KR101370575B1 - Semiconductor light emimitting device - Google Patents

Abstract

The present disclosure provides a non-conductive reflective film formed on a second semiconductor layer to reflect light from an active layer to a side of a first semiconductor layer, which is a growth substrate, comprising: a non-conductive reflective film having a distributed Bragg reflector designed based on light converted in a phosphor part; It relates to a semiconductor light emitting device comprising a.

Description

Technical Field [0001] The present invention relates to a semiconductor light emitting device,

The present disclosure relates generally to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device having a light reflecting surface.

Here, the semiconductor light emitting element means a semiconductor light emitting element that generates light through recombination of electrons and holes, for example, a group III nitride semiconductor light emitting element. The Group III nitride semiconductor is made of a compound of Al (x) Ga (y) In (1-x-y) N (0? X? 1, 0? Y? 1, 0? X + y? A GaAs-based semiconductor light-emitting element used for red light emission, and the like. The semiconductor light emitting device may be in the form of a chip, a package including a phosphor, a COB, or the like.

Herein, the background art relating to the present disclosure is provided, and these are not necessarily meant to be known arts.

FIG. 1 shows an example of a semiconductor light emitting device disclosed in U.S. Patent No. 7,262,436. The semiconductor light emitting device includes a substrate 100, an n-type semiconductor layer 300 grown on the substrate 100, an active layer 400 grown on the n-type semiconductor layer 300, a p-type semiconductor layer 500 grown on the active layer 400, electrodes 901, 902 and 903 functioning as reflective films formed on the p-type semiconductor layer 500, And an n-side bonding pad 800 formed on the exposed n-type semiconductor layer 300. The conductivity of the n-type semiconductor layer 300 and the p-type semiconductor layer 500 may be reversed. Preferably, a buffer layer (not shown) is provided between the substrate 100 and the n-type semiconductor layer 300. A chip having such a structure, that is, a chip in which both the electrodes 901, 902, 903 and the electrode 800 are formed on the opposite side of the substrate 100, and the electrodes 901, 902, 903 function as a reflection film, is called a flip chip. Electrodes 901,902 and 903 may be formed of a highly reflective electrode 901 (e.g., Ag), an electrode 903 (e.g., Au) for bonding, and an electrode 902 (not shown) to prevent diffusion between the electrode 901 material and the electrode 903 material. For example, Ni). Such a metal reflection film structure has a high reflectance and an advantage of current diffusion, but has a disadvantage of light absorption by a metal.

The semiconductor light emitting device includes a substrate 100, a buffer layer 200 grown on the substrate 100, a buffer layer 200, a buffer layer 200 formed on the substrate 100, An active layer 400 grown on the n-type semiconductor layer 300, a p-type semiconductor layer 500 grown on the active layer 400, and a p-type semiconductor layer 500 grown on the n- A p-side bonding pad 700 formed on the transparent conductive film 600, and an n-side bonding pad (not shown) formed on the n-type semiconductor layer 300 exposed by etching 800). A DBR (Distributed Bragg Reflector) 900 and a metal reflection film 904 are provided on the transmissive conductive film 600. According to this structure, although the absorption of light by the metal reflection film 904 is reduced, the current diffusion is less smooth than that using the electrodes 901, 902, and 903.

18 is a view showing an example of a semiconductor light emitting device disclosed in Japanese Laid-Open Patent Publication No. 2009-164423. The Bragg reflector 900 and the metal reflection film 904 are provided on a plurality of semiconductor layers 300, 400 and 500, And the metal reflection film 904 and the n-side bonding pad 800 are electrically connected to the external electrodes 1100 and 1200. In addition, The external electrodes 1100 and 1200 may be a lead frame of the package, or an electric pattern provided on a COB (Chip on Board) or a PCB (Printed Circuit Board). The phosphor 1000 may be conformally coated, or it may be mixed with an epoxy resin to cover the external electrodes 1100 and 1200. The phosphor 1000 is used for absorbing light generated in the active layer 400 and converting the light into light having a longer wavelength or shorter wavelength.

This will be described later in the Specification for Implementation of the Invention.

SUMMARY OF THE INVENTION Herein, a general summary of the present disclosure is provided, which should not be construed as limiting the scope of the present disclosure. of its features).

According to one aspect of the present disclosure, an according to one aspect of the present disclosure includes a first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and a first semiconductor layer and A plurality of semiconductor layers interposed between the two semiconductors and having an active layer generating light of a first wavelength through recombination of electrons and holes, the plurality of semiconductor layers sequentially grown using a growth substrate; A first electrode for supplying one of electrons and holes to the plurality of semiconductor layers; A second electrode for supplying the remaining one of electrons and holes to the plurality of semiconductor layers; A phosphor unit provided at a side of the first semiconductor layer that is a growth substrate and converting light of a first wavelength generated in the active layer into light of a second wavelength; And a non-conductive reflecting film formed on the second semiconductor layer to reflect light from the active layer to the first semiconductor layer side, which is the growth substrate side, comprising: a non-conductive reflecting film having a distributed Bragg reflector designed based on the light converted in the phosphor part. Provided is a semiconductor light emitting device comprising:

This will be described later in the Specification for Implementation of the Invention.

1 is a view showing an example of a semiconductor light emitting device shown in US Patent No. 7,262,436,
2 is a view showing an example of a semiconductor light emitting device disclosed in Japanese Laid-Open Patent Publication No. 2006-120913,
3 to 5 are views showing an example of a semiconductor light emitting device according to the present disclosure,
6 is a view showing another example of the semiconductor light emitting device according to the present disclosure,
7 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
8 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
9 and 10 illustrate still another example of the semiconductor light emitting device according to the present disclosure;
11 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
12 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
13 is a cross-sectional view taken along the line A-A 'in FIG. 12,
14 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
15 illustrates another example of the semiconductor light emitting device according to the present disclosure;
16 illustrates another example of the semiconductor light emitting device according to the present disclosure;
17 is an enlarged view of an area where an electrical connection is formed,
18 is a view showing an example of a semiconductor light emitting element disclosed in Japanese Patent Application Laid-Open No. 2009-164423,
19 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
20 is a view showing another example of a semiconductor light emitting device according to the present disclosure;
21 is a graph showing reflectance according to the wavelength of aluminum (Al), silver (Ag), and gold (Au).

The present disclosure will now be described in detail with reference to the accompanying drawing (s).

3 to 5 are views showing an example of a semiconductor light emitting device according to the present disclosure, and Fig. 3 is a sectional view taken along line A-A of Fig. 5 is a cross-sectional view taken along the line B-B in Fig. In Fig. 4, the non-conductive reflective film 91 and the electrode 92 are not shown for the sake of explanation.

The semiconductor light emitting device is grown on the substrate 10, the buffer layer 20 grown on the substrate 10, the n-type semiconductor layer 30 grown on the buffer layer 20, and the n-type semiconductor layer 30, An active layer 40 that generates light through recombination, and a p-type semiconductor layer 50 that is grown on the active layer 40. The substrate 10 is mainly made of sapphire, SiC, Si, GaN or the like, and the substrate 10 can be finally removed, and the buffer layer 20 can be omitted. The electrode 80 may be formed on the side of the n-type semiconductor layer 30 from which the substrate 10 is removed or on the side of the conductive substrate 10 when the substrate 10 is removed or has conductivity. The positions of the n-type semiconductor layer 30 and the p-type semiconductor layer 50 can be changed, and they are mainly composed of GaN in the III-nitride semiconductor light emitting device. Each semiconductor layer 20, 30, 40, 50 may be composed of multiple layers, and additional layers may be provided. An electrode 80 for supplying electrons to the n-type semiconductor layer 30 and an electrode 92 for supplying holes to the p-type semiconductor layer 50 are provided. A branch electrode 81 extending into the n-type semiconductor layer 30 forms a part of the electrode 80. [ The electrode 80 may have a height enough to be coupled to the package by using a separate bump, or may be deposited to a height sufficient to couple itself to the package as shown in FIG. The non-conductive reflective film (not shown) is formed on the p-type semiconductor layer 50 so that light from the active layer 40 is reflected toward the substrate 10 used for growth or toward the n-type semiconductor layer 30 when the substrate 10 is removed 91 are provided. The non-conductive reflective film 91 may be formed on a portion of the n-type semiconductor layer 30 and the electrode 80 which are etched and exposed. It should be borne in mind by those skilled in the art that the non-conductive reflective film 91 does not necessarily cover all the regions on the semiconductor layers 30 and 50 on the opposite side of the substrate 10. [ Non-conductive reflective film 91, but functions as a reflection film, and preferably made of a translucent material so as to prevent the absorption of light, for example, a translucent dielectric material such as SiO _x, TiO _x, Ta ₂ O _5, MgF ₂ Lt; / RTI > The non-conductive reflective film 91 has a lower refractive index than that of the p-type semiconductor layer 50 (e.g., GaN) in the case where the non-conductive reflective film 91 is made of SiO _x , so that light of a critical angle or more is partially reflected toward the semiconductor layers 30, 40, . On the other hand, when the non-conductive reflective film 91 is made of a distributed Bragg reflector (DBR, for example, a combination of SiO ₂ and TiO ₂ ), a larger amount of light is transmitted through the semiconductor layers 30, 50) side. 7 shows a dual structure in which the non-conductive reflective film 91 is composed of the distributed Bragg reflector 91a and the dielectric film 91b having a refractive index lower than that of the p-type semiconductor layer 50. [ A dielectric film 91b having a certain thickness is formed prior to the deposition of the distribution Bragg reflector 91a requiring precision so that the deposition material 50 having a heterogeneous and irregular shape existing on the semiconductor layers 30, , 60, 80, 81, and 93), it is possible to stably manufacture the distributed Bragg reflector 91a, and also to help reflect light. In the case of the dielectric film 91b, SiO ₂ is suitable as the material, and its thickness is suitably from 0.2 탆 to 1.0 탆. In the case of the distributed Bragg reflector 91a, when composed of TiO ₂ / SiO ₂ , each layer is designed to have an optical thickness of 1/4 of a given wavelength, the number of which is 4 to 20 pairs Do. The height of the branched electrodes 93 is suitably 0.5 mu m to 4.0 mu m. Too thin a thickness causes an increase in the operating voltage, while an excessively thick branch electrode can cause process stability and material cost increase. The electrode 92 is formed on the p-type semiconductor layer 50 in such a manner that the whole of the nonconductive reflective film 91 is formed on the p-type semiconductor layer 50 from the viewpoint of helping to reflect light from the active layer 30 toward the substrate 10 side or the n- Or a conductive reflective film covering almost the whole area. At this time, metals such as Al and Ag having high reflectance may be used. A branched electrode 93 extending from the electrode 92 to the p-type semiconductor layer 50 for supplying current (strictly supplying holes) is provided between the non-conductive reflective film 91 and the p-type semiconductor layer 50 Respectively. By introducing the branch electrodes 93, a foundation is provided for implementing the flip chip shown in Fig. 1 and the flip chip improved in both of the problems of the flip chip shown in Fig. An electrical connection 94 penetrating the non-conductive reflective film 91 in the vertical direction is provided for electrically communicating the electrode 92 with the non-conductive reflective film 91 and the branched electrode 93. A large number of electrical connections 94 should be formed and directly connected to the transmissive conductive film 60 provided on substantially the entire surface of the p-type semiconductor layer 50. In this case, the electrode 92 ) And the light-transmitting conductive film 60, as well as causing many problems in the manufacturing process. The present disclosure is characterized in that branch electrodes 93 are formed on a p-type semiconductor layer 50 or preferably a light-transmitting conductive film 60 prior to the formation of the non-conductive reflective film 91 and the electrode 92, So that stable electrical contact can be made between the electrodes. Al, Ag or the like having a good reflectivity is suitable as the material of the electrode 92, but materials such as Cr, Ti, Ni, or their alloys are suitable for stable electrical contact. Therefore, by introducing the branch electrode 93, It becomes easier to cope with necessary design specifications. Those skilled in the art should bear in mind that Al, Ag or the like having good reflectivity may also be used for the branch electrode 93. [ As described above, a light-transmitting conductive film 60 is preferably provided. In particular, in the case of p-type GaN, the current diffusion ability is lowered. When the p-type semiconductor layer 50 is made of GaN, most of the light-transmitting conductive film 60 should be supported. For example, a material such as ITO or Ni / Au may be used as the transparent conductive film 60. When the height of the branch electrode 93 reaches the electrode 92, the branch electrode 93 itself forms an electrical connection 94. It is not necessary to exclude that the electrode 92 is formed in the same manner as the p-side bonding pad 700 of FIG. 2, but light is absorbed by the p-side bonding pad 700 and the area of the non- Is not desirable. Those skilled in the art should not exclude that electrode 92 may be constructed by the mounting surface at the package level after fabrication of the chip, although this is not preferred. It is noted that the semiconductor light emitting device according to the present disclosure can be constituted by the constituent elements so far. However, since the branched electrode 93 itself absorbs light generated in the active layer 40, a light absorption prevention film 95 is preferably provided under the branched electrode 93 in order to prevent this. The light absorption prevention film 95 may have a function of reflecting a part or all of the light generated in the active layer 40 and may have a function of preventing a current from the branch electrode 93 from flowing directly below the branch electrode 93 Or may have both functions. For these functions, the light absorbing film 95 is a single layer of a p-type semiconductor layer 50 than the light-transmitting material having a lower refractive index (for example: SiO ₂₎ or a multilayer film (for _{example: Si0 2 / TiO 2 / SiO} 2) Or a combination of a distributed Bragg reflector or a single layer and a distributed Bragg reflector. The light absorption preventing film 95 may be made of a non-conductive material (for example, a dielectric film such as SiO _x or TiO _x ). Therefore, the light absorption preventing film 95 does not necessarily have to be made of a light-transmissive material, and it is not necessarily composed of a non-conductive substance. However, by using a translucent dielectric film, the effect can be further enhanced.

6 shows another example of the semiconductor light emitting device according to the present invention in which an opening 96 is provided in the light transmitting conductive film 60 such that the nonconductive reflecting film 91 is in contact with the p-type semiconductor layer 50 . The opening 96 may have various shapes such as a plurality of island shapes, a band shape, and the like. Absorbing part of the light generated in the active layer 40 is absorbed even in the case of ITO most commonly used as the translucent conductive film 60. As a result of forming the opening 96, absorption of light by the translucent conductive film 60 can be reduced. At this time, insufficient current diffusion into the p-type semiconductor layer 50 can be compensated for by the branch electrode 93. [ The description of the same reference numerals will be omitted.

8 is a view illustrating another example of a semiconductor light emitting device according to the present disclosure. An electrical connection 82 is provided through a substrate 10, a buffer layer 20, and an n-type semiconductor layer 30. The electrode 83 is provided in 10). The nonconductive reflective film 91 and the electrodes 92 can be formed on the entirety of the plurality of semiconductor layers 30 and 50 on the opposite side of the substrate 10. [

9 and 10 are diagrams illustrating still another example of the semiconductor light emitting device according to the present disclosure, and show a structure in which the transparent conductive film 60 is removed so that the branch electrode 93 directly contacts the light absorption prevention film 95. Doing.

11 is a view illustrating another example of the semiconductor light emitting device according to the present disclosure. Unlike FIG. 5, the light absorption prevention layer 95 is not provided.

12 is a view illustrating still another example of the semiconductor light emitting device according to the present disclosure, and FIG. 13 is a cross-sectional view taken along line AA ′ of FIG. 12. The first feature of this embodiment is that the branch electrodes 93 on the p-type semiconductor layer 50 are separated from each other and are connected to each other by the electrodes 92 through the respective electrical connections 94. The electrode 92 has a role of supplying a current to the branch electrode 93, a function of reflecting light, a function of dissipating heat, and a function of connecting the element and the outside. It is most preferable that all of the branch electrodes 93 are separated from each other. However, since two or more branch electrodes 93 are separated, branch portions connecting the branch electrodes 93 are removed, . The second feature of this embodiment is that the branch electrode 93 is elongated along one side (C) direction of the device. For example, in FIG. 12, the electrode 92 extends long toward the electrode 80. When the device is turned upside down by the elongate branch electrodes 93 and placed on a mounting portion (e.g., submount, package, COB (Chip on Board)), it can be placed without tilting. From this point of view, it is preferable to lengthen one electrode 93 to which the configuration of the device is permitted. In this disclosure, since the branch electrode 93 is placed under the non-conductive reflective film 91, it is also possible to extend long beyond the electrode 80. [ A third feature of this embodiment is that the electrode 80 is located on the non-conductive reflective film 91. [ The electrode 80 is connected to the branch electrode 81 through an electrical connection 82. The electrode 80 has the same function as the electrode 92. 3, the height of the side where the electrode 80 is located becomes higher, so that the height difference between the electrode 92 side and the electrode 80 side is reduced when the element is coupled with the mount portion, And this advantage is particularly large when using eutectic bonding. The fourth characteristic of this embodiment is that the branch electrode 81 can be arranged in the same manner as the branch electrode 93. [ The fifth feature of this embodiment is that the auxiliary heat-radiating pad 97 is provided. The auxiliary heat sink pad 97 has a function of emitting heat to the outside and / or a function of reflecting light, and is electrically separated from the electrode 92 and / or the electrode 80, (80). The auxiliary heat radiating pad 93 may be used for bonding. Particularly, in the case where the electrode 92 and the electrode 80 are electrically separated from each other, even if the electrode 92 and the electrode 80 are accidentally brought into electrical contact with the auxiliary radiating pad 93, There is no problem in the electrical operation of the battery. It should be borne in mind by those skilled in the art that this embodiment does not have to have all of the above five features.

14 is a diagram illustrating another example of the semiconductor light emitting device according to the present disclosure, and examples of the auxiliary heat dissipation pads 121, 122, 123, and 124 are illustrated between the electrode 92 and the electrode 80. Preferably the auxiliary radiator pads 121, 122, 123 and 124 are located between the branch electrodes 92 or between the branch electrodes 92 and the branch electrodes 81. Since the auxiliary heat radiating pads 121, 122, 123 and 124 are not formed on the branched electrodes 92, the entire surface of the element can be adhered to the mounting portion at a time of bonding (e.g., eutectic bonding). The auxiliary heat sink pad 121 and the auxiliary heat sink pad 122 are separated from the electrode 92 and the electrode 80. The auxiliary heat sink pad 123 is connected to the electrode 92, Is connected to the electrode (80).

FIG. 15 is a view showing another example of the semiconductor light emitting device according to the present disclosure, in which the branch electrodes 93 extend below the electrode 80 (over the reference line B). By introducing the branched electrodes 93 on the p-type semiconductor layer 50, current can be supplied to the required element region without restriction in the construction of the flip chip. Two electrical connections 94 and 94 are provided and the electrical connection 94 can be positioned where it is needed according to the requirements for current spreading. The left electrical connection 94 may be omitted. The electrode 92 also serves as an auxiliary heat radiating pad 97 (see FIG. 12). The current can be supplied by directly connecting the electrical connection 94 to the transmissive conductive film 60 even when there is no branched electrode 93. However, By introducing the branched electrode 93, it becomes possible to supply current even under the electrode 80 that supplies current to the n-type semiconductor layer 30. This also applies to the case of the electrical connection 82.

FIG. 16 is a view showing still another example of the semiconductor light emitting device according to the present disclosure, wherein the non-conductive reflecting film 91 is formed of multilayer dielectric films 91c, 91d, and 91e. For example, the non-conductive reflective film 91 may be composed of a dielectric film 91c made of SiO ₂ , a dielectric film 91d made of TiO ₂ , and a dielectric film 91e made of SiO ₂ , . Preferably, the non-conductive reflective film 91 is formed to include the DBR structure. The formation of the semiconductor light emitting device according to the present disclosure requires a structure such as the branch electrode 93 or the branch electrode 81 and the electrical connection 94 or the electrical connection 82). Therefore, after the production of the semiconductor light emitting device, the reliability of the device, such as the generation of leakage current, may be affected. Therefore, in forming the dielectric film 91c made of SiO ₂ , Needs to be. For this purpose, first, it is necessary to form the dielectric film 91c thicker than the thickness of the subsequent dielectric films 91d and 91e. Secondly, it is necessary to form the dielectric film 91c by a method more suitable for securing device reliability. For example, the chemical vapor deposition of a dielectric film (91c) with a SiO ₂ (CVD; Chemical Vapor Deposition), among them (preferably) plasma enhanced chemical vapor deposition; formed by (PECVD Plasma Enhanced CVD), and TiO ₂ A dielectric film 91d / SiO ₂ DBR / dielectric film 91e may be formed by physical vapor deposition (PVD), electron beam evaporation (Electron Beam Evaporation) or sputtering (sputtering) ) Or a thermal evaporation method, the function of the nonconductive reflective film 91 can be ensured while securing the reliability of the semiconductor light emitting device according to the present disclosure. (Step coverage) such as mesa etched regions because chemical vapor deposition is more advantageous than physical vapor deposition, especially electron beam deposition.

17 is an enlarged view of a region where the electrical connection is formed and includes a transmissive conductive film 60, a branched electrode 93 overlying the transmissive conductive film 60, a non-conductive reflective film 91 surrounding the branched electrode 93, An electrode 92 and an electrical connection 94 connecting the branch electrode 93 to the electrode 92 are shown. Generally, when an electrode, a branch electrode, and a bonding pad are formed in a semiconductor light emitting element, the metal layer is composed of a plurality of metal layers. The lowermost layer should have high bonding force with the light transmissive conductive film 60, and materials such as Cr and Ti are mainly used, and Ni, Ti, TiW and the like can also be used, and there is no particular limitation. For the top layer, Au is used for wire bonding or connection with external electrodes. When Ni, Ti, TiW, W or the like is used in accordance with the required specification between the lowest and the uppermost layers in order to reduce the amount of Au and to complement the characteristics of Au, , Al, Ag and the like are used. In the present disclosure, since the branch electrode 93 should be electrically connected to the electrical connection 94, Au may be considered as the uppermost layer. However, the present inventors have found that it is not suitable to use Au as the uppermost layer of the branch electrode 93. There is a problem in that when the non-conductive reflective film 91 is deposited on Au, the bonding force between the two is weak, so that it easily peels off. In order to solve such a problem, if the uppermost layer of the branch electrodes is made of a material such as Ni, Ti, W, TiW, Cr, Pd, or Mo instead of Au, the adhesive force to the non-conductive reflective film 91 to be deposited is maintained So that the reliability can be improved. Further, in the process (wet or dry etching) for forming the hole for the electrical connection 94 in the non-conductive reflective film 91, the above metal is sufficient to serve as a barrier, thereby assuring the stability of the subsequent process and electrical connection do.

19 is a view showing another example of a semiconductor light emitting device according to the present disclosure, the semiconductor light emitting device further comprises a phosphor (220). The phosphor 220 is mixed with an epoxy resin to form an encapsulant 230, and a semiconductor light emitting device is placed on the reflective cup 210. The electrode 80 and the electrode 92 are electrically connected to the outside through the conductive binders 240 and 250. The phosphor 220 may be conformally coated, directly applied, or positioned at a distance from the semiconductor light emitting device as shown in FIG. 18. The light emitted from the active layer 40 is absorbed by the phosphor 220 and is converted into long- or short-wavelength light L1 and exits to the outside, but some of the light L2 remains in the semiconductor light emitting device, or Reflected by the light source 210, the light is returned back to the inside of the semiconductor light emitting device, and it disappears to reduce the efficiency of the semiconductor light emitting device. In the case where the non-conductive reflecting film 91 has a distributed Bragg reflector 91-1, the reflection efficiency of the distributed Bragg reflector 91-1 depends on the wavelength. For example, when the light emitted from the active layer 40 is blue, the wavelength is 450 nm, and when the distribution Bragg reflector 91-1 is composed of a combination of SiO ₂ / TiO ₂ , the refractive index of SiO ₂ is n ₁ . If the refractive index of TiO ₂ is n ₂ , the thickness of SiO ₂ is adjusted based on 450 nm / 4n ₁ , and the thickness of TiO ₂ is adjusted based on 450 nm / 4n ₂ . However, when the phosphor 220 is a yellow phosphor (eg, YAG: Ce, (Sr, Ca, Ba) ₂ SiO ₄ : Eu), the wavelength of the phosphor 220 is 560 nm, so that the distribution Bragg adapted to blue light The reflector 91-1 is greatly reduced in efficiency. This problem can be solved by further introducing the distributed Bragg reflector 91-2 adapted to the wavelength of the phosphor 220 provided in the semiconductor light emitting element in the nonconductive reflecting film 91. This generalized screen, distributed Bragg reflector (91-1) is a λ _{Active / 4n 1, λ Active / 4n} 2 ( where, λ is the wavelength of the active layer _Active (40), n _1, n ₂ is a distributed Bragg reflector (91- 1) the refractive index of the materials), and the distribution Bragg reflector 91-2 is λ _Phosphor / 4n ₁ , λ _Phosphor / 4n ₂ , where λ _Phosphor is the wavelength of the phosphor 220, n ₁ , n ₂ is designed based on the index of refraction of the distribution Bragg reflector 91-2 materials. The fact that it is designed as a reference herein does not mean that the distribution Bragg reflector 91-1 must have a thickness meeting this criterion. The distribution Bragg reflector 91-1 can be formed slightly thicker or thinner than the reference thickness as necessary. However, this need does not change the fact that the distribution Bragg reflector 91-1 should be designed based on λ _Active / 4n ₁ , λ _Active / 4n ₂ . If the phosphor 220 is composed of various wavelengths such as blue, green, orange, red, and the like, a distribution Bragg reflector 91-2 may be added accordingly. Of course, some or all of the materials constituting the distributed Bragg reflector 91-1 and the materials constituting the Distributed Bragg reflector 91-2 may be different. By forming the distributed Bragg reflector 91-1 and the Distributed Bragg reflector 91-2 between 2 cycles and 10 cycles, respectively, it is possible to correspond to a desired wavelength, and it does not function even if it is formed below or longer cycles. .

FIG. 20 is a diagram illustrating still another example of the semiconductor light emitting device according to the present disclosure. The semiconductor light emitting device further includes a distribution Bragg reflector 91-3. This is the case where the phosphor 220 includes two materials having different wavelengths. The distribution Bragg reflector 91-2 is designed based on λ _Phosphor1 / 4n ₁ and λ _Phosphor1 / 4n ₂ , and the distribution Bragg reflector 91-3 is designed based on λ _Phosphor2 / 4n ₁ and λ _Phosphor2 / 4n ₂ . do. In general, when (λ _Phosphor1 >....> λ _Phosphorn ; where n is a positive integer), their placement within the distribution Bragg reflector 91 is problematic. Various arrangements are possible from the p-type semiconductor layer 50 in order of shortest wavelengths and in order of longest wavelengths. Further, in general, it is possible to design a distributed Bragg reflector of various wavelength bands in consideration of the wavelength of light and / or phosphor from the active layer 40. By arranging a distributed Bragg reflector designed on the basis of a relatively short wavelength on the side close to the p-type semiconductor layer 50, the light of this short wavelength is located far from the branch electrode 93 and the electrode 92. (3) and the absorption of light of a short wavelength by the electrode 92 can be fundamentally blocked. By arranging the distributed Bragg reflector designed on the basis of the relatively long wavelength on the side close to the p-type semiconductor layer 50, it is possible to consider the improvement of the reflectance of the diagonally incident light, instead of the perpendicular incident to the Distributed Bragg reflector. It has such an advantage.

It is also possible to place the distributed Bragg reflector made based on the shortest wavelength closest or farthest to the p-type semiconductor 50, and then intersect or mix the other two distributed Bragg reflectors. Is possible.

In addition, when the Bragg reflector is distributed for several wavelengths, the thickness of the non-conductive reflective film 91 may be too thick. Therefore, when the difference between the wavelengths of the two materials constituting the phosphor 220 is not large, the distribution considering all of them is considered. It is also possible to design Bragg reflectors. For example, it is possible to design a distributed Bragg reflector based on ((λ _Phosphor1 + λ _Phosphor2 ) / 2) / 4n ₁ , ((λ _Phosphor1 + λ _Phosphor2 ) / 2) / 4n ₂ . When the phosphor consists of wavelengths of 550 nm, 580 nm, and 600 nm, such a design is possible for 580 nm and 600 nm where the difference in wavelength is small.

In addition, when the phosphor is composed of wavelengths of 560 nm, 580 nm, and 600 nm, it is possible to reduce the thickness of the entire non-conductive reflecting film 91 by designing a distributed Bragg reflector together for 580 nm and 600 nm, which are thick wavelengths.

In addition, as described above, in designing the distribution Bragg reflector, it is possible to design the distribution Bragg reflector slightly longer than λ, that is, slightly thicker than the reference, instead of exactly matching λ / 4n ₁ and λ / 4n ₂ . When the Bragg reflector is introduced into the flip chip, the thickness of the non-conductive reflective film 91 may be increased, and when the electrical connection 94 is provided, it may be difficult to form the electrical connection 94. In order to improve this problem, only λ / 4n ₂ can be designed thick, not both the thickness of λ / 4n _{1 and} the thickness of λ / 4n ₂ . Further, even if both the thickness of λ / 4n _{1 and} the thickness of λ / 4n ₂ are thickened, it is possible to make the thickness of λ / 4n ₂ relatively thicker. For example, when the light emitted from the active layer 40 is blue, the wavelength is 450 nm, and when the distribution Bragg reflector is made of a combination of SiO ₂ / TiO ₂ , the refractive index of SiO ₂ is n ₁ (= 1.46), If the refractive index of TiO ₂ is n ₂ (= 2.4), the thickness of SiO ₂ is set on the basis of 450 nm / 4n ₁ , and the thickness of TiO ₂ is set on the basis of 450 nm / 4n ₂ . When the wavelength is changed from 450 nm to 500 nm (when designing a distributed Bragg reflector toward the longer wavelength), the larger the refractive index brings about the smaller thickness change. This brings about an improvement in the reflectance smaller than when both thicknesses are set to 500 nm, but an effect of improving the reflectance while reducing the increase in the thickness of the non-conductive reflecting film 91. This embodiment can be applied even when no phosphor 220 is introduced, and can also be applied to the distributed Bragg reflector 91-2 into which the phosphor 220 is introduced.

FIG. 21 shows reflectance according to the wavelengths of aluminum (Al), silver (Ag), and gold (Au). It is understood that the reflectivity of Al and Ag is excellent in a low wavelength band. It can be seen that the wavelength is better. Applying this to the semiconductor light emitting device according to the present disclosure shown in FIGS. 19 and 20, when the phosphor 220 contains a red phosphor, light having a shorter wavelength is treated by the non-conductive reflecting film 91, Red light emission or a wavelength band of 600 nm or more is provided with Au in the lowermost layer or lower region of the electrode 92, and can reflect using this Au. As a matter of course, it is also possible to include a distributed Bragg reflector adapted to the red light in the nonconductive reflecting film 91. It is also possible to provide Au in the lowermost or lower region of the electrode 80, the branch electrode 81, and the branch electrode 93. Here, the lower region means that a metal such as Cr or Ti, which has relatively higher adhesion than Au, can be added very thinly in the lowermost layer. In this case, Au can still maintain the reflection function. The technical idea according to the present disclosure shown in FIGS. 19 to 21 is applicable even when the branch electrode 93 is not provided, and the present disclosure should not be understood as only the sum of various features presented in the present disclosure. The auxiliary heat dissipation pad 97 and the auxiliary heat dissipation pads 121, 122, 123, and 124 shown in FIGS. 12 and 14 may also be configured as described above together with or only for the electrodes. The electrode 92 containing Au on the side facing the p-type semiconductor 50, the auxiliary heat dissipation pad 97, the auxiliary heat dissipation pads 121, 122, 123, 124, the branch electrode 93, the electrode 80, and the branch electrode 81 Etc. are called reflective metal layers.

Various embodiments of the present disclosure will be described below.

(1) a first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and a first semiconductor layer interposed between the first semiconductor layer and the second semiconductor layer and recombining electrons and holes for the first semiconductor layer; A plurality of semiconductor layers having an active layer for generating light of a wavelength; A plurality of semiconductor layers sequentially grown using a growth substrate; A first electrode for supplying one of electrons and holes to the first semiconductor layer; A second electrode supplying the other one of electrons and holes to the second semiconductor layer; A phosphor unit provided at a side of the first semiconductor layer that is a growth substrate and converting light of a first wavelength generated in the active layer into light of a second wavelength; And a non-conductive reflecting film formed on the second semiconductor layer to reflect light from the active layer to the first semiconductor layer side, which is the growth substrate side, comprising: a non-conductive reflecting film having a distributed Bragg reflector designed based on the light converted in the phosphor part. Semiconductor light emitting device comprising a. The first semiconductor layer may have n-type conductivity and the second semiconductor layer may have p-type conductivity, and their conductivity may be changed. The first electrode may have the form of the electrode 80 of FIG. 3 and the electrode 83 of FIG. 8 and may have various forms that can be formed directly on the first semiconductor layer when the substrate 10 is removed. have. The second electrode may have the form of the electrode 92 and / or the electrical connection 94 of FIG. 3, and may have various shapes in addition to the above. The phosphor part may be phosphor itself or may have various forms such as a combination of phosphor and encapsulating resin, and a conformal coated phosphor. Here, I want to say that it is designed based on light of a specific color. For example, the meaning that the wavelength of a yellow phosphor is 560 nm means the peak wavelength of this yellow phosphor. However, it will be apparent to those skilled in the art that the phosphor does not only emit light of the peak wavelength of this yellow phosphor. Therefore, due to the limitations of language technology in this specification, the meaning of words expressed as 'designed based on a specific wavelength' or 'designed based on light of a specific color' should not be interpreted as being very restrictive. This is to be interpreted to mean that it is designed for the characteristics of this particular yellow phosphor. In this case, it may be argued that the meaning of the word becomes unknown, but the meaning of designing the DBR based on the light emitted from the active layer and the designing of the DBR based on the light converted from the phosphor are those who are skilled in the art. It is self-evident to.

(2) The phosphor portion is converted into n wavelengths (n is an integer of 2 or more) including light of the first wavelength and the second wavelength, and the non-conductive reflective film is selected from the group consisting of light from the active layer and light from the phosphor portion. A semiconductor light emitting device, characterized in that it has at least two distribution Bragg reflector designed based on the light of two or more. The n wavelengths may be composed of wavelengths of green, yellow, red, and the like. It may be two or more distributed Bragg reflectors for light from at least two distributed Bragg reflector phosphor parts, but may include distributed Bragg reflectors for light from the active layer.

(3) The semiconductor light emitting device according to claim 2, wherein the at least two distributed Bragg reflectors are arranged in the order of the shortest reference wavelengths designed from the second semiconductor layer.

(4) The semiconductor light emitting device according to claim 2, wherein the at least two distributed Bragg reflectors are arranged in order of the reference wavelengths designed from the second semiconductor layer.

(5) n wavelengths include a second wavelength, a third wavelength, and a fourth wavelength, and a difference between the third wavelength and the fourth wavelength is the smallest among the differences between the three wavelengths, and the non-conductive reflecting film has the third wavelength and the third wavelength. A semiconductor light emitting device comprising one distribution Bragg reflector for four wavelengths.

(6) A semiconductor light emitting element comprising at least two reflectors having a distributed Bragg reflector designed in consideration of two wavelengths converted in the phosphor portion together.

(7) The semiconductor light emitting device according to claim 2, wherein the two wavelengths have the smallest difference between the wavelengths of the wavelengths converted by the phosphor part.

(8) The semiconductor light emitting device according to claim 2, wherein the two wavelengths are two wavelengths having the longest wavelength among the wavelengths converted in the phosphor part.

(9) A semiconductor light emitting element comprising a branch electrode interposed between the nonconductive reflecting film and the second semiconductor layer.

(10) A semiconductor light emitting element, wherein the second electrode contains gold (Au) on the side facing the second semiconductor layer.

(11) at least two distributed Bragg reflectors include a distributed Bragg reflector designed based on light from the active layer, wherein the non-conductive reflecting film comprises a dielectric film having a lower refractive index than the second semiconductor layer below the distributed Bragg reflector A semiconductor light emitting element.

(12) A semiconductor light emitting element, wherein the second electrode includes a branch electrode interposed between the dielectric film and the second semiconductor layer.

According to one semiconductor light emitting device according to the present disclosure, a new reflective film structure can be realized.

Further, according to another semiconductor light emitting device according to the present disclosure, a new type of flip chip can be realized.

In addition, according to another semiconductor light emitting device according to the present disclosure, it is possible to implement a reflective film structure in which a branch electrode is introduced.

In addition, according to another semiconductor light emitting device according to the present disclosure, it is possible to implement a flip chip introduced with a branch electrode.

In addition, according to another semiconductor light emitting device according to the present disclosure, it is possible to smooth heat radiation of the semiconductor light emitting device.

Further, according to another semiconductor light emitting device according to the present disclosure, branch electrodes are introduced to facilitate current spreading, and heat dissipation of the semiconductor light emitting device can be smoothed.

In addition, according to another semiconductor light emitting device according to the present disclosure, it is possible to design the heat radiation pad without significantly affected by the current diffusion function and the light reflection function by the electrode in the semiconductor light emitting device.

Further, according to another semiconductor light emitting device according to the present disclosure, it is possible to reduce the light absorption by the branch electrode.

In addition, according to another semiconductor light emitting device according to the present disclosure, it is possible to emit the light converted in the phosphor portion to the outside well.

Substrate (10) Semiconductor layer (30,50) Active layer (40)

Claims (14)

A first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and interposed between the first semiconductor layer and the second semiconductor layer, and having light of a first wavelength through recombination of electrons and holes A plurality of semiconductor layers having an active layer for generating a; A plurality of semiconductor layers sequentially grown using a growth substrate;
A first electrode for supplying one of electrons and holes to the plurality of semiconductor layers;
A second electrode for supplying the remaining one of electrons and holes to the plurality of semiconductor layers;
A phosphor unit provided at a side of the first semiconductor layer that is a growth substrate and converting light of a first wavelength generated in the active layer into light of a second wavelength; And,
A non-conductive reflector formed on the second semiconductor layer to reflect light from the active layer and light converted in the phosphor portion toward the first semiconductor layer, which is the growth substrate, and having a distribution Bragg reflector designed based on the light converted in the phosphor portion. A non-conductive reflective film; semiconductor light emitting device comprising a. The method according to claim 1,
The phosphor unit converts n wavelengths (n is an integer of 2 or more) including light of a first wavelength and a second wavelength,
The non-conductive reflecting film has at least two distributed Bragg reflectors designed on the basis of light of two or more selected from the group consisting of light from the active layer and light from the phosphor part. The method according to claim 1,
The at least two distributed Bragg reflectors comprise a distributed Bragg reflector designed on the basis of light from the active layer. The method according to claim 2,
And at least two distributed Bragg reflectors are arranged in the order of the shortest reference wavelengths designed from the second semiconductor layer. The method according to claim 2,
And at least two distributed Bragg reflectors are arranged in order of the reference wavelengths designed from the second semiconductor layer. The method according to claim 2,
The n wavelengths include a second wavelength, a third wavelength, and a fourth wavelength, and the difference between the third wavelength and the fourth wavelength is the smallest among the three wavelengths,
The non-conductive reflecting film has a distribution Bragg reflector for the third wavelength and the fourth wavelength, characterized in that the semiconductor light emitting device. The method according to claim 2,
At least two reflectors have a distribution Bragg reflector designed in consideration of the two wavelengths converted in the phosphor portion together. The method of claim 7,
And wherein the two wavelengths have the smallest difference between the wavelengths of the wavelengths converted by the phosphor part. The method of claim 7,
And the two wavelengths are two wavelengths having the longest wavelength among the wavelengths converted by the phosphor part. The method according to claim 1,
The second electrode includes a branch electrode interposed between the nonconductive reflecting film and the second semiconductor layer. The method according to claim 1,
A semiconductor light emitting device, characterized in that the second electrode contains gold (Au) on the side facing the second semiconductor layer. The method according to claim 2,
At least two distributed Bragg reflectors include a distributed Bragg reflector designed based on light from the active layer,
And the non-conductive reflecting film comprises a dielectric film having a lower refractive index than the second semiconductor layer under this distribution Bragg reflector. The method of claim 12,
The second electrode includes a branch electrode interposed between the dielectric film and the second semiconductor layer. The method according to claim 13,
Wherein the semiconductor is a Group III nitride semiconductor.

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