TWI738766B - Light-emitting device and manufacturing method thereof - Google Patents

Abstract

A light-emitting device comprising a substrate; a reflective layer on the substrate; a dielectric layer on the reflective layer, wherein the dielectric later has a through hole; a light-emitting stack on the dielectric layer, wherein the light-emitting stack comprises an active layer and a top surface; and an opaque layer covers a first part of the top surface of the light-emitting stack and exposes a second part of the top surface, and the second part is directly above the through hole.

Description

Light-emitting element and manufacturing method thereof

The present invention relates to a light-emitting element and a manufacturing method thereof.

Light-Emitting Diode (LED) has the characteristics of low energy consumption, long operating life, shockproof, small size, fast response speed and stable output light wavelength, so it is suitable for various purposes. Recently, in addition to general lighting applications, it has been further developed for industrial applications, such as counters, sensors, and so on.

A light-emitting element includes: a substrate; a reflective layer located above the substrate; an insulating layer located above the reflective layer, wherein the insulating layer has a first perforation; a light-emitting stack is located above the insulating layer, the light-emitting stack Comprising an active area and having an upper surface; and an opaque layer covering a first portion of the upper surface of the light-emitting laminate and exposing a second portion of the upper surface, and the second portion is positioned at the first Right above the perforation.

A method for manufacturing a light-emitting element includes: forming a light-emitting laminate, the light-emitting laminate comprising an active area; forming an insulating layer above the light-emitting laminate, wherein the insulating layer has a first through hole; and forming a reflective layer located at Above the insulating layer; providing a substrate; bonding the substrate and the light-emitting laminate so that the reflective layer is located between the substrate and the light-emitting laminate; and forming a light-impermeable layer in the bonding direction of the light-emitting laminate and the substrate The opposite side covers a first part of a surface of the light-emitting stack and exposes a second part of the surface, and the position of the second part is opposite to the position of the first perforation of the insulating layer.

The following embodiments will be accompanied by drawings to illustrate the concept of the present invention. In the drawings or descriptions, similar or identical parts use the same reference numerals, and in the drawings, the shape or thickness of the element can be expanded or reduced. It should be noted that the components not shown in the figure or described in the specification can be in the form known to those who are familiar with the art.

Fig. 1A to Fig. 1T show the light-emitting element and its manufacturing method according to the first embodiment of the present invention. As shown in FIG. 1A, first, a growth substrate 101, such as gallium arsenide (GaAs), is provided, and a buffer layer 102, a first contact layer 103, and a light-emitting stack 104 are sequentially formed thereon. Among them, the buffer layer 102 can block the etching during the subsequent step of removing the growth substrate 101 or is less likely to be etched than the growth substrate. Therefore, depending on the etching method, such as wet etching, the buffer layer 102 can be selected for use and the growth substrate 101 is larger. Materials with different etching rates, for example, when the growth substrate 101 is a gallium arsenide substrate, the material of the buffer layer 102 can be selected to use indium gallium phosphide (InGaP) or aluminum gallium arsenide (AlGaAs). In some embodiments of the present invention, if the growth substrate 101 and the first contact layer 103 have a significant difference in etching rate for the same etching solution, for example, the etching rate of the growth substrate 101 is greater than the etching rate of the first contact layer 103 by at least 2 times If the etching rate of the first contact layer 103 is greater than the etching rate of the growth substrate 101 by at least two orders of magnitude, the buffer layer 102 may not be provided. The first contact layer 103 can provide a low-resistance contact, such as less than 10 ^-3 Ω-cm, and its material is, for example, n-type doped gallium arsenide (GaAs), and its doping concentration can be higher than 1*10 ¹⁸ (/ cm ³ ). The light emitting stack 104 includes a first conductivity type semiconductor layer 104a, a second conductivity type semiconductor layer 104c, and an active region 104b located between the first conductivity type semiconductor layer 104a and the second conductivity type semiconductor layer 104c. The first electrical type semiconductor layer 104a and the second electrical type semiconductor layer 104c are electrically different. For example, the first electrical type semiconductor layer 104a is an n-type semiconductor layer, and the second electrical type semiconductor layer 104c is a p-type semiconductor layer. The first electrical type semiconductor layer 104a, the active region 104b, and the second electrical type semiconductor layer 104c are formed of III-V materials, such as aluminum gallium indium phosphide series ((Al _y Ga( _1-y )) _{1- x} In _x P, where 0≦x≦1; 0≦y≦1) material.

Next, as shown in FIG. 1B, a second contact layer 105 is formed on the light-emitting stack 104 to provide a low-resistance contact, such as less than 10 ^-3 Ω-cm, and its material is, for example, gallium phosphide (GaP). In this embodiment, the thickness of the second contact layer 105 should not be too thick, for example, not more than 1.5 μm; or the thickness of the second contact layer 105 is about 0.1 μm to 0.5 μm. Next, as shown in FIG. 1C, an insulating layer 106 is formed on the second contact layer 105. The refractive index of the insulating layer 106 can be smaller than the equivalent refractive index of the light-emitting stack 104. The material of the insulating layer 106 may include a material selected from the group consisting of silicon _{oxide (SiO x} ), magnesium fluoride (MgF ₂ ), and silicon nitride (SiN _x ). The thickness of the insulating layer 106 is about 50 nm to 300 nm The thickness of the insulating layer 106 is between 100 nm and 200 nm. Next, as shown in FIG. 1D, a first through hole 106h is formed in the insulating layer 106 through the insulating layer 106 by a yellow light and etching process, and the first through hole 106h is viewed from the insulating layer 106 to the direction of the light-emitting stack 104 It is roughly circular (not shown in the figure) and has a diameter D ₁ , the diameter D _{1 is} approximately between 20 μm and 150 μm, or the diameter D ₁ is approximately between 40 μm and 90 μm.

Next, as shown in FIG. 1E, a first transparent conductive layer 107 is formed on the insulating layer 106 and filled in the first through hole 106h, so that the first transparent conductive layer 107 and the light-emitting stack 104 are formed by the first through hole 106h Electrical connection. The size of the current supplied to the light-emitting stack 104 can be controlled by adjusting the size of the first through hole 106h. Then, as shown in FIG. 1F, a second transparent conductive layer 108 is formed on the first transparent conductive layer 107. The material of the second transparent conductive layer 107 is different from that of the first transparent conductive layer 107, or the forming method may be different. The second transparent conductive layer 108 may have a function of enhancing current diffusion in the lateral direction (that is, a direction perpendicular to the stacking direction of the light-emitting stack 104) or a function of being a light-transmitting layer. Considering the function of being a light-transmitting layer, the second transparent conductive layer 108 may select a material with a lower refractive index value than that of the light-emitting stack 104. Considering the function of lateral current spreading, the thickness of the second transparent conductive layer 108 can be thicker than the thickness of the first transparent conductive layer 107. For example, when viewed from the insulating layer 106 toward the second transparent conductive layer 108, the first transparent conductive layer The thickness of the layer 107 is between 25 Å and 200 Å, or between 40 Å and 60 Å, and the thickness of the second transparent conductive layer 108 is between 25 Å and 2000 Å, or between 600 Å and 1000 Å. In other embodiments of the present invention, the second transparent conductive layer 108 may not be formed, but the thickness of the first transparent conductive layer 107 is thickened to replace the function of the second transparent conductive layer 108. The first transparent conductive layer 107 and the second transparent conductive layer 108 respectively comprise a material selected from the group consisting of indium tin oxide (Indium Tin Oxide, ITO), aluminum oxide zinc (Aluminum Zinc Oxide, AZO), cadmium tin oxide, antimony tin oxide, oxide Zinc (ZnO), zinc tin oxide, indium zinc oxide (IZO) and graphene (Graphene) form a group. In this embodiment, the material of the first transparent conductive layer 107 is indium tin oxide (ITO), and the material of the second transparent conductive layer 108 is indium zinc oxide (IZO). The first transparent conductive layer 107 can be formed using an electron beam gun (E-gun), and the second transparent conductive layer 108 can be formed using sputtering, but the present invention is not limited to this. In another embodiment Here, the first transparent conductive layer 107 and the second transparent conductive layer 108 can also be formed using the same method. In addition, the density of the second transparent conductive layer 108 may be the same as or different from the density of the first transparent conductive layer 107. In this embodiment, the second transparent conductive layer 108 is denser than the first transparent conductive layer 107, that is, the second transparent The density of the conductive layer 108 is higher than that of the first transparent conductive layer 107 to facilitate the aforementioned lateral current spreading.

Next, as shown in FIG. 1G, a reflective layer 109 is formed on the second transparent conductive layer 108 to reflect the light emitted by the light-emitting laminate 104. In this embodiment, the reflective layer 109 can be used for the light-emitting laminate. The emitted light has a reflectivity greater than 85%, and the reflective layer 109 may include a metal material, such as gold (Au) or silver (Ag).

Next, as shown in FIG. 1H, a first bonding layer 110a is formed on the reflective layer 109, and a second bonding layer 110b is formed on the first bonding layer 110a. Figure 1I shows the inversion of Figure 1H. Next, as shown in Figure 1J, a permanent substrate 111 is provided, and a third bonding layer 110c is formed on the permanent substrate 111, and then the third bonding layer 110c and the second bonding layer 110b are bonded to each other. The situation is shown in Figure 1K. The first bonding layer 110a, the second bonding layer 110b, and the third bonding layer 110c form a bonding structure 110. The bonding structure 110 may include a low-temperature fusion material with a melting point less than or equal to 300° C., such as indium (In) or tin (Sn). In this embodiment, the material of the first bonding layer 110a is gold (Au), the material of the second bonding layer 110b is low temperature fusion material indium (In), and the material of the third bonding layer 110c is gold (Au). At low temperatures, for example, the temperature is less than or equal to 300°C, the first bonding layer 110a, the second bonding layer 110b, and the third bonding layer 110c can form an alloy due to the eutectic effect and be bonded to form the bonding structure 110, wherein The bonding structure 110 includes an alloy of indium (In) and gold (Au). In another embodiment, the second bonding layer 110b may be formed on the third bonding layer 110c, and then bonded with the first bonding layer 110a to form the bonding structure 110. Next, the growth substrate 101 is removed, and the situation is as shown in FIG. 1L. In this embodiment, the etching method of wet etching is selected to remove the growth substrate 101. The etching solution is, for example, an etching solution containing ammonia (NH ₃ ·H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), since it contains indium gallium phosphide (In _x Ga _1-x P, where 0≦x≦1) the buffer layer 102 is more difficult to etch than the growth substrate 101, so the process of removing the growth substrate 101 can be controlled without damaging the light-emitting stack 104. Then, since the buffer layer 102 containing indium gallium phosphide ((In _x Ga _1-x P, where 0≦x≦1) may absorb the light emitted by the light-emitting stack 104, it can be further removed. The situation is shown in Figure 1M.

Next, as shown in FIG. 1N, a second through hole H ₁ is formed on the first contact layer 103 to penetrate the first contact layer 103, and the second through hole H ₁ is viewed from the first contact layer 103 toward the permanent substrate 111. It is roughly circular (refer to Figure 2, detailed later) and has a diameter D ₂ . The diameter D _{2 is} approximately between 20 μm and 150 μm, or approximately between 40 μm and 90 μm. In particular, the extension of the H ₁ second perforated A-A 'line (i.e., the light emitting stack 104 to the stacking direction perpendicular to a direction) having a length area. In the present embodiment, the second perforated H ₁ is formed by an etching method and yellow. Subsequently, as shown in FIG first 1O, a contact layer is formed on the first contact layer 103 and 112 penetrating the second through hole H ₁ extending on the contact layer 112. In this embodiment, the upper contact layer 112 includes an alloy, such as an alloy of germanium (Ge), gold (Au), and nickel (Ni). Then, as shown in FIG. 10, a part of the outer periphery of each layer from the upper contact layer 112 to the second contact layer 105 is removed by a yellow light and etching process, and a part of the insulating layer 106 is exposed. Next, as shown in FIG. 1P, a sidewall insulating layer 113 is formed on the sidewall of the structure formed after removing a portion of the aforementioned periphery. The sidewall insulating layer 113 includes an insulating material, such as silicon nitride (Si ₃ N ₄ ) or silicon oxide (SiO ₂ ). In this embodiment, the sidewall insulating layer 113 includes silicon nitride (Si ₃ N ₄ ) and silicon oxide. (SiO ₂ ) laminated layer, its formation method is to first form a laminated layer of silicon nitride (Si ₃ N ₄ ) and silicon oxide (SiO ₂ ) on the structure, and then remove part of it by a yellow light and etching process , And at least leave and form the sidewall insulation layer 113 on the aforementioned sidewalls. As shown in FIG. 1P, in this embodiment, a sidewall insulating layer 113 is also formed on the exposed insulating layer 106 and on a part of the upper contact layer 112.

Next, as shown in FIG. 1Q, an upper electrode 114 is formed on the structure shown in FIG. 1P. The material of the upper electrode 114 includes a metal material. In this embodiment, it includes a stack of titanium (Ti)/platinum (Pt) formed by an electron gun evaporation (E-beam evaporation) method; in another example, the upper The electrode 114 does not include platinum (Pt), and the upper electrode 114 is composed of titanium (Ti); in another embodiment, the upper electrode 114 includes titanium (Ti) and gold (Au). And after the formation of titanium generally corresponding second perforated portion of removing H ₁ (Ti) / platinum (Pt) of the stack, so that the second perforation penetrating H ₁ and the upper electrode 114 extends. The upper electrode 114 not only serves as an electrode, but also serves as an opaque layer covering the light-emitting element. Since the upper electrode 114 positioned above the light emitting stack 104, stack 104 for over the light emitting surface, corresponding to the second perforated area H ₁ region of the light emitting element, namely, the light emitting device of the present invention based emitted from light aperture, i.e., the second light perforated H _1, the upper electrode 114 is not covered and the exposed portion of the surface area is the area of the light emitting element of the light emitting stack 104, and the upper electrode 114 while covering the upper surface of the light emitting stack 104 other parts. In addition, the opaque layer formed by the upper electrode 114 further covers the sidewall of the light-emitting stack 104, and the aforementioned sidewall insulating layer 113 is located between the opaque layer formed by the upper electrode 114 and the sidewall of the light-emitting stack 104. In order to prevent the light-emitting stack 104 from failing due to a short circuit. In addition, in one embodiment, the size, shape, and position of the light hole (ie, the second perforation H ₁ ) are preset, and the size, shape, and position of the first perforation 106h need to be approximately the _{same as that of the second perforation H 1} correspondence with the first through hole 106h is located directly below the second perforation ₁ H, 106h and the first perforations size and / or shape of the second perforated ₁ H size and / or shape may be designed to be the same. Specifically, before manufacturing the first perforation 106h as shown in Figure 1D, the parameters of the second perforation H1 (such as the above-mentioned size, shape, and position parameters) are preset to determine the first perforation. 106h corresponding parameters and manufacture.

In addition, since the material of the upper electrode 114 is not easily formed on the sidewall insulating layer 113, the thickness of the upper electrode 114 may be too thin. Therefore, in this embodiment, as shown in FIG. 1R, a metal layer 114S can be formed. To reinforce the insufficient thickness of the upper electrode 114 on the sidewall insulating layer 113. The metal layer 114S may include a chemical plating method formed on the upper electrode 114, such as immersing the structure shown in Figure 1Q in a metal material (such as gold (Au), silver (Ag), titanium (Ti) or platinum ( Pt), which is a metal material layer formed by redox in a gold (Au) solution in this embodiment, that is, the metal layer 114S may include a gold (Au) layer. The gold (Au) layer is removed approximately corresponding to the second through hole H _{1 , so that the second through hole H 1} extends and penetrates the metal layer 114S. In an embodiment of the present invention, as an opaque layer for covering the light emitting element, the thickness of the upper electrode 114 is at least greater than 100 Å. In this embodiment, the thickness of the titanium (Ti) and platinum (Pt) of the upper electrode 114 and the gold (Au) layer of the metal layer 114S are respectively about 200 Å to 400 Å, 2 μm to 4 μm, and 2000 Å to 4000 Å. between.

Next, as shown in FIG. 1S, a protective layer 115 is formed on the structure shown in FIG. 1R. After the protective layer 115 is filled with the second through hole H _{1 along the side wall surrounding the second through hole H 1} , the diameter of the hole formed by the inner diameter of the protective layer 115 is D ₃ . The material of the protective layer 115 is an insulating material, such as silicon nitride (Si ₃ N ₄ ) or silicon oxide (SiO ₂ ). After formation, as shown in FIG. 1T, part of the protective layer 115 is removed to form the third through hole 115h, and the bottom electrode 111E is formed on the permanent substrate 111. The third through hole 115h exposes a part of the metal layer 114S (in another embodiment of the present invention without the metal layer 114S, a part of the upper electrode 114 is exposed), which serves as a soldering pad for the wiring and The metal layer 114S (or the upper electrode 114) is in contact with each other.

Fig. 1T is a schematic diagram of the light-emitting device according to the first embodiment of the present invention, and Fig. 2 is a schematic top view of Fig. 1T. Please refer to these two figures at the same time. Above the substrate 111, the reflective layer 109 is located above the bonding structure 110, and the insulating layer 106 is located above the reflective layer 109. The insulating layer 106 has a first through hole 106h, and the first transparent conductive layer 107 is filled in the first through hole 106h of the insulating layer 106 , And the first through hole 106h is in direct contact with the second contact layer 105 to form an electrical connection with the light-emitting stack 104. And a first perforation 106h located in the first transparent conductive layer 105 in direct contact with the second contact layer 107 is a current-conducting region, a second current-conducting region which is located on the surface of the perforated H ₁ and the light emitting stack 104, a second portion Directly below, the current conducting area allows current to flow into the light-emitting stack 104. Specifically, the contact resistance between the first transparent conductive layer 107 and the second contact layer 105 is smaller than the contact resistance between the insulating layer 106 and the second contact layer 105, for example, less than two orders of magnitude or less than five orders of magnitude. Preferably, the contact resistance between the first transparent conductive layer 107 and the second contact layer 105 is between 10 ^-3 and 10 ^-5 Ω cm ² . The insulating layer 106 in the non-current conducting area surrounds the second contact layer 105. The light-emitting stack 104 is located above the insulating layer 106, the light-emitting stack 104 includes an active area 104b and has an upper surface (refer to Figure 2, the area formed by the rectangular dotted line), and the opaque layer formed by the upper electrode 114 is located Above the light-emitting stack, the opaque layer formed by the upper electrode 114 covers a first portion of the upper surface of the light-emitting stack 104, that is, the portion other than the second through hole H1 (refer to Figure 2, except for the circle dashed line) constituting region) on one of the exposed surface of the second portion, a second portion that is located directly below the second perforated portion of H ₁ (refer to FIG. 2, the dotted circle formed region). That is, the area of the upper surface of the light-emitting stack 104 _{outside the second portion directly below the second through hole H 1} is covered by the opaque layer formed by the upper electrode 114. Light emitted from light emitting stack 104 may be _an escape from the second part of its upper surface and a second perforated H. The ratio of the cross-sectional area of the second through hole H _{1 to} the upper surface area of the light-emitting stack 104 is about 1.5-5%. As shown in Figure 2, the soldering pad is usually formed on the first part covered by the upper electrode 114. Specifically, it is formed in the third through hole 115h to form an electrical connection with the light-emitting stack 104. The soldering pad is generally rectangular or square. The third through hole 115h is approximately at least 80 μm on the short side of the rectangle or any side of the square. Specifically, the area of the first part of the upper surface of the light-emitting stack 104 is larger than the area of the second part. The first transparent conductive layer 107 is filled in the first through hole 106h of the insulating layer 106, and is electrically connected to the light-emitting stack 104 by directly contacting the second contact layer 105. Since the insulating layer 106 of a first substantially perforated 106h cooperate with _a corresponding second perforation H in the size, shape, and position, so that a first cross-sectional area ratio of the surface area of the perforations of the light emitting stack 104 and also approximately 106h 1.5~5%.

Figure 3 shows that in the embodiment of the present invention, when the thickness of the second contact layer 105 of the light-emitting element is 0.2 μm and 1 μm, respectively, the diameter of the first hole 106h (horizontal axis) corresponds to the light-emitting element. Luminous power (Po, vertical axis on the left) and forward voltage (Vf, vertical axis on the right). As shown in Figure 3, the luminous power and forward voltage of the light-emitting element will vary with the size of the first hole 106h, that is, the element design is predictable and controllable, and the first hole can be adjusted according to different needs. The size of 106h meets the requirements. It can be seen from further experimental results that the thickness of the second contact layer 105 should not be greater than 1.5 μm. When the thickness of the second contact layer 105 is too thick, for example, greater than 1.5 μm, the current blocking effect of the insulating layer 106 is not easily changed with the diameter of the first through hole 106h, that is, in this case, the light-emitting element emits light The power and forward voltage will not change significantly with the diameter of the first through hole 106h, and it is not easy to control or predict the luminous power and forward voltage of the light-emitting element by adjusting the diameter of the first through hole 106h.

In addition, the light-emitting element can be operated at a normal current value (for example, 50mA in this embodiment). According to different applications of the element, some applications require the light-emitting element to operate at a relatively high current value (for example, in this embodiment). Operate under the condition of 300mA) and emit light in a pulse mode (that is, the light emitted by the light-emitting element changes intermittently over time, rather than continuous). The light-emitting element structure of this embodiment can meet the above two situations at the same time. Figure 4 shows that in an embodiment of the present invention, the active region 104b is a light emitting element with a multiple quantum well (MQW) structure when emitting light in the same pulse mode, the multiple quantum well structure includes 18, 38, and 48 well layers, respectively. Under the condition of (well), corresponding to the relative high current (300mA) luminous power (Po, the right vertical axis) and the luminous power ratio (the left vertical axis means that when the light-emitting element is in the same pulse light emission pattern, the light-emitting element is at a relatively high current The ratio of the luminous power under operation to the luminous power under normal current operation). The figure shows that when the multi-quantum well structure contains 38 and 48 well layers, the luminous power ratio can be as high as 2.8 or more. According to further experimental results, when the multiple quantum well (MQW) structure contains 30-50 well layers, the luminous power ratio can reach more than 2.6.

Figure 5 shows that in the light-emitting element of the above embodiment, the active region 104b is a multiple quantum well (MQW) structure light-emitting element when the light is emitted in the same pulse mode, the aluminum gallium indium phosphide series ((Al) in the multiple quantum well structure _y Ga( _1-y )) _1-x In _x P, where 0≦x＜1; 0≦y≦1) The barrier layer of the material contains 30%, 50%, and 70% aluminum, respectively (Al) (refers to the proportion of aluminum (Al) in the composition of aluminum (Al) and gallium (Ga), which is equivalent to the y in the above formula). Under the condition of the content, the luminous power (Po) corresponding to the relatively high current (300mA), the right vertical axis ) And the ratio of luminous power (Factor, refers to the ratio of the luminous power of a relatively high current to the luminous power of a normal current when the light emitting element is in the same pulse light emission pattern, the left vertical axis), in which the barrier layer has multiple layers. The figure shows that the barrier layer (Barrier) in the multiple quantum well structure contains 50% and 70% of the aluminum (Al) content, respectively, and the luminous power ratio can be as high as 3.1 or more. Considering the electrical requirements of other light-emitting devices, such as the appropriate range of forward voltage, further experiments show that the barrier layer in the multiple quantum well structure contains about 40% to 60% aluminum (Al) content. , Luminous power ratio and forward voltage have good performance at the same time. In another embodiment, in the plurality of barrier layers, two of the barrier layers have different aluminum contents, and the barrier layer closer to the first electrical type semiconductor layer 104a has lower aluminum content than the barrier layer farther away from the first electrical type semiconductor layer 104a. The aluminum content of the barrier layer of the semiconductor layer 104a. Preferably, in the plurality of barrier layers, at least more than half of the barrier layers close to the first electrical type semiconductor layer 104a (ie, the n-type semiconductor layer) have a lower aluminum content than the rest close to the second electrical type semiconductor layer 104c ( That is, the aluminum content of the barrier layer of the p-type semiconductor layer). Specifically, the barrier layer near the first electrical type semiconductor layer 104a includes (Al _a Ga _1-a ) _1-b In _b P, and the barrier layer near the second electrical type semiconductor layer 104 _c includes (Al c Ga _{1- c} ) _1-d In _d P, in the case of b≒d, c>a. In one embodiment, the multiple quantum well structure includes 38 barrier layers, and the first 20 barrier layers closer to the first conductivity type semiconductor layer 104a include (Al _0.5 Ga _0.5 ) _1-b In _b P, and The remaining 18 barrier layers far away from the first electrical type semiconductor layer 104a, that is, the 18 barrier layers closer to the second electrical type semiconductor layer 104c include (Al _0.7 Ga _0.3 ) _1-d In _d P, which are implemented here In the example, b and d are approximately equal to 0.5, but not limited to this. In one embodiment, the multiple quantum well structure includes 38 barrier layers, and the first 28 barrier layers closer to the first conductivity semiconductor layer 104a include (Al _0.5 Ga _0.5 ) _1-b In _b P, which is closer to The first 10 barrier layers of the second conductivity type semiconductor layer 104c include (Al _0.7 Ga _0.3 ) _1-d In _d P. In this embodiment, b and d are approximately equal to 0.5, but are not limited thereto. In one embodiment, the multiple quantum well structure includes 38 barrier layers, and the first 36 barrier layers closer to the first electrical type semiconductor layer 104a include (Al _0.5 Ga _0.5 ) _1-b In _b P, which is closer to The two barrier layers of the second conductivity type semiconductor layer 104c include (Al _0.7 Ga _0.3 ) _1-d In _d P. In this embodiment, b and d are approximately equal to 0.5, but are not limited thereto. In one embodiment, the aluminum content in the plurality of barrier layers gradually increases from the n-type semiconductor layer to the p-type semiconductor layer, that is, each closer to the first conductivity type semiconductor layer 104a (ie, the n-type semiconductor layer The aluminum content of the barrier layer of) is lower than that of the barrier layer adjacent to the second conductivity semiconductor layer 104c (ie, the p-type semiconductor layer). In one embodiment, the dopant of the second conductivity type semiconductor layer 104c includes carbon (C), magnesium (Mg), or zinc (Zn). Preferably, the dopant includes magnesium. In the present disclosure, the barrier layer has different aluminum content, and the aluminum content of the barrier layer closer to the n-type semiconductor layer is lower than the aluminum content of the barrier layer farther from the n-type semiconductor, which can avoid or reduce the p-type The diffusion of the p-type dopant in the semiconductor layer into the active region 104b further improves the reliability of the light-emitting device without greatly increasing the forward voltage of the light-emitting device.

Fig. 6 is a schematic cross-sectional view of a light-emitting device according to a second embodiment of the present invention. The structure of the light-emitting element of the second embodiment of the present disclosure is substantially the same as that of the first embodiment, and the difference is as follows. As shown in Figure 6, the light emitting element includes a first semiconductor layer 116 and a second semiconductor layer 117. The first semiconductor layer 116 is located between the first contact layer 103 and the light emitting stack 104, and the second semiconductor layer 117 is located on the second semiconductor layer. Between the contact layer 105 and the light-emitting stack 104. The first semiconductor layer 116 and the second semiconductor layer 117 are used to improve light extraction and/or improve current spreading so that the current spreads to the entire light-emitting stack 104. The thickness of the first semiconductor layer 116 is greater than the thickness of the first conductivity type semiconductor layer 104a. Preferably, the thickness of the first semiconductor layer 116 is greater than 2000 nm, and more preferably, between 2500 nm and 7000 nm. The thickness of the second semiconductor layer 117 is greater than the thickness of the second conductivity type semiconductor layer 104c. Preferably, the thickness of the second semiconductor layer 117 is greater than a thickness of 1000 nm, and more preferably, between 1500 nm and 2000 nm. The first semiconductor layer 116 has an energy level which is smaller than the energy level of the first conductivity type semiconductor layer 104a. The second semiconductor layer 117 has an energy level which is smaller than the energy level of the second conductivity type semiconductor layer 104c. The energy levels of the first semiconductor layer 116 and the second semiconductor layer 117 are greater than the energy levels of the well layer in the active region 104b. The light emitted from the active region 104b can substantially penetrate the first semiconductor layer 116. The first semiconductor layer 116 and the second semiconductor layer 117 each have a ^{doping concentration higher than 1´10 17} /cm ³ , and the doping concentration of the first semiconductor layer 116 is less than the doping concentration of the first contact layer 103, The doping concentration of the second semiconductor layer 117 is less than the doping concentration of the second contact layer 105. Preferably, the doping concentration of the first contact layer 103 is at least twice the doping concentration of the first semiconductor layer 116 (inclusive). The doping concentration of the second contact layer 105 is at least twice the doping concentration of the second semiconductor layer 117 (inclusive). The first semiconductor layer 116, the second semiconductor layer 117, the first contact layer 103, and the second contact layer 105 comprise Group III and V semiconductor materials, such as AlGaAs or AlGaInP. As shown in Fig. 6, the second contact layer 105 has a width W ₁ whose ratio to the width of the light-emitting area of the light-emitting element is not less than 0.5 and not more than 1.1. That is, in the same cross-section, the second contact layer 105 _{The ratio} of the width W1 of φ to the width of the area not covered by the upper electrode 114 (ie, the second portion of the upper surface of the light-emitting stack 104) is not less than 0.5 and not more than 1.1. _{In one embodiment, the ratio of the width W 1 of the} second contact layer 105 to the diameter D ₂ of the second through hole H ₁ (ie, W ₁ /D ₂ ) is not less than 0.5 and not more than 1.1. _{Preferably, the ratio of the width W 1 of the} second contact layer 105 to the width of the light-emitting area of the light-emitting element is not less than 0.55 and not more than 0.8. _{In one embodiment, the ratio of the width W 1 of the} second contact layer 105 to the diameter D ₂ of the second through hole H ₁ (ie, W ₁ /D ₂ ) is not less than 0.55 and not more than 0.8. In addition, in the second embodiment, as shown in FIG. 6, the second contact layer 105 is located directly under the light-emitting area of the light-emitting element, that is, located in the area not covered by the upper electrode 114 (ie, on the light-emitting stack 104). The second part of the surface) directly below. The contact resistance between the second contact layer 105 and the first transparent conductive layer 107 is much smaller than the contact resistance between the first transparent conductive layer 107 and the second semiconductor layer 117, for example, less than two orders of magnitude or less than five orders of magnitude. Therefore, the second contact layer 105 with a width W ₁ is a current conducting region, which allows current to flow into the light-emitting stack 104, and the other of the first transparent conductive layer 107 is not in contact with the second contact layer 105 and surrounds the second contact layer The area of 105 cannot allow current to flow or it is difficult for current to flow into the light-emitting stack 104. In the present embodiment, the second contact layer 105 is located directly below the second perforation of H _1. Preferably, the second contact layer 105 does not overlap the upper contact layer 112 and the upper electrode 114 in the stacking direction of the light-emitting stack 104. In this embodiment, as shown in FIG. 6, the thickness of part of the second semiconductor layer 117 is greater than the thickness of other parts of the second semiconductor layer 117, and the thicker part of the second semiconductor layer 117 corresponds to the light emitting area, That is, the area not covered by the upper electrode 114 (that is, the second part of the upper surface of the light-emitting stack 104). In this embodiment, the thicker part of the second semiconductor layer 117 corresponds to the second through hole H ₁ . The second contact layer 105 is located on the thicker part of the second semiconductor layer 117. Specifically, the thinner part of the second semiconductor layer 117 includes a surface 1171 away from the light-emitting stack 104, and the second contact layer 105 includes a surface 1051 away from the light-emitting stack 104, which is compared with the second semiconductor layer 117. The surface 1171 of the thinner part and the surface 1051 of the second contact layer 105 are farther away from the light-emitting stack 104. Specifically, the height h between the surface 1051 of the second contact layer 105 away from the light emitting stack 104 and the surface 1171 of the second semiconductor layer 117 away from the light emitting stack 104 is not less than 50 nm and not more than 200 nm. In one embodiment, the thickness of the second contact layer 105 is not less than 20 nm and not more than 0.5 μm. Preferably, the thickness of the second contact layer 105 is not less than 20 nm and not more than 0.1 μm. Since the second embodiment comprises a light emitting element having a width W ₁ of the second contact layer 105 and located directly below the light area of the second contact layer 105, when current flows through the light emitting stack 104, current is easily concentrated The area corresponding to the second contact layer 105 can greatly increase the current density, thereby increasing the brightness of the light-emitting element.

The manufacturing method of the light-emitting element of the second embodiment of the present disclosure is substantially the same as the manufacturing method of the first embodiment. The difference includes that before forming the light-emitting stack 104, it further includes forming the first semiconductor layer 116 on the first contact. On the layer 103, after forming the light-emitting stack 104 and before forming the second contact layer 105, the second semiconductor layer 117 as described above is further formed. After the second contact layer 105 is formed, the second contact layer 105 is patterned by yellow light and an etching process so that the second contact layer 105 has a width W ₁ , and then the first transparent layer is formed as in the manufacturing method of the first embodiment. The conductive layer 107, the second transparent conductive layer 108 and other subsequent steps. Compared with the manufacturing method of the first embodiment, the manufacturing method of this embodiment does not need to form the insulating layer 106 and does not need to use yellow light and etching process to form the first through hole 106h in the insulating layer 106, which greatly reduces the cost of the manufacturing process and Increase process simplicity.

In one embodiment immediately below, the light emitting element does not comprise a second perforated H1, having a width W region of the light-emitting element ₁ of the second contact layer 105, i.e. not located on the coverage area of electrode 114 (i.e., the light emitting The second part of the upper surface of the laminate 104) is directly below.

Fig. 7 is a cross-sectional view of a light-emitting device according to a third embodiment of the present invention. Compared with the foregoing embodiments of the present invention, the light-emitting element of this embodiment further includes a thermally conductive layer 118 disposed on the second portion of the upper surface of the light-emitting stack 104. In detail, the thermally conductive layer 118 is disposed on the upper surface of the light emitting stack 104 by a second perforated exposed by H _1, and the thermally conductive layer 118 having a higher thermal conductivity than the light emitting stack 104 (thermal conductivity), the light emitting element in operation, heat generated by the light emitting stack 104 by a thermally conductive layer 118 may be conductive or radiation to escape to the outside, so can reduce the heat accumulated in the second light emitting stack 104 perforation H ₁ below, the emission mitigation Material decay caused by heat inside the element, and increase the service life and reliability of the light-emitting element. The thermal conductive layer 118 may include a material with a thermal conductivity of not less than 100W/(mÏK), for example, diamond, graphene, or aluminum nitride (AlN _X ) with a thermal conductivity of about 140W/(mÏK)～180W/(mÏK), The present invention is not limited to this. More detail, in the present embodiment, the thermally conductive layer 118 along the second perforation line sidewall ₁ H H ₁ filled in the second perforation, and covers the first layer of the second conductivity type semiconductor exposed by _a perforated H on 104a, and extending to a direction away from the second perforated H ₁ around the light emitting element, and in contact with the metal layer 114S or the upper electrode 114, the light emitting stack 104 to the heat generated is transmitted to the metal layer through the thermally conductive layer 118 or 114S As for the upper electrode 114, since the metal layer 114S and the upper electrode 114 are usually selected as metal, the thermal conductivity is high, and the heat inside the light emitting element can be discharged through the thermal conductive layer 118 and the metal layer 114s or the upper electrode 114. In some embodiments, the thermally conductive layer 118 may not be in contact with the metal layer 114S or the upper electrode 114, the heat generated in the light-emitting stack 104 can be radiated to the outside through the thermally conductive layer 118, or the thermally conductive layer 118 can conduct heat to the outside. The structures are connected, so that the heat generated in the light-emitting stack 104 can be dissipated to the outside through the heat-conducting layer 118 in a conductive manner. Compared with the first embodiment, the light-emitting element in this embodiment includes a protective layer 115 covering the metal layer 114S, and the protective layer 115 also covers the thermally conductive layer 118. In this embodiment, the protective layer 115 can be intact. Covers the thermal conductive layer 118. In detail, the thermal conductive layer 118 of this embodiment has a top surface 118t and a side surface 118s. The top surface 118t is parallel to the upper surface of the light-emitting stack 104. Parallel to the upper surface of the light-emitting stack 104, the protective layer 115 simultaneously covers the top surface 118t and the side surface 118s of the heat-conducting layer 118, so as to prevent the material of the heat-conducting layer 118 from contacting the external environment and causing qualitative changes during the operation of the light-emitting element. The present invention is not limited to this; in another embodiment, the protective layer 115 may be replaced by the thermally conductive layer 118, so that the thermally conductive layer 118 fully covers the surface of the upper electrode 114 or the metal layer 114S except the position of the third through hole 115h , In order to increase the heat conduction area of the light-emitting element. In one embodiment, the thermally conductive layer 118 has a high transmittance to the light emitted by the light-emitting stack 104. For example, the thermally conductive layer 118 includes a material that has a transmittance higher than 85% for the emitted light from the active region 104b; in addition, In another embodiment, the thermal conductive layer 118 also has a refractive index greater than 1.5, or 2.1 to 2.5, and the refractive index difference between the thermal conductive layer 118 and the first electrical type semiconductor layer 104a is not more than 1.5, which can reduce the The interface between the electrical semiconductor layer 104a and the thermal conductive layer 118 has a probability of total reflection, which increases the light extraction efficiency of the light-emitting element. The thickness of the thermally conductive layer 118 may be 300-2000 Å. In this embodiment, the thickness of the thermally conductive layer 118 is 1000 Å, but it is not limited thereto. The thermal conductive layer 118 may be formed after the upper electrode 114 is formed as shown in FIG. 1Q, or after the metal layer 114S is formed as shown in FIG. 1R, so as to cover the upper electrode 114 or the metal layer 114S.

8A to 8B are a schematic cross-sectional view and a schematic top view of a light-emitting device according to a fourth embodiment of the present invention. Compared with the previous embodiment, the thermally conductive layer of the light emitting device 118 according to the present embodiment is provided on the light emitting stack 104, and the thermally conductive layer 118 having a substantially H ₄ fourth perforations in the second perforation of the H _1, the insulating layer 106 to Viewed from the direction of the light-emitting stack 104, the fourth through hole H _{4 is} first substantially circular (see FIG. 8B), and _{the top view area of the fourth through hole H 4} is larger than that of the second portion of the light-emitting stack 104 The top view area, in other words, the top view area of the fourth through hole H ₄ is larger than the top view area of the second through hole H ₁ . In detail, the heat-conducting layer 118 is located between the light-emitting stack 104, the first contact layer 103 and the insulating layer 106. In more detail, the heat-conducting layer 118 of this embodiment penetrates the first electrical semiconductor layer of the light-emitting stack 104 104a, the active region 104b, the second conductivity type semiconductor layer 104c, and the second contact layer 105, so that the thermally conductive layer 118 is surrounded by the light-emitting stack 104, the first contact layer 103, and the insulating layer 106; in another embodiment, the thermally conductive layer 118 penetrates the first electrical type semiconductor layer 104a, the active region 104b, and the second electrical type semiconductor layer 104c but does not penetrate the second contact layer 105, so that the thermally conductive layer 118 is covered by the light-emitting stack 104, the first contact layer 103, and the second contact layer 105 surrounds, but the structure of the thermal conductive layer 118 is not limited to the above-mentioned embodiment. The fourth through hole H _{4 of the} thermal conductive layer 118 has a diameter D ₄ greater than the diameter D _{2 of the} second through hole H 1, and the diameter D _{4 is} approximately between 30 μm and 200 μm, or the diameter D ₄ is approximately between 50 μm and 120 μm. As shown in Figure 8B, 118 having an inner contour and an outer contour 118a 118b surrounding the inner contour of the embodiment of the present embodiment thermally conductive layer 118a, 118a of the inner ring to surround the contour of the second perforation H ₁ and the light emitting stack 104 is formed below The fourth perforation H ₄ . Depends on the minimum distance d from the concept of the present embodiment, the shape of the inner contour 118a is circular, and its center is located substantially on the center of the second through hole H _1, the inner contour of the outer profile 118a and 118b is between 10μm to 50μm between. In addition, the heat-conducting layer 118 of this embodiment passes through the second contact layer 105, and in the stacking direction parallel to the light-emitting stack 104, the heat-conducting layer 118 has a thickness W between 2 μm and 15 μm. Another embodiment, the inner contour of the outer profile 118a and 118b of the center of the thermally conductive layer 118 are located in substantially the center of the second through hole H ₁ of the embodiment.

Fig. 9 is a schematic cross-sectional view of a light-emitting device according to a fifth embodiment of the present invention. Compared with the foregoing embodiment, the heat-conducting layer 118 of the light-emitting element of this embodiment is located in the light-emitting stack 104, and the range of the heat-conducting layer 118 is larger than that of the fourth embodiment. In detail, as shown in FIG. 9, the total area of the heat conducting layer 118 of the light-emitting element can be larger than the area of the light-emitting stack 104 from the cross-sectional view, so as to more efficiently transfer the heat generated during the operation of the light-emitting element to outside world. The light-emitting elements of the fourth and fifth embodiments of the present invention can be formed through the steps shown in Figures 1A to 1Q, and after the second contact layer 105 is formed on the light-emitting stack 104, the position where the thermally conductive layer 118 is scheduled to be formed Part of the light-emitting stack 104 and the second contact layer 105 on it are removed. The method of removal can be reactive ion etching through inductively coupled plasma (ICP), but it is not limited to this. In the fifth embodiment, the area of the light-emitting stack 104 removed in this step is larger than the area of the light-emitting stack 104 removed in the fourth embodiment. In detail, in one embodiment, before forming the thermal conductive layer 118, the second contact layer 105, the active region 104b, the second electrical type semiconductor layer 104c, and the first electrical type semiconductor layer at the positions where the thermal conductive layer 118 is formed The light-emitting stack 104 of the layer 104a and other parts is removed. In this case, an etching stop layer (not shown) is provided between the first contact layer 103 and the first conductivity semiconductor layer 104a to avoid removing the part The first contact layer 103 is destroyed when the light-emitting stack 104 is lit. Next, deposit the thermally conductive layer 118 where the light-emitting stack 104 has been removed, and in the stacking direction parallel to the light-emitting stack 104, the thermally conductive layer 118 has a thickness W. The thickness W is preferably such that the top of the thermally conductive layer 118 The surface 118t is flush with the second portion of the surface of the light-emitting stack 104. The thermally conductive layer 118 can be deposited by sputtering or evaporation, for example, formed by atomic layer chemical vapor deposition (ALD) or electron beam physical vapor deposition (EBPVD). The thermal conductive layer 118 of this embodiment is formed by a two-stage growth method, that is, the first part of the denser thermal conductive layer 118 is deposited by atomic layer chemical vapor deposition, and then the first part of the thermal conductive layer 118 is deposited with an electron beam The second part of the thermal conductive layer 118 is continuously deposited, but the method of forming the thermal conductive layer 118 is not limited to this.

It should be noted that the various embodiments listed in the present invention are only used to illustrate the present invention, and are not intended to limit the scope of the present invention. Any obvious modification or alteration made by anyone to the present invention does not depart from the spirit and scope of the present invention. The same or similar components in different embodiments, or components with the same number in different embodiments, all have the same physical or chemical properties. In addition, the above-mentioned embodiments of the present invention can be combined or replaced with each other under appropriate circumstances, and are not limited to the specific embodiments described. The connection relationship between specific components and other components described in detail in one embodiment can also be applied to other embodiments, and all fall within the scope of protection of the present invention as described later.

101‧‧‧Growth substrate 102‧‧‧Buffer layer 103‧‧‧First contact layer 104‧‧‧Light emitting stack 104a‧‧‧First electrical type semiconductor layer 104b‧‧‧Active area 104c‧‧‧Second electrical Sexual semiconductor layer 105‧‧‧Second contact layer 106‧‧‧Insulation layer 106h‧‧‧First through hole 107‧‧‧First transparent conductive layer 108‧‧‧Second transparent conductive layer 109‧‧‧Reflective layer 110‧ ‧‧ first bonding layer bonding structure 110a‧‧‧ 110b‧‧‧ second bonding layer 110c‧‧‧ third bonding the permanent substrate layer 111‧‧‧ 112‧‧‧ second contact layer perforated H H ₁ ‧‧‧ ₄ ‧‧‧Fourth through hole 113‧‧‧Sidewall insulation layer 114‧‧‧Upper electrode 114S‧‧‧Metal layer 115‧‧‧Protection layer 115h‧‧‧Third through hole 111E‧‧‧Bottom electrode D ₁ , D ₂ , D ₃ , D ₄ ‧‧‧Hole diameter 116‧‧‧First semiconductor layer 117‧‧‧Second semiconductor layer d‧‧‧Minimum distance W‧‧‧Thickness W ₁ ‧‧‧Width h‧‧‧Height 1051 ‧‧‧Surface 1071‧‧‧Surface 118‧‧‧Conductive layer 118t‧‧‧Top surface 118s

1A to 1T are schematic diagrams of the light-emitting device and the manufacturing method thereof according to the first embodiment of the present invention.

Fig. 2 is a schematic top view of the light-emitting device according to the first embodiment of the present invention.

Figure 3 shows in the first embodiment of the present invention, when the thickness of the second contact layer is 0.2μm and 1μm, under the condition of the diameter size (horizontal axis) of various first holes, they correspond to the light emission of the light-emitting element. Distribution diagram of power (Po, vertical axis on the left) and forward voltage (Vf, vertical axis on the right).

Figure 4 shows in the first embodiment of the present invention, when the light-emitting element emits light in the same pulse mode, the multiple quantum well structure includes 18, 38, and 48 wells, respectively, corresponding to relatively high Distribution diagram of luminous power (Po, vertical axis on the right) and luminous power ratio (vertical axis on the left) of current (300mA).

Figure 5 shows that in the first embodiment of the present invention, when the light-emitting element emits light in the same pulse mode, the barrier layers (Barrier) included in the multiple quantum well structure respectively contain different aluminum (Al) contents, corresponding to relative Distribution diagram of high current (300mA) luminous power (Po, vertical axis on the right) and luminous power ratio (vertical axis on the left).

Fig. 6 is a schematic cross-sectional view of a light-emitting device according to a second embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view of a light-emitting device according to a third embodiment of the present invention.

FIG. 8A is a schematic cross-sectional view of a light-emitting device according to a fourth embodiment of the present invention.

Fig. 8B is a schematic top view of a light emitting device according to a fourth embodiment of the present invention.

Fig. 9 is a schematic cross-sectional view of a light-emitting device according to a fifth embodiment of the present invention.

101‧‧‧Growth substrate

102‧‧‧Buffer layer

103‧‧‧First contact layer

104‧‧‧Light-emitting stack

104a‧‧‧The first electrical semiconductor layer

104b‧‧‧Active area

104c‧‧‧Second electrical semiconductor layer

105‧‧‧Second contact layer

106‧‧‧Insulation layer

106h‧‧‧First piercing

107‧‧‧First transparent conductive layer

108‧‧‧Second transparent conductive layer

109‧‧‧Reflective layer

110‧‧‧Joint structure

110a‧‧‧First bonding layer

110b‧‧‧Second bonding layer

110c‧‧‧The third bonding layer

111‧‧‧Permanent substrate

112‧‧‧Upper contact layer

H ₁ ‧‧‧Second perforation

113‧‧‧Sidewall insulation layer

114‧‧‧Upper electrode

114S‧‧‧Metal layer

115‧‧‧Protection layer

115h‧‧‧Third perforation

111E‧‧‧Lower electrode

D ₂ , D ₃ ‧‧‧Hole diameter

Claims (10)

A light-emitting element includes: a substrate; a light-emitting stack located on the substrate and comprising an active area, a side wall and an upper surface. The upper surface has a first part and a second part surrounded by the first part Part; a bonding structure between the substrate and the light-emitting stack; an electrode covering the first part and the sidewall and exposing the second part; a sidewall insulating layer between the sidewall and the electrode; And an insulating layer located between the bonding structure and the electrode. The light-emitting device described in claim 1 further includes a protective layer, wherein the electrode includes a first through hole whose position corresponds to the second portion, and the protective layer is located in the first through hole. The light-emitting device according to claim 1, wherein, in a stacking direction of the light-emitting stack, the insulating layer has a first region overlapping with the light-emitting stack, and a self-contained light-emitting stack The second area exposed. The light-emitting device according to claim 1, wherein the area of the first part of the upper surface is larger than the area of the second part of the upper surface. According to the light-emitting device described in claim 1, wherein the electrode includes a first through hole, and the ratio of the cross-sectional area of the first through hole to the area of the upper surface is about 1.5% to 5%. The light-emitting device described in the first item of the scope of patent application further includes a reflective layer located between the insulating layer and the substrate. The light-emitting element described in item 1 of the scope of patent application further includes a contact layer located at Between the substrate and the electrode. The light-emitting device according to claim 7, wherein, in a stacking direction of the light-emitting stack, the contact layer overlaps the second portion. According to the light-emitting device described in claim 2, wherein the protective layer covers the electrode and has a second through hole to expose a part of the electrode. The light-emitting element according to claim 9, wherein, in a stacking direction of the light-emitting laminate, the first through hole and the second through hole do not overlap with each other.

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