Light-emitting semiconductor device

Abstract

Light-emitting semiconductor device (100; 200; 300), comprising: a semiconductor layer of a first conductivity type (32), an active layer (34) and a semiconductor layer of a second conductivity type (36) stacked in succession on a substrate (10); a first electrode (60) which is arranged on a section of the semiconductor layer of the first conductivity type (32); a current diffusion layer (40; 240) arranged on the semiconductor layer of the second conductivity type (36) and containing an opening (A, B; B'); a second electrode (70; 370) arranged on a section of the current diffusion layer (40; 240) and on an exposed section defined by the opening (A, B; B') of the current diffusion layer (40; 240), wherein the section of the current diffusion layer (40; 240) is near the opening (A, B; B'); and a reflective layer (50) which is arranged between the second electrode (70; 370) and the semiconductor layer of the second conductivity type (36) and is spaced apart from the current diffusion layer (40; 240).

Description

Technical field

[0001] The present invention relates to a light-emitting semiconductor device. Discussion of the state of the art

[0002] Light-emitting semiconductor devices provide light of various colors via electron-hole recombination, which occurs at pn junctions between p-doped and n-doped semiconductor layers when an electric current is applied. Light-emitting semiconductor devices exhibit a relatively long lifetime, low power consumption, better initial operating characteristics, and higher vibration resistance compared to filament-based light-emitting devices. Light-emitting semiconductor devices can incorporate group III nitride semiconductors, which can emit light with blue / short wavelengths.

[0003] US Patent 2010 / 0 155 752 A1 discloses a light-emitting semiconductor device comprising a first-type conductivity semiconductor layer, a first electrode, an insulating layer, and an electrode layer. The first electrode has at least one branch on the first-type conductivity semiconductor layer. The insulating layer is arranged on the first electrode. The electrode layer is arranged on the insulating layer.

[0004] KR 10 2011 0 083 292 A discloses a light-emitting semiconductor device with a substrate, a buffer layer formed on the substrate, a first semiconductor layer formed on the buffer layer, an active layer formed on the first semiconductor layer, a second semiconductor layer formed on the active layer and a transparent electrode with an opening formed on the second semiconductor layer.

[0005] US 2011 / 0 210 345 A1 discloses a light-emitting device. The light-emitting device comprises a light-emitting structural layer comprising a semiconductor layer of the first conductivity type, an active layer, and a semiconductor layer of the second conductivity type; a first electrode connected to the semiconductor layer of the first conductivity type; a current distribution layer on the semiconductor layer of the second conductivity type; an insulating layer on the first electrode; and a second electrode having at least one bridging section on the insulating layer and a first contact section that contacts the semiconductor layer of the second conductivity type and / or the current distribution layer.

[0006] US Patent 2010 / 0 072 487 A1 discloses a light-emitting diode (LED) and a manufacturing process for it. The LED comprises a substrate, a first semiconductor layer arranged on the substrate, an active layer arranged on the first semiconductor layer, a second semiconductor layer arranged on the active layer, a current-distribution modifying pattern, a first electrode, and a second electrode. The active layer and the second semiconductor layer form a mesa structure and expose a portion of the first semiconductor layer. The current-distribution modifying pattern is arranged on the second semiconductor layer. The first electrode is arranged on the first semiconductor layer exposed by the mesa structure and electrically connected to it. The second electrode is arranged on the current-distribution modifying pattern and electrically connected to the second semiconductor layer.

[0007] US 2011 / 0 012 152 A1 discloses a light-emitting device comprising: a light-emitting structure comprising a semiconductor layer of the first conductivity type, an active layer on the semiconductor layer of the first conductivity type, and a semiconductor layer of the second conductivity type on the active layer; a first electrode having at least one arm shape and contacting a portion of the semiconductor layer of the first conductivity type; an insulating layer covering the first electrode; and a second electrode comprising at least one arm shape, wherein the second electrode is arranged on at least one of the insulating layer and the semiconductor layer of the second conductivity type. Summary of the invention

[0008] The object of the invention is to provide a light-emitting semiconductor device with improved light uniformity and a reduced operating voltage.

[0009] The problem is solved by a light-emitting semiconductor device according to claim 1. Advantageous further developments are the subject of the dependent claims. Brief description of the characters

[0010] These and other features of the invention will become apparent through a detailed description of their exemplary embodiments with reference to the accompanying figures, in which: Fig. 1 a schematic cross-sectional view of a light-emitting semiconductor device according to an exemplary embodiment of the invention; Fig. 2 a schematic top view of the light-emitting semiconductor device of Fig. 1 is; Fig. 3 a cross-sectional view along line III-III of Fig. 2 is; Fig. 4 a cross-sectional view along line IV-IV of Fig. 2 is; Fig. 5 a cross-sectional view along line VV of Fig. 2 is; Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20, Fig. 21, Fig. 22, Fig. 23, Fig. 24 to Fig. 25 cross-sectional or top views are shown, illustrating a method for manufacturing a light-emitting semiconductor device according to an exemplary embodiment of the invention; Fig. 26 a schematic top view of a light-emitting semiconductor device according to an exemplary embodiment of the invention; Fig. 27 a schematic top view of a light-emitting semiconductor device according to an exemplary embodiment of the invention; and Fig. 28 is a view that illustrates the exemplary use of a light-emitting semiconductor device according to an exemplary embodiment of the invention. Detailed description of the embodiments

[0011] Exemplary embodiments of the invention are shown in more detail below with reference to the accompanying figures. However, the invention can be embodied in various embodiments and should not be interpreted as limiting the embodiments presented herein. For clarity, the thickness of the layers and areas may be exaggerated in the figures. It is also understood that when a layer is described as being "on" another layer or substrate, it may lie directly on top of the other layer or substrate, or intervening layers may be present. The same reference numerals in the description and in the figures consistently refer to the same components.

[0012] Fig. Figure 1 shows a schematic cross-sectional view of a light-emitting semiconductor device according to an exemplary embodiment of the invention and Fig. Figure 2 shows a schematic view of the light-emitting semiconductor device of Fig. 1.

[0013] With reference to Fig. 1 and Fig. Figure 2, the light-emitting semiconductor device 100 comprises a substrate 10, a buffer layer 20, and a light-emitting structure 30. The light-emitting structure 30 includes a semiconductor layer of first conductivity type 32, an active layer 34, and a semiconductor layer of second conductivity type 36. The first electrode 60 is arranged on a surface of the semiconductor layer of first conductivity type 32. A current diffusion layer 40 and a second electrode 70 are arranged on a surface of the semiconductor layer of second conductivity type 36.

[0014] A reflective layer 50 is formed under the first electrode 60 and the second electrode 70.

[0015] Substrate 10 can contain sapphire, SiC, MgAl₂O₄, MgO, LiAlO₂, LiGaO₂, GaN, or the like. For example, a sapphire substrate has a crystal structure with hexagonal-rhombohedral R3c symmetry and a lattice constant of 13.001 Å along the C-axis and 4.758 Å along the A-axis. The crystal structure of the sapphire substrate includes a C(0001) plane, an A(1120) plane, an R(1102) plane, and so on. The C-plane can be used as a nucleation layer for the growth of a nitride layer that is stable at high temperatures.

[0016] The buffer layer 20 serves to reduce the number of lattice defects in the light-emitting structure 30 when the first conductivity type semiconductor 32 has grown on the substrate 10. The buffer layer 20 may contain an undoped layer containing nitride or the like. For example, the buffer layer 20 serves to reduce a lattice constant mismatch between a sapphire substrate 10 and the first conductivity type semiconductor layer 32, which contains a gallium nitride (GaN) semiconductor layer. The buffer layer 20 may contain an undoped GaN layer, an undoped aluminum nitride (AlN) layer, an undoped indium gallium nitride (InGaN) layer, or the like, and may be grown with a thickness of tens to hundreds of Å at a relatively low temperature of approximately 500 °C to approximately 600 °C.In this case, the "undoped" semiconductor layer refers to a semiconductor layer that is not intentionally doped with a dopant, but may contain some dopants inevitably. For example, if a GaN semiconductor layer has been grown by a metal-organic chemical vapor deposition (MOCVD) process, dopants such as silicon (Si) or the like may be present in the semiconductor layer at a concentration of approximately 10. 14 / cm 3 up to about 10 18 / cm 3 to be available.

[0017] The semiconductor layers of the first and second conductivity types 32 and 36 can each be n-doped and p-doped semiconductors and can contain nitride semiconductors. The terms "first conductivity type" and "second conductivity type" refer to "n-doped" and "p-doped" respectively; however, the invention is not limited thereto. The semiconductor layers of the first and second conductivity types 32 and 36 can have a composition of AlxInyGa(1-xy)N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). For example, materials such as GaN, AlGaN, InGaN, or the like can be used for this purpose. The active layer 34, which is formed between the semiconductor layers of the first and second conductivity types 32 and 36, emits light at a predetermined energy level by electron-hole recombination. The active layer 34 can be a quantum mechanical multiple potential well orIt can be a multi-quantum-well (MQW) structure in which quantum well layers and quantum barrier layers are stacked alternately. For example, an InGaN / GaN structure can be used.

[0018] The current diffusion layer 40, which is formed on the semiconductor layer of the second conductivity type 36, can contain a transparent conductive oxide, such as indium tin oxide (ITO), Cu-doped indium oxide (CIO), zinc oxide (ZnO) or the like, with high light transmittance and low ohmic contact resistance.

[0019] In an exemplary embodiment, the current diffusion layer 40 includes a contact point opening A and a finger opening B, which expose the corresponding sections of the semiconductor layer of the second conductivity type 36. The second electrode 70 is in contact with the exposed sections of the semiconductor layer of the second conductivity type 36 via the contact point opening A and the finger opening B. The contact point opening A and the finger opening B are described in detail below.

[0020] The first and second electrodes 60 and 70 can be in contact with a conductive wire, a solder point, or the like, and serve to apply external electrical signals to the light-emitting structure 30. The first and second electrodes 60 and 70 can contain a light-reflecting material, such as Au, Ag, Al, Cu, Ne, or the like, and can have multilayer structures, such as Cr / Au, Ti / Au, or the like. In this case, the first electrode 60 is formed on a section of the upper surface of the semiconductor layer of the first conductivity type 32. The surface of the semiconductor layer of the first conductivity type 32 is provided by removing sections of the active layer 34 and the semiconductor layer of the second conductivity type 36. The second electrode 70 is formed on the semiconductor layer of the second conductivity type 36.

[0021] As in Fig. As shown in Figure 2, the first and second electrodes 60 and 70 each contain contact sections 60a and 70a and finger sections 60b and 70b. The finger sections 60b and 70b extend from the contact sections 60a and 70a and are narrower than the contact sections 60a and 70a. The finger sections 60b and 70b serve to distribute current evenly across the light-emitting structure 30. For example, the first electrode 60 contains a first contact section 60a and a first finger section 60b extending towards the second contact section 70a, and the second electrode 70 contains the second contact section 70a and the second finger section 70b extending towards the first contact section 60a.In this case, the first contact section 70a and the first finger section 60b are formed along an edge of the upper surface of the semiconductor layer of the first conductivity type 32.

[0022] Fig. Figure 3 shows a cross-sectional view along line III-III of Fig. 2.

[0023] As in Fig. 2 and Fig. As shown in Figure 3, the second contact section 70a of the second electrode 70 is larger than the contact opening A of the current diffusion layer 40 and covers the section of the semiconductor layer of the second conductivity type 36 that is exposed through the contact opening A of the current diffusion layer 40 and a section of the current diffusion layer 40 near the contact opening A.

[0024] Therefore, the second contact section 70a of the second electrode is in contact with the current diffusion layer 40 in a region C around the circumference of the contact opening A of the current diffusion layer. In an exemplary embodiment, the second contact section 70a can have contact regions of varying sizes. When the second contact section 70a is in contact with the current diffusion layer 40, the current flowing from the second electrode 70 to the semiconductor layer of the second conductivity type 36 is distributed through the current diffusion layer 40.

[0025] For example, the current is distributed evenly in one lateral direction across the current diffusion layer 40 and is prevented from being concentrated (or densified) in a lower region of the second contact section 70a of the second electrode 70, which is in contact with the semiconductor layer of the second conductivity type 36. This current distribution serves to increase the light uniformity of the light-emitting semiconductor device 100 and to reduce heat due to current density in the lower region of the second contact section 70a. This increases the reliability and luminance of the light-emitting semiconductor device 100.

[0026] The reflective layer 50 is formed between the semiconductor layer of the second conductivity type 36 and the second bridge section 70a and serves to prevent light emitted by the active layer from being absorbed by the electrodes 60 and 70.

[0027] As in Fig. As shown in Figure 2, the second finger section 70b of the second electrode 70 is in contact with the current diffusion layer 40 and a section of the semiconductor layer of the second conductivity type 36, which is exposed through the opening B of the current diffusion layer 40. For example, the second finger section 70b of the second electrode 70 is smaller than that of the finger opening B of the current diffusion layer 40, and the second finger section 70b of the second electrode 70 is longer than the finger opening B of the current diffusion layer 40.

[0028] Fig. Figure 4 shows a cross-sectional view along line IV-IV of Fig. 2.

[0029] As in Fig. As shown in Figure 4, the second finger section 70b of the second electrode 70 is formed within the finger opening B of the current diffusion layer 40, and the second finger section 70b of the second electrode 70 is separated from the current diffusion layer 40 in the IV-IV region of Fig. 2 spaced apart. Therefore, current flows to the semiconductor layer of the second conductivity type via the second finger section 70b without the current diffusion layer 40 distributing the current in a first direction that crosses a direction in which the second finger section 70b is located in the Fig. 4 shows area B.

[0030] Fig. Figure 5 shows a cross-sectional view along line VV of Fig. 2.

[0031] As in Fig. Figure 2 shows that the second finger section 70b of the second electrode 70 is longer than the finger opening B of the current diffusion layer 40 and accordingly, as in Fig. Figure 5 shows the current diffusion layer 40 in contact with an end section of the second finger section 70b of the second electrode.

[0032] The second finger section 70b of the second electrode 70 has an end section in contact with the current diffusion layer 40 and the current diffusion layer 40 serves to distribute the current directed to the semiconductor layer of the second conductivity type 36 through the end section of the second finger section 70b.

[0033] For example, the current is distributed evenly in one lateral direction across the current diffusion layer 40, preventing it from concentrating in the lower region of the second finger section 70b of the second electrode 70, which is in contact with the semiconductor layer of the second conductivity type 36. This current distribution serves to increase the light uniformity of the light-emitting semiconductor device and to reduce heat generated by current concentration in the lower region of the second finger section 70b. Therefore, the reliability and luminance of the light-emitting semiconductor device are increased. Furthermore, the increased luminance allows the light-emitting semiconductor device to operate at a lower operating voltage.

[0034] The following describes a method for manufacturing a light-emitting semiconductor device according to an exemplary embodiment. Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20, Fig. 21, Fig. 22, Fig. 23, Fig. 24 to Fig. Figure 25 shows cross-sectional or top views illustrating a method for manufacturing a light-emitting semiconductor device according to an exemplary embodiment of the invention.

[0035] As in Fig. As shown in Figure 6, the buffer layer 20 is formed on the substrate 10. However, in an exemplary embodiment, the buffer layer 20 can be omitted.

[0036] Next, regarding Fig. 7 the light-emitting structure 30, which contains the semiconductor layer of the first conductivity type 32, the active layer 34 and the semiconductor layer of the second conductivity type 36, is formed on the buffer layer 20.

[0037] Next, with reference to Fig. 8. The current diffusion layer 40 is formed on the semiconductor layer of the second conductivity type 36. The current diffusion layer 40 can contain a transparent conductive material, such as ITO, CIO, ZnO, or the like.

[0038] Next, with reference to Fig. 9 a first mask M1 is formed at the current diffusion layer 40. The first mask M1 is designed such that it covers a region 32a, as shown in Fig. 11 shown, defined, on which the first electrode is to be formed.

[0039] The first mask M1 can be formed by a photolithographic process or the like.

[0040] Using the first mask M1, the active layer 34, the semiconductor layer of the second conductivity type 36, and the current diffusion layer 40 are etched. The semiconductor layer of the first conductivity type 32 is partially etched to provide the area 32a on which the first electrode is to be formed.

[0041] The semiconductor layer of the second conductivity type 36, the current diffusion layer 40, and the active layer 34 can be etched using different etching solutions depending on the materials and thicknesses of the active layer 34, the semiconductor layer of the second conductivity type 36, and the current diffusion layer 40. For example, a wet etching process can be carried out using acidic or base chemicals.

[0042] Fig. Figure 10 is a schematic top view after the sections of the active layer 34, the semiconductor layer of the second conductivity type 36 and the current diffusion layer 40 have been etched. Fig. Figure 11 shows a cross-sectional view along line XI-XI of Fig. 10.

[0043] As in Fig. 10 and Fig. As shown in Figure 11, the region 32a of the semiconductor layer of the first conductivity type 32 is exposed by etching the active layer 34, the semiconductor layer of the second conductivity type 36, and the current diffusion layer 40 using the first mask M1. As shown in Fig. Figure 10 shows the first electrode 60 being formed on area 32a.

[0044] Fig. 12, Fig. 13, Fig. 14, Fig. 15 to Fig. 16 show cross-sectional views along line III-III of Fig. 2 of a representation of a manufacturing process of a light-emitting semiconductor device according to an exemplary embodiment of the invention.

[0045] Fig. Figure 12 shows that a second mask M2 is formed on the current diffusion layer 40. The current diffusion layer 40, exposed by the second mask M2, is partially etched to form the contact opening A and the finger opening B, which expose the semiconductor layer of the second conductivity type 36.

[0046] Next, with reference to Fig. 13 The reflective layer 50 is formed on the sections of the semiconductor layers of the first and second conductivity types 32 and 36 that are exposed through the contact point opening A and the finger opening B. The reflective layer 50 is formed within the contact point opening A without being in contact with the current diffusion layer 40.

[0047] For example, if the contact point opening A is formed by etching the current diffusion layer 40 in a wet etching process using the second mask M2 as the etching mask, the contact point opening A contains an undercut section formed beneath the second mask M2. Subsequently, if the reflective layer 50 is formed using the second mask M2, the reflective layer 50 is formed within the contact point opening A without contacting the current diffusion layer 40. For example, the reflective layer 50 can be formed using a physical vapor deposition process, such as a low-level coverage sputtering process.

[0048] Next, with reference to Fig. 14 a third mask M3 for forming the first and second electrodes on the light-emitting structure 30, which contains the current diffusion layer 40 formed therein.

[0049] The third mask M3 is designed such that it has a larger opening E than the contact point opening A, which is formed in the current diffusion layer 40.

[0050] Next, with reference to Fig. 15 a metallic layer M was deposited on the third mask M3 to form the first and second electrodes 60 and 70.

[0051] The metallic layer M can consist of a metal with high electrical conductivity. The metallic layer M can be formed by a coating process, a sputtering process, a deposition process, or the like.

[0052] Next, with reference to Fig. 16 the third mask M3 with the metallic layer M deposited on it is removed and the first and second electrodes 60 and 70 are formed.

[0053] This means that the second contact section 70a of the second electrode 70 and the current diffusion layer 40 are in contact with each other along the circumference of the contact opening A of the current diffusion layer 40.

[0054] Fig. 17, Fig. 18, Fig. 19, Fig. 20 to Fig. Figure 21 shows cross-sectional views along line IV-IV of Fig. 2 of a representation of a manufacturing process of a light-emitting semiconductor device according to an exemplary embodiment of the invention.

[0055] With reference to Fig. 17. The second mask M2 is created using the same process as in Fig. Figure 12 shows the formation on the current diffusion layer 40. The second mask M2 defines and exposes an area of ​​the current diffusion layer 40 in which the finger opening B is to be formed.

[0056] Next, with reference to Fig. 18 The finger opening B is formed by partially etching the exposed current diffusion layer 40 using the second mask M2 as an etching mask. The width of the finger opening B is larger than that of finger section 70b of the second electrode 70, and the length of the finger opening B is shorter than that of finger section 70b of the second electrode 70.

[0057] The reflective layer 50 is then formed on the portion of the semiconductor layer of the second conductivity type 36 that is exposed through the finger opening D. The reflective layer 50 is formed within the finger opening B, without being in contact with the current diffusion layer 40.

[0058] For example, if the finger opening B is formed by etching the current diffusion layer 40 in a wet etching process using the second mask M2 as the etching mask, the finger opening B contains an undercut section formed beneath the second mask M2. Subsequently, the reflective layer 50 is formed within the finger opening B using the second mask M2, without being in contact with the current diffusion layer 40. The reflective layer 50 can be formed using a physical vapor deposition process, such as a low-step coverage sputtering process.

[0059] Next, with reference to Fig. 19 using the in Fig. In the same process shown in Figure 14, the third mask M3 is formed to form the first and second electrodes on the light-emitting structure 30, which contains the current diffusion layer 40 formed on it.

[0060] The third mask M3 contains a smaller opening F than the finger opening B formed in the current diffusion layer 40.

[0061] Next, regarding Fig. 20 a metal layer M deposited on the third mask M3 to form the second electrode 70.

[0062] The metal layer M contains a metal with high electrical conductivity through a coating process, sputtering process, deposition process or the like.

[0063] Next, with reference to Fig. 21 the third mask M3 with the metal layer M deposited on it is removed to form the second electrode 70.

[0064] Here, the second electrode 70 and the current diffusion layer 40 do not touch each other. The second electrode 70 is smaller than the reflective layer 50. In an exemplary embodiment, the second electrode 70 and the reflective layer 50 can be the same size, or one of them can be larger than the other.

[0065] Fig. 22, Fig. 23, Fig. 24 to Fig. 25 show cross-sectional views along line VV of Fig. 2, which describe a manufacturing process of a light-emitting semiconductor device according to an exemplary embodiment.

[0066] As in Fig. As shown in Figure 22, the current diffusion layer 40 is formed on the semiconductor layer of the second conductivity type.

[0067] Next, with reference to Fig. 23 using the in Fig. In the same process shown in Figure 14, the third mask M3 is formed to form the second electrode 70 on the current diffusion layer 40.

[0068] Next, with reference to Fig. 24 the metal layer M on the third mask M3 was deposited to form the second electrode 70.

[0069] The metal layer M can contain a metal with high electrical conductivity through a coating process, a sputtering process, a deposition process or the like.

[0070] Next, with reference to Fig. 25 The third mask M3 with the metal layer M deposited on it is removed to form the second electrode 70. When the current diffusion layer 40 is in contact with the second electrode 70, the current diffusion layer 40 serves to distribute the current directed towards the second electrode 70 laterally.

[0071] Next, although not shown, an insulating layer is formed to cover the light-emitting structure containing the first and second electrodes 60 and 70 formed on it. Subsequently, a photolithographic process is carried out to expose the first and second contact sections 60a and 70a of the first and second electrodes 60 and 70, respectively.

[0072] According to an exemplary embodiment, the second electrode 70 is in contact with the current diffusion layer 40 and the semiconductor layer of the second conductivity type 36, and thus the current directed by the second electrode 70 to the semiconductor layer of the second conductivity type 36 is distributed laterally across the semiconductor layer of the second conductivity type 36 by the current diffusion layer 40. For example, the current diffusion layer 40 serves to distribute the current directed to the second electrode 70 laterally and to reduce current density in the lower region of the second electrode 70. The lateral distribution of the current across the semiconductor layer of the second conductivity type 36 increases the light uniformity of the light-emitting semiconductor device.

[0073] If the current is prevented from being concentrated (or compressed) in the lower region of the second electrode 70, the light-emitting semiconductor device 100 will be operated at a lower operating voltage.

[0074] Fig. Figure 26 shows a schematic top view of the light-emitting semiconductor device according to an exemplary embodiment of the invention. The light-emitting semiconductor device 200 of Fig. 26 is essentially similar to the light-emitting semiconductor device 100 of Fig. 1 with the exception of a current diffusion layer 240.

[0075] As in Fig. As shown in Figure 26, the current diffusion layer 240 contains three finger openings B'. The three finger openings B' are spaced apart from each other. The number of finger openings B' is not limited and can be two or more than three. The further description refers to the differences of the light-emitting semiconductor device of Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 directed and towards the description of the elements which are the same as those of the light-emitting semiconductor device of Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. If there are 5, it will be waived.

[0076] For example, the finger opening B', which is formed in the current diffusion layer 140, contains three openings. The second finger section 70b of the second electrode 70 and the current diffusion layer 240 are in contact with each other via the finger openings B'.

[0077] This distributes the current directed via the second electrode 70 to the semiconductor layer of the second conductivity type 36 through the current diffusion layer 240 via the semiconductor layer of the second conductivity type 36.

[0078] In an exemplary embodiment, the contact areas between the second finger section 70b of the second electrode 70 and the current diffusion layer 240 can be increased. If the in Fig. By separating the 26 contact areas shown, the current is distributed more effectively and the light uniformity of the light-emitting semiconductor device is increased.

[0079] Fig. Figure 27 shows a schematic view of a light-emitting semiconductor device according to an embodiment of the present invention. The light-emitting semiconductor device 300 is essentially identical to the light-emitting semiconductor device 100 of Fig. 2 with the exception of a second electrode 170'. The further description refers to the differences to the light-emitting semiconductor device of Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 directed and towards the description of the elements which are the same as those of the light-emitting semiconductor device of Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. If there are 5, it will be waived.

[0080] In the light-emitting semiconductor device 300, a second finger section 370b of the second electrode 370 is formed at one end of the finger opening B. The second electrode 370 comprises two sections 370a and 370b, which are spaced apart from each other. The second finger section 370b is a section that is separated from a body section 370a, which covers the contact opening A. The second finger section 370b receives the current from the body section 370a via the semiconductor layer of the second conductivity type 36 and distributes the current via the semiconductor layer of the second conductivity type 36 through the current diffusion layer 240.

[0081] As described above, the second electrode can have different finger section shapes and / or a finger opening of a current diffusion layer can have different shapes when the second finger section of the second electrode is in direct contact with the semiconductor layer of the second conductivity type exposed through the finger opening.

[0082] A light-emitting semiconductor device according to an exemplary embodiment can be used in various technical fields.

[0083] Fig. Figure 28 shows a view illustrating the exemplary use of a light-emitting semiconductor device according to an exemplary embodiment of the invention. With reference to Fig.Figure 28 comprises a lighting device 300, a light-emitting module 301, a structure 304 with the light-emitting module mounted thereon, and a power supply unit 303. One or more light-emitting semiconductor devices 302, according to an exemplary embodiment of the invention, are arranged on the light-emitting module 301. For example, the light-emitting semiconductor devices 302 can be individually mounted on the light-emitting module 301 or can be provided as a housing. The power supply unit 303 includes an interface part 305, which receives power, and a power control part 306, which controls the power supply to the light-emitting module 301. The interface part 305 can include a fuse for blocking overcurrent and an electromagnetic interface (EMI) filter, which shields against EMI signals.

[0084] When AC power is received as input power, the power control unit 306 can include a rectifier that converts AC power to DC power and a constant voltage controller that converts the DC power to a voltage suitable for the light-emitting module 301. For example, if the power supply unit is a DC power source (e.g., a battery) with a voltage suitable for the light-emitting module 301, the rectifier and the constant voltage controller can be omitted. For example, if the light-emitting module 301 is used with AC LEDs, AC power can be supplied directly to the light-emitting module 301, thus eliminating the need for the rectifier and the constant voltage controller. Furthermore, the power control unit can control the color temperature or similar parameters, and a variety of illumination levels can be achieved according to human sensitivity.The power supply unit 303 may also include a feedback circuit that compares the amount of light emitted by the light-emitting devices 302 with a predetermined amount of light, and a memory that stores information about a desired luminance, color rendering and the like.

[0085] The lighting device 300 can be used as a backlight unit or a lamp in a display device, such as a liquid crystal display (LCD) with a display panel, an indoor lighting device, such as a flat panel light device or the like, and an outdoor lighting device, such as a street light, an electric sign, or the like. The lighting device 300 can also be used in various lighting devices for a vehicle, such as a car, a ship, an aircraft, or the like. Furthermore, the lighting device 300 can be used in a household appliance, such as a TV or a refrigerator, in a medical device, and the like.

[0086] As explained above, in a light-emitting semiconductor device according to an exemplary embodiment of the invention, the phenomenon in which current is concentrated on a limited area is significantly reduced, thus increasing light uniformity and reducing the operating voltage.

[0087] Furthermore, a simplified manufacturing process for the light-emitting semiconductor device according to an exemplary embodiment reduces the manufacturing costs of the light-emitting semiconductor device.

Claims

[1] Light-emitting semiconductor device (100; 200; 300), comprising: a semiconductor layer of a first conductivity type (32), an active layer (34) and a semiconductor layer of a second conductivity type (36) stacked in succession on a substrate (10); a first electrode (60) which is arranged on a section of the semiconductor layer of the first conductivity type (32); a current diffusion layer (40; 240) arranged on the semiconductor layer of the second conductivity type (36) and containing an opening (A, B; B'); a second electrode (70; 370) arranged on a section of the current diffusion layer (40; 240) and on an exposed section defined by the opening (A, B; B') of the current diffusion layer (40; 240), wherein the section of the current diffusion layer (40; 240) is near the opening (A, B; B'); and a reflective layer (50) which is arranged between the second electrode (70; 370) and the semiconductor layer of the second conductivity type (36) and is spaced apart from the current diffusion layer (40; 240). [2] Light-emitting semiconductor device (100; 200; 300) according to claim 1, wherein the second electrode (70; 370) comprises a contact point section (70a; 370a) and a finger section (70b; 370b) extending from the contact point section (70a; 370a). [3] Light-emitting semiconductor device (100; 200; 300) according to claim 2, wherein the finger section (70b; 370b) is narrower than the contact point section (70a; 370a). [4] Light-emitting semiconductor device (100; 200; 300) according to claim 2 or 3, wherein the opening (A, B; B') includes a contact point opening (A) and a finger opening (B; B'), wherein the contact point section (70a; 370a) and the finger section (70b; 370b) with semiconductor layer of the second conductivity type (36) are connected via the contact point opening (A) and the finger opening (B; B'), respectively. [5] Light-emitting semiconductor device (100; 200; 300) according to claim 4, wherein the contact point section (70a; 370a) covers the contact point opening (A) and partially covers a section of the current diffusion layer (40; 240) around the contact point opening (A), and the finger section (70b; 370b) partially covers the finger opening (B; B') and partially covers a section of the current diffusion layer (40; 240) at one end of the finger opening (B; B'). [6] Light-emitting semiconductor device (100; 300) according to claim 4, wherein the contact point opening (A) is smaller than the contact point section (70a; 370a) of the second electrode (70; 370), and wherein the finger opening (B) is elongated in a first direction, wherein the finger opening (B) is wider than the finger section (70b; 370b) of the second electrode (70; 370) in a second direction which crosses the first direction and is shorter than the finger section (70b; 370b) of the second electrode (70; 370) in the first direction. [7] Light-emitting semiconductor device (200) according to claim 4, wherein the contact point opening (A) is smaller than the contact point section (70a) of the second electrode, and wherein the finger opening (B') contains a plurality of finger openings spaced apart from each other along a first direction, each of the plurality of finger openings being wider than the finger section (70b) of the second electrode (70) in a second direction intersecting the first direction and shorter than the finger section (70b) of the second electrode (70) in the first direction. [8] Light-emitting semiconductor device (100; 200; 300) according to any one of claims 1 to 7, wherein the section of the current diffusion layer (40; 240) covered by the second electrode (70; 370) surrounds the opening (A) of the current diffusion layer (40; 240). [9] Light-emitting semiconductor device (100; 200; 300) according to any one of claims 1 to 8, wherein the reflective layer (50) is arranged under the first electrode (60) and the second electrode (70; 370). [10] Light-emitting semiconductor device (100; 200; 300) according to any one of claims 1 to 9, wherein the second electrode (70; 370) is directly connected to the semiconductor layer of the second conductivity type (36) through the opening (A, B, B').

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