JP5298927B2 - Light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element for enhancing light emitting output. <P>SOLUTION: The light-emitting element 1 includes: a semiconductor laminated structure 10 which includes a first semiconductor layer, a second semiconductor layer, and an active layer 105 sandwiched between the first semiconductor layer and the second semiconductor layer; a surface electrode 110 which includes a center electrode provided on one surface of the semiconductor laminated structure 10 and a thin wire electrode extending from the periphery of the center electrode; and a contact portion 120 which is provided in a portion, excluding a portion located directly below the surface electrode 110, on another surface of the semiconductor laminated structure 10 so as to be in parallel with the thin wire electrode and includes multiple first regions forming a first current pathway that is the shortest current pathway from the thin wire electrode and a second region connecting the multiple first regions. The shortest current pathway between the surface electrode 110 and the contact portion 120 is the first current pathway. The percentage of the first current pathway is greater than that of a second current pathway that is a current pathway, excluding the first current pathway, between the surface electrode 110 and the contact portion 120. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a light emitting element. In particular, the present invention relates to a light emitting element having a high light emission output.

  Conventionally, a silicon support substrate having an anode electrode on one surface, a metal reflection layer provided on the other surface of the silicon support substrate, a light transmission film provided on the metal reflection layer and in ohmic contact with the metal reflection layer, A semiconductor stacked structure having an active layer sandwiched between a p-type semiconductor layer and an n-type semiconductor layer provided on the light transmitting film and in ohmic contact with the light transmitting film, and a cathode electrode provided on the semiconductor stacked structure A light-emitting element provided is known (for example, see Patent Document 1).

  In the light emitting device described in Patent Document 1, a light-transmitting film having conductivity is disposed between a semiconductor multilayer structure and a metal reflective layer, and is in ohmic contact with both the semiconductor multilayer structure and the metal reflective layer. Since the light-transmitting film suppresses alloying between the structure and the metal reflection layer, a metal reflection layer having excellent light reflection characteristics can be formed, and a light-emitting element with improved luminous efficiency can be provided. it can.

JP 2005-175462 A

  However, in the light emitting device described in Patent Document 1, a current of the same level as that of the active layer in the region except for the region directly under the cathode electrode is supplied to the active layer directly under the cathode electrode. The absorbed light is absorbed by the cathode electrode, and there is a limit to improving the light emission output of the light emitting element.

  Accordingly, an object of the present invention is to provide a light emitting device capable of improving the light emission output.

In order to achieve the above object, the present invention provides a light-emitting element having a substantially square shape when viewed from above, and having a first semiconductor layer of a first conductivity type and a second conductivity type different from the first conductivity type. A semiconductor stacked structure having a second semiconductor layer, an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, a center electrode provided on one surface of the semiconductor stacked structure, and a thin wire extending from the outer periphery of the center electrode A first current path that is provided in parallel along the fine line electrode in a portion other than the surface electrode on the other side of the semiconductor multilayer structure, and is the shortest current path between the fine line electrode Each of the first semiconductor layer, the second semiconductor layer, and the active layer is made of n-type AlGaInP, each of the first semiconductor layer, the second semiconductor layer, and the active layer. p-type AlGaInP, undoped AlGa consists nP, the shortest current path between the surface electrode and the contact portion is a first current path, the ratio of the first current path, the current path between the surface electrode and the contact portion except for the first current path greater than the proportion of the second current path is, the first current path, the square root of the sum of the squares of the minimum distance W ₁ in the top view between the square of the thickness of the semiconductor multilayer structure, the surface electrode and the contact portion The second current path is obtained by calculating the square of the film thickness of the semiconductor multilayer structure and the distance W ₂ in the top view between the surface electrode portion and the contact portion excluding the surface electrode portion having the shortest distance W ₁ . determined by the square root of the sum of the squares, the shortest distance _{W 1} and distance _{W 2,} satisfy the relationship of W 1 _{<W 2,} the first current path, have a distance of 20μm or 50μm or less, the first The ratio of the current path is the total length of the outer edge of the surface electrode Against, is defined as a percentage distance in top view has a total length of the outer edge of the surface electrode serving as the shortest distance W ₁ between the contact portion, the ratio of the second current path, with respect to the total length of the outer edge of the surface electrode, a contact portion is defined as the length ratio of the total of the outer edge of the surface electrode distance is the distance W ₂ in the top view of the width of the thin wire electrodes is 10 [mu] m, fine-line electrodes are in proximity to one side of the light emitting element , A first thin wire electrode provided substantially parallel to one side, a second thin wire electrode provided close to the opposite side of one side and substantially parallel to the opposite side, a first fine wire electrode and a second fine wire A third thin wire electrode provided substantially parallel to the first thin wire electrode and the second thin wire electrode at a substantially equal distance from both the first thin wire electrode and the second thin wire electrode, , First fine wire electrode, second fine wire electrode, and third fine wire electrode The first thin wire electrode extends in a direction substantially perpendicular to the longitudinal direction of each of the first thin wire electrode, the second thin wire electrode, and the third thin wire electrode in the vicinity of the middle in the longitudinal direction. A thin wire electrode and a fourth thin wire electrode provided in contact with the third thin wire electrode, and the center electrode is provided in a region including an intersection of the third thin wire electrode and the fourth thin wire electrode. The electrode is a circular electrode having a diameter of 100 μm, the width of the contact portion is 10 μm, the contact portion extends from the side of the square along the outer periphery of the light emitting element, and one side of the outer periphery to the center substantially perpendicularly. A first fine wire portion provided with one end thereof in contact with the outer peripheral portion, and provided in a direction parallel to the first fine wire portion from one side of the outer peripheral portion and provided at a distance from the first thin wire portion. The second thin line portion and the center of the outer peripheral portion that is substantially perpendicular to the opposite side of one side A third thin line portion and a fourth thin line portion provided opposite to the first thin line portion and the second thin line portion, respectively, and extending to the first thin line portion and the second thin line portion. The fine wire portion, the third fine wire portion, and the fourth fine wire portion have substantially the same length, a part of the outer peripheral portion parallel to the first fine wire electrode, a part of the first fine wire portion, There is provided a light emitting element in which any one of the second thin line portion, the third thin line portion, and the fourth thin line portion corresponds to the first region .

Also, a supporting substrate having a reflective layer for reflecting light from the active layer is emitted, further comprising a transparent layer provided between the reflective layer and the semiconductor multilayer structure, the semiconductor laminated structure, supported by a transparent layer substrate The contact portion may penetrate the transparent layer and electrically connect the semiconductor multilayer structure and the reflective layer. And the semiconductor laminated structure may have an uneven | corrugated shaped part whose arithmetic mean roughness is 100 nm or more in a part of one surface. Further, the shortest distance W ₁ is the shortest distance in top view between the thin wire electrode and the contact portion, the distance W ₂ is the shortest distance in top view between the center electrode and the contact portion It may be.

  The light emitting device according to the present invention can provide a light emitting device capable of improving the light emission output.

It is a typical top view of the light emitting element concerning a 1st embodiment. It is a typical longitudinal cross-sectional view of the light emitting element which concerns on 1st Embodiment. It is detail drawing of the upper surface of the light emitting element which concerns on 1st Embodiment. It is a figure which shows a part of longitudinal section of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure of the manufacturing process of the light emitting element which concerns on 1st Embodiment. It is a figure which shows the light emission output by the difference in the value of D of a light emitting element. It is a figure which shows the forward voltage by the difference in the value of S of a light emitting element. It is a figure which shows the luminous efficiency by the difference in the value of S of a light emitting element. It is a typical top view of the light emitting element concerning a 2nd embodiment. It is a typical top view of the light emitting element concerning a 3rd embodiment. It is sectional drawing of the light emitting element which concerns on 3rd Embodiment.

[First Embodiment]
FIG. 1A shows a schematic top view of a light emitting device according to a first embodiment of the present invention. FIG. 1B shows a schematic longitudinal section of the light emitting device according to the first embodiment of the present invention. 1B is a cross-sectional view taken along the line AA in FIG. 1A.

(Outline of structure of light-emitting element 1)
First, refer to FIG. 1B. The light emitting element 1 according to the first embodiment is electrically connected to a semiconductor multilayer structure 10 having an active layer 105 that emits light of a predetermined wavelength and a partial region on one surface of the semiconductor multilayer structure 10. A surface electrode 110; a pad electrode 115 as a wire bonding pad provided on the surface of the surface electrode 110; a contact portion 120 electrically connected to a part of the other surface of the semiconductor multilayer structure 10; A transparent layer 140 provided on the other surface of the semiconductor multilayer structure 10 excluding the provided region, and a reflective portion 130 provided on the surface of the contact portion 120 and the transparent layer 140 opposite to the surface in contact with the semiconductor multilayer structure 10; Is provided.

  Furthermore, the light-emitting element 1 includes an adhesion layer 200 having electrical conductivity provided on the opposite side of the surface in contact with the contact portion 120 and the transparent layer 140 of the reflection portion 130 and the opposite side of the surface of the adhesion layer 200 in contact with the reflection portion 130. The support substrate 20 having electrical conductivity provided on the back surface, and a back electrode 210 provided on the surface of the support substrate 20 opposite to the surface in contact with the adhesion layer 200 are provided.

  Further, the semiconductor multilayer structure 10 of the light emitting element 1 according to the present embodiment is in contact with the p-type contact layer 109 provided in contact with the contact portion 120 and the transparent layer 140 and the transparent layer 140 of the p-type contact layer 109. A p-type cladding layer 107 as a second conductive type second semiconductor layer provided on the opposite side of the surface, and an active layer 105 provided on the opposite side of the surface of the p-type cladding layer 107 in contact with the p-type contact layer 109. An n-type cladding layer 103 as a first semiconductor layer of the first conductivity type provided on the opposite side of the surface of the active layer 105 in contact with the p-type cladding layer 107, and an active layer 105 of the n-type cladding layer 103. And an n-type contact layer 101 provided in a partial region on the opposite side of the contacting surface.

  The surface of the semiconductor multilayer structure 10 opposite to the side in contact with the transparent layer 140 is a light extraction surface of the light emitting element 1 according to this embodiment. Specifically, a part of the surface opposite to the surface in contact with the active layer 105 of the n-type cladding layer 103 becomes the light extraction surface. Then, on the light extraction surface of the n-type clad layer 103, a concavo-convex shape portion 103a in which a concavo-convex portion having one concave portion and one convex portion as one pair is formed is formed. For example, one concave portion and another concave portion, or one convex portion and another convex portion are formed on the surface of the n-type cladding layer 103 at a predetermined interval, whereby the surface of the n-type cladding layer 103 is formed. An uneven shape portion 103a is provided. The concavo-convex shape portion 103a according to the present embodiment is formed with concavo-convex having an arithmetic average roughness of 100 nm or more, for example.

  Further, the reflective portion 130 is provided in contact with the reflective layer 132 on the opposite side of the reflective layer 132 provided in contact with the contact portion 120 and the transparent layer 140 and the surface of the reflective layer 132 in contact with the contact portion 120 and the transparent layer 140. The barrier layer 134 includes a bonding layer 136 provided in contact with the barrier layer 134 on the side opposite to the surface of the barrier layer 134 in contact with the reflective layer 132. The adhesion layer 200 includes a bonding layer 202 that mechanically and electrically bonds to the bonding layer 136 of the reflective portion 130, and a barrier layer 204 that is provided on the opposite side of the surface of the bonding layer 202 that contacts the reflective portion 130. And a contact electrode 206 provided on the opposite side of the surface in contact with the bonding layer 202 of the barrier layer 204.

  Here, the light emitting element 1 has a side surface 10 a as an etching side surface including the side surface of the active layer 105. Specifically, the light emitting element 1 has a side surface 10 a including a side surface of the n-type cladding layer 103, a side surface of the active layer 105, a side surface of the p-type cladding layer 107, and a side surface of the p-type contact layer 109. The side surface 10 a is formed substantially perpendicular to the surface of the support substrate 20. Furthermore, the light emitting element 1 has a side surface 10b as a processed side surface including the side surface of the reflecting portion 130, the side surface of the adhesion layer 200, and the side surface of the support substrate 20.

  In the side surface 10a, a part of the n-type cladding layer 103, a part of the active layer 105, a part of the p-type cladding layer 107, and a part of the p-type contact layer 109 are removed by wet etching or the like. It is a surface formed. On the other hand, the side surface 10b is formed by mechanically cutting a part of the reflecting portion 130, a part of the adhesion layer 200, and a part of the support substrate 20 by dicing using a dicing apparatus or the like. Surface. Therefore, the side surface 10a has a smooth surface compared to the side surface 10b.

  As shown in FIG. 1A, the light emitting device 1 according to this embodiment is formed in a substantially square shape when viewed from above. As an example, the vertical dimension and the horizontal dimension of the light emitting element 1 are 500 μm, respectively. The thickness of the light emitting element 1 is formed to about 200 μm. In addition, the light-emitting element 1 according to the present embodiment can be, for example, a light-emitting element having a chip size with a planar dimension of about 300 μm or a light-emitting element having a large chip size with a planar dimension of about 1000 μm.

(Details of surface electrode 110 and contact portion 120)
FIG. 1C shows details of the upper surface of the light emitting device according to the first embodiment of the present invention, and FIG. 1D shows a part of a longitudinal section of the light emitting device according to the first embodiment of the present invention.

  First, details of the surface electrode 110 and the contact part 120 will be described with reference to FIG. 1C. The surface electrode 110 includes a circular electrode as a central electrode provided on the n-type cladding layer 103 and a plurality of thin wire electrodes. For example, the surface electrode 110 includes a thin wire electrode 110a provided substantially horizontally on the one side in the vicinity of one side of the light emitting element 1 formed in a substantially rectangular shape when viewed from above, and the opposite side of the one side. Between the thin wire electrode 110a and the thin wire electrode 110c, and between the thin wire electrode 110a and the thin wire electrode 110c, the thin wire electrode 110a and the thin wire electrode 110c are located at substantially equal positions between the thin wire electrode 110a and the thin wire electrode 110c. 110c and a thin wire electrode 110b provided substantially horizontally. In addition, although the circular electrode of the surface electrode 110 is formed in a circular shape in a top view as an example, it can also be formed having a polygonal shape (for example, a hexagon).

  The surface electrode 110 extends in a direction substantially perpendicular to the longitudinal direction of each of the fine wire electrode 110a, the fine wire electrode 110b, and the fine wire electrode 110c, and is in contact with these fine wire electrodes in the vicinity of the middle of these fine wire electrodes. A thin wire electrode 110d is further provided. Further, the surface electrode 110 has a circular electrode in a region including an intersection of the fine wire electrode 110b and the fine wire electrode 110d. That is, among the plurality of thin wire electrodes, the thin wire electrode 110b and the thin wire electrode 110d are each directed away from the outer periphery of the circular electrode (in other words, from the outer periphery of the circular electrode to the outer edge of the light emitting element 1 in a top view). ) And extending from the outer periphery of the circular electrode. In FIG. 1C, the circular electrode is not shown because it is located immediately below the pad electrode 115. Further, the pad electrode 115 is provided at a position where the center of the light emitting element 1 and the center of the pad electrode 115 substantially coincide with each other when viewed from above.

  Next, the contact part 120 is provided in the opening located in the part except the area | region of the transparent layer 140 directly under the surface electrode 110 by the top view. For example, the contact portion 120 includes an outer peripheral portion 120a having a shape along the outer periphery of the light emitting element 1 in a top view (for example, a rectangular shape when the light emitting element 1 is rectangular in a top view), and an outer peripheral portion 120a extends from one side to the center with a predetermined length, and has a thin line portion 120b provided with one end in contact with the outer peripheral portion 120a, and a thin line portion from the one side of the outer peripheral portion 120a. 120b extends in a horizontal direction and is provided with a predetermined distance from the thin line portion 120b, and extends with a predetermined length from the opposite side of the one side of the outer peripheral portion 120a toward the center. The thin wire portion 120b and the thin wire portion 120c are provided so as to be opposed to the thin wire portion 120b and the thin wire portion 120c, respectively. The thin line portion 120b to the thin line portion 120e have substantially the same length.

In addition, the contact portion 120 in the first embodiment is provided in parallel to the thin wire electrode, and electrically connects the plurality of first regions with the shortest distance from the thin wire electrode and the plurality of first regions. 2nd area | region connected to this. For example, as shown in FIG. 1C, a part of the outer peripheral part 120a and a part of the fine line part 120b to the fine line part 120e are provided in parallel along the longitudinal direction of the fine line electrode 110a to the fine line electrode 110c. Corresponds to the area. Further, a part of the outer peripheral portion 120a corresponds to a first region provided in parallel along the longitudinal direction of the thin wire electrode 110d. Here, referring to FIG. 1C, the thin wire electrode 110 d according to the first embodiment is provided in parallel to the contact portion 120. The thin wire electrode 110d has a structure in which the distance between the contact portion 120 is longer than _{W 1.} Therefore, in the first embodiment, there is no first region for the thin wire electrode 110d.

  In addition, when the surface electrode 110 and the contact part 120 have a curved region, a parallel curve formed by providing the curves at equal intervals is also included in the region provided in “parallel” in the present embodiment. And

  Then, the surface electrode 110 and the contact portion 120 are arranged so as not to overlap each other when viewed from above. For example, the fine wire portion 120b and the fine wire portion 120d are positioned between the fine wire electrode 110a and the fine wire electrode 110b, and the fine wire portion 120b and the fine wire portion 120d have a length that does not contact the fine wire electrode 110d. Is done. Similarly, the fine wire portion 120c and the fine wire portion 120e are located between the fine wire electrode 110b and the fine wire electrode 110c, and each of the fine wire portion 120c and the fine wire portion 120e has a length that does not contact the fine wire electrode 110d. It is formed.

Here, in the top view of the light emitting element 1, the shortest distance from the outer edge of the thin wire electrode of the surface electrode 110 to the outer edge of the thin wire portion of the contact portion 120 is defined as “W ₁ ” and the outer periphery of the pad electrode 115 (that is, , The shortest distance from the outer periphery of the circular electrode of the surface electrode 110 to the contact portion 120 is defined as “W ₂ ”. Here, the shortest distance W ₁ is, for example, a distance from the longitudinal line of thin wire electrode to the longitudinal direction of the line of the thin line portion of the contact portion 120. Further, the shortest distance W ₂ is, for example, a distance from the outer periphery of the circular electrode to the thin line portion end of the contact portion 120. For example, the shortest distance from the outer edge of the thin wire electrode 110a to the outer portion 120a, and the shortest distance from the outer edge of the thin wire electrode 110a to the fine line portion 120b becomes _{W 1.} Further, the shortest distance from the outer edge of the pad electrode 115 to the thin line portion 120b, and the shortest distance from the outer edge of the pad electrode 115 to the thin line portion 120e is _{W 2.}

  Also, referring to FIG. 1D, in the present embodiment, the film thickness of semiconductor laminated structure 10, that is, the thickness from the surface of n-type contact layer 101 to the bottom surface of p-type contact layer 109 is defined as “T”. To do.

  Here, in the light emitting element 1 according to the present embodiment, the ratio of the shortest current path as the first current path to all the current paths between the surface electrode 110 and the contact part 120 excludes the shortest current path. The surface electrode 110 and the contact part 120 are provided in a shape that is larger than the ratio of the other current path as the second current path. For example, it is obtained by the square root of the sum of the square of the film thickness of the semiconductor multilayer structure 10 and the square of the distance in the top view between each part of the outer edge of the surface electrode 110 and each part of the outer edge of the contact part 120. Of each distance, the ratio of the value of the square root of the sum of the square of the film thickness of the semiconductor multilayer structure 10 and the square of the shortest distance in the top view between the surface electrode 110 and the contact portion 120 is 50% or more. The surface electrode 110 and the contact part 120 are provided.

  In the present embodiment, the “current path” refers to a path through which a current flows between the surface electrode 110 and the contact portion 120. Here, the semiconductor multilayer structure 10 exists between the surface electrode 110 and the contact portion 120, and the semiconductor multilayer structure 10 emits light although the resistivity of the plurality of semiconductor layers constituting the semiconductor multilayer structure 10 is different. Thin compared to the size of the element 1. Therefore, since the fluctuation of the current path due to the difference in resistivity can be substantially ignored, the current path is determined based on the film thickness of the semiconductor multilayer structure and the distance in the top view between the surface electrode and the contact portion. be able to. In addition, the “ratio of the current path” is the contact portion 120 of the outer edge of the surface electrode 110 with respect to the entire length of the outer edge (that is, the outer periphery) of the surface electrode 110 including the circular electrodes and the thin wire electrodes 110a to 110d. As a ratio of the total length of the outer edges of the surface electrode 110 serving as the position (however, the position on the surface of the light emitting element 1) of W1 (however, the distance in the top view of the light emitting element 1) constituting the shortest straight line distance. It is prescribed.

For example, in this embodiment, between the shortest distance W ₁ in the top view between the fine line portions of the thin wire electrode and the contact portion 120 of the surface electrode 110, and the circular electrode and the contact portion 120 fine line portions of the surface electrode 110 there is a shortest distance W ₂ in the top view. Here, as an example, the surface electrode 110 and the contact portion 120 are formed so as to have an arrangement where W ₁ <W ₂ . In this case, the shortest current path between the surface electrode 110 and the contact portion 120 (or, the distance S shortest between the surface electrode 110 and the contact portion 120) is a portion that becomes the shortest distance W ₁ .

Here, the shortest distance W ₂ between the circle electrode portion and the contact portion 120 of the surface electrode 110, the reason for longer than the shortest distance W ₁ between the thin wire electrodes 110a, etc. and the contact portion 120 is as follows. That is, light emitted immediately below and in the vicinity of the circular electrode portion (that is, the pad electrode 115) of the surface electrode 110 is absorbed by the circular electrode portion and the pad electrode 115, and the light extraction efficiency decreases. That is, even if the light emission amount in the vicinity of the pad electrode 115 is increased, it is difficult to improve the light extraction amount as the light emitting element 1. On the other hand, the thin wire electrode 110a or the like has a narrower width than the pad electrode 115 and can reduce the influence of shadowing or absorbing the light emitted from the active layer 105. Therefore, in the present embodiment, it is preferable to satisfy the relationship of W ₁ <W ₂ .

  S is expressed by the following “Equation 1”.

  In the present embodiment, the surface electrode 110 and the contact portion 120 having a shape in which the portion satisfying “Equation 1” is 50% or more are formed. Furthermore, the surface electrode 110 and the contact portion 120 are formed so that “S” represented by “Equation 1” falls within a range of, for example, 20 μm ≦ S ≦ 50 μm. By providing the surface electrode 110 and the contact part 120 satisfying this arrangement relationship, that is, the expression of “Equation 1”, the ratio of the shortest current path among the current paths between the surface electrode 110 and the contact part 120 is It is provided in a shape larger than the ratio of other current paths excluding the shortest current path. Therefore, the current supplied to the pad electrode 115 preferentially flows in the shortest current path between the thin wire electrode of the surface electrode 110 and the contact portion 120. Then, by forming the surface electrode 110 and the contact portion 120 having a shape in which the portion satisfying “Equation 1” is 50% or more, the uneven current density in the light emitting element 1 is reduced.

  The circular electrode of the surface electrode 110 has a diameter of at least 75 μm or more according to the diameter of the ball portion of the wire made of a metal material such as Au connected to the pad electrode 115 provided on the circular electrode. Is done. As an example, the circular electrode of the surface electrode 110 is formed in a circular shape having a diameter of 100 μm. Further, the thin wire electrodes 110a to 110d of the surface electrode 110 are formed in a linear shape having a width of 10 μm. Further, the contact portion 120 is provided on the surface of the p-type contact layer 109 except for the region immediately below the surface electrode 110. Specifically, the contact part 120 is formed in an opening provided through the transparent layer 140 to electrically connect the semiconductor multilayer structure 10 and the reflective layer 132. As an example, the contact part 120 is formed from a metal material containing Au and Zn.

(Semiconductor laminated structure 10)
The semiconductor multilayer structure 10 according to this embodiment is formed by including an AlGaInP-based compound semiconductor that is a III-V group compound semiconductor. Specifically, the semiconductor stacked structure 10 includes an active layer 105 formed from a bulk of an undoped AlGaInP-based compound semiconductor that is not doped with an impurity dopant, and an n-type cladding formed by containing n-type AlGaInP. The structure is sandwiched between the layer 103 and the p-type cladding layer 107 formed to include p-type AlGaInP.

The active layer 105 emits light of a predetermined wavelength when a current is supplied from the outside. For example, the active layer 105 is formed of a compound semiconductor material that emits red light having a wavelength of around 630 nm. The active layer 105 is, for example, be formed from an undoped _{(Al 0.1 Ga 0.9) 0.5 In} 0.5 P layer. The n-type cladding layer 103 includes an n-type dopant such as Si or Se at a predetermined concentration. As an example, the n-type cladding layer 103 is formed of an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P layer doped with Si. Furthermore, the p-type cladding layer 107 contains a p-type dopant such as Zn or Mg at a predetermined concentration. As an example, the p-type cladding layer 107 is formed of a p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P layer doped with Mg.

  Furthermore, the p-type contact layer 109 included in the semiconductor multilayer structure 10 is formed of, for example, a p-type GaP layer doped with Mg as a p-type dopant at a predetermined concentration. For example, the n-type contact layer 101 is formed of a GaAs layer doped with Si as an n-type dopant at a predetermined concentration. Here, the n-type contact layer 101 is provided in a region where the surface electrode 110 is provided on the upper surface of the n-type cladding layer 103.

(Transparent layer 140)
The transparent layer 140 is provided on the surface of the p-type contact layer 109 where the contact part 120 is not provided. Transparent layer 140 is formed of a material transparent to the wavelength of light emitted from the active layer 105, as an _example, is formed of a transparent dielectric layer such as _{SiO 2, TiO 2, SiN x} . The transparent layer 140 has a wavelength of light emitted from the active layer 105 of λ, and the refractive index of the material constituting the transparent layer 140 is n (2 × λ) / (4 × n) or more. The thickness is formed. The transparent layer 140 can also be formed from a transparent conductor layer containing a metal oxide material such as ITO (Indium Tin Oxide) having a conductivity lower than that of the contact portion 120.

Moreover, the transparent layer 140 can also be formed from the laminated structure of the thin film which consists of a several material from which each refractive index differs. That is, the transparent layer 140 can have a distributed black reflector (DBR) structure. For example, the transparent layer 140 having a DBR structure in which a pair layer in which a layer made of SiO ₂ having a predetermined thickness and a layer made of TiO ₂ having a predetermined thickness are paired can be formed.

(Reflecting part 130)
The reflective layer 132 of the reflective unit 130 is formed of a conductive material having a high reflectance with respect to light emitted from the active layer 105. As an example, the reflective layer 132 is formed of a conductive material having a reflectance of 80% or more with respect to the light. The reflection layer 132 reflects the light reaching the reflection layer 132 out of the light emitted from the active layer 105 toward the active layer 105 side. The reflective layer 132 is formed of, for example, a metal material such as Al, Au, or Ag, or an alloy containing at least one metal material selected from these metal materials. As an example, the reflective layer 132 is made of Al having a predetermined thickness. The barrier layer 134 of the reflection unit 130 is formed of a metal material such as Ti or Pt, and as an example, is formed of Ti having a predetermined thickness. The barrier layer 134 suppresses propagation of the material forming the bonding layer 136 to the reflective layer 132. The bonding layer 136 is formed of a material that is electrically and mechanically bonded to the bonding layer 202 of the adhesion layer 200, and is formed of Au having a predetermined thickness as an example.

(Supporting substrate 20)
The support substrate 20 is formed from a conductive material. The support substrate 20 can be formed of a p-type or n-type conductive Si substrate, a Ge substrate, a GaAs substrate, a semiconductor substrate such as a GaP substrate, or a metal substrate made of a metal material such as Cu. For example, in this embodiment, a conductive Si substrate can be used as the support substrate 20.

  Then, the bonding layer 202 of the adhesion layer 200 can be formed of Au having a predetermined film thickness, similarly to the bonding layer 136 of the reflecting portion 130. The barrier layer 204 is formed of a metal material such as Ti or Pt, and can be formed of Pt having a predetermined thickness as an example. The barrier layer 204 prevents the material constituting the bonding layer 202 from propagating to the contact electrode 206. Further, the contact electrode 206 is formed from a material that is electrically bonded to the support substrate 20 and is formed from a metal material including Au, Ti, Al, or the like. As an example, the contact electrode 206 is formed of Ti having a predetermined film thickness.

  The back electrode 210 is formed from a material that is electrically bonded to the support substrate 20, and is formed from a metal material such as Ti or Au, for example. In the present embodiment, the back electrode 210 has Ti and Au. Specifically, Ti having a predetermined thickness is provided by being electrically bonded to the support substrate 20, and Au having a predetermined thickness is further provided on the Ti. The light-emitting element 1 is a stem formed from a metal material such as Al or Cu using a conductive bonding material such as Ag paste or a eutectic material such as AuSn with the back electrode 210 facing down. It is mounted at a predetermined position.

(Modification)
The light emitting element 1 according to the present embodiment emits light including red having a wavelength of 630 nm, but the wavelength of light emitted from the light emitting element 1 is not limited to this wavelength. The light emitting element 1 that emits light in a predetermined wavelength range can also be formed by controlling the structure of the active layer 105 of the semiconductor multilayer structure 10. Examples of light emitted from the active layer 105 include light in a wavelength range such as orange light, yellow light, or green light. The semiconductor multilayer structure 10 included in the light emitting element 1 can also be formed from an InGaN-based or InAlGaN-based compound semiconductor including an active layer 105 that emits light in the ultraviolet region, the purple region, or the blue region.

  Furthermore, in the semiconductor multilayer structure 10 included in the light emitting element 1, the conductivity type of the compound semiconductor layer constituting the semiconductor multilayer structure 10 can be made opposite to that of the first embodiment. For example, the conductivity type of the n-type contact layer 101 and the n-type cladding layer 103 can be p-type, and the conductivity type of the p-type cladding layer 107 and the p-type contact layer 109 can be n-type. The uneven portion 103 a can also be provided on the surface of the n-type cladding layer 103 by forming uneven portions having no regularity on the surface of the n-type cladding layer 103.

  In addition, the contact portion 120 is formed in a single shape without a cut portion. However, in a modified example, the contact portion 120 formed of a plurality of regions is formed by forming a cut portion in a part of the contact portion 120. It can also be formed. For example, the contact part 120 can be formed in a plurality of dots. Also in this case, the plurality of contact portions are provided in a region excluding the portion directly below the surface electrode 110.

  Moreover, the planar dimension of the light emitting element 1 is not restricted to said embodiment. For example, the planar dimension of the light emitting element 1 can be designed such that the vertical dimension and the horizontal dimension are each about 300 μm, or can be designed to be a dimension exceeding 1 mm. Further, the light emitting element 1 can also be formed by appropriately changing the vertical dimension and the horizontal dimension according to the use application of the light emitting element 1. As an example, the planar dimension of the light emitting element 1 can be designed such that the vertical dimension is shorter than the horizontal dimension. In this case, the shape of the light emitting element 1 in a top view is substantially rectangular.

  The active layer 105 can also be formed with a quantum well structure. The quantum well structure can be formed from any structure of a single quantum well structure, a multiple quantum well structure, or a strained multiple quantum well structure.

(Method for Manufacturing Light-Emitting Element 1)
2A to 2L show the flow of the manufacturing process of the light emitting device according to the first embodiment of the present invention.

First, as shown in FIG. 2A (a), an AlGaInP-based material including a plurality of compound semiconductor layers on an n-type GaAs substrate 100 by, for example, metal organic vapor phase epitaxy (MOVPE method). A semiconductor multilayer structure 11 is formed. Specifically, on the n-type GaAs substrate 100, an etching stop layer 102 having undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P, and an n-type doped with Si N-type contact layer 101 having GaAs, n-type cladding layer 103 having n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P doped with Si, and undoped (Al _{0 .1} Ga _0.9 ) _0.5 In _0.5 P active layer 105 and Mg-doped p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P A p-type cladding layer 107 and a p-type contact layer 109 containing p-type GaP doped with Mg are formed in this order using the MOVPE method. As a result, an epitaxial wafer in which the semiconductor multilayer structure 11 is formed on the n-type GaAs substrate 100 is formed.

Here, the formation of the semiconductor multilayer structure 11 using the MOVPE method is performed at a growth temperature of 650 ° C., a growth pressure of 6666.1 Pa (50 Torr), and a growth rate of each of the plurality of compound semiconductor layers included in the semiconductor multilayer structure 11. Is set from 0.3 nm / sec to 1.0 nm / sec, and the V / III ratio is set to about 200. The V / III ratio is a group V such as arsine (AsH ₃ ) and phosphine (PH ₃ ) based on the number of moles of a group III raw material such as trimethylgallium (TMGa) or trimethylaluminum (TMAl). It is the ratio of the number of moles of raw materials.

The raw materials used in the MOVPE method are organometallic compounds such as trimethylgallium (TMGa), triethylgallium (TEGa), trimethylaluminum (TMAl), trimethylindium (TMIn), arsine (AsH ₃ ), and phosphine (PH ₃ ). A hydride gas such as can be used. Furthermore, disilane (Si ₂ H ₆ ) can be used as a raw material for the n-type dopant. Then, the raw material of p-type dopant can be used biscyclopentadienyl magnesium (Cp 2 _Mg).

Alternatively, hydrogen selenide (H ₂ Se), monosilane (SiH ₄ ), diethyl tellurium (DETe), or dimethyl tellurium (DMTe) can be used as a raw material for the n-type dopant. And dimethyl zinc (DMZn) or diethyl zinc (DEZn) can also be used as a raw material of a p-type dopant.

  The semiconductor multilayer structure 11 on the n-type GaAs substrate 100 can also be formed using molecular beam epitaxy (MBE), halide vapor phase epitaxy (HALide Vapor Phase Epitaxy: HVPE), or the like. .

Next, as shown in FIG. 2A (b), after the epitaxial wafer formed in FIG. 2A (a) is unloaded from the MOVPE apparatus, a transparent layer 140 is formed on the surface of the p-type contact layer 109. Specifically, a SiO ₂ film as the transparent layer 140 is formed on the surface of the p-type contact layer 109 using a plasma CVD (Chemical Vapor Deposition) apparatus. In addition, when forming the transparent layer 140 from a several layer, it can form by a vacuum evaporation method.

  Next, as shown in FIG. 2B (c), an opening 140a is formed in the transparent layer 140 by using a photolithography method and an etching method. For example, a photoresist pattern having a groove in a region where the opening 140 a is to be formed is formed on the transparent layer 140. The opening 140 a is formed to penetrate from the surface of the transparent layer 140 to the interface between the p-type contact layer 109 and the transparent layer 140. Specifically, an opening 140a is formed in the transparent layer 140 by removing the transparent layer 140 in a region where the photoresist pattern is not formed using an etchant as a hydrofluoric acid-based etchant. The opening 140a is formed in a region where the contact portion 120 described in FIG. 1A is provided.

  Subsequently, as shown in FIG. 2B (d), an AuZn alloy which is a material constituting the contact portion 120 is formed in the opening 140a by using a vacuum deposition method. For example, the contact portion 120 is formed by vacuum-depositing AuZn in the opening 140a using a photoresist pattern used for forming the opening 140a as a mask. As a result, as shown in FIG. 2C, the contact portion 120 made of AuZn is formed on the transparent layer 140. Since the shape of the contact portion 120 has been described in detail in “(Details of the surface electrode 110 and the contact portion 120)”, the description thereof is omitted.

  Next, as shown in FIG. 2D (e), using a vacuum deposition method or a sputtering method, an Al layer as the reflective layer 132, a Ti layer as the barrier layer 134, and an Au layer as the bonding layer 136, Form. Thereby, the semiconductor laminated structure 1a is formed. Note that, for the reflective layer 132, a material having a high reflectance with respect to the wavelength of the light is selected in accordance with the wavelength of the light emitted from the active layer 105.

  2E (f), Ti as the contact electrode 206, Pt as the barrier layer 204, and Au as the bonding layer 202 are formed on the conductive Si substrate as the support substrate 20. It forms in order using a vacuum evaporation method. Thereby, the support structure 20a is formed. Subsequently, the bonding surface 136a, which is the surface of the bonding layer 136 of the semiconductor multilayer structure 1a, and the bonding surface 202a, which is the surface of the bonding layer 202 of the support structure 20a, are overlapped with each other, and this state is formed from carbon or the like. Hold with a jig to be done.

Subsequently, a jig holding the state in which the semiconductor multilayer structure 1a and the support structure 20a are overlapped is introduced into the wafer bonding apparatus. And the inside of a wafer bonding apparatus is made into a predetermined pressure. As an example, the pressure is set to 1.333 Pa (0.01 Torr). Then, pressure is applied to the semiconductor laminated structure 1a and the support structure 20a that are overlapped with each other via a jig. As an example, a pressure of 30 kgf / cm ² is applied. Next, the jig is heated to a predetermined temperature at a predetermined temperature increase rate.

  Specifically, the temperature of the jig is heated to 350 ° C. And after the temperature of a jig reaches about 350 degreeC, a jig is hold | maintained at the said temperature for about 30 minutes. Thereafter, the jig is slowly cooled. The temperature of the jig is sufficiently lowered to, for example, room temperature. After the temperature of the jig has dropped, the pressure applied to the jig is released. And the pressure in a wafer bonding apparatus is made into atmospheric pressure, and a jig is taken out. As a result, as shown in FIG. 2E (g), a bonded structure 1b is formed in which the semiconductor multilayer structure 1a and the support structure 20a are mechanically and electrically bonded between the bonding layer 136 and the bonding layer 202. Is done.

  In the present embodiment, the semiconductor multilayer structure 1 a includes the barrier layer 134. Therefore, even when the semiconductor multilayer structure 1a and the support structure 20a are bonded to each other at the bonding surface 136a and the bonding surface 202a, the material forming the bonding layer 136 and the bonding layer 202 diffuses into the reflective layer 132. This can be suppressed and deterioration of the reflection characteristics of the reflective layer 132 can be suppressed.

  Next, the bonding structure 1b is affixed to the jig of the polishing apparatus with affixing wax. Specifically, the support substrate 20 side is attached to the jig. Then, the n-type GaAs substrate 100 of the bonded structure 1b is polished until it reaches a predetermined thickness. Subsequently, the polished bonded structure 1b is removed from the jig of the polishing apparatus, and the wax adhering to the surface of the support substrate 20 is removed by washing. Then, as shown in FIG. 2F (h), the n-type GaAs substrate 100 is selectively and completely removed from the bonded structure 1b after polishing using an etchant for GaAs etching to expose the etching stop layer 102. The joined structure 1c is formed. As an etchant for GaAs etching, for example, a mixed solution of ammonia water and hydrogen peroxide water can be used. It is also possible to remove all n-type GaAs substrate 100 by etching without polishing n-type GaAs substrate 100.

  Then, as shown in FIG. 2F (i), the etching stop layer 102 is removed from the bonded structure 1c by etching using a predetermined etchant. Thereby, the bonded structure 1d from which the etching stop layer 102 has been removed is formed. When the etching stop layer 102 is formed of an AlGaInP-based compound semiconductor, an etchant containing hydrochloric acid can be used as the predetermined etchant. As a result, the surface of the n-type contact layer 101 is exposed to the outside.

  Subsequently, the surface electrode 110 is formed at a predetermined position on the surface of the n-type contact layer 101 by using a photolithography method and a vacuum deposition method. The surface electrode 110 is formed of a circular electrode having a diameter of 100 μm and a plurality of thin wire electrodes having a width of 10 μm. The surface electrode 110 is formed by evaporating, for example, AuGe, Ti, and Au on the n-type contact layer 101 in this order. In this case, the surface electrode 110 is formed so as not to be located immediately above the contact portion 120. The details of the shape of the surface electrode 110 have been described in “(Details of the surface electrode 110 and the contact portion 120)”, and are omitted here. As a result, as shown in FIG. 2G, the bonded structure 1e having the surface electrode 110 is formed.

Next, as shown in FIG. 2H, using the surface electrode 110 formed in FIG. 2G as a mask, the n-type contact layer 101 except for the n-type contact layer 101 corresponding directly below the surface electrode 110 is made of sulfuric acid and hydrogen peroxide solution. Etching is performed using a mixed solution of water and water. Thereby, the joined structure 1f is formed. By using the mixed solution, the n-type contact layer 101 formed of GaAs is changed to an n-type clad formed of n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P. The layer 103 can be selectively etched. Therefore, in the junction structure 1f, the surface of the n-type cladding layer 103 is exposed to the outside.

  Next, as shown in FIG. 2I, an uneven shape portion 103 a is formed on a part of the surface of the n-type cladding layer 103. Specifically, a mask pattern in which a concave pattern or a convex pattern is repeated at a predetermined interval is formed on the surface of the n-type cladding layer 103 using a photolithography method. For example, a mask pattern is formed in which a concave pattern or a convex pattern is repeated with an interval in the range of 1.0 μm to 3.0 μm. In addition, the pattern for a recessed part or the pattern for a convex part is formed with arrangement | positioning, such as a matrix form and a honeycomb form, for example. Then, using the formed mask pattern as a mask, the concavo-convex shape portion 103a is formed on the surface of the n-type cladding layer 103 using a wet etching method. As a result, a bonded structure 1g having the uneven portion 103a is formed.

  Subsequently, a mask pattern for separating the light emitting elements is formed on the surface of the bonding structure 1g by using a photolithography method. That is, a mask pattern for separating light emitting elements is formed on the surface of the n-type cladding layer 103 of the bonded structure 1g. Using the mask pattern as a mask, the light emitting elements are separated by removing the surface from the n-type cladding layer 103 to the p-type contact layer 109 by wet etching. As a result, as shown in FIG. 2J, a bonded structure 1h in which a plurality of light emitting elements are separated is formed. Note that the side surface 10a is a surface exposed by wet etching, and has a smooth surface as compared with the case where the semiconductor multilayer structure 10 is mechanically cut. Thereby, the damage of the end surface of the light emitting element manufactured can be reduced, and the leak current in the end surface of the light emitting element can be reduced.

  Next, the back electrode 210 is formed on substantially the entire back surface of the support substrate 20 by vacuum deposition. The back electrode 210 is formed by depositing Ti and Au on the bottom surface of the support substrate 20 in this order. Thereafter, between the contact portion 120 and the p-type contact layer 109, between the front surface electrode 110 and the n-type contact layer 101, between the contact electrode 206 and the support substrate 20, and between the back electrode 210 and the support substrate 20. An alloying process, which is an alloying process for forming the respective electrical joints, is applied to the joint structure 1h including the back electrode 210. As an example, the bonded structure 1h is subjected to heat treatment at 400 ° C. for 5 minutes in a nitrogen atmosphere as an inert atmosphere. Subsequently, the pad electrode 115 is formed on a part of the surface of the surface electrode 110, specifically on the circular electrode, by using a photolithography method and a vacuum evaporation method. The pad electrode 115 is formed, for example, by depositing Ti and Au on the surface of the circular electrode of the surface electrode 110 in this order. Thereby, the joined structure 1i as shown in FIG. 2K is formed. Note that the pad electrode 115 is not subjected to heat treatment.

  Then, using a dicing apparatus having a dicing blade, the bonded structure 1i is separated. Thereby, as shown to FIG. 2L, the several light emitting element 1 which concerns on this Embodiment is formed. In this case, the side surface 10b is generated in the region mechanically cut by the dicing blade. Since the side surface 10b is a mechanically cut region, there are large irregularities compared to the surface of the side surface 10a.

  The light-emitting element 1 manufactured through the processes of FIGS. 2A to 2L is, for example, a light-emitting diode (Light Emitting Diode: LED) having an element size (planar dimension) having a substantially square shape with a planar dimension of 500 μm square. . The light-emitting element 1 is die-bonded to the TO-18 stem using a conductive bonding material, and a predetermined region of the surface electrode 110 and the TO-18 stem is connected by a wire such as Au. Thereby, the characteristic of the light emitting element 1 can be evaluated by supplying an electric current from the outside to the pad electrode 115 via a wire.

  Specifically, the initial characteristics of the light-emitting element 1 manufactured in this manufacturing process were evaluated by applying a resin mold. Specifically, initial characteristics of the light-emitting element 1 having the following configuration were evaluated. The light emitting element 1 has the structure shown in FIGS. 1A to 1D.

First, the semiconductor laminated structure 10 includes an n-type contact layer 101 made of n-type GaAs doped with Si, and an n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 doped with Si. An n-type cladding layer 103 made of P, an active layer 105 made of undoped (Al _0.1 Ga _0.9 ) _0.5 In _0.5 P, and a p-type (Al _0.7 doped with Mg) The p-type cladding layer 107 made of Ga _0.3 ) _0.5 In _0.5 P and the p-type contact layer 109 made of p-type GaP doped with Mg were formed.

In addition, a conductive Si substrate was used as the support substrate 20, a Ti layer was used as the contact electrode 206, a Pt layer was used as the barrier layer 204, and an Au layer was used as the bonding layer 202. The bonding layer 136 of the reflection unit 130 is an Au layer, the barrier layer 134 is a Ti layer, and the reflection layer 132 is an Al layer. Further, the transparent layer 140 using the SiO _2, the contact unit 120 using AuZn. The width of the contact part 120 was 10 μm. Further, AuGe, Ti, and Au were used for the surface electrode 110. The diameter of the circular electrode of the surface electrode 110 was 100 μm, and the width of the thin wire electrode was 10 μm. The pad electrode 115 was formed from Ti / Au. That is, the Ti layer is in contact with the n-type contact layer 101. The element size was 500 μm square when viewed from above.

Here, the light emitting element 1 includes the sum of the square of the film thickness T of the semiconductor multilayer structure 10 and the square of the shortest distance W ₂ in a top view between the pad electrode 115 (circular electrode of the surface electrode 110) and the contact portion 120. the square root of the value (S1) is, than the square root of the value of the sum of the square of the shortest distance W ₁ in the top view between the square and the thin wire electrode and the contact portion 120 of the thickness T of the semiconductor multilayer structure 10 (S2) A structure having an arrangement relationship between the surface electrode 110 and the contact portion 120 having a large value was adopted. And while setting to S1 = 25 micrometer and defining as D = S2-S1, the light emitting element which changed the value of D was manufactured.

  FIG. 3 shows the light emission output by the difference of the value of D of a light emitting element.

  The light emission output of the light emitting element was implemented by passing a current of 20 mA through the light emitting element. As a result, as shown in FIG. 3, when D exceeds 0, that is, according to the first embodiment of the present invention having a positional relationship between the surface electrode 110 and the contact portion 120 that satisfy S1> S2. It was confirmed that the light emission output of the light emitting element was high. This is because the current path between the thin line electrode of the surface electrode 110 and the contact part 120 is more current than the current path between the circular electrode part of the surface electrode 110 that absorbs light emitted from the active layer 105 and the contact part 120. This is considered to be because the light emission in the active layer 105 that is short and located directly under the circular electrode of the surface electrode 110 could be suppressed.

  FIG. 4 shows the forward voltage due to the difference in the value of S of the light emitting element.

FIG. 4 shows the forward voltage due to the difference in the value of S expressed by the expression of “Equation 1” of the light emitting element when energized with 20 mA. That is, FIG. 4 shows the influence of the forward voltage of varying the W _1. Referring to FIG. 4, the forward voltage increased in proportion to the increase in the value of S. This is because electrons supplied from the pad electrode 115 to the surface electrode 110 flow from the surface electrode 110 through the semiconductor multilayer structure 10 to the support substrate 20 side through the contact portion 120. Therefore, if the value of S is large, the semiconductor This is considered because the resistance to current in the laminated structure 10 is large.

  FIG. 5 shows the light emission efficiency depending on the difference in the value of S of the light emitting element.

  The active layer 105 located between the surface electrode 110 and the contact part 120, for example, the active layer 105 located on a line connecting the position where the surface electrode 110 is located and the position where the contact part 120 is located, is not located on the line. It emits light brighter than part of the active layer 105. The surface electrode 110 and the contact part 120 easily absorb light emitted from the active layer 105. Therefore, when the value of S is larger, that is, when the surface electrode 110 and the contact portion 120 are separated from each other in a top view, the surface electrode 110 and the contact are directly above or directly below the active layer 105 in the portion located on the line. Since the portion 120 does not exist, light absorption is reduced.

  Here, in FIG. 5, when the value of S is 20 μm or more, the light emission efficiency is significantly improved as compared to the case where the value of S is less than 20 μm. The luminous efficiency is 60 lm / W or more when the value of S is in the range of 20 μm to 50 μm. When the value of S exceeds 50 μm, the rate of decrease in light emission efficiency increases and the light emission efficiency decreases. This is because if the value of S becomes too large, the forward voltage increases as shown in FIG. 4 and the luminous efficiency tends to decrease. Therefore, in the light emitting device according to the present embodiment, considering the two viewpoints of increasing the forward voltage and improving the light emission efficiency, for example, the surface electrode 110 and the contact whose S value is 20 μm to 50 μm. The shape and arrangement of the part 120 are preferable.

(Effects of the first embodiment)
In the light emitting element 1 according to the present embodiment, the surface electrode 110 and the contact part 120 are excluded from the ratio of the shortest current path among the current paths between the surface electrode 110 and the contact part 120 except for the shortest current path. By providing a shape larger than the ratio of the other current paths, absorption of the light emitted from the active layer 105 in the surface electrode 110 and the contact portion 120 can be suppressed, so that the light output efficiency is increased and the light output is large. A light emitting element can be provided.

  Further, in the light emitting element 1 according to the present embodiment, the ratio of the shortest current path among the current paths between the surface electrode 110 and the contact part 120 is determined for all the current paths. Since the current supplied to the surface electrode 110 can be prevented from concentrating on a part of the current path by providing the shape and arrangement with a ratio of 50% or more with respect to the current, the large current is supplied to the light emitting element 1. Even in this case, a light-emitting element with improved luminous efficiency can be provided.

  Furthermore, since the light emitting element 1 according to the present embodiment includes the surface electrode 110 and the contact portion 120 having a shape in which the portion satisfying “Equation 1” is 50% or more, the current density in the light emitting element 1 is uneven. Can be reduced. Thereby, since the electrons injected into the light emitting element 1 are likely to spread in the light emitting element 1, it is possible to suppress the active layer 105 from emitting light locally. Furthermore, a decrease in light emission efficiency due to heat generated when the active layer 105 emits light locally can be suppressed, and the reliability of the light emitting element 1 can be improved.

[Second Embodiment]
FIG. 6 shows a schematic top view of a light emitting device according to the second embodiment of the present invention.

  The light-emitting element 2 according to the second embodiment of the present invention is the same as the light-emitting element 1 according to the first embodiment except that the arrangement of the thin-line electrode of the surface electrode and the arrangement of the thin-line part of the contact portion are different. It has substantially the same configuration. Therefore, detailed description is omitted except for the differences.

  The surface electrode 111 of the light emitting element 2 according to the second embodiment includes a circular electrode immediately below the pad electrode 115, and a plurality of thin line electrodes extending from the center of the circular electrode toward the outer edge of the light emitting element 2 in a top view. Have In FIG. 6, the circular electrode is not shown because it is located immediately below the pad electrode 115.

  Specifically, the surface electrode 111 includes a thin wire electrode 111a provided in a direction along one diagonal line of the substantially square light emitting element 2 in a top view, and a thin wire electrode 111c provided in a direction along the other diagonal line, A thin wire electrode 111b provided on one side of the light emitting element 2 along a substantially horizontal direction and provided on a part of a line connecting the substantially center of the two sides perpendicular to the one side, and the length of the thin wire electrode 111d And a thin wire electrode 111d provided along a direction perpendicular to the direction. The intersection of the fine wire electrode 111a and the fine wire electrode 111c and the intersection of the fine wire electrode 111b and the fine wire electrode 111d are set at substantially the same position. The lengths of the fine wire electrode 111a and the fine wire electrode 111c are longer than the lengths of the fine wire electrode 111b and the fine wire electrode 111d. The circular electrode is in contact with each of the fine wire electrode 111a to the fine wire electrode 111d, and is provided at the approximate center of the light emitting element 2 in a top view.

  Further, the contact portion 122 is provided in an opening located in a portion excluding the region of the transparent layer 140 immediately below the surface electrode 111 in a top view. For example, the contact portion 122 includes, as viewed from above, an outer peripheral portion 122a having a shape along the outer periphery of the light emitting element 2, a portion extending in a direction along one side of the light emitting element 2, and a direction along a diagonal line. A plurality of overhang portions including an extending portion. For example, the overhang portion 122b is formed to include a portion extending in the direction along the fine wire electrode 111d and a portion extending in the direction along the fine wire electrode 111a. Similarly, the overhang portion 122c is formed including a portion extending in the direction along the fine line electrode 111a and a portion extending in the direction along the fine line electrode 111b.

[Third Embodiment]
FIG. 7 shows a schematic top view of a light emitting device according to the third embodiment of the present invention, and FIG. 8 shows an outline of a cross section of the light emitting device according to the third embodiment of the present invention.

  The light-emitting element 3 according to the third embodiment has substantially the same configuration as the light-emitting element 1 according to the first embodiment, except that a current is supplied from the upper surface side of the light-emitting element 3. Therefore, detailed description is omitted except for the differences.

  Referring to FIG. 7, the light-emitting element 3 according to the third embodiment includes a semiconductor multilayer structure 10, a surface electrode 112 electrically connected to a partial region of one surface of the semiconductor multilayer structure 10, a surface A first pad electrode 115a as a wire bonding pad provided on a part of the surface of the electrode 112, a contact part 123 in ohmic contact with a part of the other surface of the semiconductor multilayer structure 10, and a contact part 123 are provided. A transparent layer 140 provided in contact with the other surface of the semiconductor multilayer structure 10 excluding a region being present, and a reflective part 130 provided on the surface of the contact portion 123 and the transparent layer 140 opposite to the surface in contact with the semiconductor multilayer structure 10. Prepare. The adhesion layer 201 according to the third embodiment is provided on the opposite side of the bonding layer 202 that is mechanically bonded to the bonding layer 136 of the reflective portion 130 and the surface of the bonding layer 202 that is in contact with the reflective portion 130. Barrier layer 204 to be provided. Note that the support substrate 20 according to the third embodiment can also be formed from a non-conductive material, such as a glass substrate or a sapphire substrate.

  Here, in the light emitting element 3 according to the present embodiment, a partial region of the semiconductor multilayer structure 10 is removed from one surface of the semiconductor multilayer structure 10 to the other surface. Then, the second pad electrode 115b is provided in the contact portion 123 corresponding to the region from which the semiconductor multilayer structure 10 has been removed. The surface of the first pad electrode 115a and the surface of the second pad electrode 115b are exposed in the same direction. The second pad electrode 115b is provided on a part of the contact portion 123 exposed to the outside in the region where the semiconductor multilayer structure 10 is removed. Thereby, the current supplied to the second pad electrode 115 b is supplied to the semiconductor multilayer structure 10 through the contact portion 123.

(About the positional relationship of the electrodes)
As shown in FIG. 7, the surface electrode 112 has a circular electrode formed in a substantially circular shape on the n-type cladding layer 103 and a plurality of linear electrodes electrically connected to the circular electrode. Formed. In FIG. 7, the circular electrode is not shown because it is located immediately below the first pad electrode 115a.

  The surface electrode 112 is provided in contact with the n-type contact layer 101 and has, for example, a substantially comb shape when viewed from above. As an example, the surface electrode 112 includes a thin wire electrode 112a provided in the vicinity of one side of the light-emitting element 3 and substantially horizontally on the one side, and a surface of the light emitting element 3 in the vicinity of the opposite side of the one side. The fine wire electrode 112c is provided, and the fine wire electrode 112b is provided between the fine wire electrode 112a and the fine wire electrode 112c and at a position where the distance from the fine wire electrode 112a and the distance from the fine wire electrode 112c are substantially equal.

  Further, the surface electrode 112 extends in a direction perpendicular to the longitudinal direction of the fine wire electrode 112a, the fine wire electrode 112b, and the fine wire electrode 112c, and the fine wire electrode 112a is at the end of the fine wire electrode 112a, the fine wire electrode 112b, and the fine wire electrode 112c. The thin wire electrode 112b and the thin wire electrode 112c are electrically connected to each other, and the thin wire electrode 112d is a circular electrode positioned immediately below the region where the first pad electrode 115a is provided. In the third embodiment, the first region of the contact portion 123 for the thin wire electrode 112d does not exist. The lengths of the fine wire electrode 112a and the fine wire electrode 112b are substantially equal, and the length of the fine wire electrode 112c provided farthest from the first pad electrode 115a is longer than the length of the fine wire electrode 112a and the length of the fine wire electrode 112b. Formed short. The circular electrode of the surface electrode 112 is provided at a position including the intersection of the fine wire electrode 112a and the fine wire electrode 112d.

  Further, the contact portion 123 is provided in an opening provided in the transparent layer 140 and is provided in a region other than directly below the surface electrode 112 according to the shape of the surface electrode 112 in a top view. The contact part 123 is provided on the other surface of the semiconductor multilayer structure 10 so as to have a shape capable of diffusing current substantially uniformly.

  For example, the contact portion 123 has a substantially comb shape like the surface electrode 112. As an example, the contact portion 123 is provided close to one side of the light emitting element 3 in a top view, and is close to the linear portion 123a that is substantially horizontal to the one side and the opposite side of the one side. A linear portion 123d that is substantially horizontal to the opposite side, a linear portion 123b that is provided closer to the linear portion 123a than the linear portion 123d, and a linear portion 123d that is closer to the linear portion 123a. And a linear portion 123c provided.

  Furthermore, the contact part 123 extends in a direction perpendicular to the longitudinal direction of the linear part 123a, the linear part 123b, the linear part 123c, and the linear part 123d, and the linear part 123a, the linear part 123b, the line A linear portion 123e that electrically connects each of the linear portion 123a, the linear portion 123b, the linear portion 123c, and the linear portion 123d at the ends of the linear portion 123c and the linear portion 123d, and the second pad And a circular portion located immediately below a region where the electrode 115b is provided. Note that the circular portion of the contact portion 123 is not shown in FIG. 7 because it is located immediately below the second pad electrode 115b.

  Moreover, the linear part 123a is formed shorter than the other linear parts, and the linear part 123d is formed longer than the other linear parts. Moreover, the length of the linear part 123b and the length of the linear part 123c are formed substantially equal. And the linear part 123a, the linear part 123b, the linear part 123c, and the linear part 123d are arrange | positioned at substantially the same space | interval, respectively. The circular part of the contact part 123 is provided in a region including the intersection of the linear part 123d and the linear part 123e, and is provided at a diagonal position of the first pad electrode 115a in the top view of the light emitting element 3. It is done.

  Moreover, the linear part 123a and the linear part 123b are arrange | positioned in the position which pinches | interposes the linear electrode 112a by the top view. As an example, the first pad electrode 115a and the second pad electrode 115b are formed in a circular shape having a diameter of 100 μm, and the plurality of linear electrodes and the plurality of linear portions are formed in a linear shape having a width of 10 μm. The

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1, 2 and 3 Light emitting element 1a Semiconductor laminated structure 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i Junction structure 10 Semiconductor laminated structure 10a Side surface 10b Side surface 11 Semiconductor laminated structure 20 Support substrate 20a Support structure 100 n-type GaAs substrate 101 n-type contact layer 102 etching stop layer 103 n-type cladding layer 103a uneven portion 105 active layer 107 p-type cladding layer 109 p-type contact layers 110, 111, 112 surface electrodes 110a, 110b, 110c, 110d Electrode 115 Pad electrode 115a First pad electrode 115b Second pad electrode 120, 122, 123 Contact part 120a Peripheral part 120b, 120c, 120d, 120e Thin line part 130 Reflecting part 132 Reflecting layer 134, 204 Barrier layer 136, 202 If layer 136a, 202a bonding surface 140 transparent layer 140a opening 200, 201 contact layer 206 contacts the electrode 210 back-surface electrode

Claims (4)

A light-emitting element having a substantially square shape in top view,
A first conductivity type first semiconductor layer; a second conductivity type second semiconductor layer different from the first conductivity type; and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer. A semiconductor laminated structure;
A surface electrode having a center electrode provided on one surface of the semiconductor multilayer structure, and a thin wire electrode extending from an outer periphery of the center electrode;
A plurality of portions that are provided in parallel along the fine wire electrode in a portion of the other surface of the semiconductor multilayer structure except directly under the surface electrode, and form a first current path that is the shortest current route between the fine wire electrode. A contact portion having a first region and a second region connecting the plurality of first regions,
The first semiconductor layer, the second semiconductor layer, and the active layer are made of n-type AlGaInP, p-type AlGaInP, and undoped AlGaInP, respectively.
The shortest current path between the surface electrode and the contact portion is the first current path ,
Ratio of the pre-Symbol first current path is greater than the ratio of the second current path is a current path between the surface electrode and the contact portion except for the first current path,
The first current path, and the square of the film thickness of the semiconductor multilayer structure, obtained by the square root of the sum of the squares of the minimum distance W ₁ in the top view between the surface electrode and the contact portion,
The second current path, the distance in top view between the semiconductor and the square of the thickness of the laminated structure, the shortest distance W becomes ₁ the portion and the contact portion of the surface electrodes except the portion of the surface electrode W Obtained by the square root of the sum of the square of ₂ and
The shortest distance W ₁ and the distance W ₂ satisfy a relationship of W ₁ <W ₂ ,
The first current path, have a distance of 20μm or 50μm or less, the ratio of the first current path, said with respect to the total length of the outer edge of the surface electrode, the distance is the shortest distance W ₁ in the top view of the contact portion Is defined as a percentage of the total length of the outer edge of the surface electrode,
The ratio of the second current path, with respect to the total length of the outer edge of the surface electrode, the distance in top view of the contact portion is defined as the length ratio of the total of the outer edge of the surface electrode serving as the distance W _2,
The fine wire electrode has a width of 10 μm,
The thin wire electrode is close to one side of the light emitting element and is substantially parallel to the one side, and is close to the opposite side of the one side and is substantially parallel to the opposite side. Between the second thin wire electrode provided, and between the first thin wire electrode and the second thin wire electrode, at a position where the distance from both the first thin wire electrode and the second thin wire electrode is substantially equal. The first thin wire electrode, the third thin wire electrode provided substantially parallel to the second thin wire electrode, and the lengths of the first thin wire electrode, the second thin wire electrode, and the third thin wire electrode, respectively. Extending in a direction substantially perpendicular to the direction, the first thin wire electrode in the vicinity of the middle of the longitudinal direction of the first thin wire electrode, the second thin wire electrode, and the third thin wire electrode, A second fine wire electrode and a fourth fine wire electrode provided in contact with the third fine wire electrode It includes a thin wire electrode,
The central electrode is a circular electrode having a diameter of 100 μm provided in a region including an intersection of the third fine wire electrode and the fourth fine wire electrode;
The width of the contact portion is 10 μm,
The contact portion is provided with a square outer peripheral portion along the outer periphery of the light emitting element, and extends substantially vertically from one side of the outer peripheral portion toward the center, and has one end in contact with the outer peripheral portion. A first thin wire portion; a second thin wire portion extending in a direction parallel to the first thin wire portion from the one side of the outer peripheral portion; and provided at a distance from the first thin wire portion; A third thin wire portion and a fourth thin wire portion that extend from the opposite side of the one side of the outer peripheral portion substantially vertically toward the center and are provided to face the first thin wire portion and the second thin wire portion, respectively. And a thin wire portion,
The first fine wire portion, the second fine wire portion, the third fine wire portion, and the fourth fine wire portion have substantially the same length,
A portion of the outer peripheral portion parallel to the first thin wire electrode, a portion of the first thin wire portion, a portion of the second thin wire portion, a portion of the third thin wire portion, and the A light emitting element in which any one of the fourth thin line portions corresponds to the first region . A support substrate having a reflective layer for reflecting the light emitted by the active layer;
A transparent layer provided between the reflective layer and the semiconductor multilayer structure;
The semiconductor laminated structure is supported on the support substrate through the transparent layer,
2. The light emitting device according to claim 1, wherein the contact portion penetrates through the transparent layer and electrically connects the semiconductor multilayer structure and the reflective layer.   The light-emitting element according to claim 2, wherein the semiconductor multilayer structure has a concavo-convex shape portion having an arithmetic average roughness of 100 nm or more on a part of the one surface. The shortest distance W ₁ is the shortest distance in top view between the thin wire electrode and the contact portion,
The distance W ₂ is the shortest distance in top view between the center electrode and the contact portion,
The light emitting element of any one of Claim 1 to 3.

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