Light-emitting element

Abstract

To disclose a light-emitting element.SOLUTION: A light-emitting element capable of emitting radiation comprises: a substrate; an epitaxial structure located on the substrate and including a first DBR stack, a light-emitting stack, a second DBR stack and a contact layer in turn; an electrode; a current block layer located between the contact layer and the electrode; a first opening formed in the current block layer; and a second opening formed in the electrode and located in the first opening. A part of the electrode is embedded in the first opening and is put in contact with the contact layer. The light-emitting element has no oxide layer nor ion implanted layer in the second DBR stack.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a light emitting device, and more particularly to a light emitting device having laser and light emitting diode properties. [Background technology]

[0002] Light-emitting diodes (LEDs) are widely used in solid-state lighting sources. Compared with traditional incandescent lamps and fluorescent lamps, LEDs have the advantages of low power consumption and long life, so LEDs are gradually replacing traditional light sources and are applied in various fields such as traffic signs, backlight modules, street lighting, and medical equipment.

[0003] FIG. 24 shows a cross-sectional view of a conventional vertical-cavity surface-emitting laser (VCSEL). A vertical-cavity surface-emitting laser can emit coherent light in a direction perpendicular to the active region. The VCSEL includes a substrate 300 and a pair of distributed Bragg reflector (DBR) stacks 200, 210 located on the substrate 300, sandwiching an active region 230. The active region 230 is where electrons and holes combine to generate light. A first electrode 240 and a second electrode 250 are provided to inject current into the active region 230 to generate light, and the light escapes through an aperture located on the top surface of the VCSEL.

[0004] In DBR stack 210, the vertical cavity surface emitting laser can have an undercut 260. In the example of Figure 24, undercut 260 is formed by selectively removing the periphery of one layer in DBR stack 210 to form a gap, which can contain air, and because the conductivity of air is significantly lower than that of semiconductor materials, undercut 260 formed in DBR stack 210 has a relatively low conductivity compared to the conductivity of the other layers in DBR stack 210. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a light-emitting device. [Means for solving the problem]

[0006] Disclosed is a light-emitting device capable of emitting radiation, the light-emitting device comprising: a substrate; an epitaxial structure located on the substrate and including, in order, a first DBR (Distributed Bragg Reflector) stack, a light-emitting stack, a second DBR stack, and a contact layer; an electrode; a current blocking layer located between the contact layer and the electrode; a first opening formed in the current blocking layer; and a second opening formed in the electrode and located within the first opening, wherein a portion of the electrode is embedded in the first opening and is in contact with the contact layer; and the light-emitting device does not have an oxidation layer or an ion-implanted layer in the second DBR stack. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1 is a plan view of a light-emitting device according to a first embodiment of the present disclosure. [Figure 1B] 1B is a cross-sectional view of the light-emitting device according to the first embodiment of the present disclosure taken along line AA' in FIG. 1A. [Figure 2] FIG. 2 is a diagram showing a relationship curve between optical output power and forward current of the light-emitting device according to the first embodiment of the present disclosure. [Figure 3A] 1A and 1B are diagrams illustrating a method for manufacturing the light-emitting device shown in FIG. 1A and FIG. [Figure 3B] 1A and 1B are diagrams illustrating a method for manufacturing the light-emitting device shown in FIG. 1A and FIG. [Figure 4A] 1A and 1B are diagrams illustrating a method for manufacturing the light-emitting device shown in FIG. 1A and FIG. [Figure 4B] 1A and 1B are diagrams illustrating a method for manufacturing the light-emitting device shown in FIG. 1A and FIG. [Figure 5A]FIG. 10 is a plan view of a light-emitting device according to a second embodiment of the present disclosure. [Figure 5B] 5B is a cross-sectional view of the light-emitting device according to the first embodiment of the present disclosure taken along line AA' in FIG. 5A. [Figure 6] FIG. 10 is a cross-sectional view of a light-emitting device according to a third embodiment of the present disclosure. [Figure 7] FIG. 10 is a cross-sectional view of a light-emitting device according to a fourth embodiment of the present disclosure. [Figure 8A] FIG. 10 is a plan view of a light-emitting device according to a fifth embodiment of the present disclosure. [Figure 8B] 8B is a cross-sectional view of a light-emitting device according to a fifth embodiment of the present disclosure taken along line AA' of FIG. 8A. [Figure 9A] FIG. 10 is a plan view of a light-emitting device according to a sixth embodiment of the present disclosure. [Figure 9B] 9B is a cross-sectional view of a light-emitting device according to a sixth embodiment of the present disclosure taken along line AA' of FIG. 9A. [Figure 10A] FIG. 9B is a plan view of a current blocking layer of a light-emitting device according to a sixth embodiment shown in FIG. 9A of the present disclosure. [Figure 10B] 10B is a cross-sectional view of the light-emitting device of the present disclosure taken along line AA' of FIG. 10A. [Figure 11A] FIG. 10 is a plan view of a light-emitting device according to a seventh embodiment of the present disclosure. [Figure 11B] 11B is a cross-sectional view of the light-emitting device of the present disclosure taken along line AA' of FIG. 11A. [Figure 12A] FIG. 10 is a graph showing a relationship curve between optical output power and forward current of a light-emitting device according to a seventh embodiment of the present disclosure. [Figure 12B] FIG. 12B is an enlarged view of region I in FIG. 12A. [Figure 13A] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 13B] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 14A] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 14B]11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 15A] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 15B] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 16A] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 16B] 11A and 11B are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 11A and FIG. [Figure 17A] FIG. 13 is a plan view of a light-emitting device according to an eighth embodiment of the present disclosure. [Figure 17B] 17B is a cross-sectional view of the light-emitting device of the present disclosure taken along line AA' of FIG. 17A. [Figure 18] FIG. 13 is a cross-sectional view of a light-emitting device according to a ninth embodiment of the present disclosure. [Figure 19A] 19A to 19C are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 18. [Figure 19B] 19A to 19C are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 18. [Figure 19C] 19A to 19C are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 18. [Figure 19D] 19A to 19C are diagrams illustrating a method for manufacturing the light-emitting element shown in FIG. 18. [Figure 20A] FIG. 19 is a plan view of a light-emitting device according to a tenth embodiment of the present disclosure. [Figure 20B] 20B is a cross-sectional view of the light-emitting device of the present disclosure taken along line AA' of FIG. 20A. [Figure 21A] FIG. 19 is a plan view of a light-emitting device according to an eleventh embodiment of the present disclosure. [Figure 21B] 21B is a cross-sectional view of the light-emitting device of the present disclosure taken along line AA' of FIG. 21A. [Figure 22] FIG. 23 is a plan view of a light-emitting device according to a twelfth embodiment of the present disclosure. [Figure 23] FIG. 23 is a plan view of a light-emitting device according to a thirteenth embodiment of the present disclosure. [Figure 24]FIG. 1 is a cross-sectional view of a conventional vertical-cavity surface-emitting laser (VCSEL). DETAILED DESCRIPTION OF THE INVENTION

[0008] The concept of the present invention will be described below with reference to the drawings, in which the same reference numerals are used for similar or identical parts in the drawings or description, and the shape or thickness of elements in the drawings may be exaggerated or reduced, and elements not shown in the drawings or described in the specification may have shapes that are obvious to those skilled in the art.

[0009] In this disclosure, unless otherwise specified, the general formula AlGaAs is Al x Ga (1-x) As, 0≦x≦1, commonly known as AlInP x In (1-x) P, 0≦x≦1, and the general formula is AlGaInP (Al y Ga (1-y) ) 1-x In x P, 0≦x≦1, 0≦y≦1, and the general formula is AlGaN. x Ga (1-x) N, 0≦x≦1, and the formula AlAsSb is AlAs (1-x) Sb x where 0≦x≦1, and the general formula InGaP is In x Ga 1-x P, where 0≦x≦1. By adjusting the content of the elements, different purposes can be achieved, such as adjusting the energy level or the main emission wavelength.

[0010] FIG. 1A is a plan view of a light-emitting device according to a first embodiment of the present disclosure. FIG. 1B is a cross-sectional view of the light-emitting device according to the first embodiment of the present disclosure taken along line A-A' in FIG. 1A. In this embodiment, the light-emitting device includes a substrate 10, an epitaxial structure 20 disposed on the substrate 10, a current blocking layer 30, a first electrode 40, and a second electrode 50. The epitaxial structure 20 sequentially includes a first DBR (Distributed Bragg Reflector) stack 21, a light-emitting stack 22, a second DBR stack 23, and a contact layer 24. The conductivity type of the first DBR stack 21 is different from that of the second DBR stack 23. In this embodiment, the first DBR stack 21 is n-type, and the second DBR stack 23 is p-type. The current blocking layer 30 is located between the contact layer 24 and the first electrode 40. A first opening 31 is formed in the current blocking layer 30 to expose the contact layer 24. The first opening 31 has a first maximum width W1. A portion of the first electrode 40 is embedded in the first opening 31 and is in direct contact with the contact layer 24. A second opening 25 is formed in the first electrode 40 to expose the contact layer 24, the second opening 25 having a second maximum width W2 smaller than the first maximum width W1. The second electrode 50 is located on the side of the substrate 10 facing the epitaxial structure 20. The light-emitting device is capable of emitting radiation R, the radiation R having a peak wavelength between 600 nanometers (nm) and 1600 nanometers (nm), preferably between 830 nanometers and 1000 nanometers.

[0011] As shown in FIG. 1B, in this embodiment, the width of the substrate 10, the width of the epitaxial structure 20, and the width of the current blocking layer 30 are approximately the same. In this embodiment, the shape of the first opening 31 is circular, and the first maximum width W1 is the diameter of the circle. The shape of the first opening 31 is not limited to this embodiment, and may be elliptical, rectangular, square, diamond, or any other shape. The first maximum width W1 may be 20 microns (μm) to 50 microns, but is not limited thereto. The current blocking layer 30 is made of aluminum oxide (AlO x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), silicon nitride (Six N y The current blocking layer 30 may comprise an insulating material including, for example, epoxy, polyimide, perfluorocyclobutane, benzocyclobutene (BCB), or silicone. Preferably, the radiation emitted by the light emitting stack can be substantially transmitted through the current blocking layer 30. The current blocking layer 30 has a thickness greater than 100 nm, preferably less than 2 μm, and more preferably close to or equal to nλ / 4, where λ is the peak wavelength of the radiation emitted by the light emitting stack 22, and n is an odd positive integer.

[0012] In this embodiment, the shape of the second opening 25 is circular, and the second maximum width W2 is the diameter of the circle. The shape of the second opening 25 is not limited to this embodiment and may be elliptical, rectangular, square, diamond, or any other shape. Preferably, the shape of the second opening 25 is substantially the same as the shape of the first opening 31. Preferably, the first opening 31 and the second opening 25 are substantially concentric circles.

[0013] As shown in FIGS. 1A and 1B , the first electrode 40 is a continuous layer and includes a wire bonding portion 41 for connecting to a lead wire, a current injection portion 42 for injecting current and passing it through the epitaxial structure 20, and a bridging portion 43 for connecting the wire bonding portion 41 and the current injection portion 42. The wire bonding portion 41 is located on the current blocking layer 30. The current injection portion 42 is embedded in the first opening 31 and contacts the contact layer 24. In one embodiment, the first opening 25 is formed within the current injection portion 42, so that the current injection portion 42 has an annular shape. Specifically, in this embodiment, as shown in FIGS. 1A and 1B , a portion of the current injection portion 42 is separated from the sidewall of the current blocking layer 30, forming a gap between the current injection portion 42 and the sidewall of the current blocking layer 30 and exposing a portion of the epitaxial structure 20. In this embodiment, the first electrode 40 covers less than 50% of the surface area of ​​the current blocking layer 30. The portion of the current blocking layer 30 located between the bridging portion 43 and the epitaxial structure 20 and the portion located between the wire bonding portion 41 and the epitaxial structure 20 are intended to prevent current from flowing directly from the wire bonding portion 41 and the bridging portion 43 to the epitaxial structure 20.

[0014] In this embodiment, the light-emitting device does not have a high-resistance structure in the second DBR stack 23. Here, the high-resistance structure refers to a layer in the second DBR stack 23 that is located directly below the first electrode 40 and is covered by the first electrode 40, and has a relatively low conductivity compared to other layers in the second DBR 23 that are located directly below the first electrode 40 and are covered by the first electrode 40. Specifically, the high-resistance structure is an oxide layer, an ion-implanted layer, or an undercut as shown in FIG. 24 . Preferably, the portion of the second DBR stack 23 located directly below the current blocking layer 30 and / or the portion located directly below the first electrode 40 does not have an oxide layer, ion-implanted layer, or undercut. That is, the conductivity of the portion of the second DBR stack 23 located directly below the first opening 31 is, when viewed as a whole, approximately the same as the conductivity of the portion of the second DBR stack 23 that is covered by the current blocking layer 30.

[0015] Preferably, the second DBR stack 23 consists essentially of a III-V semiconductor material, such as AlGaAs. The second DBR stack 23 does not have any oxides, such as intentionally formed alumina, where alumina is Al a O b where a and b are natural numbers excluding zero. The second DBR stack 23 does not contain any ions that reduce conductivity, and the ions that reduce conductivity are intentionally formed to reduce the conductivity of a portion of the second DBR stack 23 by at least three orders of magnitude, preferably at least five orders of magnitude, compared to the conductivity of the second DBR stack 23 in other conductive portions. The ions that reduce conductivity include argon (Ar) ions, helium (He) ions, and hydrogen (H) ions. The second DBR stack 23 may contain unavoidable ions present in the environment, but these unavoidable ions should not be considered in the present disclosure because they do not substantially change the conductivity of the second DBR stack 23, for example, they do not substantially reduce the conductivity of the second DBR stack 23 by at least one order of magnitude compared to the conductivity of the second DBR stack 23 in other conductive portions. In one embodiment, the light-emitting device does not have the undercut shown in FIG. 24 in the second DBR stack 23, so that each layer of the second DBR stack 23 is substantially made of a III-V semiconductor material and no air gaps exist in any layer of the second DBR stack 23.

[0016] When a current flows into the epitaxial structure 20, the current injection portion 42 in the first opening 31 is in direct contact with the contact layer 24 of the epitaxial structure 20, and the wire bonding portion 41 and the bridging portion 43 are separated and insulated from the epitaxial structure 20 by the current blocking layer 30. Therefore, the current flows mainly through the portion of the epitaxial structure 20 that is not covered by the current blocking layer 30 and is in direct contact with the current injection portion 42. That is, when a current flows into the epitaxial structure 20, the current density in the portion of the second DBR stack 23 located directly under the current blocking layer 30 is much lower than the current density in the portion of the second DBR stack 23 that is not covered by the current blocking layer. Therefore, the portion of the epitaxial structure 20 that is in direct contact with the current injection portion 42 and is located approximately directly under the first opening 31 becomes a radiation emission region I that generates radiation R. The radiation R escapes from the light-emitting element through the first opening. Specifically, the top layer of the epitaxial structure 20, i.e., the contact layer 24 in this embodiment, is the first semiconductor layer in the epitaxial structure 20 that conducts the current after limiting the light-emitting device. FIG. 2 shows the optical output power (P0) and forward current (I) of the light-emitting device in the first embodiment of the present disclosure. f ) is a graph showing the relationship between the forward voltage V f , laser threshold current I th , and saturation current I sat The light emitting element has a forward voltage V f The laser begins to conduct an apparent forward current at .times. ... th is the minimum current at which stimulated emission of radiation emitted by the radiation-emitting region of the light-emitting device exceeds spontaneous emission, and is therefore the laser threshold current I th The radiation at is coherent. The saturation current I sat is the current at which the radiation output does not increase with increasing forward current. f Operating voltage V opand the laser threshold current I th Preferably, when the light-emitting device is operated at a forward current less than V, the radiation emitted by the radiation-emitting region I of the light-emitting device of the present disclosure is incoherent light. f Operating voltage V op and the laser threshold current I th When the light emitting device is operated at a forward current less than 1000 kHz, the incoherent light has a far-field angle greater than 60 degrees. th Larger and saturation current I sat When operated at a forward current less than 15°, the radiation R emitted by the radiation-emitting region I of the light-emitting device is coherent light with a far-field angle less than 15°. Specifically, when the forward current of the light-emitting device is less than the laser threshold current I th , the current density in the non-radiative emitting region of the epitaxial structure 20 is much smaller than the current density in the radiation emitting region I, and the wire bonding portion 41 and the bridging portion 43 block the radiation emitted by the epitaxial structure 20, so that the non-radiative emitting region of the epitaxial structure 20 that is not covered by the first electrode 40 emits incoherent light R1.

[0017] In this example, the laser threshold current I th is approximately 20 mA. The laser threshold current I th , saturation current I sat and the laser threshold current I th and saturation current I sat The difference between the first maximum width W1 of the first aperture 31 can be adjusted according to different application requirements. For example, a high laser threshold current I th , high saturation current I sat and high laser threshold current I th and saturation current I sat When a difference between the first maximum width W1 and the laser threshold current I is required, it is preferable that the first maximum width W1 is large. th and the first maximum width W1 satisfies the following formula.

[0018] 0.4W1(μm)-7≦I th(milliampere)≦0.4W1(μm)+7 Table 1 shows the far-field angle of emission of the light-emitting element for different forward currents. To clearly describe the divergence of the luminous flux, the far-field angle in this disclosure is the divergence angle of half the beam width.

[0019] [Table 1] As can be seen from Table 1, the forward current is the laser threshold current I th and the saturation current I sat If the radiation angle is lower than 15 degrees, the far field angle of the radiation is less than 15 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 5 degrees and 13 degrees.

[0020] In the present disclosure, the light-emitting device does not have a high-resistivity structure including an oxide layer and an ion-implanted layer in the second DBR stack 23, but includes the current blocking layer 30 and the first electrode, so that the top layer of the epitaxial structure 20 becomes the first layer to conduct current after limiting the light-emitting device of the epitaxial structure 20, and the forward current does not exceed the laser threshold current I th and saturation current I sat When the forward current is between 100 and 150, the light-emitting device has a far-field angle smaller than 15 degrees. Also, since the prior art light-emitting device includes a high-resistance structure such as an oxide layer in the second DBR stack 23, the prior art light-emitting device has a large far-field angle under normal operating conditions, especially when operating at a high forward current. However, when the forward current is greater than the laser threshold current I th and saturation current I sat and the light emitting element of the present disclosure has a far field angle of less than 15 degrees. The light emitting element may be applied to sensors such as proximity sensors, night vision systems, or blood oxygen detectors.

[0021] 3A to 4B are diagrams illustrating a method for manufacturing the light-emitting device shown in FIGS. 1A and 1B. FIG. 3B is a cross-sectional view taken along line A-A' in FIG. 3A of the present disclosure. FIG. 4B is a cross-sectional view taken along line A-A' in FIG. 4A of the present disclosure. The method includes the following steps:

[0022] As shown in Figures 3A and 3B, a substrate 10 is provided.

[0023] b. Forming an epitaxial structure 20 on the substrate 10 by epitaxial growth.

[0024] c. Form a current blocking layer 30 over the epitaxial structure 20 by any suitable method, such as sputtering or evaporation.

[0025] d. Pattern the current blocking layer 30 with a photolithography mask to form a first opening 31 by any suitable method to expose a portion of the epitaxial structure 20 .

[0026] e. A metal layer (not shown) is formed on the current blocking layer 30 to cover the first opening 31 shown in FIGS. 4A and 4B.

[0027] f. Patterning the metal layer using a photolithography mask to form a first electrode 40, the first electrode including a current injection portion 42, a wire bonding portion 41, and a bridging portion 43 connecting the wire bonding portion 41 and the current injection portion 42, the wire bonding portion 41 and the bridging portion 43 being located on the current blocking layer 30, the current injection portion 42 being embedded in the first opening 31, and a second opening 25 being formed in the current injection portion 42 to expose the epitaxial structure 20.

[0028] g. Form a second electrode 50 on the other side of the substrate 10 opposite the epitaxial structure 20 by any suitable method.

[0029] h. Cutting the structure formed in step g to obtain the light-emitting devices formed as shown in FIGS. 1A and 1B, respectively.

[0030] The method of the present disclosure does not include a step of reducing the conductivity of the second DBR stack 23, such as an oxidation step of oxidizing at least one layer of the second DBR stack 23 so that the conductivity of the oxidized region, the conductivity of the ion-implanted region, or the conductivity of the undercut shown in FIG. 24 is lower than the conductivity of other portions of the second DBR stack 23 other than the processed region; a step of implanting ions that at least reduce the conductivity of the at least one layer of the second DBR stack 23; and / or a step of selectively etching the periphery of the at least one layer of the second DBR stack 23 to form the undercut shown in FIG. 24. The oxidation step, the ion implantation step, and the step of etching one layer of the second DBR stack 23 are intended to convert the portion of the second DBR stack 23 directly under the first electrode 40 into a substantially insulating region, thereby forming a high-resistance structure in the second DBR stack 23. The method of the present disclosure uses up to four different photolithography masks in the patterning process. In this example, the method uses two different photolithography masks in the patterning process. Therefore, the manufacturing method of the light emitting device of the present disclosure has the advantages of being simple and low cost.

[0031] FIG. 5A is a plan view of a light-emitting device according to a second embodiment of the present disclosure. FIG. 5B is a cross-sectional view of a light-emitting device according to a first embodiment of the present disclosure taken along line A-A' in FIG. 5A. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all identical or substantially identical structures, materials, material compositions, and / or manufacturing methods described herein. The light-emitting device according to the second embodiment of the present disclosure includes substantially the same configuration as the first embodiment, except that the width of the current blocking layer 30 is smaller than the width of the epitaxial structure 20. Therefore, in the plan view of the light-emitting device, the peripheral portion of the epitaxial structure 20 is exposed from the current blocking layer 30. Furthermore, the first electrode 40 has a different shape from that of the first embodiment. Specifically, the first electrode 40 covers the entire sidewall surrounding the first opening 31 of the current blocking layer 30, leaving only the portion of the contact layer 24 directly below the second opening 25 exposed. Therefore, the epitaxial structure 20 is in direct contact with the current injection portion 42, and the portion located approximately directly below the first opening 31 becomes the radiation emission region I, and radiation R escapes mainly from the surface of the light-emitting device through the second opening 25. The first electrode 40 covers 50% or more of the surface area of ​​the current blocking layer 30, and has substantially the same shape as the current blocking layer 30. Preferably, the first electrode 40 covers 80% or more of the surface area of ​​the current blocking layer 30, and more preferably, the first electrode 40 covers 90% or more of the surface area of ​​the current blocking layer 30. The portion of the first electrode 40 away from the second opening 25 is for connection to a lead wire. Since the first electrode 40 covers 50% or more of the surface area of ​​the current blocking layer 30 and covers the entire sidewall of the current blocking layer 30 surrounding the first opening 31, the forward current does not exceed the laser threshold current I of the light-emitting device. th , incoherent light emitted by the light-emitting stack 22 located approximately directly below the first electrode 40 is blocked by the first electrode 40, while coherent light emitted by the light-emitting stack 22 escapes through the second opening 25. The method for manufacturing the light-emitting device shown in Figures 5A and 5B is substantially the same as the method for manufacturing the light-emitting device shown in Figures 1A and 1B. The difference is that the pattern of the first electrode 40 in the second embodiment is different from the pattern of the first electrode in the first embodiment because a photolithography mask for patterning the metal layer is different.

[0032] FIG. 6 is a cross-sectional view of a light-emitting device according to a third embodiment of the present disclosure. Unless otherwise specified, the same reference numerals in different drawings throughout this specification correspond to the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described herein. The light-emitting device according to the third embodiment of the present disclosure includes substantially the same configuration as the second embodiment, except that the peripheral portion of the epitaxial structure 20 is removed by any suitable method to form a protrusion 26 having a width. The width of the protrusion 26 is smaller than the width of the substrate 10, and the protrusion 26 has an exposed pedestal sidewall 261. The pedestal sidewall 261 is closer to the second opening 25 than the outermost edge of the substrate 10. Specifically, the current blocking layer 30 covers the pedestal sidewall 261 and the upper surface of the first DBR stack 21. In this embodiment, the current blocking layer 30 protects the pedestal sidewall 261 of the protrusion 26 of the epitaxial structure 20. This improves the reliability of the epitaxial structure 20 and the light-emitting device. The method for manufacturing the light-emitting device shown in FIG. 6 is substantially the same as the method for manufacturing the light-emitting device shown in FIGS. 5A and 5B . The difference is that before forming the current blocking layer 30 on the epitaxial structure 20, the method further includes a step of patterning the epitaxial structure 20, removing the peripheral portions of the second DBR stack 23, the peripheral portion of the light-emitting stack 22, and the peripheral portion of the first DBR stack 21 of the epitaxial structure 20 by any suitable method to form the protrusion 26 including the pedestal sidewall 261. In this embodiment, the method of the present disclosure uses three or fewer different photolithography masks in the patterning process. Therefore, the method for manufacturing the light-emitting device of the present disclosure has the advantages of being simple and low-cost.

[0033] FIG. 7 is a cross-sectional view of a light-emitting device according to a fourth embodiment of the present disclosure. Unless otherwise specified, the same reference numerals in different drawings correspond to the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described throughout the present disclosure. The light-emitting device according to the fourth embodiment of the present disclosure includes substantially the same components as the third embodiment, except that the first electrode 40 covers the pedestal sidewall 261 along the pedestal sidewall 261, and thus the current blocking layer 30 is positioned between the epitaxial structure 20 and the first electrode 40. The first electrode 40 covers the current blocking layer 30 along the pedestal sidewall 261, thereby preventing radiation emitted by the light-emitting stack 22 from escaping through the pedestal sidewall 261. The manufacturing method of the light-emitting device shown in FIG. 7 is substantially the same as the manufacturing method of the light-emitting device shown in FIG. 6. The only difference is that a different photolithography mask is used to pattern the metal layer.

[0034] FIG. 8A is a plan view of a light-emitting device according to a fifth embodiment of the present disclosure. FIG. 8B is a cross-sectional view of the light-emitting device according to the fifth embodiment of the present disclosure taken along line A-A' in FIG. 8A. Unless otherwise specified, the same reference numerals in different drawings correspond to the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described herein. The light-emitting device according to the fifth embodiment of the present disclosure includes substantially the same configuration as the fifth embodiment, except that the first opening 31 is annular and defined by the current blocking layer 30. The current blocking layer 30 includes an inner portion 301 and an outer portion 302, and the diameter of the circle surrounded by the outer portion 302 is a first maximum width W1. The first opening 31 separates the inner portion 301 of the current blocking layer 30 from the outer portion 302 of the current blocking layer 30, thereby protecting the inner portion 301 of the current blocking layer 30 from a radiation emission region. In this embodiment, the current blocking layer 30 has a thickness approximately equal to nλ / 4, where λ is the peak wavelength of the radiation emitted from the light-emitting stack, and n is an odd positive integer. The first electrode is embedded in the first opening 31, covers the sidewall of the interior 301 of the current blocking layer 30, and is located outside the interior 301 of the current blocking layer 30. The second opening 25 exposes the interior 301 of the underlying current blocking layer 30. The method for manufacturing the light-emitting device shown in FIGS. 8A and 8B is substantially the same as the method for manufacturing the light-emitting device shown in FIG. 7, except that a different photolithography mask is used to pattern the current blocking layer 30.

[0035] FIG. 9A is a plan view of a light-emitting device according to a sixth embodiment of the present disclosure. FIG. 9B is a cross-sectional view of the light-emitting device according to the sixth embodiment of the present disclosure taken along line A-A' in FIG. 9A. FIG. 10A is a plan view of the current blocking layer 30 of the light-emitting device according to the sixth embodiment of the present disclosure shown in FIG. 9A. FIG. 10B is a cross-sectional view of the light-emitting device according to the sixth embodiment of the present disclosure taken along line A-A' in FIG. 10A. Unless otherwise specified, the same reference numerals in different drawings correspond to all described identical or substantially identical structures, materials, material compositions, and / or manufacturing methods of the present disclosure. The light-emitting device according to the sixth embodiment of the present disclosure includes substantially the same configuration as the fourth embodiment, except that the light-emitting device according to this embodiment includes multiple radiation-emitting regions I arranged in a two-dimensional array on a single die. Specifically, multiple first openings 31 are formed in the current blocking layer 30, exposing the contact layer 24. As shown in FIG. 10A, the current blocking layer 30 is a continuous layer. The first openings 31 are separated from each other by the current blocking layer. A plurality of second openings 25 arranged in a two-dimensional array are formed in the first electrode 40 and are separated from one another. Each second opening 25 is formed in a corresponding first opening 31, exposing the contact layer 24. Therefore, the corresponding first opening 31 and second opening 25 are concentric. The first electrode 40 is a continuous layer and has a wire bonding portion 41 but does not have any second openings for connecting to lead wires. A portion of the first electrode 40 is embedded in the first opening 31, covers the sidewall of the current blocking layer 30 surrounding the first opening 31, and is in direct contact with the contact layer 24 of the epitaxial structure 20. The portion of the epitaxial structure 20 that is in direct contact with the first electrode 40 and is generally located directly below the first opening 31 constitutes a radiation-emitting region. The arrangement of the radiation-emitting regions I is not limited to this embodiment. For example, the radiation-emitting regions I may be arranged to intersect, or the number of radiation-emitting regions I in two adjacent rows and / or columns may be different.

[0036] FIG. 11A is a plan view of a light-emitting device according to a seventh embodiment of the present disclosure. FIG. 11B is a cross-sectional view of the light-emitting device according to the present disclosure taken along line A-A' in FIG. 11A. Unless otherwise specified, the same reference numerals in different drawings throughout this specification correspond to all identical or substantially identical structures, materials, material compositions, and / or manufacturing methods described herein. In this embodiment, the substrate 10, the first DBR stack 21, the light-emitting stack 22, and the second DBR stack 23 are substantially the same as those in the second embodiment. The difference is that the contact layer 24 has a third width W3, and the second DBR stack 23 has a fourth width W4 greater than the third width W3. The light-emitting device further includes a conductive layer 60 covering the contact layer 24 and disposed between the first electrode 40 and the contact layer 24. The conductive layer 60 has a fifth width W5 substantially equal to the fourth width W4 of the second DBR stack 23. The first electrode 40 covers 50% or more of the surface area of ​​the conductive layer 60. Preferably, the first electrode 40 covers 80% or more of the surface area of ​​the conductive layer 60, more preferably 90% or more of the surface area of ​​the conductive layer 60. The contour of the first electrode 40 is substantially the same as the contour of the conductive layer 60. The first electrode 40 is in direct contact with the conductive layer 60, not with the contact layer 24. The radiation emission region I includes the second DBR stack 23, the light-emitting stack 22, and the first DBR stack 21, which are located directly below the contact layer 24. Radiation R escapes from the light-emitting element through the second opening 25.

[0037] The second opening 25 is located directly above the contact layer 24 and exposes the underlying conductive layer 60. The ratio of the third width W3 of the contact layer 24 to the second maximum width W2 of the second opening 25 is 0.1 to 3, preferably 0.5 to 1.1, and more preferably 0.6 to 0.8. By setting the ratio of the third width W3 to the second maximum width W2 to be less than 1, the first electrode 40 is less likely to block the light emitted by the radiation emission region I, and more light can escape through the second opening.

[0038] The conductivity of the portion of the second DBR stack 23 located directly under the contact layer 24 is approximately the same as the conductivity of the portion of the second DBR stack 23 not covered by the contact layer 24. The conductive layer 60 has a thickness close to or equal to nλ / 4, where λ is the peak wavelength of the radiation emitted from the light emitting stack 22, and n is an odd positive integer. The conductive layer 60 includes a transparent conductive metal oxide material, such as indium tin oxide (ITO), aluminum zinc oxide (AZO), cadmium tin oxide (SnCdO), antimony tin oxide (ATO), zinc oxide (ZnO), zinc tin oxide (ZTO), or indium zinc oxide (IZO). The conductive layer 60 is substantially transparent to the radiation emitted by the light emitting stack 22.

[0039] When a current flows from the first electrode 40 into the epitaxial structure 20, the contact resistance between the contact layer 24 and the second DBR stack 23 is relatively low compared to the contact resistance between the conductive layer 60 and the epitaxial structure 20. Therefore, most of the current flows from the conductive layer 60 to the contact layer 24 and then into the epitaxial structure 20 via the contact layer 24. That is, the current density in the portion of the second DBR stack 23 located directly under the contact layer 24 is higher than the current density in the portion of the second DBR stack 23 that is not covered by the contact layer 24. Specifically, the top layer of the epitaxial structure 20, i.e., the contact layer 24 in this embodiment, is the first semiconductor layer in the epitaxial structure 20 that conducts current after limiting the light-emitting element.

[0040] 12A is a graph showing the relationship curve of the optical output power versus forward current of a light-emitting device according to a seventh embodiment of the present disclosure, where the ratio of the third width W3 of the contact layer 24 to the second maximum width W2 of the second opening 25 is about 1. FIG. 12B is an enlarged view of region I in FIG. 12A. In this embodiment, the laser threshold current I th is about 13 mA, and the saturation current I sat The laser threshold current I is approximately 79 mA. th , saturation current I sat and the laser threshold current Ith and saturation current I sat The difference between the third width W3 of the contact layer 24 can be adjusted according to different application requirements. For example, a high laser threshold current I th , high saturation current I sat and high laser threshold current I th and saturation current I sat When a difference between the laser threshold current I and the third width W3 is required, it is preferable that the third width W3 is large. th and the third width W3 satisfies the following formula:

[0041] 0.4W3(μm)-7≦I th (milliampere)≦0.4W3(μm)+7 In one embodiment, the radiation has a peak wavelength of about 850±10 nanometers. In one embodiment, the radiation has a peak wavelength of about 940±10 nanometers.

[0042] Table 2 shows the far-field angle of the emission of the light-emitting device of the seventh embodiment for different forward currents, and the emission has a peak wavelength of about 850±10 nanometers.

[0043] [Table 2] Table 3 shows the far-field angle of the emission of the light-emitting device of Example 7 for different forward currents, where the emission has a peak wavelength of about 940±10 nanometers. th is about 13 mA, and the saturation current I sat is about 80 milliamps.

[0044] [Table 3] As shown in Tables 2 and 3, the forward current is the laser threshold current I th and the saturation current I sat If the radiation angle is lower than 15 degrees, the far field angle of the radiation is less than 15 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 8 degrees and 13 degrees.

[0045] In the present disclosure, the light-emitting device does not have a high-resistivity structure including an oxide layer and an ion-implanted layer in the second DBR stack 23, but includes the contact layer 24 and the conductive layer 60, so that the top layer of the epitaxial structure 20 becomes the first layer to conduct current after limiting the light-emitting device of the epitaxial structure 20, and the forward current exceeds the laser threshold current I th and saturation current I sat If the light emitting element has a far field angle of less than 15 degrees, the light emitting element has a far field angle of less than 15 degrees.

[0046] 13A to 16B are diagrams illustrating a method for manufacturing the light emitting device shown in Fig. 11A and Fig. 11B. The method includes the following steps.

[0047] As shown in Figures 13A and 13B, a substrate 10 is provided.

[0048] b. Forming an epitaxial structure 20 on the substrate 10 by epitaxial growth.

[0049] c. Pattern the contact layer 24 with a photolithography mask.

[0050] d. As shown in Figures 14A and 14B, a conductive layer 60 is formed over the patterned contact layer 24 by any suitable method, such as sputtering or evaporation.

[0051] e. As shown in Figures 15A and 15B, a metal layer (not shown) is formed on metal layer 60.

[0052] f. Patterning the metal layer with a photolithography mask to form a first electrode 40 and form a second opening 25 in the first electrode 40, wherein the first electrode 40 has a pattern that is substantially complementary to the pattern of the contact layer 24, i.e., the pattern of the contact layer 24 is substantially identical to the pattern of the second opening 25 in the first electrode 40, and the second opening 25 is located generally directly above the contact layer 24.

[0053] 16A and 16B, the periphery of the epitaxial structure 20 is removed to form a protrusion 26. The protrusion 26 includes exposed pedestal sidewalls 261 and is closer to the second opening 25 than the outermost edge of the substrate 10.

[0054] h. Form a second electrode 50 on the other side of the substrate 10 opposite the epitaxial structure 20.

[0055] i. The structure formed in step h is cut to obtain the light-emitting devices formed as shown in FIGS. 11A and 11B.

[0056] The method of the present disclosure does not include a step of reducing the conductivity of a portion of the second DBR stack 23, such as an oxidation step of oxidizing at least one layer of the second DBR stack 23, such that the conductivity of the oxidized region, the conductivity of the ion-implanted region, or the conductivity of the undercut shown in FIG. 24 is lower than the conductivity of other portions of the second DBR stack 23 other than the processed region; a step of implanting ions that at least reduce the conductivity of at least one layer of the second DBR stack 23; and / or a step of selectively etching the periphery of at least one layer of the second DBR stack 23 to form the undercut shown in FIG. 24. The oxidation step, the ion implantation step, and the step of etching one layer of the second DBR stack 23 are intended to convert the portion of the second DBR stack 23 located directly under the first electrode 40 into a substantially insulating region, thereby forming a high-resistance structure in the second DBR stack 23. Preferably, the method of the present disclosure uses three or fewer different photolithography masks in the patterning process. Therefore, the method of manufacturing the light-emitting device of the present disclosure has the advantages of being simple and low-cost.

[0057] FIG. 17A is a plan view of a light-emitting device according to an eighth embodiment of the present disclosure. FIG. 17B is a cross-sectional view of the light-emitting device according to the present disclosure taken along line A-A' in FIG. 17A. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all of the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described herein. The light-emitting device according to the eighth embodiment of the present disclosure includes substantially the same configuration as the seventh embodiment, except that the light-emitting device further includes a passivation layer 110 covering the epitaxial structure 20, the conductive layer 60, and the first electrode 40 so as to have the same shape as the epitaxial structure 20, the conductive layer 60, and the first electrode 40. The passivation layer 110 includes an opening 111 that exposes the underlying first electrode 40 and is spaced from the contact layer 24 so as to connect to a lead wire. The manufacturing method of the light-emitting device shown in FIGS. 17A and 17B is substantially the same as the manufacturing method of the light-emitting device shown in FIGS. 16A and 16B. The difference is that after forming the protrusion 26 including the exposed pedestal sidewall 261, the present method further includes forming a passivation layer 110 having the same shape along the exposed pedestal sidewall 261 of the epitaxial structure 20, the sidewall of the conductive layer 60, and the sidewall of the first electrode 40, so that the passivation layer 110 covers the conductive layer 60 and the first electrode 40. Next, the passivation layer 110 is patterned, and an opening 111 is formed in the passivation layer 110 to expose the underlying first electrode 40. The method of the present disclosure uses four or fewer different photolithography masks in the patterning process. Therefore, the method of manufacturing the light-emitting device of the present disclosure has the advantages of being simple and low-cost.

[0058] FIG. 18 is a cross-sectional view of a light-emitting device according to a ninth embodiment of the present disclosure, and its plan view is the same as FIG. 11A. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all of the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described in the present disclosure. The light-emitting device according to the ninth embodiment of the present disclosure includes substantially the same configuration as the seventh embodiment, except that the light-emitting device according to this embodiment includes a permanent substrate 90 and an adhesive layer 100 between the permanent substrate 90 and the epitaxial structure 20. In this embodiment, the permanent substrate 90 has a higher thermal conductivity than the substrate 10. The adhesive layer 100 is used to connect the permanent substrate 90 and the epitaxial structure 20. FIGS. 19A to 19D are diagrams illustrating a method for manufacturing the light-emitting device shown in FIG. 18. The manufacturing method for the light-emitting device shown in FIG. 18 is substantially the same as the manufacturing method for the light-emitting device shown in FIGS. 11A and 11B. 19B , the substrate 10 is removed by any suitable method. As shown in FIG. 19C , the epitaxial structure 20 is bonded to a permanent substrate 90 by an adhesive layer 100. As shown in FIG. 19D , the temporary substrate 70 and the temporary adhesive layer 80 are removed. In this embodiment, due to the adhesive step, the light-emitting device includes a permanent substrate 90 with high thermal conductivity. Therefore, the light-emitting device can achieve high output power.

[0059] FIG. 20A is a plan view of a light-emitting device according to a tenth embodiment of the present disclosure. FIG. 20B is a cross-sectional view of the light-emitting device according to the present disclosure taken along line A-A' in FIG. 20A. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described in the present disclosure. The light-emitting device according to the tenth embodiment of the present disclosure includes substantially the same configuration as the seventh embodiment, except that the light-emitting device according to this embodiment includes multiple radiation-emitting regions I arranged in an array on a single die. Specifically, the contact layer 24 includes multiple separate contact regions 241, which are arranged in a two-dimensional array as shown in FIG. 20A. Each contact region 241 has a third width W3. In this embodiment, the third width W3 of the multiple contact regions 241 is substantially equal. As shown in FIG. 20B, the conductive layer 60 is a continuous layer and covers the multiple separate contact regions 241. The first electrode 40 is located on the conductive layer 60 and is a continuous layer. A plurality of second openings 25 are formed in the first electrode 40 and are separated from one another. Each second opening 25 is aligned with a corresponding contact region 241. The second openings 25 expose the conductive layer 60. The ratio of the third width W3 of the contact region 241 to the second width W2 of the corresponding second opening 25 is 0.1 to 3, preferably 0.9 to 1.1. In this embodiment, these ratios are approximately equal. The second DBR stack 23, the light-emitting stack 22, and the first DBR stack 21 located directly below the contact layer 24 form radiation emission regions I. The number of contact regions 241 and second openings 25 is not limited to this embodiment, and the arrangement of the radiation emission regions I is also not limited to this embodiment. For example, the radiation emission regions I may be arranged to intersect, or the number of radiation emission regions I in two adjacent rows and / or columns may be different. Specifically, the top layer of the epitaxial structure 20, that is, the contact layer 24 in this embodiment, is the first semiconductor layer of the epitaxial structure 20 that conducts the current after confinement of the light emitting device.

[0060] FIG. 21A is a plan view of a light-emitting device according to an eleventh embodiment of the present disclosure. FIG. 21B is a cross-sectional view of the light-emitting device according to the present disclosure taken along line A-A' in FIG. 21A. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all of the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described in the present disclosure. The light-emitting device according to the eleventh embodiment of the present disclosure includes substantially the same configuration as the tenth embodiment, with the difference being that the third width W3' of at least one contact region 241 is different from the third width W3 of the other contact regions 241, and multiple different laser threshold currents I th In this embodiment, as shown in FIG. 21B, the third width W3' of the central contact region 241 is smaller than the third width W3 of the other contact regions 241. The difference between the third width W3' of the central contact region 241 and the third width W3 of one of the other two contact regions 241 is 3 microns (μm) or more, preferably greater than 8 microns and less than 40 microns. As shown in FIG. 21, the second opening 25 corresponding to the central contact region 241 is smaller than the other second openings 25. The ratio of the third width of the contact region 241 to the second maximum width W2 of the second opening 25 corresponding to each contact region 241 is 0.1 to 3, preferably 0.5 to 1.1, and more preferably 0.6 to 0.8. The light-emitting device has a plurality of different laser threshold currents I th Each laser has a threshold current I th is used to generate coherent light in the radiation-emitting region I. Specifically, since the third width W3′ of the central contact region 241 is smaller than the third width W3 of the other contact regions 241, the laser threshold current I th is the laser threshold current I for emitting coherent light in one of the other two radiation-emitting regions I. th Therefore, in this embodiment, the forward current is smaller than the laser threshold current I for causing the central radiation emitting region I to emit coherent light. th a laser threshold current I that is greater than 1000 .mu.m and causes the other radiation-emitting region I to emit coherent light; thWhen the far-field angle is smaller than 15 degrees, the radiation emitted by the central radiation-emitting region I is coherent light with a far-field angle smaller than 15 degrees, while the radiation emitted by the other radiation-emitting regions I is incoherent light with a far-field angle larger than 60 degrees. Therefore, the light-emitting device is suitable for applications requiring both long-distance and short-distance characteristics, such as surveillance equipment. The arrangement of the contact regions 241 having the third width is not limited to this embodiment. For example, the contact regions 241 having a third width smaller than the third widths of the other contact regions 241 may be provided at the end. Alternatively, contact regions 241 having a relatively small third width and contact regions 241 having a relatively large third width may be provided in a cross-shaped arrangement in rows and / or columns, spaced apart from each other.

[0061] 22 is a plan view of a light-emitting device according to a twelfth embodiment of the present disclosure. In this specification, unless otherwise specified, the same reference numerals in different drawings correspond to all of the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described in the present disclosure. The light-emitting device according to the twelfth embodiment of the present disclosure includes substantially the same configuration as the eleventh embodiment, with the difference being that the light-emitting device according to this embodiment has a plurality of identical laser threshold currents I th Each laser has a threshold current I thare used to generate coherent light in the radiation emission region I. According to different layouts of the first electrode 40, different amounts of current are controlled to flow into different contact regions 241, and when current flows into the light-emitting element, one contact region 241 absorbs more current than the other contact regions 241. Specifically, in this embodiment, the width of the central contact region 241 is approximately equal to the width of the other contact regions 241. The width of the second opening 25 corresponding to the central contact region 241 is approximately equal to the width of the other second openings 25. Compared with the first electrode 40 shown in FIG. 21A , the first electrode 40 on the conductive layer 60 in this embodiment has a different layout. Specifically, the first electrode 40 includes a wire bonding portion, a plurality of first elongated electrodes 44, and a second elongated electrode 45. The wire bonding portion 41 is used for connecting to a lead wire. Each first elongated electrode 44 surrounds a second opening 25. Each second elongated electrode 45 extends substantially perpendicularly from the wire bonding portion 41 and is connected to at least three first elongated electrodes 44. In this embodiment, the width of each first elongated electrode 44 is approximately the same. The width of each second elongated electrode 45 is approximately the same. The first elongated electrode 44 surrounding the central second opening 25 is connected to two second elongated electrodes 45, and the first elongated electrodes 44 surrounding the other two second openings 25 are connected to only one second elongated electrode 45. Therefore, when driving the light-emitting element, the central contact region 241 absorbs more current than the current absorbed by the other contact regions 241. The forward current flowing through each central contact region 241 is equal to the laser threshold current I of the corresponding radiation emission region I. th , the forward current through each of the other two contact regions 241 still exceeds the laser threshold current I of the corresponding radiation-emitting region I. th. Therefore, the radiation emitted by the central radiation-emitting region I is coherent light with a far-field angle smaller than 15 degrees, while the radiation emitted by the other radiation-emitting regions I is incoherent light with a far-field angle larger than 60 degrees. Therefore, the light-emitting device is suitable for applications requiring both long-distance and short-distance characteristics, such as surveillance equipment. In another embodiment, the width of the central first elongated electrode 44 may be larger than the width of the other two first elongated electrodes 44 to achieve similar results. In another embodiment, the width of the central second elongated electrode 45 may be larger than the width of the other two second elongated electrodes 45, and the two second elongated electrodes 45 may not be connected to the central first elongated electrode 44. The arrangement of the first elongated electrodes 44 and the second elongated electrodes 45 is not limited to this embodiment. For example, the first elongated electrode 44 surrounding the second opening 25 at the end may be connected to two second elongated electrodes 45, and the width of the first elongated electrode 44 and the width of the second elongated electrode 45 may be changed accordingly.

[0062] FIG. 23 is a plan view of a light-emitting device according to a thirteenth embodiment of the present disclosure. Unless otherwise specified, the same reference numerals in different drawings correspond to the same or substantially the same structures, materials, material compositions, and / or manufacturing methods described herein. The light-emitting device according to the thirteenth embodiment of the present disclosure includes substantially the same configuration as the twelfth embodiment, except that the first electrode 40 located on the conductive layer 60 of the light-emitting device according to this embodiment has a different pattern. The first electrode 40 includes a third elongated electrode 46 having a width, which is greater than the widths of the first elongated electrode 44 and the second elongated electrode 45. Therefore, the third elongated electrode 46 covers a wider area around the second opening 25 than the area covered by the first elongated electrode 44 and the second elongated electrode 45 around the second opening 25. Therefore, the contact area between the conductive layer 60 surrounding the central second opening 25 and the first electrode 40 is larger than the contact area between the conductive layer 60 surrounding the other second openings 25 and the first electrode 40. Therefore, when driving the light-emitting device, the central contact region 241 absorbs a larger current than the current absorbed by the other contact regions 241. The forward current flowing through each central contact region 241 is proportional to the laser threshold current I of the corresponding radiation-emitting region I. th , the forward current through each of the other two contact regions 241 still exceeds the laser threshold current I of the corresponding radiation-emitting region I. th 4. Therefore, the radiation emitted by the central radiation-emitting region I is coherent light with a far-field angle smaller than 15 degrees, while the radiation emitted by the other radiation-emitting regions I is incoherent light with a far-field angle larger than 60 degrees. Therefore, the light-emitting device is suitable for applications requiring both long-distance and short-distance characteristics, such as surveillance equipment. The patterns of the first elongated electrode 44 and the second elongated electrode 45 are not limited to this embodiment. For example, the first electrode 40 may cover more of the peripheral area of ​​the second opening 25 at the end rather than the central second opening 25.

[0063] The light-emitting stack 22 includes an active region, which may comprise a single heterostructure (SH), a double heterostructure (DH), or a multiple quantum well (MQW). Preferably, the active region comprises a multiple quantum well (MQW), which comprises alternating well layers and barrier layers. The energy level of each barrier layer is greater than the energy level of the well layers. The peak wavelength emitted by the active region is changed by varying the thickness or material of the well layers. Preferably, the material of the well layers comprises a III-V semiconductor material, such as aluminum gallium arsenide (AlGaAs). The material of the barrier layers comprises a III-V semiconductor material, such as aluminum gallium arsenide (AlGaAs). The light-emitting stack 22 may further include spacer layers between the active region and the first DBR stack 21 and / or between the active region and the second DBR stack 23 to adjust the thickness of the light-emitting stack 22 to be close to or equal to a thickness of nλ / 2, where λ is the peak wavelength of the radiation emitted by the light-emitting stack 22 and n is a positive integer. The material of the spacer layer includes a III-V semiconductor material, such as aluminum gallium arsenide (AlGaAs).

[0064] The first DBR stack 21 and the second DBR stack 23 include a plurality of alternating high-refractive-index semiconductor layers and low-refractive-index semiconductor layers. The material of the first DBR stack 21 and the second DBR stack 23 is a III-V group semiconductor material, such as gallium aluminum arsenide (Al). x Ga( 1-x )As / Al y Ga( 1-y)As, where x is not equal to y, and the aluminum and gallium contents may be adjusted to reflect light in a wavelength range. Each semiconductor layer has a thickness close to or equal to λ / 4n, where λ is the peak wavelength of the radiation emitted by the light-emitting stack 22, and n is the refractive index of the layer. The first DBR stack 21 has a reflectivity of 99% or more at the peak wavelength. The second DBR stack 23 has a reflectivity of 98% or more at the peak wavelength. Preferably, the reflectivity of the first DBR stack 21 is greater than the reflectivity of the second DBR stack 23. The number of pairs in the first DBR stack 21 is greater than the number of pairs in the second DBR stack 23, with a high-refractive-index semiconductor layer and a low-refractive-index semiconductor layer being considered as one pair. Preferably, the number of pairs in the first DBR stack 21 is greater than 15, more preferably greater than 30 and less than 80. The number of pairs in the second DBR stack 23 is greater than 15, more preferably greater than 20 and less than 80.

[0065] In this embodiment, substrate 10 has an upper surface for epitaxially growing epitaxial structure 20. Substrate 10 has a thickness sufficient to support the layers or structures grown thereon. Preferably, substrate 10 has a thickness of 100 microns or more, and more preferably, a thickness of 250 microns or less. Substrate 10 is a single crystal substrate and comprises a semiconductor material, such as a III-V semiconductor material or a Group IV semiconductor material. In one embodiment, the substrate comprises an n-type or p-type III-V semiconductor material. In this embodiment, the III-V semiconductor material is n-type gallium arsenide (GaAs), and the n-type dopant is silicon (Si).

[0066] The permanent substrate 80 is electrically conductive and conducts electrical current between the first electrode 40 and the second electrode 50. The permanent substrate 80 has a thickness sufficient to support the layers or structures thereon, for example, a thickness of 100 microns or greater. The permanent substrate 80 comprises a conductive material including silicon (Si), germanium (Ge), copper (Cu), molybdenum (Mo), tungsten-molybdenum (MoW), aluminum nitride (AlN), zinc oxide (ZnO), or copper-tungsten (CuW). Preferably, the permanent substrate 80 comprises silicon or copper-tungsten (CuW).

[0067] The first electrode 40 and the second electrode 50 are connected to an external power source and are used to conduct current between them. The material of the first electrode 40 and the second electrode 50 includes a transparent conductive material or a metallic material. The transparent conductive material includes a transparent conductive oxide, and the metallic material includes gold (Au), platinum (Pt), germanium-nickel-gold (GeAuNi), titanium (Ti), beryllium-gold (BeAu), germanium-gold (GeAu), aluminum (Al), zinc-gold (ZnAu), or nickel.

[0068] The first electrode 40 forms a low resistance or ohmic contact with the contact layer 24 and the second DBR stack 23, and the resistance between the first electrode 40 and the second DBR stack 23 is 10 -2 The conductivity type of the contact layer 24 is the same as the conductivity type of the second DBR stack 23. In one embodiment, the contact layer 24 is p-type and has a high p-type doping concentration, e.g., 10 18 / cm 3 Higher than 10 19 / cm 3 Higher than 1×10 19 / cm 3 ~5×10 22 / cm 3 The material of the contact layer 24 includes a III-V semiconductor material, such as gallium arsenide (GaAs) or aluminum gallium arsenide (AlGaAs).

[0069] The adhesive layer 100 and / or the temporary adhesive layer 80 may include transparent conductive oxides, metallic materials, insulating oxides, or polymeric materials. Transparent conductive oxides include indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), and indium zinc oxide (IZO). Metallic materials include indium, tin, gold, titanium, nickel, platinum, tungsten, or alloys thereof. Insulating oxides include alumina (AlO x ), silicon oxide (SiO x ) or silicon oxynitride (SiO x N y The polymer material includes epoxy, polyimide, perfluorocyclobutane, benzocyclobutene (BCB), or silicone. The adhesive layer 100 has a thickness of 400 nanometers to 5000 nanometers.

[0070] Epitaxial methods include, but are not limited to, metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), and liquid-phase epitaxy (LPE).

[0071] In other embodiments of the present disclosure, the structures of the above embodiments may be combined or modified. For example, the light-emitting device shown in Figure 1A or 1b may include a passivation layer.

[0072] It should be noted that the listed embodiments of the present invention are merely illustrative of the present invention and do not limit the scope of the present invention. Obvious modifications or variations may be made to the present invention without departing from the spirit or scope of the present invention. Identical or similar components in different embodiments, or components with the same reference numerals in different embodiments, have the same physical or chemical properties. Furthermore, the embodiments of the present invention may be combined or substituted with each other where appropriate, and are not limited to the specific embodiments described above. The connection relationship between a specific component and other components described in detail in one embodiment may also be applied to other embodiments, and falls within the scope of protection of the present invention. [Explanation of symbols]

[0073] 10 Substrate 20 Epitaxial structure 30 Current Blocking Layer 40 1st electrode 50 2nd electrode 60 Conductive layer 21 First DBR stack 31 First Opening 22 Luminous Stacks 23 Second DBR stack 24 Contact layer 25 Second Opening W1 1st maximum width W2 2nd maximum width R radiation 41 Wire Bonding Section 42 Current injection part 43 Bridging Section I Radiation emission area 26 Protrusion 261 Platform side wall 301 Internal 302 External W3 3rd width W4 4th width W5 5th width W3' 3rd width I th Laser Threshold Current 110 Passivation Layer 111 Open hole 90 permanent base plate 100 Next layer 70 Temporary Na substrate 44 The first extension at the electrode 45 The second extension at the electrode 46 The third extension at the electrode 241 コンタクト domain I sat Saturation current I sat

Claims

1. A light-emitting element, A substrate; an epitaxial structure overlying the substrate and including a first region, a second region, and a third region; an electrode overlying the epitaxial structure, the electrode having a plurality of first openings, a second opening, and a plurality of third openings; a contact layer having a first contact portion, a second contact portion, and a third contact portion that are separated from one another; the first region includes a plurality of first radiation-emitting regions; the second region includes a plurality of second radiation-emitting regions; the third region includes a plurality of third radiation-emitting regions; the plurality of first openings correspond to the plurality of first radiation-emitting areas; the second opening corresponds to the second radiation-emitting area; the plurality of third openings correspond to the plurality of third radiation-emitting regions; a width of each of the second openings is smaller than a width of each of the first openings and a width of each of the third openings; the first contact portion is located on the first region; the second contact portion is located on the second region; the third contact portion is located on the third region, each of the first region, the second region, and the third region sequentially includes a first DBR stack, a light-emitting stack, and a second DBR stack; The plurality of second radiation-emitting regions are located between the plurality of first radiation-emitting regions and the plurality of third radiation-emitting regions.

2. A light-emitting element, A substrate; an epitaxial structure overlying the substrate and including a plurality of first and second regions; an electrode overlying the epitaxial structure, the electrode having a plurality of first openings and a plurality of second openings; each of the plurality of first regions having a plurality of first radiation-emitting regions; the second region includes a plurality of second radiation-emitting regions; the plurality of first openings correspond to the plurality of first radiation-emitting areas; the plurality of second openings correspond to the plurality of second radiation-emitting areas; each of the plurality of first regions and the second regions sequentially includes a first DBR stack, a light-emitting stack, a second DBR stack, and a contact layer; When the light-emitting device is operated, the plurality of first radiation-emitting regions and the plurality of second radiation-emitting regions simultaneously emit light, and a first current flowing through each of the first radiation-emitting regions is smaller than a second current flowing through each of the second radiation-emitting regions; the plurality of second radiation-emitting regions are located between corresponding ones of the plurality of first radiation-emitting regions; The number of the plurality of first radiation-emitting regions is greater than the number of the plurality of second radiation-emitting regions.

3. The light-emitting device according to claim 1 , wherein the electrode is electrically connected to the first region and the second region.

4. The light-emitting device according to claim 2 , wherein the substrate has an edge, and the second region is farther from the edge than the plurality of first regions.

5. The light-emitting device according to claim 1 or 2, further comprising a conductive layer located between the electrode and the epitaxial structure.

6. The light emitting device according to claim 1 , wherein the width of the first contact portion is different from the width of the second contact portion.

7. The light-emitting element according to claim 1 , wherein a width of the third contact portion is different from a width of the second contact portion.

8. The light-emitting device according to claim 1 , wherein the first radiation-emitting region and the second radiation-emitting region emit radiation having the same peak wavelength.

9. The light-emitting element according to claim 1 , wherein the distance between two adjacent first openings is smaller than the distance between two adjacent second openings.

10. The light-emitting device of claim 2 , wherein a width of each of the first openings is equal to a width of each of the second openings.

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