called a so-called lead frame, and a conductive layer is provided on the surface of the insulating base (for example, plastic, ceramics, glass, etc.) and / or in the base. It may be a so-called mounting substrate formed. The lead frame may be in the form of a rod for a bullet-type LED (with a cup portion) in addition to a plate shape.

The conductive member is preferably made of a metal having a linear expansion coefficient larger than that of the translucent substrate.
For example, a single-layer structure or a stacked structure using a metal or alloy such as copper, aluminum, gold, silver, tungsten, iron, or nickel, or an iron-nickel alloy, phosphor bronze, iron-containing copper, or the like can be used. Especially, what contains 1 or more types of copper, silver, and gold | metal | money is preferable.

The conductive member is preferably a metal having a linear expansion coefficient of, for example, about 15 to 20 ppm, and more preferably a metal having a linear expansion coefficient of about 16 to 18 ppm. Among them, the conductive member is preferably made of a metal having a linear expansion coefficient larger than that of the light-transmitting substrate, and a metal having a linear expansion coefficient that is twice or more that of the light-transmitting substrate. Is preferred.
From another viewpoint, in consideration of light reflection from the conductive member, it is preferable that the surface of the conductive member contains silver or a silver alloy.

  The thickness and shape of the conductive member are not particularly limited, and the thickness and shape can be appropriately set within a range known in the art.

Any method known in the art may be used for the electrical connection between the light emitting element and the conductive member. For example, it can be electrically connected using a wire.
The wire preferably has good ohmic properties with the electrode of the light emitting element, good mechanical connectivity, or good electrical and thermal conductivity. The thermal conductivity, preferably ^{0.01cal / S · cm 2 · ℃} / than about cm further ^{0.5cal / S · cm 2 · ℃} / cm or higher order is more preferable. In consideration of workability and the like, the diameter of the wire is about 10 to 200 μm, and preferably about 20 to 150 μm. Examples of such wires include those formed of metals such as gold, copper, platinum, and aluminum, and alloys thereof.

  It is preferable that the light emitting device includes a resin molded body that has a recess for housing the light emitting element, exposes a part of the conductive member at the bottom surface of the recess, and embeds a part of the conductive member. This resin molded body may be an insulating base that constitutes the mounting substrate described above, and when the conductive member is constituted by a so-called lead frame, it is referred to as a so-called resin package or a sealing member. It may be a member. Thus, the resin molded body can function as an optical member that adjusts the light emission intensity distribution while accommodating a part of the light emitting element and the conductive member.

The resin molded body only needs to embed a part of the conductive member and preferably cover it integrally or in a lump shape to ensure electrical insulation with respect to the light emitting element or the like. For example, thermosetting resins such as silicone resins, silicone modified resins, epoxy resins, epoxy modified resins, phenol resins, acrylic resins, polyimides, BT resins, unsaturated polyester resins, or polyphthalamide (PPA), liquid crystal polymers (LCP) ), A thermoplastic resin such as a polycarbonate resin or polycyclohexane terephthalate. These materials may contain a colorant, a light diffusing agent, a filler, a reinforcing fiber, a phosphor described later, and the like known in the art. Among them, it is preferable to use a material having a good reflectance, and therefore, it is preferable to use a material to which a white colorant such as titanium oxide is added.
The shape of the resin molded body is not particularly limited, and may be any shape such as a cylinder, an elliptical column, a sphere, an oval, a triangular column, a quadrangular column, a polygonal column, or a shape similar to these. It is preferable to provide a side wall.

The resin molded body has a recess for accommodating the light emitting element, and the recess serves as a reflection side wall to reflect light emitted from the light emitting element placed on the conductive member to the light extraction surface side. . The concave portion has a shape that becomes wider from the light emitting element mounting surface (upper surface of the conductive member) toward the upper surface (light extraction surface) side of the resin molded body, that is, the plane area on the bottom surface side is larger than the plane area on the upper surface side. A small truncated cone or truncated pyramid and a shape similar to these are preferable.
The sizes of the resin molded body and the recess are not particularly limited, and can be appropriately adjusted depending on the number of mounted light emitting elements, the performance of the target light emitting device, and the like.
The resin molded body can be formed using a method known in the art, typically a transfer molding method, an injection molding method, or the like.

In the light-emitting device, it is preferable that a light-transmitting member covering a part of the light-emitting element and the conductive member is filled in the concave portion of the resin molded body.
The translucent member is substantially in contact with the entire surface of the upper surface of the light emitting element, preferably the wire connecting portion when a wire or the like is present, and more preferably the side surface of the light emitting element. It is preferable that they are arranged.
The translucent member is usually formed of a resin. As the resin here, a thermosetting resin can be preferably used. Examples thereof include epoxy resins, phenol resins, silicone resins, acrylic resins, and modified resins thereof. Among these, a silicone resin or a modified resin thereof is preferable because it is excellent in heat resistance and light resistance and has little volume shrinkage after curing.

The translucent member may contain a diffusing agent, a phosphor, and the like. The diffusing agent diffuses light, can reduce the directivity of light from the light emitting element, and can increase the viewing angle. For example, silica, alumina, titanium oxide and the like can be mentioned.
The phosphor converts light from the light emitting element, and can convert the wavelength of light emitted from the light emitting element to the outside through the translucent member. For example, perylene derivatives that are organic phosphors, ZnCdS: Cu, YAG: Ce, Eu, and / or nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ activated by Cr, Si _6-Z Al activated by Eu _Z O _Z N _8-Z , inorganic phosphors such as K ₂ SiF ₆ activated with Mn, and the like are suitably used.

  In addition to the light emitting element, the light emitting device may include one or more protection elements (for example, a Zener diode and a capacitor) that protect the light receiving elements, the semiconductor elements such as the light emitting elements and the light receiving elements from overvoltage.

  Hereinafter, a light-emitting element and a light-emitting device of the present invention will be described with reference to the drawings. However, it is not limited to the embodiment shown below.

Embodiment 1
As shown in FIG. 1, the light emitting device 20 of this embodiment includes a translucent substrate 1, an n-type nitride semiconductor layer 2 constituting a semiconductor light emitting structure, an active layer 3 containing InGaN, and a p-type nitride semiconductor layer. 4 and a reflective layer 8.
The translucent substrate 1 is a sapphire substrate.
In the region for forming the n-side electrode 5 of the semiconductor light emitting structure, the p-type nitride semiconductor layer 4, the active layer 3, and the n-type nitride semiconductor layer 2 are partially removed, and the exposed n-type nitride semiconductor is exposed. An n-side electrode 5 is formed on the layer 2. On the p-type nitride semiconductor layer 4, a translucent p-side full-surface electrode 6 made of ITO is formed on substantially the entire surface, and a p-side pad electrode 7 is formed on a part of the p-side full-surface electrode 6. Is formed.

The reflective layer 8 formed on substantially the entire surface of the back surface of the transparent substrate 1 is a Ag layer containing 0.4 mol% of In as the metal _{M SEL.} In the reflective layer 8, In is segregated at the Ag grain boundaries. Such a reflective layer 8 can be formed by, for example, using a sputtering method and placing an In piece on an Ag target. The thickness of the reflective layer 8 here is 120 nm. In addition, content of metal _MSEL in a reflection layer is obtained by SEM-EDX.
Further, an isolation layer 9 in which a single layer film of Ni and Rh is laminated is disposed on the reflective layer 8. The thickness of the isolation layer 9 here is 300 nm.
Further, an Au—Sn adhesive layer 10 is disposed on the isolation layer 9. The thickness of the adhesive layer here is 3.5 μm.

The reflective layer 8 has a structure similar to that of the light-emitting element 20 of Embodiment 1 except that the reflective layer 8 includes 0.6 mol% of Mn instead of In and the Mn is segregated at the Ag crystal grain boundary. Element 21 is fabricated.
Furthermore, the reflective layer 8 has a structure similar to that of the light-emitting element 20 of Embodiment 1 except that the reflective layer 8 includes 0.5 mol% of Al instead of In, and the Al is segregated at the Ag grain boundaries. Element 22 is produced.
Furthermore, the reflective layer 8 has a structure similar to that of the light-emitting element 20 of the first embodiment except that the reflective layer 8 includes a layer containing 0.4 mol% of Cu instead of In, and the Cu is segregated at the grain boundary of Ag. Element 23 is produced.
For comparison, a light-emitting element X having the same configuration as that of the light-emitting element 20 of Embodiment 1 is manufactured except that the reflective layer 8 includes a reflective layer formed of pure silver that does not contain a different metal. To do.

Embodiment 2
As shown in FIG. 2, the light emitting device 30 according to this embodiment includes the light emitting element 20 according to the first embodiment, a conductive member 11 that is a copper alloy lead frame that has been subjected to Ag plating surface treatment, and one of the conductive members 11. And a resin molded body 12 of a titanium oxide-containing epoxy resin in which a portion is embedded and a part is exposed at the bottom surface of the recess.
The resin molded body is formed by sandwiching the conductive member 11 between upper and lower molds and subjecting it to a transfer molding method.
The light emitting element 20 is formed on the upper surface of the resin molded body 12, and is mounted on the conductive member 11 exposed on the bottom surface of the recess in the recess defined by the reflecting side wall 12a (six). The light-emitting element 20 is mounted on the conductive member 11 by placing the above-described light-emitting element 20 (on the adhesive layer 10 side) on the conductive member 11 via an Au—Sn solder joint member. It is made by joining and fixing by reflow at an ultimate temperature of 330 ° C.
The light emitting element 20 is electrically connected to the conductive member 11 by a wire made of a gold wire.
The concave portion of the resin molded body 12 is further filled with a light-emitting element 20 and a translucent member 14 that covers the conductive member 11 exposed in the concave portion.
The translucent member 14 is made of a silicone resin containing a YAG: Ce phosphor.

For the light-emitting elements 21, 22, and 23 described above, light-emitting devices 31, 32, and 33 each having the same configuration as that of the second embodiment are manufactured.
For the light-emitting element X described above, a light-emitting device Y having the same configuration as that of Embodiment 2 is manufactured.

(Measurement of initial luminous flux)
With respect to the light emitting devices 30, 31, 32 and 33 of the second embodiment and the light emitting device Y which is a comparative example, light flux measurement using an integrating sphere is performed. Measurement conditions are a 10 inch integrating sphere, pulse current drive (maximum 700 mA, pw / pe = 0.05 / 5 ms).
The result is shown in FIG.
In this result, the luminous flux of the light emitting devices 30, 31, 32, and 33 of the second embodiment is shown with the luminous flux of the light emitting device Y of the comparative example as 100.
It is confirmed that the light emitting device of the embodiment can obtain a luminous flux equivalent to or higher than that of the light emitting device Y of the comparative example.

  From this result, it is confirmed that the dissimilar metal segregates at the Ag crystal grain boundary of the reflective layer, so that the decrease in the luminous flux due to the thermal history in the manufacturing process of the light emitting device can be suppressed.

(Interface observation)
After the light-emitting elements 20, 21, 22, 23, and X described above are exposed to a thermal cycle of −40 ° C. to 100 ° C., the state change at the interface between the light-transmitting substrate and the reflective layer is visually observed from the light-transmitting substrate side. Observe by. Then, in the light emitting element X, it is confirmed that the diffusion of Au—Sn proceeds from the corner every time the number is repeated 109 times, 269 times, whereas in the light emitting elements 20, 21, 22, and 23, Such progress of Au—Sn diffusion is not observed.

  From this result, it is confirmed that the diffusion of Au—Sn to the Ag of the reflective layer is suppressed by the segregation of the dissimilar metal at the Ag crystal grain boundary of the reflective layer. In addition, it is considered that a decrease in reflectance of the reflective layer can be suppressed, and as a result, a decrease in luminous flux of the light emitting device can be suppressed.

(Surface observation)
An Ag layer containing the same metal (content is shown in the table below) as the light-emitting elements 20, 21, 22, 23 and X described above has a thickness of about 1 μm and a slide glass (having a Ti layer having a thickness of about 100 nm on the surface). The surface state before and after heating is observed by SEM. Heating is performed in air at 250 ° C. for 2 hours. Moreover, the reflectance with respect to the light of wavelength 450nm is measured by Hitachi High Technology spectrophotometer U-3010. Further, the average particle diameter and Ra are measured with a scanning laser microscope LEXT OLS3000 manufactured by Olympus.
The results are shown in Table 1.

From this result, it is confirmed that the coarsening of the silver due to the thermal history can be suppressed by the segregation of the dissimilar metal at the grain boundary of Ag. Moreover, it is confirmed that the fall of the reflectance of Ag by a heat history can be suppressed.
It is considered that the adhesion and adhesion with the layer bonded to the surface of the reflective layer can be maintained and improved by suppressing such silver coarsening.

(Evaluation of thermal resistance)
The occurrence of peeling of the reflective layer can be confirmed by the behavior of ΔVf (change in forward voltage) having a correlation with the thermal resistance. Therefore, the light emitting devices 30, 31, 32, 33 and Y are exposed to −40 ° C. to 125 ° C. and 1540 thermal cycles, and ΔVf before and after that is measured. Then, a large change in ΔVf is confirmed in the light emitting device Y, whereas a large change in ΔVf is not recognized in the light emitting devices 30, 31, 32, and 33. In particular, a remarkable advantage is confirmed in the light emitting device 32 on which the light emitting element 22 having the Ag layer containing Al as a reflective layer is mounted.

  From this result, it is confirmed that the occurrence of peeling of the reflective layer due to thermal history can be suppressed by the segregation of different metals at the Ag crystal grain boundaries of the reflective layer.

  The light-emitting device of the present invention is a variety of light-emitting devices, particularly backlight light sources such as illumination light sources, LED displays, and liquid crystal display devices, traffic lights, illumination switches, various sensors and various indicators, video illumination auxiliary light sources, and other general light sources. It can be suitably used for light sources for consumer products.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 2 N type nitride layer semiconductor layer 3 Active layer 4 N type nitride layer semiconductor layer 5 N side electrode 6 P side whole surface electrode 7 P side pad electrode 8 Reflective layer 9 Isolation layer 10 Adhesive layer 20 Light emitting element DESCRIPTION OF SYMBOLS 11 Conductive member 12 Resin molding 12a Side wall for reflection 13 Wire 14 Translucent member

Claims (9)

A translucent substrate comprising a first main surface and a second main surface opposite to the first main surface;
A semiconductor light emitting structure formed on the first main surface;
Equipped with a reflective layer containing silver as a main component formed on said second main surface,
The average particle diameter of the silver in the reflective layer is 50 nm or more and 1.0 μm or less,
The reflective layer includes one or more metals selected from In, Mn, Al, Cu, Au, Sn, Zn, Ge, and Co in a range of 0.1 mol% to 1 mol%, and the metal is made of the silver. A semiconductor light emitting device characterized by being segregated at a grain boundary.   2. The semiconductor light emitting device according to claim 1, further comprising: a single layer of Ni, Ni alloy, Rh, or Rh alloy, or an isolation layer made of a stacked structure thereof on a surface of the reflective layer opposite to the translucent substrate. element.   3. The semiconductor light emitting element according to claim 2, further comprising an Au—Sn or Pd—Sn adhesive layer on a surface of the isolation layer opposite to the reflective layer.   The semiconductor light-emitting element according to claim 1, wherein the translucent substrate is a sapphire substrate. A semiconductor light emitting device according to any one of claims 1 to 4,
The light emitting device characterized in that it comprises a conductive member mounted said semiconductor light emitting element.   The light emitting device according to claim 5, wherein the conductive member is made of a metal having a linear expansion coefficient larger than that of the translucent substrate.   The light emitting device according to claim 6, wherein a linear expansion coefficient of the conductive member is twice or more a linear expansion coefficient of the translucent substrate.   8. The resin molded body according to claim 5, further comprising: a resin molded body that has a recess for accommodating the semiconductor light emitting element, exposes a part of the conductive member at a bottom surface of the recess, and embeds a part of the conductive member. The light emitting device according to one.   The light emitting device according to claim 8, wherein a translucent member that covers a part of the semiconductor light emitting element and the conductive member is filled in the concave portion of the resin molded body.