Source: http://www.patentsencyclopedia.com/app/20110210311
Timestamp: 2018-03-23 05:34:37
Document Index: 559882620

Matched Legal Cases: ['art 108', 'art 108', 'art 109', 'art 109', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 411', 'art 609']

Patent application number: 20110210311
21. A semiconductor light emitting device comprising: a substrate; a plurality of light emitting cells arranged on the substrate, each of the light cells including a first-conductivity-type semiconductor layer, a second-conductivity-type semiconductor layer, and an active layer disposed therebetween; and an interconnection structure electrically connecting at least one of the first-conductivity-type semiconductor layer and the second-conductivity-type semiconductor layer of the light emitting cell to at least one of the first-conductivity-type semiconductor layer and the second-conductivity-type semiconductor layer of another light emitting cell, wherein a part of the light emitting cells emit red light, a part of the light emitting cells emit green light, and the others emit blue light.
22. The semiconductor light emitting device of claim 21, further comprising a base layer formed between the substrate and the first-conductivity-type semiconductor layers and connecting the first-conductivity-type semiconductor layers of the light emitting cells.
23. The semiconductor light emitting device of claim 22, wherein the base layer is formed of a first-conductivity-type semiconductor material.
24. The semiconductor light emitting device of claim 22, wherein the base layer is formed of an undoped semiconductor material.
25. The semiconductor light emitting device of claim 21, wherein the first-conductivity-type semiconductor layers of the light emitting cells are integrally formed.
26. A method for manufacturing a semiconductor light emitting device, the method comprising: forming a first light emitting structure by sequentially growing a first-conductivity-type semiconductor layer, a first active layer, and a second-conductivity-type semiconductor layer on a first region of a substrate; forming a second light emitting structure by sequentially growing a first-conductivity-type semiconductor layer, a second active layer, and a second-conductivity-type semiconductor layer on a second region of a substrate; forming a third light emitting structure by sequentially growing a first-conductivity-type semiconductor layer, a third active layer, and a second-conductivity-type semiconductor layer on a third region of a substrate; and forming an interconnection structure to electrically connect the first to third light emitting structures, wherein one of the first to third active layers emits red light, another emits green light, and the other emits blue light.
27. The method of claim 26, further comprising, before forming the first light emitting structure, forming a mask layer having a first open region on the substrate, wherein the first light emitting structure is formed in the first open region.
28. The method of claim 27, further comprising, before forming the second light emitting structure, forming a mask layer having a second open region on the substrate, wherein the second light emitting structure is formed in the second open region.
29. The method of claim 26, further comprising, before forming the third light emitting structure, forming a mask layer having a third open region on the substrate, wherein the third light emitting structure is formed in the third open region.
30. The method of claim 26, wherein the first to third light emitting structures are not contacted with one another.
31. The method of claim 26, further comprising, before forming the first to third light emitting structures, forming a base layer on the substrate.
32. The method of claim 31, wherein the base layer is formed of a first-conductivity-type semiconductor material.
33. The method of claim 31, wherein the base layer is formed of an undoped semiconductor layer.
34. The method of claim 32, wherein the process of growing the first-conductivity-type semiconductor layer is a process of re-growing the first-conductivity-type semiconductor layer on the base layer.
35. A method for manufacturing a semiconductor light emitting device, the method comprising: growing a first-conductivity-type semiconductor layer on a substrate; growing first to third active layers in first to third regions of the first-conductivity-type semiconductor layer; growing a second-conductivity-type semiconductor layer to cover the first to third active layers; forming first to third light emitting structures by removing a portion of the second-conductivity-type semiconductor layer so that the second-conductivity-type semiconductor layer corresponding to positions of the first to third active layers is left; and forming an interconnection structure to electrically connect the first to third light emitting structures, wherein one of the first to third active layers emits red light, another emits green light, and the other emits blue light.
36. The method of claim 35, wherein the forming of the first to third light emitting structures comprises removing a portion of the first-conductivity-type semiconductor layer so that the first-conductivity-type semiconductor layer corresponding to the positions of the first to third active layers is left.
37. A semiconductor light emitting device comprising: a plurality of light emitting cells arranged on a conductive substrate, each of the light emitting cells including a first-conductivity-type semiconductor layer, a second-conductivity-type semiconductor layer, an active layer formed therebetween, wherein the second-conductivity-type semiconductor layer is directed to the conductive substrate and electrically connected to the conductive substrate; and an interconnection structure electrically connecting the first-conductivity-type semiconductor layer of at least one of the light emitting cells to the first-conductivity-type semiconductor layer of other light emitting cells.
38. The semiconductor light emitting device of claim 37, further comprising a reflective metal layer formed between the conductive substrate and the plurality of light emitting cells.
39. The semiconductor light emitting device of claim 37, wherein the interconnection structure is formed of a metal.
40. The semiconductor light emitting device of claim 37, wherein a portion of the interconnection structure which is formed on the top surface of at least the first-conductivity-type semiconductor layer is formed of a transparent conductive material.
41. The semiconductor light emitting device of claim 37, further comprising a barrier layer formed between the conductive substrate and the plurality of light emitting cells.
42. The semiconductor light emitting device of claim 41, wherein the barrier layer is electrically connected to the second-conductivity-type semiconductor layers of the light emitting cells.
43. The semiconductor light emitting device of claim 37, wherein the plurality of light emitting cells are electrically connected in parallel.
[0083] Referring to FIGS. 1 and 2, the semiconductor light emitting device 100 according to the embodiment of the present invention includes a substrate 101 and a plurality of light emitting cells C arranged on the substrate 101. The light emitting cells C are electrically connected together by an interconnection structure 106. In this case, the term "light emitting cell" represents a semiconductor multilayer structure having an active layer region, which is distinguished from other cells. In this embodiment, twenty-five light emitting cells are arranged in a 5×5 pattern; however, the number and arrangement of the light emitting cells C maybe variously changed. As an additional element, first and second pads 107a and 107b for the application of external electric signals may be formed on the substrate 101. In this embodiment, the pads 107a and 107b directly contact the light emitting cells C. However, in another embodiment, the pads 107a and 107b and the light emitting cells may be spaced apart from one another and connected together by the interconnection structure 106. In this embodiment, in which the cell is separated into the plurality of light emitting cells C, current density per unit area may be further reduced than in a case in which a single cell is used. Hence, the luminous efficiency of the semiconductor light emitting device 100 may be improved.
[0084] As illustrated in FIG. 2, each of the light emitting cells C1, C2 and C3 includes a first-conductivity-type semiconductor layer 102, an active layer 103, and a second-conductivity-type semiconductor layer 104, which are formed on the substrate 101. As illustrated in FIG. 3, the light emitting cells C1, C2 and C3 are connected in series by the interconnection structure 106. In this case, a transparent electrode 105 formed of a transparent conductive oxide may be disposed on the second-conductivity-type semiconductor layer 104. In the series connection structure of the light emitting cells C1, C2 and C3, the second-conductivity-type semiconductor layer 104 of the first light emitting cell C1 and the first-conductivity-type semiconductor layer 102 of the second light emitting cell C2 may be connected together. In addition to the series connection, a parallel connection or a series-parallel connection can also be used herein, which will be described later. In this embodiment, the interconnection structure 106 is not a wire and is formed along the surfaces of the light emitting cells C1, C2 and C3 and the substrate 101, and an insulation part 108 may be disposed between the light emitting cells C1, C2 and C3 and the interconnection structure 106 to thereby prevent unintended electrical shorting. In this case, the insulation part 108 maybe formed of a material known in the art, such as silicon oxide or silicon nitride. In this embodiment, since wires are not used as the structure for electrical connection between the cells, the probability of electrical shorting maybe reduced and the ease of the interconnection process may be improved.
[0086] The first-conductivity-type semiconductor layer 102 and the second-conductivity-type semiconductor layer 104 may be formed of a nitride semiconductor having a composition of AlxInyGa.sub.(1-x-y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1), and may be doped with n-type impurity or p-type impurity. In this case, the first-conductivity-type semiconductor layer 102 and the second-conductivity-type semiconductor layer 104 may be grown by a process known in the art, such as a Metal Organic Chemical Vapor Deposition (MOCVD) process, a Hydride Vapor Phase Epitaxy (HVPE) process, or a Molecular Beam Epitaxy (MBE) process. The active layer 103 formed between the first-conductivity-type semiconductor layer 102 and the second-conductivity-type semiconductor layer 104 emits light having a predetermined level of energy by electron-hole recombination. The active layer 103 may have a structure in which a plurality of layers having a composition of InxGa1-xN (0≦x≦1) are laminated to adjust a band gap energy according to the content of indium (In). In this case, the active layer 103 may have a multi quantum well (MQW) structure in which a quantum barrier layer and a quantum well layer are alternately laminated, for example, an InGaN/GaN structure. Although not necessarily required, a transparent layer formed of a transparent conducive oxide maybe formed on the second-conductivity-type semiconductor layer 104. The transparent electrode may serve to perform an ohmic contact and current distribution function. Meanwhile, as will be described later, the light emitting cells C, each including the first-conductivity-type semiconductor layer 102, the second-conductivity-type semiconductor layer 104, and the active layer 103, may be obtained by a separate growth or may be obtained by growing a light emitting lamination body and separating it into individual cells.
[0090] Examples of a red phosphor which can be used in the red light conversion part 109R include a nitride phosphor having a composition of MAlSiNx:Re (1≦x≦5) or a sulfide phosphor having a composition of MD:Re. M is at least one selected from Ba, Sr, Ca, and Mg; D is at least one selected from S, Se, and Te; and Re is at least one selected from Eu, Y, La, Ce, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, F, Cl, Br, and I. In addition, examples of a green phosphor which can be used in the green light conversion part 109G include a silicate phosphor having a composition of M2SiO4:Re, a sulfide phosphor having a composition of MA2D4:Re, a phosphor having a composition of β-SiAlON:Re, and an oxide phosphor having a composition of MA'2O4:Re'. M is at least one selected from Ba, Sr, Ca, and Mg; A is at least one selected from Ga, Al, and In; D is at least one selected from S, Se, and Te; A' is at least one selected from Sc, Y, Gd, La, Lu, Al, and In; Re is at least one selected from Eu, Y, La, Ce, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, F, Cl, Br, and I; and Re+ is at least one selected from Ce, Nd, Pm, Sm, Tb, Dy, Ho, Er, Tm, Yb, F, Cl, Br, and I.
[0091] In addition, the quantum dot is a nano crystal particle having a core and a shell. The core of the quantum dot has a size ranging from 2 nm to 100 nm. By adjusting the size of the core, the quantum dot may be used as a phosphor material which emits various colors, such as blue (B), yellow (Y), green (G), and red (R). The core-shell structure constituting the quantum dot may be formed by a heterojunction of at least two kinds of semiconductors selected from group II-VI compound semiconductors (ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, MgTe, etc.), group III-V compound semiconductors (GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlAs, AlP, AlSb, AlS, etc.), or group IV semiconductors (Ge, Si, Pb, etc.). In this case, an organic ligand using a material such as oleic acid may be formed in the outer shell of the quantum dot in order to terminate the molecular bond of the shell surface, to suppress the agglomeration of the quantum dot, to improve the dispersion within a resin, such as silicon resin or an epoxy resin, or to improve the function of the phosphor.
[0097] As illustrated in FIG. 8, due to such an electrical connection structure, the sixteen light emitting cells C are connected in parallel. Such a parallel connection structure maybe useful as a high-power light source under a DC voltage. The semiconductor light emitting device 200' of FIG. 9 is similar to the embodiment of FIG. 1 in that the first-conductivity-type semiconductor layers 202 are provided to the individual light emitting cells C, but the electrical connection structure thereof corresponds to the parallel connection structure of FIG. 7. The first interconnection structure 206a extending from the first pad 207a is not directly connected to the light emitting cell C but is connected to the first-conductivity-type semiconductor layer 202 of the light emitting cell C through the connection part m.
[0106] In this embodiment, the multi-chip devices 400G1 and 400G2 include red and green light conversion materials having different mixture ratios, as in the embodiments of FIGS. 12 and 13. In this embodiment, the multi-chips are divided into two groups 400G1 and 400G2. Therefore, the total color temperature and color rendering index of the semiconductor light emitting device may be precisely controlled by independently adjusting the currents applied to the groups 400G1 and 400G2. Meanwhile, in this embodiment, the light conversion part includes a dam part 411. The inside of the dam part 411 is filled with a light conversion material 412. The dam part 411 may be formed by a dam and fill process. The dam and fill process is a process which forms the dam part 411 to surround the light emitting cell in the package substrate 410 or the light emitting cell substrate 401 and fills the dam part 411 with the light conversion material 412. In this embodiment, the dam part 411 may include the same material as the light conversion material 412. Furthermore, the dam part 411 itself may be formed of the same material as the filled part thereof. That is, the dam part 411 may further include a phosphor as well as a resin and a filler (Al2O3, SiO2, TiO2, etc.). Accordingly, a thixotropy thereof is improved to facilitate the formation of the dam. In addition, light maybe emitted to the outside through the dam part 411. Moreover, since the wavelength conversion may be performed, it can be expected that light loss caused by the dam part 411 will be minimized and light efficiency and light orientation property will be improved.
[0111] FIGS. 17 through 20 are cross-sectional views explaining a method for manufacturing the semiconductor light emitting device of FIG. 14 according to an embodiment of the present invention. As illustrated in FIG. 17, a base layer 502' is grown on a substrate 501. As described above, the base layer 502' may be formed of a first-conductivity-type semiconductor material or an undoped semiconductor material. For example, the base layer 502' maybe formed of a nitride semiconductor. In this case, the base layer 502' may be formed using a semiconductor thin film growth process known in the art, such as an MOCVD process, an HVPE process, or an MBE process.
[0113] As illustrated in FIG. 20, another open region is formed in the mask layer 510. a light emitting cell including a first-conductivity-type semiconductor layer 502, an active layer 503G emitting green light, and a second-conductivity-type semiconductor layer 504 is formed on the base layer 502'. A light emitting cell including a first-conductivity-type semiconductor layer 502, an active layer 503B emitting blue light, and a second-conductivity-type semiconductor layer 504 is formed on the base layer 502'. In this step, the light emitting cells may be independently arranged without contacting one another. Although not illustrated, a transparent electrode maybe formed on the second-conductivity-type semiconductor layer 504. An interconnection structure is formed to electrically connect the light emitting cells, thereby obtaining a structure of FIG. 14. In the above-described method for manufacturing the semiconductor light emitting device, an etching process is not used for separation into the light emitting cells C. Instead, the re-growth of the semiconductor layer is used to spontaneously separate the light emitting cells. In addition, the first-conductivity-type semiconductor layer 502 may not be etched in order to connect the interconnection structure to the first-conductivity-type layer 502. Accordingly, it is possible to prevent the damage of the light emitting cells C which is caused during the etching process. Since the area of the active layer 503 is sufficiently ensured, the luminous efficiency of the semiconductor light emitting device can be improved.
[0117] Referring to FIGS. 21 and 22, the semiconductor light emitting device 600 includes a plurality of light emitting cells C arranged on a conductive substrate 606. Each of the light emitting cells C includes a first-conductivity-type semiconductor layer 601, an active layer 602, and a second-conductivity-type semiconductor layer 603. A reflective metal layer 604 may be disposed between the light emitting cells C and the conductive substrate 606, specifically, between the second-conductivity-type semiconductor layer 603 and the conductive substrate 606. The reflective metal layer 604 is not a requisite element but an optional element. An interconnection structure 607 for electrically connecting the plurality of light emitting cells C is formed on the first-conductivity-type semiconductor layer 601. A pad 608 connected to the interconnection structure 607 maybe further provided. An external electric signal is applied through the pad 608. In this case, as illustrated in FIG. 22, the interconnection structure 607 is formed along the surfaces of the light emitting cells C1 and C2 to connect the first-conductivity-type semiconductor layers 601 provided in the two light emitting cells C1 and C2. The active layer 602, the second-conductivity-type semiconductor layer 603, the reflective metal layer 604, and the conductive substrate 606 may be electrically separated from one another by an insulation part 609. In this embodiment, since the electrical connection structure of the second-conductivity-type semiconductor layer 603 can be performed by the conductive substrate 606, an additional interconnection structure need not be formed. In addition, since the first-conductivity-type semiconductor layer 601 or the second-conductivity-type semiconductor layer 603 need not be mesa-etched, a sufficient light emitting area can be ensured.
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