Semiconductor light emitting device

Abstract

A semiconductor light emitting device includes: a light emitting structure having a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer; a transparent electrode layer located on the second conductive type semiconductor layer; and a reflective electrode structure located on the transparent electrode layer. The reflective electrode structure includes: a light-transmitting insulating layer located on the transparent electrode layer and having an insulating pattern, a portion of the side of the insulating pattern is open, and a contact area of ​​the transparent electrode layer is defined by an area between the insulating patterns; an air gap located between the transparent electrode layer and the insulating pattern, the air gap extending in the open portion of the side of the insulating pattern; and a reflective electrode layer located on the insulating pattern to cover the open portion of the insulating pattern, the reflective electrode layer being connected to the contact area of ​​the transparent electrode layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The entire contents of Korean Patent Application No. 10-2018-0048855, entitled “Semiconductor Light Emitting Device”, filed on April 27, 2018 in the Korean Intellectual Property Office are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a semiconductor light emitting device. Background Art

[0004] Compared with the light source according to the related art, the semiconductor light emitting device is considered to be a next-generation light source having many positive features, such as a longer lifespan, low power consumption, a fast response rate, environmentally friendly characteristics, etc. The semiconductor light emitting device has been used as an important light source in various products such as lighting devices, backlight units of display devices, etc. Summary of the invention

[0005] According to example embodiments, a semiconductor light emitting device includes: a light emitting structure including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer; a transparent electrode layer located on the second conductive type semiconductor layer; and a reflective electrode structure located on the transparent electrode layer, the reflective electrode structure including: a light-transmitting insulating layer located on the transparent electrode layer and including a plurality of insulating patterns, a portion of sides of the plurality of insulating patterns being open, and a contact area of ​​the transparent electrode layer being defined by an area between the plurality of insulating patterns; a plurality of air gaps located between the transparent electrode layer and the plurality of insulating patterns, respectively, the plurality of air gaps extending in the open portions of sides of the plurality of insulating patterns; and a reflective electrode layer located on the plurality of insulating patterns to cover the open portions of sides of the plurality of insulating patterns, the reflective electrode layer being connected to the contact area of ​​the transparent electrode layer.

[0006] According to example embodiments, a semiconductor light emitting device includes: a light emitting structure including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer; a transparent electrode layer located on the second conductive type semiconductor layer; a light-transmitting insulating layer located on the transparent electrode layer and including a plurality of insulating patterns, a plurality of air gaps are respectively defined between the transparent electrode layer and the plurality of insulating patterns, and a contact area of ​​the transparent electrode layer is defined by an area between the plurality of insulating patterns; a reflective electrode layer located on the transparent electrode layer to cover the plurality of insulating patterns and connected to the contact area of ​​the transparent electrode layer; a first insulating layer located on the reflective electrode layer and having at least one opening connected to the reflective electrode layer; and a connecting electrode located on the first insulating layer and connected to the reflective electrode layer through the at least one opening.

[0007] According to an example embodiment, a semiconductor light emitting device includes: a light emitting structure including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer; a transparent electrode layer located on the second conductive type semiconductor layer; a base insulating layer and a light-transmitting insulating layer, which are sequentially disposed on the transparent electrode layer and have a plurality of openings connected to the transparent electrode layer; and a reflective electrode layer, which is located on the light-transmitting insulating layer and connected to the transparent electrode layer through the plurality of openings, wherein the base insulating layer is spaced farther from the plurality of openings than the light-transmitting insulating layer, so that an air gap is defined between the light-transmitting insulating layer and the transparent electrode layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0009] Figure 1 shows a cross-sectional view of a semiconductor light emitting device according to an example embodiment;

[0010] Figure 2 Shown with Figure 1 A top view of the area corresponding to portion "A";

[0011] Figure 3 Shown with Figure 2 A schematic perspective view of a region corresponding to portion "B" of the invention;

[0012] Figure 4 Shown along Figure 2 A cross-sectional view taken along line II' in FIG.

[0013] Figure 5 Shown along Figure 2 A cross-sectional view taken along line II-II';

[0014] Figure 6 Shown along Figure 2 A cross-sectional view taken along line III-III';

[0015] Figure 7 A graph showing reflectivity of a structure according to a reflective electrode structure;

[0016] Figure 8 A graph showing reflectivity according to thickness variations of an air gap and a light-transmitting insulating layer in a reflective electrode structure according to example embodiments;

[0017] Fig. 9 , Fig.11A , Fig. 11B , Fig.13A , Fig. 13B , Fig.15A , Fig. 15B , Fig.16A and Fig. 16B A cross-sectional view showing a stage in a method of manufacturing a semiconductor light emitting device according to an example embodiment;

[0018] Fig.10 , Fig.12 and Fig.14 A top plan view showing a stage in a method of manufacturing a semiconductor light emitting device according to an example embodiment;

[0019] Fig.17 and Fig.18 A cross-sectional view and a top view respectively illustrate a semiconductor light emitting device according to an example embodiment; and

[0020] Fig.19 A schematic cross-sectional view illustrating an example in which a semiconductor light emitting device according to example embodiments is applied to a package. DETAILED DESCRIPTION

[0021] Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings.

[0022] Figure 1 is a cross-sectional view of a semiconductor light emitting device according to example embodiments.

[0023] Reference Figure 1 The semiconductor light emitting device 100 according to the example embodiment may include a substrate 101, a light emitting structure 110, a transparent electrode layer 120 and a reflective electrode structure RS. The reflective electrode structure RS employed in the example embodiment may include an air gap 130A, a light-transmitting insulating layer 140 and a reflective electrode layer 150.

[0024] In addition, the semiconductor light emitting device 100 according to example embodiments may further include a first insulating layer 161 , a first connection electrode 170 n , a second connection electrode 170 p , a second insulating layer 162 , a first electrode pad 180 n , and a second electrode pad 180 p .

[0025] The substrate 101 may have a first surface 101A and a second surface 101B facing the first surface 101A. The substrate 101 may be a substrate for semiconductor growth and may be formed using an insulating material, a conductive material, or a semiconductor material, such as sapphire, silicon (Si), SiC, MgAl 2 O 4 、MgO、LiAlO 2 、LiGaO 2, GaN, etc. Sapphire may be a crystal having hexa-rhombo R3c symmetry, and at the same time has electrical insulating properties, and may be used as a substrate for growing nitride semiconductors.

[0026] Throughout the specification, terms such as "first surface", "second surface", etc. are used to distinguish relative positions in components, and example embodiments are not limited by these terms. Terms such as "first surface", "second surface", etc. may be used to describe components in example embodiments where they may be replaced by other terms such as "upper surface", "lower surface", etc.

[0027] The light emitting structure 110 may be disposed on the first surface 101A of the substrate 101. In one example, a concavo-convex structure P may be formed on the first surface 101A of the substrate 101, and the light emitting structure 110 may be disposed on the concavo-convex structure P.

[0028] In detail, the concavo-convex structure P can improve the crystal characteristics and light extraction efficiency of the semiconductor layer constituting the light emitting structure 110. In this exemplary embodiment, the concavo-convex structure P of the first surface 101A of the substrate 101 is shown as having a dome-shaped convex shape, but exemplary embodiments thereof are not limited thereto. For example, the concavo-convex structure P can be formed to have various shapes, such as a quadrilateral, a triangle, etc.

[0029] In certain examples, depending on example embodiments, the substrate 101 may be removed later. For example, the substrate 101 may be provided as a growth substrate for growth of the light emitting structure 110 and then may be removed by a separation process. The substrate 101 may be separated from the light emitting structure 110 using, for example, laser lift-off (LLO), chemical lift-off (CLO), etc.

[0030] A buffer layer may be further provided on the first surface 101A of the substrate 101. The buffer layer may be provided to reduce lattice defects of the semiconductor layer grown on the substrate 101, and the buffer layer may be formed of an undoped semiconductor layer, which is formed of a nitride or the like. As the buffer layer, a layer of undoped GaN, AlN, InGaN or the like may be used. The buffer layer may be formed at a relatively low temperature of 500° C. to 600° C. to have a thickness of several tens to several hundreds of angstroms. In this case, "undoped" means that the semiconductor layer does not undergo an impurity doping process alone. However, according to example embodiments, such a buffer layer is not necessary and may be omitted.

[0031] The light emitting structure 110 employed in the example embodiment may include a first conductive type semiconductor layer 112, an active layer 115, and a second conductive type semiconductor layer 117. For example, Figure 1As shown, the first conductive type semiconductor layer 112 , the active layer 115 , and the second conductive type semiconductor layer 117 may be stacked on the first surface 101A of the substrate 101 in the order listed.

[0032] The first conductive type semiconductor layer 112 may be formed of a semiconductor doped with n-type impurities, or may be an n-type nitride semiconductor layer. The second conductive type semiconductor layer 117 may be formed of a semiconductor doped with p-type impurities, or may be a p-type nitride semiconductor layer. For example, the first conductive type semiconductor layer 112 and the second conductive type semiconductor layer 117 may be nitride semiconductors that satisfy the empirical chemical formula Al x In y Ga (1-x-y) N(0≤x<1, 0≤y<1, 0≤x+y<1). In another example embodiment, the positions of the first conductive type semiconductor layer 112 and the second conductive type semiconductor layer 117 may also be reversed.

[0033] The active layer 115 may be between the first conductive type semiconductor layer 112 and the second conductive type semiconductor layer 117. When the semiconductor light emitting device 100 is operating, the active layer 115 may emit light having a predetermined energy level by recombination of electrons and holes. For example, when the first conductive type semiconductor layer 112 and the second conductive type semiconductor layer 117 are nitride semiconductors, the active layer 115 may include an InGaN compound semiconductor having a narrower energy band gap than that of GaN. In addition, the active layer 115 may be a multiple quantum well (MQW) structure in which quantum well layers and quantum barrier layers are alternately stacked, for example, an InGaN / GaN structure, but example embodiments thereof are not limited thereto. For example, the active layer 115 may have a single quantum well (SQW) structure.

[0034] The light emitting structure 110 may include a recessed region ME formed by removing (eg, etching) a portion of the second conductive type semiconductor layer 117, the active layer 115, and the first conductive type semiconductor layer 112, and a mesa region MS surrounding the recessed region ME. Figure 1 As shown, the remaining portions of the second conductive type semiconductor layer 117, the active layer 115, and the first conductive type semiconductor layer 112 in the mesa region MS extend above the recessed region ME. The mesa region MS may have a form that gradually narrows from the lower portion to the upper portion. Therefore, the mesa region MS may have an inclined side surface, for example, the mesa region MS may have a trapezoidal cross section in a side view.

[0035] A portion of the upper surface of the recess region ME may be defined as a first contact region CT1. In an exemplary embodiment, the recess region ME may be divided into a first recess region ME1 providing the first contact region CT1, for example, Figure 1and a second recessed region ME2 located at the periphery of the semiconductor light emitting device 100.

[0036] like Figure 1 As shown, the transparent electrode layer 120 may be disposed on the upper surface of the mesa region MS, for example, on the upper surface of the second conductive type semiconductor layer 117 of the light emitting structure 110. For example, the transparent electrode layer 120 may include, for example, indium tin oxide (ITO), zinc-doped indium tin oxide (ZITO), zinc indium oxide (ZIO), gallium indium oxide (GIO), zinc tin oxide (ZTO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), Indium 4 Sn 3 O 12 and Zn (1-x) Mg x At least one of O (zinc magnesium oxide, 0≤x≤1). The thickness of the transparent electrode layer 120 may be in the range of about 1 nm to about 5 nm, but is not limited thereto.

[0037] The reflective electrode structure RS may be, for example, directly disposed on the transparent electrode layer 120. The reflective electrode structure RS used in the present embodiment may be configured to include: a light-transmitting insulating layer 140 disposed on the transparent electrode layer 120; and a reflective electrode layer 150 connected to the contact region of the transparent electrode layer 120 and disposed on the light-transmitting insulating layer 140. The reflective electrode structure RS may also be configured to have a plurality of air gaps 130A between the light-transmitting insulating layer 140 and the transparent electrode layer 120.

[0038] The reflective electrode structure RS employed in the example embodiment may operate as an omnidirectional reflector (ODR) having a low refractive index region including the air gap 130A, the light-transmitting insulating layer 140, and the reflective electrode layer 150. In detail, the low refractive index region may include the air gap 130A having a refractive index of about 1 and the reflective electrode layer 150 having a relatively low refractive index (e.g., lower than SiO 2 In this structure, the total internal reflection (also called total reflection) (TIR) ​​characteristic can be determined according to the refractive index of the low refractive index region. Since the low refractive index region has a refractive index lower than 2.4, that is, lower than the refractive index of GaN, the critical angle can be reduced, thereby improving the total internal reflection characteristic. In this way, since the reflectivity of the reflective electrode structure RS can be significantly increased, the extraction efficiency of the light emitted from the active layer 115 can be greatly improved.

[0039] For example, the light-transmitting insulating layer 140 may include NaF, Na 3 AlF 6 、LiF、MgF 2 , CaF 2 andBaF2 For example, the reflective electrode layer 150 may include at least one of silver (Ag), chromium (Cr), nickel (Ni), titanium (Ti), aluminum (Al), rhodium (Rh), ruthenium (Ru), palladium (Pd), gold (Au), copper (Cu), and combinations thereof. In a specific example, the light-transmitting insulating layer 140 may include MgF 2 , the reflective electrode layer 150 may include Ag.

[0040] The light-transmitting insulating layer 140 employed in the exemplary embodiment may include a plurality of insulating patterns 140P configured to form the air gap 130A. The plurality of insulating patterns 140P may be respectively configured in such a manner that a portion of the side of the air gap 130A may be open to form the air gap 130A. For example, the plurality of insulating patterns 140P may be formed as protrusions arranged, for example, in a matrix pattern on the transparent electrode layer 120, so that each protrusion may have a bridge shape extending over the air gap on the transparent electrode layer 120. The reflective electrode layer 150 may cover the open portion of the side of the air gap 130A. Reference will be made to the following. Figures 3 to 6 The reflective electrode structure RS having the air gap 130A is described in more detail.

[0041] A portion of the transparent electrode layer 120 may be exposed between the plurality of insulating patterns 140P, and the exposed region of the transparent electrode layer 120 may be provided as the contact region CL. The reflective electrode layer 150 may be electrically connected to the contact region CL of the transparent electrode layer 120.

[0042] The insulating pattern 140P employed in the exemplary embodiment may have a quadrilateral plane. Figures 2 to 6 A detailed structure of the reflective structure (ie, reflective electrode structure) RS including the air gap 130A when the insulating pattern 140P is formed to have a quadrangular shape will be described.

[0043] Figure 2 is with Figure 1 A top view of the area corresponding to portion "A", Figure 3 is with Figure 2 It should be noted that, Figure 2 A plane is shown in which components located on the reflective electrode layer 150 are removed (ie, the reflective electrode layer 150 is shown as a top layer, and the insulating pattern 140P is shown in dotted lines below the top layer).

[0044] Reference Figure 2 and Figure 3 , the reflective electrode layer 150 may have a quadrangular protruding shape to correspond to the quadrangular insulating pattern 140P. Figures 2 to 3As shown, the reflective electrode layer 150 may be a continuous layer that conformally covers all the insulating patterns 140P and the regions between all the insulating patterns 140P, for example, it may conformally extend along the bridge shape of the insulating pattern 140P, and may cover the open side of the insulating pattern 140P, and therefore, the reflective electrode layer 150 may have a shape of a plurality of quadrilateral protrusions connected to each other and arranged in a matrix pattern. As described above, the contact region CL of the transparent electrode layer 120 may be defined as a region between a plurality of insulating patterns 140P, for example, a region where the reflective electrode layer 150 contacts the exposed portion of the transparent electrode layer 120 between the plurality of insulating patterns 140P.

[0045] As described in example embodiments, the plurality of insulating patterns 140P may be arranged in a matrix pattern (ie, rows and columns) to have substantially the same quadrilateral shape as each other. Figure 2 As shown, the quadrilateral shapes of the plurality of insulating patterns 140P may be spaced apart from each other in two directions (e.g., along the x-direction and along the y-direction) to define spaces between the plurality of insulating patterns 140P in a grid pattern corresponding to the exposed portions of the transparent electrode layer 120. Figure 2 As shown, the first contact region CL1 and the second contact region CL2 of the transparent electrode layer 120 may correspond to the mesh pattern (i.e., the space between the insulating patterns 140P), and may have a linear shape extending along at least two insulating patterns. In addition, the contact region CL in the example embodiment may include a plurality of first contact regions CL1 extending in a row direction (e.g., in an x-direction) and a plurality of second contact regions CL2 extending in a column direction (e.g., in a y-direction), and the first contact regions CL1 and the second contact regions CL2 may be formed to cross each other.

[0046] Figure 4 is along Figure 2 A cross-sectional view taken along line II' in FIG. Figure 5 is along Figure 2 A cross-sectional view taken along line II-II' in FIG. Figure 6 is along Figure 2 A cross-sectional view taken along line III-III' in FIG. Figure 6 It should be noted that the dashed structure shown above the second contact region CL2 refers to an element seen from a side view from the perspective of the cross section (e.g., along Figure 2 The insulating pattern 140P adjacent to the line III-III' in the x direction.

[0047] First, refer to Figures 3 to 5 , the insulating pattern 140P used in the exemplary embodiment may be formed on the transparent electrode layer 120 to define the air gap 130A, and the insulating pattern 140P may be configured so that portions of the sides of the air gap 130A may be open. Figures 3 to 5, the insulating patterns 140P may have bridge shapes arranged adjacent to each other in the x direction such that each bridge shape has a central portion protruding above the transparent electrode layer 120 and two opposite ends in the x direction contacting the transparent electrode layer 120 ( Figure 4 ), while the opposite edges of each bridge along the y direction are spaced apart from the transparent electrode layer 120 ( Figure 5 ), so as to define the open sides of the insulating pattern 140P. For example, the open sides of the insulating pattern 140P may be adjacent to each other along the y direction.

[0048] The open side of the insulating pattern 140P may be used as a path for removing the sacrificial layer used to form the air gap 130A. The open portions of the sides of the air gap 130A not covered by the insulating pattern 140P may be positioned to face each other in one direction (e.g., in the y direction). In this arrangement, the sacrificial layer removal process may be smoothly performed, as will be discussed in more detail below (see Fig.15A and Fig. 15B The open portions of the side surfaces of the air gap 130A not covered by the insulating pattern 140P may be covered by the reflective electrode layer 150 .

[0049] In detail, as in the example embodiment, when the quadrilateral insulating pattern 140P is adopted, two opposite sides of the air gap 130A may be defined by the reflective electrode layer 150 instead of being defined by the insulating pattern 140P. Figure 5 As shown, both sides of the air gap 130A (eg, along the y direction) may not be covered by the insulating pattern 140P, but may be covered by the reflective electrode layer 150 formed on the insulating pattern 140P.

[0050] On the other hand, refer to Figure 3 and Figure 4 , the other side of the air gap 130A (e.g., along the x direction) may be covered by the extension portion 140S of the insulating pattern 140P, and the extension portion 140S may serve as a support member of the insulating pattern 140P providing the air gap 130A. The other side of the air gap 130A (e.g., along the x direction) may be located in a direction different from the arrangement direction of the open side of the air gap 130A (e.g., along the y direction). In this way, since the support members (i.e., the extension portions 140S) of the insulating pattern 140P are disposed opposite to each other along the x direction to contact the transparent electrode layer 120, the air gap 130A may be maintained more stably.

[0051] As in the example embodiment, when the insulating pattern 140P having a quadrilateral shape is employed, two opposite sides of the air gap 130A (eg, along the x-direction) may be defined by the insulating pattern 140P, that is, by the extension portion 140S contacting the transparent electrode layer 120. Figure 5As shown, two opposing sides of the air gap 130A (eg, along the y-direction) may be covered by the reflective electrode layer 150 .

[0052] Reference Figures 3 to 5 , the reflective electrode layer 150 may be formed on the insulating pattern 140P, and may be connected to the first contact region CL1 and the second contact region CL2 of the transparent electrode layer 120. Figure 3 As shown, the reflective electrode layer 150 may be formed to substantially cover (e.g., overlap) the entirety of the transparent electrode layer 120 and the light-transmitting insulating layer 140. In addition, as described above, since the reflective electrode layer 150 defines both sides of the air gap 130A that are not defined by the insulating pattern 140P, the shape of the final air gap 130A may be completed.

[0053] On the other hand, the air gap 130A implemented by the quadrilateral insulating pattern 140P can be described as having a substantially hexahedral structure, such as a prism with four sides. The upper surface and two opposite side surfaces of the air gap 130A having the hexahedral structure can be covered with a light-transmitting insulating layer 140 (e.g., an insulating pattern), and the other two opposite surfaces can be covered with a reflective electrode layer 150.

[0054] like Figure 6 As shown, the second contact region CL2 of the transparent electrode layer 120 may have a linear shape extending along the region between the quadrilateral insulating patterns 140P, and the reflective electrode layer 150 may be connected thereto along the second contact region CL2 having a linear shape. Therefore, compared with a point-shaped (e.g., circular-shaped) contact region, the contact according to the example embodiment may provide a relatively wide and sufficient connection region (or connection area), thereby ensuring smooth current injection. Since the first contact region CL1 also has a linear shape, a contact structure similar to that of the second contact region CL2 may be ensured.

[0055] like Figure 1 As shown, the first insulating layer 161 may be disposed on the reflective electrode layer 150 and the light emitting structure 110. The first insulating layer 161 may include a first opening OPa exposing the first contact region CT1 of the first conductive type semiconductor layer 112, and a second opening OPb exposing the second contact region CT2 of the reflective electrode layer 150. The first opening OPa may be located in the first recessed region ME1, and the second opening OPb may be located in the mesa region MS.

[0056] The first connection electrode 170n may be disposed on the first insulating layer 161 and may extend through the first opening OPa onto the first contact region CT1 of the first conductive type semiconductor layer 112 to be electrically connected to the first conductive type semiconductor layer 112. The first connection electrode 170n may be connected to the first contact region CT1 of the first conductive type semiconductor layer 112.

[0057] The second connection electrode 170p may be disposed on the first insulating layer 161 and may extend through the second opening OPb onto the second contact region CT2 of the reflective electrode layer 150 to be electrically connected to the reflective electrode layer 150. Therefore, the second connection electrode 170p may be electrically connected to the second conductive type semiconductor layer 117 through the reflective electrode layer 150.

[0058] For example, the first connection electrode 170n and the second connection electrode 170p may include a material containing, for example, one or more of aluminum (Al), gold (Au), tungsten (W), platinum (Pt), silicon (Si), iridium (Ir), silver (Ag), copper (Cu), nickel (Ni), titanium (Ti), chromium (Cr), and alloys thereof. The first connection electrode 170n and the second connection electrode 170p may be formed by the same deposition process.

[0059] The second insulating layer 162 may be disposed on the first insulating layer 161 in such a manner that a portion of the first connection electrode 170n and a portion of the second connection electrode 170p are exposed. The first electrode pad 180n may be disposed on a portion of the first connection electrode 170n, and the second electrode pad 180p may be disposed on a portion of the second connection electrode 170p. The first electrode pad 180n and the second electrode pad 180p may be an under-bump metallurgy layer (UBM). In an example, the number and arrangement of the first electrode pad 180n and the second electrode pad 180p may be modified in various ways.

[0060] In addition, the first conductive bump and the second conductive bump may be disposed on the first electrode pad 180n and the second electrode pad 180p, respectively. For example, the conductive bump may include a metal or an alloy, such as tin (Sn) or Au-Sn.

[0061] As described above, the reflective electrode structure RS employed in the exemplary embodiment may have an ODR structure and may include a low refractive index region having a double-layer structure and a reflective electrode layer. In this case, the double-layer structure may be composed of an air gap 130A and a light-transmitting insulating layer 140. In detail, since the air gap 130A has a refractive index equal to 1, the total reflection characteristic may be significantly enhanced, thereby improving the reflectivity. In addition, the light-transmitting insulating layer 140 having a support structure may include a layer having a refractive index lower than that of SiO 2 The refractive index of the dielectric material is increased to improve the reflectivity. Figure 7 and Figure 8 The detailed reflectivity improvement effect will be described in detail.

[0062] The reflectivity was measured by providing reflective electrode structures with different configurations, as shown in Table 1 below. It can be understood that the samples of the reflective electrode structure below are provided on the p-type GaN layer and the transparent electrode layer ITO, and the same layer in each sample is implemented to have the same thickness, for example, the MgF2 and the thickness of MgF of Comparative Example 3 2 The thicknesses are equal to each other.

[0063] Table 1

[0064] Classification Example Comparative Example 1 Comparative Example 2 Comparative Example 3 structure <![CDATA[Air / MgF 2 / Ag]]> Ag <![CDATA[SiO 2 / At]]> <![CDATA[SiO 2 / MgF 2 / Ag]]> Reflectivity(%) 97.1 95.4 96.5 96.7

[0065] Figure 7 A graph showing reflectivity of a structure according to a reflective electrode structure.

[0066] Reference Figure 7 , in the case of Comparative Example 1, the reflectivity of Ag is lower than the reflectivity of Ag itself (95.9%) due to the absorption of light by ITO. In Comparative Examples 2 and 3 with ODR structures, the reflectivities are 96.5% and 96.7%, respectively, and the results are slightly improved. In the case of the reflective structure according to the example embodiment, the highest reflectivity of 97.1% was measured. As described above, since the air gap 130A has a relatively lowest refractive index (n=1), it can be understood that the total reflection characteristics are significantly enhanced to improve the substantial reflectivity. The reflective electrode structure of the embodiment in Table 1 above Air / MgF 2 / Ag(Air / MgF 2 / Ag) in the air gap and the light-transmitting insulating layer (MgF 2 ) was kept constant at 600 nm, the reflectivity was measured at different thickness ratios.

[0067] Figure 8 A graph illustrating reflectivity according to thickness variations of an air gap and a light-transmitting insulating layer in a reflective electrode structure according to example embodiments.

[0068] Reference Figure 8 , when the thickness ratio of the air gap to the light-transmitting insulating layer is 0.5 or more, the reflectivity is increased to 97% or more, and as the thickness ratio increases, the reflectivity is slightly increased, and then, after passing through a thickness ratio range of about 1.3, it is confirmed that when the thickness ratio of the air gap to the light-transmitting insulating layer is 0.5 to 1.3 (that is, the thickness of the air gap is in the range of about 50% to about 130% of the thickness of the light-transmitting insulating layer), the reflective electrode structure exhibits a relatively high reflectivity.

[0069] In the following, reference will be made to Figure 9 to Figure 1 6 to describe an example of a method of manufacturing the semiconductor light emitting device 100 according to example embodiments.

[0070] Fig. 9 , Fig.11A , Fig. 11B , Fig.13A , Fig. 13B , Fig.15A , Fig. 15B , Fig.16A and Fig. 16B Cross-sectional views illustrating stages in a method of manufacturing a semiconductor light emitting device according to example embodiments. Fig.10 , Fig.12 and Fig.14 A top plan view illustrating stages in a method of manufacturing a semiconductor light emitting device according to example embodiments. Fig.11A and Fig. 11B is along Fig.10 The cross-sectional view taken along the corresponding lines II-I' and II-II', Fig.13A and Fig. 13B is along Fig.12 The cross-sectional view taken along the corresponding lines II-I' and II-II', Fig.15A and Fig. 15B is along Fig.14 Cross-sectional views taken along the corresponding lines II-I' and II-II'. Fig.16A and Fig. 16B Corresponding to Figure 4 and Figure 5 .

[0071] Reference Fig. 9 The light emitting structure 110 and the transparent electrode layer 120 may be formed on the substrate 101 , and the sacrificial layer 130 may be formed on the transparent electrode layer. For example, the sacrificial layer 130 may cover the entire top surface of the transparent electrode layer 120 .

[0072] The light emitting structure 110 may be formed of the above-mentioned first conductive type semiconductor layer 112, active layer 115 and second conductive type semiconductor layer 117, and may be formed using, for example, metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE) or similar processes. In addition, a transparent electrode layer 120 may be formed on the light emitting structure 110. Fig. 9 The light emitting structure shown in FIG. Figure 1 , wherein the recess region ME is formed by etching away a portion of the second conductive type semiconductor layer 117, the active layer 115, and the first conductive type semiconductor layer 112, and the mesa region MS is formed to surround the recess region ME.

[0073] The sacrificial layer 130 may be a temporary material layer for fixing the air gap. The material of the sacrificial layer 130 may be a material having a relatively high etching selectivity with respect to the light-transmitting insulating layer (140 in FIG. 13 ) to be formed in a subsequent process. For example, the sacrificial layer 130 may be SiO 2 For example, the sacrificial layer 130 may also include SiN, TiO 2 、HfO、NbO 2 or TaO2 .

[0074] Reference Fig.10 , Fig.11A and Fig. 11B , a sacrificial pattern 130P corresponding to a desired air gap may be formed by patterning the sacrificial layer 130. The patterning may be performed using a photolithography process.

[0075] In detail, the sacrificial pattern 130P having a desired shape may be formed by forming the first trench line TL1 and the second trench line TL2. For example, some portions of the sacrificial layer 130 may be removed to form the first trench line TL1 and the second trench line TL2 that partially expose the transparent electrode layer 120. The sacrificial pattern 130P may have a trapezoidal cross-section ( FIG. 11A to FIG. 11B ), and may have a flat quadrilateral shape in top view ( Fig.10 ) to have a substantially hexahedral structure, for example, a prism-shaped structure as a whole. In a subsequent process, an air gap having a shape corresponding to the shape of the sacrificial pattern 130P may be formed (see Fig.15A and Fig. 15B ).

[0076] A portion of the transparent electrode layer 120 (e.g., an area between the sacrificial patterns 130P) may be exposed along the first trench line TL1 and the second trench line TL2. The exposed area of ​​the transparent electrode layer 120 may be set as a contact area that contacts the reflective electrode layer 150 in a subsequent process. For example, most of the exposed area of ​​the second trench line TL2 may be set as a basic contact area, while the exposed area of ​​the first trench line TL1 may be partially covered by the support member ( Fig.13A The extending portion 140S) is occupied by the first trench line TL1, and thus, the basic contact area of ​​the first trench line TL1 can be narrowed.

[0077] Therefore, as in the example embodiment, the width d1 of the first trench line TL1 may be wider than the width d2 of the second trench line TL2 to ensure a sufficient contact region (contact area) in the first trench line TL1, but is not limited thereto. For example, the first trench line TL1 and the second trench line TL2 may also be designed to have substantially the same width.

[0078] Reference Fig.12 , Fig.13A and Fig. 13B , a plurality of insulating patterns 140P may be formed on the plurality of sacrificial patterns 130P, respectively. A process of forming the plurality of insulating patterns 140P may be performed using a photolithography process. The plurality of insulating patterns 140P may be disposed to correspond to the plurality of sacrificial patterns 130P, respectively.

[0079] In detail, Fig.13AAs shown, each insulating pattern 140P may be formed to cover two opposite sides of the sacrificial pattern 130P in one direction. The insulating pattern 140P may have an extension portion 140S extending along both sidewalls of the sacrificial pattern 130P to be bonded to the transparent electrode layer 120. The extension portion 140S may serve as a support member that maintains an air gap even after the sacrificial pattern 130P is removed.

[0080] like Fig. 13B As shown, a corresponding insulating pattern 140P may be formed to expose the other two sidewalls of the sacrificial pattern 130P located in different directions. Fig.12 As shown, each insulating pattern 140P conformally extends along the top and two opposite sidewalls of the corresponding sacrificial pattern 130P to have a lateral direction ( Fig.13A ), the relative edges and sidewalls of the sacrificial pattern 130P spaced apart from each other in the y direction may not be covered by the insulating pattern 140P. The two exposed side surfaces of the insulating pattern 140P may provide an etching path EP of the sacrificial pattern 130P, and the sacrificial pattern 130P may be effectively removed through two opposite surfaces (for example, through the two exposed side surfaces of the insulating pattern 140P). In addition, in order to effectively remove the sacrificial pattern 130P, the insulating pattern 140P may be formed in such a manner that the upper corner area 130e of the sacrificial pattern 130P adjacent to the two exposed side surfaces is partially exposed. In this process, the first contact area CL1 of the transparent electrode layer 120 may be disposed between the insulating patterns 140P.

[0081] Reference Fig.14 , Fig.15A and Fig. 15B , the sacrificial pattern 130P located under the plurality of insulating patterns 140P may be removed. The removal process may be performed by a wet etching process having a selectivity ratio. While the plurality of insulating patterns 140P are maintained, only the sacrificial pattern may be selectively removed.

[0082] In detail, in the etching process, the two exposed sides of the sacrificial pattern 130P provide etching paths EP facing each other, so that the sacrificial pattern 130P can be effectively removed. The sacrificial pattern 130P can be almost completely removed by the relatively large and facing etching paths EP to provide the air gap 130A (see FIG. Fig. 15B ). Even after the air gap 130A is formed, the extension portion 140S of the insulating pattern 140P may serve as a support member that contacts the transparent electrode layer 120 to stably maintain the air gap 130A (see Fig.15A ). In this process, the second contact region CL2 of the transparent electrode layer 120 may be disposed between the insulating patterns 140P.

[0083] Then, if Fig.16A and Fig. 16BAs shown, the reflective electrode layer 150 connected to the first contact region CL1 and the second contact region CL2 of the transparent electrode layer 120 may be formed on the plurality of insulating patterns 140P. The reflective electrode layer 150 may be formed to cover the open portion of the side of the air gap 130A, as shown in FIG. Fig. 16B As described above, two opposite sides of the air gap 130A may be defined by the reflective electrode layer 150 (see Fig. 16B ), and the other two opposite sides of the air gap 130A may be defined by the insulating pattern 140P (see Fig.16A ).

[0084] Then, the Figure 1 The other components shown (eg, the first insulating layer 161, the first connecting electrode 170n, the second connecting electrode 170p, the second insulating layer 162, the first electrode pad 180n and the second electrode pad 180p) are fabricated to manufacture the desired semiconductor light emitting device 100.

[0085] Fig.17 and Fig.18 2 are a cross-sectional view and a top view, respectively, of a semiconductor light emitting device according to example embodiments. Fig.17 is along Fig.18 A cross-sectional view taken along line D-D'. Fig.17 and Fig.18 The regions shown in the semiconductor light emitting device 100' correspond to Figure 4 and Figure 3 The area shown in .

[0086] Reference Fig.17 and Fig.18 , except that the base insulating layer 130P′ causing the change in the air gap form is retained, the contact area is formed by the opening H having a hole shape, and the adhesive electrode layer 151 is introduced between the reflective electrode layer 150 and the light-transmitting insulating layer 140, the description of other elements is similar to the previous description.

[0087] The description of the constituent elements of this exemplary embodiment can be found in Figures 1 to 5 Components identical or similar to those of the semiconductor light emitting device 100 shown in FIG. 1 are described herein unless otherwise specified. Figure 1 The first insulating layer 161, the first connecting electrode 170n, the second connecting electrode 170p, the second insulating layer 162, the first electrode pad 180n and the second electrode pad 180p are not shown. Fig.17 However, Figure 1 The components shown above may also be combined into the present exemplary embodiment, and reference may be made to the related description unless otherwise stated.

[0088] Reference Fig.17 and Fig.18, a semiconductor light emitting device 100 ′ according to example embodiments may include a base insulating layer 130P′ and a light-transmitting insulating layer 140 sequentially formed on a transparent electrode layer 120 .

[0089] The base insulating layer 130P′ and the light-transmitting insulating layer 140 may have a plurality of openings H connected to the contact region of the transparent electrode layer 120. The reflective electrode layer 150 may be disposed on the light-transmitting insulating layer 140 and may be connected to the contact region of the transparent electrode layer 120 through the plurality of openings H. The plurality of openings H may have a hole shape, such as Fig.18 As shown, however, the shape thereof is not limited thereto. For example, the plurality of openings H may have a linear shape or any other shape.

[0090] The base insulating layer 130P′ may be spaced farther from the openings H than the light-transmitting insulating layer 140 is spaced from the openings H, so that an air gap 130A′ may be formed between the light-transmitting insulating layer 140 and the transparent electrode layer 120 .

[0091] Likewise, in this example embodiment, the reflectivity can be significantly improved at least in the region where the air gap 130A' is provided. Since the base insulating layer 130P' and the light-transmitting insulating layer 140 are formed of different dielectric materials having relatively low refractive indices, a relatively high reflectivity can be expected. In a specific example, the base insulating layer 130P' may include SiO 2 , the light-transmitting insulating layer 140 may include MgF 2 .

[0092] The plurality of openings H may be used as wet etching paths for removing the sacrificial layer (the remaining portion of the sacrificial layer forms the base insulating layer 130P') while providing a contact area between the reflective electrode layer and the transparent electrode layer. In detail, the sacrificial layer is partially removed so that the openings H having the hole structure are formed, and the following steps may not be performed. Figure 1 The embodiment shown has a smooth etch. Fig.17 As shown, the air gap 130A' may be formed only partially around the opening H, and the base insulating layer 130P' may remain. The base insulating layer 130P' may serve as a structure supporting the air gap 130A'.

[0093] Unlike the aforementioned embodiment, the manufacturing process of the reflective structure according to this exemplary embodiment can be realized by adding only one photolithography process. For example, after sequentially depositing the sacrificial layer corresponding to the base insulating layer 130P' and the light-transmitting insulating layer 140, an opening forming process and a wet etching process can be immediately performed to form the desired air gap 130A'.

[0094] Although the plurality of openings H are shown as being arranged in a quadrilateral lattice and having a circular cross-section as an example, the plurality of openings H may be arranged in different types of arrangement shapes, for example, a dense hexagonal lattice or may have other cross-sectional shapes (e.g., polygonal, linear, or annular).

[0095] In addition, the adhesive electrode layer 151 may be disposed between the light-transmitting insulating layer 140 and the reflective electrode layer 150. The adhesive electrode layer 151 may improve the adhesive property between the reflective electrode layer 150 and the light-transmitting insulating layer 140. The adhesive electrode layer 151 may be formed of a material similar to that of the transparent electrode layer 120. For example, the adhesive electrode layer 151 may include ITO, ZITO, ZIO, GIO, ZTO, FTO, AZO, GZO, In 4 Sn 3 O 12 、Zn (1-x) Mg x O (0≤x≤1) or a combination thereof. Although the adhesive electrode layer 151 is shown to be formed only on the upper surface of the light-transmitting insulating layer 140 , the adhesive electrode layer 151 may contact the transparent electrode layer 120 through the plurality of openings H.

[0096] The semiconductor light emitting devices 100 and 100' can be manufactured as products in the form of packages. Fig.19 An example in which the semiconductor light emitting devices 100 and 100 ′ according to example embodiments are applied to a package will be described.

[0097] Fig.19 A schematic cross-sectional view illustrating an example in which a semiconductor light emitting device according to example embodiments is applied to a package.

[0098] Reference Fig.19 , the semiconductor light emitting device package 1000 may include a semiconductor light emitting device 1001 as a light source, a package body 1002, a pair of lead frames 1010, and a packaging portion 1005. In this case, the semiconductor light emitting device 1001 may be Figure 1 or Fig.17 The semiconductor light emitting device 100 or 100' is shown in FIG. 1 , and a description thereof will be omitted.

[0099] The semiconductor light emitting device 1001 may be mounted on a lead frame 1010 and may be electrically connected to the lead frame 1010. The pair of lead frames 1010 may include a first lead frame 1012 and a second lead frame 1014. The semiconductor light emitting device 1001 may be connected to the semiconductor light emitting device 1001 through a first connection electrode 170n and a second connection electrode 170p (eg, a first solder column and a second solder column) (see Figure 1 ) is connected to the first lead frame 1012 and the second lead frame 1014.

[0100] The package body 1002 may be provided with a reflective cup to improve light reflection efficiency and light extraction efficiency. In the reflective cup, a package portion 1005 formed of a light-transmitting material may be formed to package the semiconductor light emitting device 1001. The package portion 1005 may include a wavelength conversion material, for example, a fluorescent material, quantum dots, or the like.

[0101] By way of summary and review, the exemplary embodiments provide a semiconductor light emitting device in which the light flux can be improved by increasing the reflectivity of the reflective structure. That is, as described above, by introducing an air gap, a low refractive index element into the reflective structure (i.e., an omnidirectional reflector (ODR)), the reflectivity can be improved. In the exemplary embodiment, the air gap of the reflective structure can be expanded by exposing a portion of the side of the sacrificial layer for the air gap to remove a large portion of the sacrificial layer. As a result, the light extraction efficiency of the final semiconductor light emitting device can be significantly improved.

[0102] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted in a general and descriptive sense only and not for purposes of limitation. In some cases, as will be readily appreciated by those of ordinary skill in the art, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments as of the time of filing this application, unless otherwise indicated. Therefore, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A semiconductor light emitting device, comprising: A light emitting structure comprising a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer; a transparent electrode layer, which is located on the second conductive type semiconductor layer; as well as A reflective electrode structure, which is located on the transparent electrode layer, and the reflective electrode structure comprises: a light-transmitting insulating layer, which is located on the transparent electrode layer and includes a plurality of insulating patterns, a portion of the sides of the plurality of insulating patterns is open, and a contact area of ​​the transparent electrode layer is defined by an area between the plurality of insulating patterns; a plurality of air gaps respectively located between the transparent electrode layer and the plurality of insulating patterns, the plurality of air gaps extending in open portions of sides of the plurality of insulating patterns; and A reflective electrode layer is located on the plurality of insulating patterns to cover open portions of side surfaces of the plurality of insulating patterns, the reflective electrode layer being connected to the contact region of the transparent electrode layer.

2. The semiconductor light emitting device according to claim 1, wherein: Open portions of each of the plurality of insulation patterns face each other in one direction.

3. The semiconductor light emitting device according to claim 1, wherein: Each of the plurality of air gaps has a substantially hexahedral structure, an upper surface and two first opposing side surfaces of the hexahedral structure are covered by the light-transmitting insulating layer, and two second opposing side surfaces of the hexahedral structure except the two first opposing side surfaces are covered by the reflective electrode layer.

4. The semiconductor light emitting device according to claim 3, wherein: The contact region of the transparent electrode layer has a linear shape extending between the plurality of insulating patterns and arranged in a plurality of rows and columns.

5. The semiconductor light emitting device according to claim 1, wherein: The thickness of the air gap is in a range of 50% to 130% of the thickness of the light-transmitting insulating layer.

6. The semiconductor light emitting device according to claim 1, wherein: The transparent electrode layer includes indium tin oxide (ITO), zinc-doped indium tin oxide (ZITO), zinc indium oxide (ZIO), gallium indium oxide (GIO), zinc tin oxide (ZTO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), In4Sn3O 12 and zinc magnesium oxide Zn (1-x) Mg x At least one of O, where 0≤x≤1.

7. The semiconductor light emitting device according to claim 1, wherein: The light-transmitting insulating layer includes at least one of NaF, Na3AlF6, LiF, MgF2, CaF2 and BaF2.

8. The semiconductor light emitting device according to claim 1, wherein: The reflective electrode layer includes at least one of silver (Ag), chromium (Cr), nickel (Ni), titanium (Ti), aluminum (Al), rhodium (Rh), ruthenium (Ru), palladium (Pd), gold (Au), copper (Cu) and combinations thereof.

9. The semiconductor light emitting device according to claim 1, further comprising: a first insulating layer, which is located on the reflective electrode layer and has at least one opening connected to the reflective electrode layer; as well as A connecting electrode is located on the first insulating layer and connected to the reflective electrode layer through the at least one opening.

10. The semiconductor light emitting device according to claim 1, further comprising: The bonding electrode layer is located between the light-transmitting insulating layer and the reflective electrode layer.

11. The semiconductor light emitting device according to claim 10, wherein: The bonding electrode layer includes ITO, ZITO, ZIO, GIO, ZTO, FTO, AZO, GZO, In4Sn3O 12 and Zn (1-x) Mg x At least one of O, where 0≤x≤1.

12. A semiconductor light emitting device, comprising: A light emitting structure comprising a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer; a transparent electrode layer, which is located on the second conductive type semiconductor layer; a light-transmitting insulating layer comprising a plurality of insulating patterns on the transparent electrode layer, a plurality of air gaps being defined between the transparent electrode layer and the plurality of insulating patterns, respectively, and a contact area of ​​the transparent electrode layer being defined by an area between the plurality of insulating patterns, wherein the plurality of air gaps extend in open portions of sides of the plurality of insulating patterns; a reflective electrode layer, which is located on the transparent electrode layer to cover the plurality of insulating patterns and is connected to the contact region of the transparent electrode layer; a first insulating layer located on the reflective electrode layer and having at least one opening connected to the reflective electrode layer; and A connecting electrode is located on the first insulating layer and connected to the reflective electrode layer through the at least one opening.

13. The semiconductor light emitting device according to claim 12, wherein: Each of the plurality of insulating patterns has a portion extending to contact the transparent electrode layer, and a portion of a side surface of the plurality of insulating patterns is opened to expose the plurality of air gaps to the reflective electrode.

14. The semiconductor light emitting device according to claim 13, wherein: The portions of the sides of the plurality of insulating patterns are covered by the reflective electrode layer, so that two first opposing sides of each of the plurality of air gaps are covered by the reflective electrode layer, and two second opposing sides of each of the plurality of air gaps are covered by a corresponding one of the plurality of insulating patterns.

15. The semiconductor light emitting device according to claim 14, wherein: The two first opposing sides of each of the plurality of air gaps are spaced apart from each other along a first direction, and the two second opposing sides of each of the plurality of air gaps are spaced apart from each other along a second direction different from the first direction.

16. The semiconductor light emitting device according to claim 15, wherein: The plurality of insulating patterns have a substantially quadrilateral shape, and the contact region of the transparent electrode layer has a linear shape extending between the plurality of insulating patterns and is arranged in a plurality of rows and columns.

17. The semiconductor light emitting device according to claim 12, further comprising: a second insulating layer located on the first insulating layer and including at least one opening connected to a portion of the connection electrode; as well as A bonding electrode is located on the portion of the connecting electrode.

18. A semiconductor light emitting device, comprising: A light emitting structure comprising a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer; a transparent electrode layer, which is located on the second conductive type semiconductor layer; a base insulating layer and a light-transmitting insulating layer, which are sequentially disposed on the transparent electrode layer and have a plurality of openings connected to the transparent electrode layer; as well as a reflective electrode layer, which is located on the light-transmitting insulating layer and connected to the transparent electrode layer through the plurality of openings, Part of the light-transmitting insulating layer extends toward a corresponding opening among the plurality of openings while being overhung on a corresponding part of the base insulating layer, so that an air gap is surrounded by the light-transmitting insulating layer, the base insulating layer, the reflective electrode layer and the transparent electrode layer.

19. The semiconductor light emitting device according to claim 18, wherein: The light-transmitting insulating layer includes a material having a refractive index lower than that of the base insulating layer.

20. The semiconductor light emitting device according to claim 18, wherein: The plurality of openings have a hole shape or a linear shape.

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