Light emitting structure and device thereof
By designing a multi-layer structure and aperture configuration in the VCSEL light-emitting structure, and adjusting the current path and reflectivity, the aperture limitation problem was solved, achieving high-intensity, small-angle light output suitable for three-dimensional sensing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ENNOSTAR CORP
- Filing Date
- 2021-07-05
- Publication Date
- 2026-08-04
AI Technical Summary
Existing oxide VCSEL light-emitting structures are limited by aperture size, resulting in significant changes in the far field of multimode lasers with electric field and temperature, making them unsuitable for three-dimensional sensing, and also causing insufficient output light angle and intensity.
By setting semiconductor stacks, oxide layers, insulating dielectric layers and transparent conductive layers of different thicknesses in the light-emitting structure, a multi-layer structure is formed to adjust the current path and reflectivity. This includes the design of the first hole and the second hole. The transparent conductive layer is electrically connected to the semiconductor stack. The insulating dielectric layer is used to adjust the current path to generate a small-angle light pattern.
It achieves high-intensity, small-angle light output, maintains the laser intensity of VCSEL, and reduces the higher-order modes of multimode lasers, making it suitable for three-dimensional sensing.
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Figure CN115588898B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a light-emitting structure, and more particularly to a light-emitting structure capable of altering the current path within the light-emitting structure to generate a small-angle light pattern. Background Technology
[0002] A laser diode is a tiny crystal that emits intense light. Based on the way laser diodes emit light, they can be classified into edge emitting lasers (EEL), surface emitting lasers (SEL), Fabry-Perot lasers (FP lasers), and vertical cavity surface emitting lasers (VCSEL).
[0003] Currently, oxide-type VCSELs are commonly used in 3D sensing due to their high output power and good lasing threshold. However, the luminescence performance of oxide-type VCSELs is often limited by the aperture size. Furthermore, the aperture size often results in the generation of multimode lasers, whose far-field varies significantly with electric field and temperature, making them unsuitable for 3D sensing. Therefore, a VCSEL capable of generating small-angle, high-output lasers is needed. Summary of the Invention
[0004] The purpose of this disclosure is to provide a light-emitting structure that alters the current path and reflectivity within the structure, thereby generating a small-angle light pattern while maintaining high laser intensity.
[0005] This disclosure discloses a light-emitting structure, including a substrate, a first semiconductor stack, a light-emitting layer, an oxide layer, a second semiconductor stack, a first insulating dielectric layer, and a transparent conductive layer. The first semiconductor stack is disposed on the substrate and has a first thickness structure and a second thickness structure, wherein the thickness of the first thickness structure is greater than the thickness of the second thickness structure. The light-emitting layer is disposed on the first thickness structure of the first semiconductor stack. The oxide layer is disposed on the light-emitting layer and has a first hole with a first aperture. The second semiconductor stack is disposed on the oxide layer and is electrically connected to the light-emitting layer through the first hole. The first insulating dielectric layer is disposed on the second semiconductor stack and has a second hole with a second aperture. The transparent conductive layer is disposed on the first insulating dielectric layer and is electrically connected to the second semiconductor stack through the second hole.
[0006] In some implementations, the first aperture is larger than the second aperture.
[0007] In some embodiments, when projected vertically onto the substrate, the geometric center of the first hole overlaps with the geometric center of the second hole.
[0008] In some implementations, the first aperture is between about 8 micrometers and about 13 micrometers.
[0009] In some implementations, the second aperture is between about 5 micrometers and about 10 micrometers.
[0010] In some embodiments, the light-emitting layer emits a first light path and a second light path. The first light path is emitted from the light-emitting layer through a first hole, a second semiconductor stack, a second hole, and a transparent conductive layer, and the first light path has a first reflectivity. The second light path is emitted from the light-emitting layer through a first hole, a second semiconductor stack, a first insulating dielectric layer, and a transparent conductive layer, and the second light path has a second reflectivity. Furthermore, the first reflectivity is greater than the second reflectivity.
[0011] In some embodiments, the light-emitting layer emits a first light path and a second light path. The first light path is emitted from the light-emitting layer through a first aperture, a second semiconductor stack, a second aperture, and a transparent conductive layer, and the first light path has a first reflectivity of approximately 99.5%. The second light path is emitted from the light-emitting layer through a first aperture, a second semiconductor stack, a first insulating dielectric layer, and a transparent conductive layer, and the second light path has a second reflectivity of approximately 98%.
[0012] In some embodiments, the light-emitting layer emits light with a wavelength of λ, then the thickness of the first insulating dielectric layer is approximately 0.25λ×n, where n is an odd number, and the thickness of the transparent conductive layer is approximately 0.5λ×m, where m is an integer.
[0013] In some embodiments, the light-emitting layer emits light with a wavelength of λ, then the thickness of the first insulating dielectric layer is about 0.25λ, and the thickness of the transparent conductive layer is about 0.5λ.
[0014] In some embodiments, the light-emitting structure further includes a second insulating dielectric layer. The second insulating dielectric layer covers the upper surface of the transparent conductive layer, the sidewalls of the transparent conductive layer, the sidewalls of the first insulating dielectric layer, the sidewalls of the second semiconductor stack, the sidewalls of the oxide layer, the sidewalls of the light-emitting layer, the sidewalls of the first thickness structure of the first semiconductor stack, and the upper surface of the second thickness structure of the first semiconductor stack. Furthermore, in a top view, the second insulating dielectric layer has an annular hole located above the transparent conductive layer, and when projected perpendicularly onto the substrate, the annular hole surrounds both the first and second holes.
[0015] In some embodiments, the light-emitting layer emits light with a wavelength of λ, then the thickness of the first insulating dielectric layer is about 0.25λ×n, the thickness of the transparent conductive layer is about 0.25λ×n, and the thickness of the second insulating dielectric layer above the transparent conductive layer is about 0.25λ×n, where n is an odd number.
[0016] In some embodiments, the light-emitting layer emits light with a wavelength of λ, then the thickness of the first insulating dielectric layer is about 0.25λ, the thickness of the transparent conductive layer is about 0.25λ, and the thickness of the second insulating dielectric layer above the transparent conductive layer is about 0.75λ.
[0017] In some embodiments, the light-emitting structure further includes a first conductive layer and a second conductive layer. The first conductive layer is disposed beneath the substrate. The second conductive layer covers the sidewalls and part of the upper surface of the second insulating dielectric layer and is electrically connected to the transparent conductive layer through annular holes.
[0018] In some embodiments, the second conductive layer has a third hole, and when projected perpendicularly onto the substrate, the geometric center of the third hole overlaps with the geometric center of the first hole and the geometric center of the second hole.
[0019] In some implementations, the third diameter of the third hole is larger than the first and second diameters.
[0020] In some implementations, the third aperture of the third hole is between about 10 micrometers and about 20 micrometers.
[0021] In some embodiments, the light-emitting layer emits a third light path and a fourth light path. The third light path, emitted from the light-emitting layer, passes through a first aperture, a second semiconductor stack, a second aperture, a transparent conductive layer, a second insulating dielectric layer, and the third aperture, and has a third reflectivity. The fourth light path, emitted from the light-emitting layer, passes through a first aperture, a second semiconductor stack, a first insulating dielectric layer, a transparent conductive layer, a second insulating dielectric layer, and the third aperture, and has a fourth reflectivity. Furthermore, the third reflectivity is greater than the fourth reflectivity.
[0022] In some embodiments, the light-emitting layer emits a third light path and a fourth light path. The third light path exits from the light-emitting layer through a first hole, a second semiconductor stack, a second hole, a transparent conductive layer, a second insulating dielectric layer, and a third hole, and has a third reflectivity of approximately 99.778%. The fourth light path exits from the light-emitting layer through a first hole, a second semiconductor stack, a first insulating dielectric layer, a transparent conductive layer, a second insulating dielectric layer, and a third hole, and has a fourth reflectivity of approximately 97.043%.
[0023] This disclosure also proposes a light-emitting device comprising the aforementioned light-emitting structure. Attached Figure Description
[0024] The following description, taken in conjunction with the accompanying drawings, will provide the best understanding of all aspects of this disclosure. It should be understood that, according to industry practice, the various features are not drawn to scale. In fact, for clarity, the dimensions of the various features may be arbitrarily increased or decreased.
[0025] Figure 1 A cross-sectional schematic diagram illustrating a light-emitting structure according to some embodiments of this disclosure;
[0026] Figure 2 To illustrate the light emission path of the light emission structure in some embodiments of this disclosure, when the light emission structure only has a substrate, a first semiconductor stack, a light emission layer, an oxide layer, a second semiconductor stack, a first insulating dielectric layer, and a transparent conductive layer;
[0027] Figure 3 A schematic diagram illustrating the overall light-emitting path of a light-emitting structure according to some embodiments of this disclosure;
[0028] Figures 4 to 9 A cross-sectional schematic diagram is provided to illustrate the manufacturing process of the light-emitting structure according to some embodiments of this disclosure at each step.
[0029] Figure 10 A diagram illustrating the aperture comparison of various holes in a light-emitting structure according to some embodiments of this disclosure is provided.
[0030] [Symbol Explanation]
[0031] 100: Light-emitting structure
[0032] 110:Substrate
[0033] 120: First semiconductor stack
[0034] 122: First Thickness Structure
[0035] 124: Second Thickness Structure
[0036] 130: Emissive layer
[0037] 140: Oxide layer
[0038] 142: First Hole
[0039] 150: Second semiconductor stack
[0040] 160: First insulating dielectric layer
[0041] 162: Second hole
[0042] 170: Transparent conductive layer
[0043] 180: Second insulating dielectric layer
[0044] 182: Annular hole
[0045] 190a: First conductive layer
[0046] 190b: Second conductive layer
[0047] L1: First optical path
[0048] L2: Second optical path
[0049] L3: Third optical path
[0050] L4: Fourth optical path
[0051] H: Third hole Detailed Implementation
[0052] The following disclosure provides numerous different embodiments or examples for implementing various features of the provided subject matter. Specific examples of elements, values, operations, materials, configurations, and the like are described below to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. Other elements, values, operations, materials, configurations, and the like should also be considered. For example, in the following description, forming a first feature over a second feature can include embodiments in which the first and second features are formed in direct contact, and can also include embodiments in which an additional feature can be formed between the first and second features such that the first and second features are not in direct contact. Furthermore, reference numerals and / or text may be repeated in various examples. This repetition itself does not indicate a relationship between the various embodiments and / or configurations discussed.
[0053] Furthermore, for ease of description, spatially relative terms such as "below," "under," "lower than," "above," and "above" may be used in this disclosure to describe an element or feature relative to one or more other elements or features as shown in the figures. In addition to the orientations described in the figures, the spatially relative terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other directions), and the spatially relative descriptive terms used herein may be interpreted accordingly.
[0054] Typically, the light-emitting structure disclosed herein can be used in any related device with illumination or light-emitting functions. This disclosure involves forming a transparent conductive layer on a semiconductor stack and an insulating dielectric layer. Because the insulating dielectric layer has holes, the transparent conductive layer is electrically connected to the semiconductor stack through these holes. In this way, the insulating dielectric layer and the transparent conductive layer can adjust the current in the structure and change the current path and reflectivity to further form small-angle or Gaussian light patterns. Simultaneously, this structure can still maintain the laser intensity of a vertical cavity surface emitting laser (VCSEL).
[0055] In some embodiments disclosed herein, a light-emitting structure 100 capable of generating a small-angle Gaussian light pattern is provided. Please refer to... Figure 1 , Figure 1 This is a cross-sectional schematic diagram illustrating a light-emitting structure according to some embodiments of the present disclosure. The light-emitting structure 100 includes a substrate 110, a first semiconductor stack 120, a light-emitting layer 130, an oxide layer 140, a second semiconductor stack 150, a first insulating dielectric layer 160, a transparent conductive layer 170, a second insulating dielectric layer 180, a first conductive layer 190a, and a second conductive layer 190b.
[0056] In some implementations, such as Figure 1 As shown, a first semiconductor stack 120 is disposed on a substrate 110, and the first semiconductor stack 120 has a first thickness structure 122 and a second thickness structure 124, wherein the thickness of the first thickness structure 122 is greater than the thickness of the second thickness structure 124. The substrate 110 may comprise any suitable substrate. In one embodiment, the substrate 110 may be a transparent substrate or an opaque substrate. In some embodiments, the material of the substrate 110 includes, but is not limited to, composite semiconductor materials (such as GaAs, InP, GaSb), glass substrates, sapphire substrates, silicon substrates, printed circuit boards, metal substrates, ceramic substrates, acrylic substrates, or combinations thereof. In one embodiment, the material of the substrate 110 includes, but is not limited to, silicon dioxide (SiO2), silicon nitride (Si3N4), titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), gold, aluminum, copper, nickel, or combinations thereof.
[0057] In one embodiment, the first semiconductor stack 120 may be an N-type distributed Bragg reflector (DBR). In some embodiments, the first semiconductor stack 120 may be an N-type DBR formed by stacking multiple N-type III-V semiconductor layers. In some embodiments disclosed herein, the III-V semiconductor layers may include, but are not limited to, binary epitaxial materials such as gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), and indium arsenide (InAs), or ternary or quaternary epitaxial materials such as gallium arsenide (GaAsP), aluminum gallium arsenide (AlGaAs), indium gallium phosphide (InGaP), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum indium gallium nitride (AlGaInN), aluminum indium gallium phosphide (AlInGaP), and indium gallium arsenide phosphide (InGaAsP). Therefore, the N-type III-V semiconductor layer may be formed by doping the aforementioned III-V semiconductor layers with silicon or tellurium.
[0058] Please continue reading. Figure 1 In some embodiments, the light-emitting layer 130 is disposed on the first thickness structure 122 of the first semiconductor stack 120. In one embodiment, the light-emitting layer 130 may include, but is not limited to, multiple quantum wells (MQWs), single-quantum wells (SQWs), homojunctions, heterojunctions, or other similar structures.
[0059] Please continue reading. Figure 1 In some embodiments, an oxide layer 140 is disposed on the light-emitting layer 130, and the oxide layer 140 has a first hole 142 having a first aperture. In one embodiment, the oxide layer 140 is made of an oxide material, thereby restricting the current path so that the current entering the light-emitting layer 130 can be confined within the first hole 142. The material of the oxide layer 140 may include, but is not limited to, Al. x O y Insulating materials such as SiO2. The first hole 142 in the oxide layer 140 specifically serves as a window through which current passes. Furthermore, in one embodiment, the first aperture of the first hole 142 is between about 8 micrometers and about 13 micrometers. In some embodiments, the first aperture may be 8 micrometers, 8.4 micrometers, 8.8 micrometers, 9.2 micrometers, 9.6 micrometers, 10 micrometers, 10.4 micrometers, 10.8 micrometers, 11.2 micrometers, 11.6 micrometers, 12 micrometers, 12.4 micrometers, 12.8 micrometers, 13 micrometers, or any value between any two of these values.
[0060] Please refer to the same document. Figure 1 In some embodiments, the second semiconductor stack 150 is disposed on the oxide layer 140, and the second semiconductor stack 150 is electrically connected to the light-emitting layer 130 through the first via 142. In one embodiment, the second semiconductor stack 150 may be a P-type DBR. In some embodiments, the second semiconductor stack 150 may be a P-type DBR formed by stacking multiple P-type III-V semiconductor layers. In some embodiments disclosed herein, the III-V semiconductor layers may include, but are not limited to, binary epitaxial materials such as gallium arsenide, gallium nitride, gallium phosphide, indium arsenide, aluminum nitride, indium nitride, and indium phosphide, or ternary or quaternary epitaxial materials such as gallium arsenide, aluminum gallium arsenide, indium gallium phosphide, indium gallium nitride, aluminum gallium nitride, aluminum indium gallium nitride, aluminum indium phosphide, and indium gallium arsenide phosphide. Therefore, the P-type III-V semiconductor layer may be formed by doping the above-mentioned III-V semiconductor layers with, for example, carbon, beryllium, magnesium, zinc, etc.
[0061] Specifically, the oxide layer 140 is disposed on the top surface of the light-emitting layer 130 and embedded in the second semiconductor stack 150. In this way, the second semiconductor stack 150 can be electrically connected to the light-emitting layer 130 through the first hole 142 of the oxide layer 140.
[0062] Please refer to the same document. Figure 1 In some embodiments, a first insulating dielectric layer 160 is disposed on the second semiconductor stack 150, and the first insulating dielectric layer 160 has a second hole 162 with a second aperture. In one embodiment, the first insulating dielectric layer 160 is formed by thin film growth. Compared to the insulating region formed by conventional ion implantation, the first insulating dielectric layer 160 formed by thin film growth can more precisely control the thickness and distribution area of the insulating region and can avoid damage to the underlying second semiconductor stack 150. In some embodiments, the material used for the first insulating dielectric layer 160 may include, but is not limited to, SiO2, SiN, SiON, SiBCN, SiOCN, AlxOy epoxy resin, or other suitable dielectric materials, or other suitable insulating materials.
[0063] In some embodiments, the second aperture of the second hole 162 in the first insulating dielectric layer 160 is between about 5 micrometers and about 10 micrometers. In one embodiment, the second aperture may be 5 micrometers, 5.4 micrometers, 5.8 micrometers, 6.2 micrometers, 6.6 micrometers, 7 micrometers, 7.4 micrometers, 7.8 micrometers, 8.2 micrometers, 8.6 micrometers, 9 micrometers, 9.4 micrometers, 9.8 micrometers, 10 micrometers, or any value between any two of these values.
[0064] In one embodiment, the second aperture of the second hole 162 is smaller than the first aperture of the first hole 142. Specifically, for example, but not limited to, when the first aperture is 8 micrometers, the second aperture is 5 micrometers; when the first aperture is 9 micrometers, the second aperture is 6 micrometers, and so on. In one embodiment, when projected perpendicularly onto the substrate 110, the geometric center of the first hole 142 overlaps with the geometric center of the second hole 162. It should be noted that when the first hole 142 and the second hole 162 are circular, the aforementioned geometric center is the center of the circle of the first hole 142 and the second hole 162. However, this is not limited to this; the first hole 142 and the second hole 162 can also be non-circular shapes such as rectangles, triangles, polygons, etc. If they are non-circular, the geometric center of the first hole 142 and the second hole 162 is the centroid.
[0065] Please continue reading below. Figure 1 In some embodiments, a transparent conductive layer 170 is disposed on the first insulating dielectric layer 160, and the transparent conductive layer 170 is electrically connected to the second semiconductor stack 150 through the second hole 162. In one embodiment, the material of the transparent conductive layer 170 includes, but is not limited to, light-transmitting conductive materials including indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), or materials with light-transmitting and conductive effects. Specifically, the transparent conductive layer 170 utilizes the current-adjustable characteristics of materials such as ITO to further concentrate the current to the second hole 162 of the first insulating dielectric layer 160, thereby enabling the emitted light pattern to generate a Gaussian light pattern.
[0066] Specifically, the first insulating dielectric layer 160 is disposed on the top surface of the second semiconductor stack 150 and embedded in the transparent conductive layer 170. In other words, the transparent conductive layer 170 fills the second hole 162 of the first insulating dielectric layer 160 and is electrically connected to the second semiconductor stack 150 through the second hole 162. Accordingly, the transparent conductive layer 170 can conduct current, and the first insulating dielectric layer 160 can generate an electrically insulating region. Therefore, when current flows in the light-emitting structure 100, the transparent conductive layer 170 and the first insulating dielectric layer 160 can highly concentrate the current within the area of the second hole 162.
[0067] It should be noted that, with appropriate layer thicknesses, the light-emitting structure 100 can produce excellent light-emitting effects even when it only comprises a substrate 110, a first semiconductor stack 120, a light-emitting layer 130, an oxide layer 140, a second semiconductor stack 150, a first insulating dielectric layer 160, and a transparent conductive layer 170. The thicknesses of each layer will be described below. For some embodiments, please refer to... Figure 2 , Figure 2To illustrate the light emission path of the light-emitting structure according to some embodiments of this disclosure, when the light-emitting structure only has a substrate, a first semiconductor stack, a light-emitting layer, an oxide layer, a second semiconductor stack, a first insulating dielectric layer, and a transparent conductive layer. In some embodiments, the light-emitting layer 130 emits a first light path L1 and a second light path L2. The first light path L1 is emitted from the light-emitting layer 130 through a first hole 142, a second semiconductor stack 150, a second hole 162, and a transparent conductive layer 170, and the first light path L1 has a first reflectivity. The second light path L2 is emitted from the light-emitting layer 130 through a first hole 142, a second semiconductor stack 150, a first insulating dielectric layer 160, and a transparent conductive layer 170, and the second light path L2 has a second reflectivity. Furthermore, the first reflectivity is greater than the second reflectivity. Specifically, the first reflectivity is approximately 99.5%, and the second reflectivity is approximately 98%.
[0068] In one embodiment, in order to achieve a sufficient reflectivity difference between the first optical path L1 and the second optical path L2, when the first optical path L1 and the second optical path L2 emitted by the light-emitting layer 130 have an emission wavelength of λ, the thickness of the first insulating dielectric layer 160 is approximately 0.25λ×n, where n is an odd number, and the thickness of the transparent conductive layer 170 is approximately 0.5λ×m, where m is an integer. In some embodiments, the thickness of the first insulating dielectric layer 160 is approximately 0.25λ, and the thickness of the transparent conductive layer 170 is approximately 0.5λ.
[0069] Please continue reading. Figure 1 The second insulating dielectric layer 180 covers a portion of the upper surface of the transparent conductive layer 170, the sidewalls of the transparent conductive layer 170, the sidewalls of the first insulating dielectric layer 160, the sidewalls of the second semiconductor stack 150, the sidewalls of the oxide layer 140, the sidewalls of the light-emitting layer 130, the sidewalls of the first thickness structure 122 of the first semiconductor stack 120, and the upper surface of the second thickness structure 124 of the first semiconductor stack 120. Furthermore, in top view, the second insulating dielectric layer 180 has an annular hole 182 located above the transparent conductive layer 170, and when projected perpendicularly onto the substrate 110, the annular hole 182 surrounds the first hole 142 and the second hole 162. Specifically, the first hole 142 and the second hole 162 are obscured by the second insulating dielectric layer 180 in top view. Accordingly, when the second insulating dielectric layer 180 is provided, the second insulating dielectric layer 180 can further adjust the reflectivity of the aforementioned first optical path L1 and second optical path L2.
[0070] In one embodiment, the material of the second insulating dielectric layer 180 may be the same as or different from that of the first insulating dielectric layer 160. In one embodiment, the material of the second insulating dielectric layer 180 may include, but is not limited to, SiO2, SiN, SiON, SiBCN, SiOCN, epoxy resin, or other suitable dielectric materials or other suitable insulating materials.
[0071] Please refer to Figure 1 The first conductive layer 190a is disposed below the substrate 110. The second conductive layer 190b covers the sidewalls and part of the upper surface of the second insulating dielectric layer 180, and is electrically connected to the transparent conductive layer 170 through the annular hole 182. Specifically, the annular hole 182 and the second conductive layer 190b provide a path for the transparent conductive layer 170 to be electrically connected to an external power source.
[0072] In some embodiments, the second conductive layer 190b has a third hole H, and when projected perpendicularly onto the substrate 110, the geometric center of the third hole H overlaps with the geometric centers of the first hole 142 and the second hole 162. It should be noted that, as previously described, when the first hole 142, the second hole 162, and the third hole H are circular, the aforementioned geometric centers are the centers of the first hole 142, the second hole 162, and the third hole H. However, this is not limited to this; the first hole 142, the second hole 162, and the third hole H can also be non-circular shapes such as rectangles, triangles, or polygons. If they are non-circular, then the geometric centers of the first hole 142, the second hole 162, and the third hole H are the centroids. In one embodiment, the third aperture of the third hole H is between approximately 10 micrometers and approximately 20 micrometers. In some embodiments, the third aperture may be 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, or any value between any two of these values.
[0073] In some embodiments, the third aperture of the third hole H is larger than the first aperture and the second aperture. Specifically, in one embodiment, when the third aperture of the third hole H is 10 micrometers, the first aperture is 8 micrometers and the second aperture is 5 micrometers; when the third aperture of the third hole H is 11 micrometers, the first aperture is 9 micrometers and the second aperture is 6 micrometers, and so on.
[0074] In one embodiment, the material of the first conductive layer 190a includes, but is not limited to, a light-transmitting conductive material comprising indium tin oxide, indium zinc oxide, aluminum zinc oxide, or a material having a light-transmitting conductive effect; or comprising an opaque metallic material, for example, an opaque metallic material comprising germanium (Ge), gold (Au), titanium (Ti), aluminum (Al), nickel (Ni), or similar opaque metallic materials.
[0075] In one embodiment, the material of the second conductive layer 190b includes, but is not limited to, a light-transmitting conductive material comprising indium tin oxide, indium zinc oxide, aluminum zinc oxide, or a material having a light-transmitting conductive effect; or comprising an opaque metallic material, for example, gold, titanium, aluminum, nickel (Ni), platinum (Pt), palladium (Pd), or similar opaque metallic materials.
[0076] Please refer to this. Figure 3 , Figure 3 This is a schematic diagram illustrating the overall light-emitting path of a light-emitting structure according to some embodiments of this disclosure. Figure 2 The difference lies in that the laser beam further penetrates the second insulating dielectric layer 180. In some embodiments, the light-emitting layer 130 emits a third light path L3 and a fourth light path L4. The third light path L3, emanating from the light-emitting layer 130, passes through the first hole 142, the second semiconductor stack 150, the second hole 162, the transparent conductive layer 170, the second insulating dielectric layer 180, and the third hole H, and has a third reflectivity. The fourth light path L4, emanating from the light-emitting layer 130, passes through the first hole 142, the second semiconductor stack 150, the first insulating dielectric layer 160, the transparent conductive layer 170, the second insulating dielectric layer 180, and the third hole H, and has a fourth reflectivity. Furthermore, the third reflectivity is greater than the fourth reflectivity. Specifically, the third light path L3 has a third reflectivity of approximately 99.778%, and the fourth light path L4 has a fourth reflectivity of approximately 97.043%.
[0077] In one embodiment, when the light-emitting layer 130 emits a third light path L3 and a fourth light path L4 with a wavelength of λ, the thickness of the first insulating dielectric layer 160 is approximately 0.25λ×n, the thickness of the transparent conductive layer 170 is approximately 0.25λ×n, and the thickness of the second insulating dielectric layer 180 above the transparent conductive layer is approximately 0.25λ×n, where n is an odd number. In some embodiments, when the light-emitting layer 130 emits light with a wavelength of λ, the thickness of the first insulating dielectric layer 160 is approximately 0.25λ, the thickness of the transparent conductive layer 170 is approximately 0.25λ, and the thickness of the second insulating dielectric layer 180 above the transparent conductive layer 170 is approximately 0.75λ.
[0078] As disclosed above, by providing a first insulating dielectric layer 160 and a transparent conductive layer 170, the transparent conductive layer 170 can conduct current, and the first insulating dielectric layer 160 can create an electrically insulating region. Therefore, when current flows in the light-emitting structure 100, the transparent conductive layer 170 and the first insulating dielectric layer 160 can highly concentrate the current within the range of the second aperture 162, thereby making it difficult for higher-order modes at the edge of the second aperture 162 to be amplified. Furthermore, because the second aperture of the second aperture 162 is smaller than the first aperture of the first aperture 142, the laser can have two paths with different reflectivities, further generating a laser beam with a Gaussian beam pattern.
[0079] Please see Figures 4 to 10 , Figures 4 to 10 The following is a cross-sectional schematic diagram illustrating the various steps in manufacturing the light-emitting structure according to some embodiments of this disclosure. The manufacturing process of the light-emitting structure disclosed herein will be described below. For ease of description, the same symbols will be used to label the same elements, and repeated descriptions will not be repeated.
[0080] First, such as Figure 4 As shown, in one embodiment, substrate 110 serves as a growth substrate for epitaxial growth, and a first semiconductor stack 120, a light-emitting layer 130, and a second semiconductor stack 150 are sequentially deposited or stacked from bottom to top. Subsequently, a first insulating dielectric layer 160 and a second hole 162 are formed.
[0081] Next, as Figure 5 As shown, in Figure 4 A transparent conductive layer 170 is formed on the resulting structure. However, because the thickness of all film layers in a VCSEL structure needs to be controlled very precisely, otherwise the light emission effect will not be as expected. Therefore, this disclosure uses a thin film growth process to form the device thickness (0.25λ, 0.5λ, 0.75λ, etc.) as disclosed above, while achieving the expected light emission effect.
[0082] like Figure 6 As shown, Figure 6The process includes etching a portion of a transparent conductive layer 170, a portion of a first insulating dielectric layer 160, a portion of a second semiconductor stack 150, a portion of a light-emitting layer 130, and a portion of a first semiconductor stack 120. In this step, a mask or etching resist (not shown) is first applied to the upper surface of a portion of the transparent conductive layer 170, and etching is performed downwards until a portion of the first semiconductor stack 120 is also etched. The mask or etching resist is then removed. This forms a first thickness structure 122 and a second thickness structure 124 of the first semiconductor stack 120, thus the first thickness of the first thickness structure 122 is greater than the second thickness of the second thickness structure 124. This step includes an etching process applicable to deep etching depths. In some embodiments, the etching process includes, but is not limited to, dry etching (such as plasma etching), wet etching (such as chemical etching), or other suitable processes and / or combinations thereof. In one embodiment, this disclosure uses plasma etching to expose the upper surface of the second thickness structure 124 of the first semiconductor stack 120. An oxidation process is then performed to form an oxide layer 140 and a first hole 142.
[0083] Next, please refer to Figure 7 ,exist Figure 6 A second insulating dielectric layer 180 is formed on the resulting light-emitting structure, and an etching process is performed to form annular holes 182. For the sake of brevity, the step of pre-setting the resist layer is not shown in the diagram. Figure 8 In this embodiment, the annular hole 182 exposes a portion of the upper surface of the transparent conductive layer 170, meaning that the second insulating dielectric layer 180 covers a portion of the upper surface of the transparent conductive layer 170, the sidewalls of the transparent conductive layer 170, the sidewalls of the first insulating dielectric layer 160, the sidewalls of the second semiconductor stack 150, the sidewalls of the oxide layer 140, the sidewalls of the light-emitting layer 130, the sidewalls of the first thickness structure 122 of the first semiconductor stack 120, and the upper surface of the second thickness structure 124 of the first semiconductor stack 120. In one embodiment, the second insulating dielectric layer 180 is formed by, but not limited to, chemical vapor deposition, physical vapor deposition, plasma-assisted chemical vapor deposition, atomic layer deposition, or other suitable processes and / or combinations thereof. In one embodiment, the etching method for forming the annular hole 182 includes, but is not limited to, wet etching, dry etching, chemical etching, physical etching, selective etching, or other suitable processes and / or combinations thereof.
[0084] Finally, as Figure 8 as well as Figure 9 As shown, a second conductive layer 190b is formed in Figure 8The structure shown is such that a first conductive layer 190a is formed beneath the substrate 110. In one embodiment, the formation of the first conductive layer 190a and the second conductive layer 190b includes, but is not limited to, chemical vapor deposition, physical vapor deposition, plasma-assisted chemical vapor deposition, atomic layer deposition, electroplating, chemical plating, or other suitable processes and / or combinations thereof.
[0085] In summary Figures 4 to 10 This completes the light-emitting structure in some embodiments disclosed herein. Its characteristic lies in that the first insulating dielectric layer 160 and the transparent conductive layer 170 effectively change the current path, concentrating the current and making it difficult for the higher-order modes generated at the edge of the second hole 162 to be amplified, thereby obtaining a small-angle Gaussian light pattern.
[0086] Please see Figure 10 , Figure 10 This diagram illustrates a comparison of the aperture sizes of various holes in a light-emitting structure according to some embodiments of this disclosure. Figure 10 It can be understood that, in some embodiments, the third aperture of the third hole H in the second conductive layer 190b is larger than the first aperture of the first hole 142 in the oxide layer 140, and both the third aperture and the first aperture are larger than the second aperture of the second hole 162 in the first insulating dielectric layer 160. Furthermore, due to... Figure 10 It is also understood that, in some embodiments, when projected vertically onto the substrate 110, the annular holes 182 of the second insulating dielectric layer 180 will surround the periphery of the first hole 142 and the second hole 162. In summary, when the light-emitting layer 130 emits light, the laser will have two light-emitting paths with different reflectivities (the reflectivity difference is about 2.7%), thereby achieving a small-angle light pattern with a Gaussian light pattern.
[0087] In summary, this disclosure effectively adjusts the current path through the transparent conductive layer 170 and the first insulating dielectric layer 160. Simultaneously, the first hole 142, the second hole 162, and the portion of the second insulating dielectric layer 180 above them allow for two different reflectivities in the emitted light energy. Thus, as described in this disclosure, when current flows through the light-emitting structure 100, the transparent conductive layer 170 and the first insulating dielectric layer 160 can highly concentrate the current within the range of the second hole 162, thereby making the light pattern at the edge of the second semiconductor stack 150 less susceptible to amplification. Furthermore, because the second aperture of the second hole 162 is smaller than the first aperture of the first hole 142, the laser energy follows two paths with different reflectivities, further generating a small-angle laser beam with a Gaussian pattern. At the same time, the laser light intensity of the VCSEL is still maintained.
[0088] The foregoing disclosure outlines features of several embodiments, enabling those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art will understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or benefits as the embodiments described herein. Those skilled in the art should also understand that although this disclosure has been presented above in various embodiments, it is not intended to limit this disclosure. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure shall be determined by the scope defined in the appended claims.
Claims
1. A light-emitting structure, characterized in that, include: substrate; A first semiconductor stack is disposed on the substrate, wherein the first semiconductor stack has a first thickness structure and a second thickness structure, and the thickness of the first thickness structure is greater than the thickness of the second thickness structure. A light-emitting layer is disposed on the first thickness structure of the first semiconductor stack; An oxide layer is disposed on the light-emitting layer, wherein the oxide layer has a first hole and the first hole has a first aperture; A second semiconductor stack is disposed on the oxide layer, and the second semiconductor stack is electrically connected to the light-emitting layer through the first hole; A first insulating dielectric layer is disposed on the second semiconductor stack, wherein the first insulating dielectric layer has a second hole and the second hole has a second aperture; A transparent conductive layer is disposed on the first insulating dielectric layer, and the transparent conductive layer is electrically connected to the second semiconductor stack through the second hole; A second insulating dielectric layer covers the upper surface of the transparent conductive layer, the sidewalls of the transparent conductive layer, the sidewalls of the first insulating dielectric layer, the sidewalls of the second semiconductor stack, the sidewalls of the oxide layer, the sidewalls of the light-emitting layer, the sidewalls of the first thickness structure of the first semiconductor stack, and the upper surface of the second thickness structure of the first semiconductor stack. In a top view, the second insulating dielectric layer has an annular hole located above the transparent conductive layer, and when projected vertically onto the substrate, the annular hole surrounds the first hole and the second hole. as well as The second conductive layer covers the sidewalls and part of the upper surface of the second insulating dielectric layer and is electrically connected to the transparent conductive layer through the annular hole. The second conductive layer has a third hole with a third hole diameter larger than the first hole diameter and the second hole diameter. When projected vertically onto the substrate, the geometric center of the third hole overlaps with the geometric center of the first hole diameter and the geometric center of the second hole diameter. The first aperture is larger than the second aperture.
2. A light-emitting structure, characterized in that, include: substrate; A first semiconductor stack is disposed on the substrate, wherein the first semiconductor stack has a first thickness structure and a second thickness structure, and the thickness of the first thickness structure is greater than the thickness of the second thickness structure. A light-emitting layer is disposed on the first thickness structure of the first semiconductor stack; An oxide layer is disposed on the light-emitting layer, wherein the oxide layer has a first hole and the first hole has a first aperture; A second semiconductor stack is disposed on the oxide layer, and the second semiconductor stack is electrically connected to the light-emitting layer through the first hole; A first insulating dielectric layer is disposed on the second semiconductor stack, wherein the first insulating dielectric layer has a second hole and the second hole has a second aperture; A transparent conductive layer is disposed on the first insulating dielectric layer, and the transparent conductive layer is electrically connected to the second semiconductor stack through the second hole; A second insulating dielectric layer covers the upper surface of the transparent conductive layer, the sidewalls of the transparent conductive layer, the sidewalls of the first insulating dielectric layer, the sidewalls of the second semiconductor stack, the sidewalls of the oxide layer, the sidewalls of the light-emitting layer, the sidewalls of the first thickness structure of the first semiconductor stack, and the upper surface of the second thickness structure of the first semiconductor stack. In a top view, the second insulating dielectric layer has an annular hole located above the transparent conductive layer, and when projected vertically onto the substrate, the annular hole surrounds the first hole and the second hole. as well as The second conductive layer covers the sidewalls and part of the upper surface of the second insulating dielectric layer and is electrically connected to the transparent conductive layer through the annular hole. The second conductive layer has a third hole with a third hole diameter larger than the first hole diameter and the second hole diameter. When projected vertically onto the substrate, the geometric center of the third hole overlaps with the geometric center of the first hole diameter and the geometric center of the second hole diameter.
3. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The first aperture is between 8 micrometers and 13 micrometers.
4. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The second aperture is between 5 micrometers and 10 micrometers.
5. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The light-emitting layer emits a first light path and a second light path; The first light path originates from the light-emitting layer, passes through the first hole, the second semiconductor stack, the second hole, and the transparent conductive layer, and the first light path has a first reflectivity; and The second light path is emitted from the light-emitting layer through the first hole, the second semiconductor stack, the first insulating dielectric layer and the transparent conductive layer, and the second light path has a second reflectivity; The first reflectivity is greater than the second reflectivity.
6. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The light-emitting layer emits a first light path and a second light path; The first light path originates from the light-emitting layer, passes through the first hole, the second semiconductor stack, the second hole, and the transparent conductive layer, and the first light path has a first reflectivity of 99.5%; and The second light path is emitted from the light-emitting layer through the first hole, the second semiconductor stack, the first insulating dielectric layer and the transparent conductive layer, and the second light path has a second reflectivity of 98%.
7. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The light-emitting layer emits light with a wavelength of λ. The thickness of the first insulating dielectric layer is 0.25λ×n, where n is an odd number. The thickness of the transparent conductive layer is 0.5λ×m, where m is an integer.
8. The light-emitting structure according to any one of claims 1 to 2, characterized in that, The light-emitting layer emits light with a wavelength of λ, the thickness of the first insulating dielectric layer is 0.25λ, and the thickness of the transparent conductive layer is 0.5λ.
9. The light-emitting structure according to any one of claims 1 to 2, characterized in that, Viewed from above, when the second insulating dielectric layer is projected vertically onto the substrate, the annular hole surrounds both the first hole and the second hole.
10. The light-emitting structure according to claim 9, characterized in that, The light-emitting layer emits light with a wavelength of λ. The thickness of the first insulating dielectric layer is 0.25λ×n, the thickness of the transparent conductive layer is 0.25λ×n, and the thickness of the second insulating dielectric layer above the transparent conductive layer is 0.25λ×n, where n is an odd number.
11. The light-emitting structure according to claim 9, characterized in that, The light-emitting layer emits light with a wavelength of λ. The thickness of the first insulating dielectric layer is 0.25λ, the thickness of the transparent conductive layer is 0.25λ, and the thickness of the second insulating dielectric layer above the transparent conductive layer is 0.75λ.
12. The light-emitting structure according to claim 9, characterized in that, Also includes: A first conductive layer is disposed beneath the substrate.
13. The light-emitting structure according to claim 12, characterized in that, The geometric center of the first hole, the second hole, and the third hole is the center of gravity.
14. The light-emitting structure according to claim 13, characterized in that, The diameter of the third aperture is between 10 micrometers and 20 micrometers.
15. The light-emitting structure according to claim 13, characterized in that, The light-emitting layer emits a third light path and a fourth light path; The third optical path originates from the light-emitting layer, passes through the first hole, the second semiconductor stack, the second hole, the transparent conductive layer, the second insulating dielectric layer, and exits through the third hole, and the third optical path has a third reflectivity; and The fourth light path is emitted from the light-emitting layer through the first hole, the second semiconductor stack, the first insulating dielectric layer, the transparent conductive layer, the second insulating dielectric layer and the third hole, and the fourth light path has a fourth reflectivity; The third reflectivity is greater than the fourth reflectivity.
16. The light-emitting structure according to claim 15, characterized in that, The third reflectance is 99.778%; and the fourth reflectance is 97.043%.
17. A light-emitting device, characterized in that, Includes the light-emitting structure as described in any one of claims 1 to 16.