CN116646432A - Light emitting diode and light emitting device - Google Patents

Light emitting diode and light emitting device Download PDF

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Publication number
CN116646432A
CN116646432A CN202310859619.7A CN202310859619A CN116646432A CN 116646432 A CN116646432 A CN 116646432A CN 202310859619 A CN202310859619 A CN 202310859619A CN 116646432 A CN116646432 A CN 116646432A
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China
Prior art keywords
layer
light emitting
emitting diode
ohmic contact
sub
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CN202310859619.7A
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Chinese (zh)
Inventor
吴志伟
王燕云
熊伟平
郭桓卲
彭钰仁
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Quanzhou Sanan Semiconductor Technology Co Ltd
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Quanzhou Sanan Semiconductor Technology Co Ltd
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Priority to CN202310859619.7A priority Critical patent/CN116646432A/en
Publication of CN116646432A publication Critical patent/CN116646432A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/04—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier

Abstract

The application relates to the technical field of semiconductor manufacturing, in particular to a light-emitting diode, which comprises a semiconductor epitaxial lamination, wherein the semiconductor epitaxial lamination is provided with a first surface and a second surface which are opposite, a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer are sequentially arranged along the direction from the first surface to the second surface, and a composite ohmic contact layer is arranged on one side of the second conductive type semiconductor far away from the active layer; the direction of the composite ohmic contact layer from the first surface to the second surface at least comprises a first sub-layer and a second sub-layer, and the band gap width of the composite ohmic contact layer is larger than 1.8eV. By arranging the composite ohmic contact layer, the light absorption of the ohmic contact layer can be reduced, the flatness of the interface between the ohmic contact layer and the contact electrode can be improved, and the luminous efficiency of the light-emitting diode can be improved.

Description

Light emitting diode and light emitting device
Technical Field
The application relates to a light-emitting diode, belonging to the technical field of semiconductor optoelectronic devices.
Background
The light-emitting diode (Light Emitting Diode, LED) is a semiconductor light-emitting element, typically formed of, for example, gaN, gaAs, gaP, alGaAs, al x Ga y The core of the semiconductor is PN structure with luminous characteristic, electricThe electrons are injected into the P region from the N region, the holes are injected into the N region from the P region, and the electrons and the holes are recombined to enable the light-emitting diode to emit light. The LED has the advantages of high luminous intensity, high efficiency, small volume, long service life and the like, and is widely applied to various fields.
The GaAs crystal has good quality, can form good metal-semiconductor ohmic contact with metal, and is an ohmic contact layer material widely used by the current LEDs. But is very light absorbing in the red, yellow and green bands because its intrinsic wavelength is 860 nm. Therefore, the optimization design of the ohmic contact material is used to solve the problem of insufficient luminous efficiency of the light emitting diode, which is one of the technical difficulties to be solved by the skilled in the art.
Disclosure of Invention
In order to solve the above-described problems, the present application provides a light emitting diode including; the semiconductor epitaxial lamination is provided with a first surface and a second surface which are opposite, the semiconductor epitaxial lamination sequentially comprises a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer along the direction from the first surface to the second surface, and a composite ohmic contact layer is arranged on one side of the second conductive type semiconductor far away from the active layer; the direction of the composite ohmic contact layer from the first surface to the second surface at least comprises a first sub-layer and a second sub-layer, and the band gap width of the composite ohmic contact layer is larger than 1.8eV.
In some alternative embodiments, the first sub-layer has a bandgap width that is less than a bandgap width of the second sub-layer.
In some alternative embodiments, the material of the first sub-layer is Al x1 Ga 1-x1 As, wherein 0.5.ltoreq.X 1<1。
In some alternative embodiments, the first sub-layer has a thickness of 100-300nm and the second sub-layer has a doping concentration of 1×10 17 cm -3 ~1×10 19 cm -3 。
In some alternative embodiments, the material of the second sub-layer is Al x2 Ga y2 InP where 0.ltoreq.x2.ltoreq.1 or 0.ltoreq.y2.ltoreq.1.
In some alternative embodiments, the second sub-layer has a thickness of 5-50nmThe doping concentration of the second sub-layer is 1×10 18 cm -3 ~ 1×10 22 cm -3 。
In some alternative embodiments, the composite ohmic contact layer is a patterned structure.
In some alternative embodiments, the light emitting diode further includes first and second contact electrodes electrically connected to the first conductivity type semiconductor layer and the composite ohmic contact layer, respectively.
In some alternative embodiments, the light emitting diode further includes first and second pad electrodes electrically connected to the first and second contact electrodes.
In some alternative embodiments, the second contact electrode comprises at least three elements of Au, ge, ni, and alloys thereof.
In some alternative embodiments, the second contact electrode further comprises Pt and Ti.
In some alternative embodiments, the interface between the second contact electrode and the composite ohmic contact layer contains Ni element.
In some alternative embodiments, the light emitting diode further includes an insulating layer having a first opening and a second opening, the first and second pad electrodes being electrically connected to the first and second contact electrodes through the first and second openings.
In some alternative embodiments, the first and second pad electrodes comprise Ti, al, pt, au, ni, sn, in or an alloy of any combination thereof or a stack of any combination thereof.
In some alternative embodiments, the thickness of the first contact electrode and the second contact electrode is 0.5-3 μm.
In some alternative embodiments, the thickness of the first pad electrode and the second pad electrode is 1-5 μm.
In some alternative embodiments, the light emitting diode radiates light with a wavelength of 550-950 nm.
The present application provides a light emitting device comprising the light emitting diode of any one of the preceding claims.
By arranging the composite ohmic contact layer, the application can reduce the light absorption of the ohmic contact layer, improve the flatness of the interface between the ohmic contact layer and the contact electrode and improve the luminous efficiency of the light-emitting diode.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
While the application will be described in conjunction with certain exemplary embodiments and methods of use, those skilled in the art will recognize that they are not intended to limit the application to these embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the application as defined by the appended claims.
Drawings
For a clearer description of embodiments of the application or of the solutions of the prior art, the drawings that are needed in the description of the embodiments or of the prior art will be briefly described, it being obvious that the drawings in the description below are some embodiments of the application, and that other drawings can be obtained from them without inventive effort for a person skilled in the art; the positional relationships described in the drawings in the following description are based on the orientation of the elements shown in the drawings unless otherwise specified.
Fig. 1 is a schematic cross-sectional view of a light emitting diode according to embodiment 1 of the present application.
Fig. 2 is a cross-sectional view of a FIB with a rough interface between the ohmic contact layer and the contact electrode as described in example 1 of the present application.
Fig. 3 is a cross-sectional view of a FIB with a planar interface between the composite ohmic contact layer and the contact electrode according to example 1 of the present application.
Fig. 4 to 8 are schematic structural diagrams of the light emitting diode according to embodiment 2 of the present application in the process of manufacturing the light emitting diode.
Fig. 9 is a schematic structural view of a light emitting device mentioned in embodiment 3 of the present application.
The reference numerals of the elements in the drawings illustrate: 10: a growth substrate; 100: a substrate; 101: a bonding layer; 102: a first conductive type semiconductor layer; 103: an active layer; 104: a second conductivity type semiconductor layer; 105: a composite ohmic contact layer; 1051: a first sub-layer of the composite ohmic contact layer; 1052: a second sub-layer of the composite ohmic contact layer; 106: a first contact electrode; s1: a first mesa; 107: a second contact electrode; 108: an insulating layer; 109: a first pad electrode; 110: a second pad electrode; 201 a metal connection layer; 200: and (5) fixing the crystal substrate.
Description of the embodiments
Other advantages and effects of the present application will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present application with reference to specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application.
It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present application by way of illustration, and only the components related to the present application are shown in the drawings rather than the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
The following will describe embodiments of the present application in detail with reference to the drawings and examples, thereby solving the technical problems by applying technical means to the present application, and realizing the technical effects can be fully understood and implemented accordingly.
Examples
Fig. 1 is a schematic cross-sectional view of a light emitting diode chip according to an embodiment of the application.
Referring to fig. 1, to achieve at least one of the advantages and other advantages of the present application, an embodiment of the present application provides a light emitting diode chip, which includes the following stacked layers: 100: a substrate; 101: a bonding layer; 102: a first conductive type semiconductor layer; 103: an active layer; 104: a second conductivity type semiconductor layer; 105: a composite ohmic contact layer; 1051: a first sub-layer of the composite ohmic contact layer; 1052: a second sub-layer of the composite ohmic contact layer; 106: a first contact electrode; 107: a second contact electrode; 108: an insulating layer; 109: a first pad electrode; 110: and a second pad electrode.
The light emitting diode chip may be a conventional sized light emitting diode chip. The light emitting diode chip may have a thickness of about 90000 μm 2 Above and about 2000000 μm 2 The following horizontal sectional areas.
The light emitting diode chip may also be a small-sized or micro-sized light emitting diode chip. The light emitting diode chip may have a thickness of about 90000 μm 2 The following horizontal sectional areas. For example, the light emitting diode chip may have a length and/or a width of 100 μm or more and 300 μm or less, and further may have a thickness of 40 μm or more and 100 μm or less.
The light emitting diode chip may also be a miniature light emitting diode chip of smaller size. The light emitting diode chip may have a thickness of about 10000 μm 2 The following light emitting diode chips of horizontal cross-sectional area. For example, the light emitting diode chip may have a length and/or width of 2 μm or more and 100 μm or less, and further may have a thickness of 2 μm or more and 100 μm or less. The light emitting diode chip of the present embodiment may have the horizontal sectional area and thickness as described above, and thus the light emitting diode chip may be easily applied to various electronic devices requiring a small and/or micro light emitting device.
Referring again to fig. 1, the semiconductor epitaxial stack has a first surface and a second surface opposite the first surface. The semiconductor epitaxial lamination is obtained by MOCVD or other growth modes, and is a semiconductor material capable of providing conventional radiation such as ultraviolet radiation, blue radiation, green radiation, yellow radiation, red radiation, infrared radiation and the like, and can be specifically 200-950 nm material such as common nitride, specifically gallium nitride-based semiconductor epitaxial lamination, wherein the gallium nitride-based epitaxial lamination is commonly doped with elements such as aluminum, indium and the like, and mainly provides radiation with a wave band of 200-550 nm; or common AlGaInP-based or AlGaAs-based semiconductor epitaxial lamination, which mainly provides radiation with the wave band of 550-950 nm. In this embodiment, the semiconductor epitaxial layer is preferably made of aluminum gallium indium phosphorus or aluminum gallium arsenic base material, and the semiconductor epitaxial layer mainly provides radiation with a wavelength band of 550-950 nm.
The semiconductor epitaxial stack includes a first conductive type semiconductor layer 102, a second conductive type semiconductor layer 104, and an active layer 103 between the first conductive type semiconductor layer 102 and the second conductive type semiconductor layer 104; the second conductive type semiconductor 104 is provided with a composite ohmic contact layer 105 on a side remote from the active layer 103. The semiconductor epitaxial stack has a first mesa S1, which first mesa S1 exposes the first conductivity type semiconductor layer 102.
The first conductive type semiconductor layer 102 and the second conductive type semiconductor layer 104 have different conductive types, electrical properties, polarities, or doping elements to provide electrons or holes, that is: the first conductive type semiconductor layer 102 has a first conductivity, the second conductive type semiconductor layer 104 has a second conductivity, wherein the first conductivity is different from the second conductivity, for example, the first conductive type semiconductor layer 102 may be a p-type semiconductor layer, and the second conductive type semiconductor layer 104 may be an n-type semiconductor layer; and vice versa. Electrons from the n-type semiconductor layer and holes from the p-type semiconductor layer are driven by an applied current, and electric energy is converted into light energy in the active layer 103 and light is emitted.
In this embodiment, the semiconductor epitaxial stack is a material of gallium arsenide (GaAs) series, in which the doping of the first conductivity type semiconductor layer 102 is p-type and the doping of the second conductivity type semiconductor layer 104 is n-type.
In other embodiments of the present disclosure, the material of the first conductive type semiconductor layer 102 includes a ii-vi material (e.g., zinc selenide (ZnSe)) or a iii-v nitride material (e.g., gallium arsenide (GaAs), gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN)), and the material of the first conductive type semiconductor layer 102 may further include dopants that may include magnesium (Mg), carbon (C), etc., but the embodiments of the present disclosure are not limited thereto. In some other embodiments, the first conductive type semiconductor layer 102 may also be a single-layer or multi-layer structure.
In other embodiments of the disclosure, the material of the second conductive type semiconductor layer 104 includes iii-v nitride material (e.g., gallium arsenide (GaAs), gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN)), and the material of the second conductive type semiconductor layer 104 may include dopants such as silicon (Si) or germanium (Ge), but the disclosure is not limited thereto. In some other embodiments, the second conductive type semiconductor layer 104 may also be a single-layer or multi-layer structure.
In this embodiment, the active layer 103 is made of a semiconductor material of gallium arsenide (GaAs) series. Specifically, when the active layer 103 is based on a semiconductor material of aluminum indium gallium phosphide (AlGaInP) series, gallium arsenide (GaAs) series, red light, orange light, or yellow light can be emitted; blue or green light may be emitted when based on semiconductor materials of the aluminum gallium indium nitride (AlGaInN) series. In some embodiments of the present application, the active layer 103 may be a Single Heterostructure (SH), a double-sided Double Heterostructure (DH), or a multi-quantum well (MQW), but the embodiments of the present disclosure are not limited thereto.
The GaAs crystal has good quality, can form good metal-semiconductor ohmic contact with metal, and is an ohmic contact layer material widely used by the current LEDs. But is very light absorbing in the red, yellow and green bands because its intrinsic wavelength is 860 nm.
The N-type AlInP or AlGaInP semiconductor material transparent to red light is adopted as the ohmic contact layer, so that the problem of light absorption of the GaAs ohmic contact layer is solved, but at an ohmic contact interface, au In the metal electrode is easy to react with Al element and In element In the N-type AlInP or AlGaInP semiconductor material, so that the ohmic contact interface between the ohmic contact layer and the metal electrode is rough and metal diffusion is deep, and as shown In fig. 2, the rough ohmic contact interface absorbs light, and therefore the luminous efficiency of the light-emitting diode is reduced.
An N-type AlGaAs semiconductor material transparent to red light is adopted as an ohmic contact layer, an ohmic contact interface between the N-type AlGaAs semiconductor material and a metal electrode is smooth, and meanwhile, the metal diffusion depth can be effectively controlled, but a window for ohmic contact between the N-type AlGaAs semiconductor material and the metal electrode is small, so that contact resistance is easily increased, and the photoelectric performance of a light-emitting element is affected.
In order to solve the above-mentioned problem that the ohmic contact interface is rough or the window of the ohmic contact is small, in this embodiment, a composite ohmic contact layer 105 is provided, and the direction from the first surface to the second surface of the composite ohmic contact layer 105 includes at least a first sub-layer 1051 and a second sub-layer 1052, and the band gap width of the composite ohmic contact layer is greater than 1.8eV. By controlling the band gap width of the composite ohmic contact layer to be greater than 1.8eV, the intrinsic wavelength of the composite ohmic contact layer 105 can be made smaller than 690nm; thereby reducing the light absorption of the composite ohmic contact layer and improving the luminous efficiency of the light emitting diode.
In this embodiment, the band gap width of the first sub-layer 1051 of the composite ohmic contact layer is preferably smaller than the band gap width of the second sub-layer 1052. In this embodiment, the material of the first sub-layer 1051 of the composite ohmic contact layer is Al x1 Ga 1-x1 As, wherein 0.5.ltoreq.X 1<1, the intrinsic wavelength of the first sub-layer 1051 of the composite ohmic contact layer may be made smaller than 640nm, thereby reducing the light absorption of the composite ohmic contact layer 105, and thus improving the light emitting efficiency of the light emitting diode. In this embodiment, the thickness of the first sub-layer 1051 of the composite ohmic contact layer is preferably 100-300nm, and the doping concentration of the first sub-layer 1051 of the composite ohmic contact layer is preferably 1×10 17 cm -3 ~1×10 19 cm -3 。
In this embodiment, the material of the second sub-layer 1052 of the composite ohmic contact layer is preferably Al x2 Ga y2 InP，Wherein x2 is more than or equal to 0 and less than or equal to 1 or y2 is more than or equal to 0 and less than or equal to 1. Specifically, the second sub-layer 1052 of the composite ohmic contact layer is made of a short-wave material such as aluminum gallium indium phosphorus (with an intrinsic wavelength of 490-650 nm) or aluminum indium phosphorus (with an intrinsic wavelength of 490 nm) or gallium indium phosphorus (with an intrinsic wavelength of 650 nm), and the light absorption of the second sub-layer is far smaller than GaAs (with an intrinsic wavelength of 860 nm), and when the second sub-layer is applied to a light emitting diode such as red light or near infrared light, the light absorption of the ohmic contact layer is greatly reduced, and the light emitting brightness of the diode can be effectively improved.
In order to ensure that the composite ohmic contact layer 105 and the second contact electrode 107 form good ohmic contact, the thickness of the second sub-layer 1052 of the composite ohmic contact layer is preferably 5-50nm, and the doping concentration of the second sub-layer 1052 of the composite ohmic contact layer is 1×10 18 cm -3 ~1×10 22 cm -3 。
In this embodiment, a flat interface is formed between the composite ohmic contact layer 105 and the second contact electrode 107 by using the composite ohmic contact layer 105, as shown in fig. 3. The flat interface between the composite ohmic contact layer 105 and the second contact electrode 107 can reduce light absorption, and can ensure that good ohmic contact is formed between the composite ohmic contact layer 105 and the second contact electrode 107, thereby improving the photoelectric performance and luminous efficiency of the light emitting diode.
In some alternative embodiments, the composite ohmic contact layer 105 is a patterned structure, the composite ohmic contact layer 105 is only located under the first contact electrode, and other regions may remove the composite ohmic contact layer 105.
Referring to fig. 1 again, the semiconductor epitaxial layer stack is bonded to the substrate 100 through the bonding layer 101, and preferably, a side of the semiconductor epitaxial layer stack facing the substrate 100 is formed into a rough surface to reduce the number of reflections during light output and improve the brightness of the light emitting diode. In this embodiment, the substrate 100 is a sapphire substrate. The substrate 100 may be a transparent substrate, the material of which comprises an inorganic material or a group iii-v semiconductor material. The inorganic material comprises silicon carbide (SiC), germanium (Ge), sapphire (sapphire), lithium aluminate (LiAlO) 2 ) Zinc oxide (ZnO), glass or quartz. The III-V semiconductor material comprises indium phosphide (InP) and gallium phosphide(GaP), gallium nitride (GaN), aluminum nitride (AlN) materials. The substrate 100 has strength sufficient to mechanically support the semiconductor epitaxial stack and is capable of transmitting light emitted from the semiconductor epitaxial stack. The thickness of the substrate 100 is preferably 50 μm or more. In addition, in order to facilitate the mechanical processing of the substrate 100 after bonding to the semiconductor epitaxial stack, a thickness of not more than 300 μm is preferable.
It should be noted that the led chip of the present application is not limited to include only one semiconductor epitaxial layer stack, but may include a plurality of semiconductor epitaxial layers stacked on the substrate 100, wherein a conductive line structure may be disposed between the plurality of semiconductor epitaxial layers to electrically connect the plurality of semiconductor epitaxial layers to each other on the substrate 100 in series, parallel, serial-parallel, etc.
The material of the bonding layer 101 may be an insulating material and/or a conductive material. Insulating materials include, but are not limited to, polyimide (PI), benzocyclobutene (BCB), perfluorocyclobutane (PFCB), magnesium oxide (MgO), su8, epoxy (Epoxy), acrylic (acrylic resin), cyclic olefin polymer (COC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), polyetherimide (Polyetheride), fluorocarbon polymer (fluorocarbon polymer), glass (Glass), alumina (Al 2 O 3 ) Silicon oxide (SiO) x ) Titanium oxide (TiO) 2 ) Tantalum oxide (Ta) 2 O 5 ) Silicon nitride (SiN) x ) Or spin-on glass (SOG). The conductive material includes, but is not limited to, 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), zinc oxide (ZnO), indium Zinc Oxide (IZO), diamond-like carbon film (DLC), gallium Zinc Oxide (GZO), or the like. When the bonding layer 101 is made of a conductive material and contacts with the first conductive type semiconductor layer 102, the bonding layer can function as a current spreading layer, improve the current spreading effect, and improve the uniformity of current distribution.
In some embodiments, the refractive index of the bonding layer 101 is preferably between the refractive index of the first conductivity type semiconductor layer 102 and the refractive index of the substrate 100. For example, the first conductive type semiconductor layer 102 has a refractive index n1, the bonding layer 100 has a refractive index n2, and the substrate 100 has a refractive index n3, wherein the refractive index n1 > the refractive index n2 > the refractive index n3. In some embodiments, the refractive index of the bonding layer 100 ranges from 1.2 to 3. The bonding layer 101 may have a single-layer structure or a multi-layer structure.
In order to dispose the first contact electrode 106 and the second contact electrode 107 described later on the same surface side of the first conductive type semiconductor layer 102 and the second conductive type semiconductor layer 104, the second conductive type semiconductor layer 104 may be laminated on the first conductive type semiconductor layer 102 so that a part of the first conductive type semiconductor layer 102 is exposed, or the first conductive type semiconductor layer 102 may be laminated on the second conductive type semiconductor layer 104 so that a part of the second conductive type semiconductor layer 104 is exposed. For example, referring to fig. 1 again, in the present embodiment, the semiconductor epitaxial stack includes a first mesa S1 at least partially penetrating the second conductivity type semiconductor layer 104 and the active layer 103 to expose the first conductivity type semiconductor layer 102.
The light emitting diode chip includes one or more first contact electrodes 106 on the first conductive type semiconductor layer 102 and directly or indirectly electrically connected to the first conductive type semiconductor layer 102, and one or more second contact electrodes 107 on the second conductive type semiconductor layer 104 and directly or indirectly electrically connected to the second conductive type semiconductor layer 104. In the case where the first conductivity type semiconductor layer 102 is p-type, the first contact electrode 106 refers to a p-side contact electrode; in the case where the first conductivity type semiconductor layer 102 is n-type, the first contact electrode 106 refers to an n-side contact electrode. And the second contact electrode 106 is opposite to the first contact electrode 107. In this embodiment, the first contact electrode 106 is preferably a p-side contact electrode.
The first contact electrode 106 and the second contact electrode 107 may be metal electrodes, and the second contact electrode 107 is composed of at least three elements of Au, ge, ni, and alloys thereof. In some embodiments, the second contact electrode 107 further comprises Ti and Pt. Specifically, the first contact electrode 106 is preferably a stack of an alloy of Au, zn, or Be, or any combination thereof, and the second contact electrode 107 is preferably a stack of an alloy of Au, ge, or Ni, or any combination thereof. The thickness of the first contact electrode 106 and the second contact electrode 107 is 0.5 to 3 μm, preferably 1 μm or more, to ensure that the first contact electrode 106 and the second contact electrode 107 form good ohmic contact with the semiconductor epitaxial stack. In this embodiment, the interface between the composite ohmic contact layer 105 and the second contact electrode 107 preferably contains Ni element, so as to ensure that the composite ohmic contact layer forms a good ohmic contact with the second contact electrode.
The insulating layer 108 covers the upper surface and the side surfaces of the semiconductor epitaxial stack and covers the first contact electrode 106 and the second contact electrode 107, and the insulating layer 108 may be formed so as to extend over the upper surface of the substrate 100 partially exposed at the periphery of the semiconductor epitaxial stack. Thus, the insulating layer 108 can be in contact with the upper surface of the substrate 100, and thus can cover the side surface of the semiconductor epitaxial stack more stably. The insulating layer 108 is used to protect the semiconductor epitaxial stack from moisture or contaminants and to ensure the optical and electrical properties of the semiconductor epitaxial stack. The insulating layer can be a single-layer or multi-layer structure, and the insulating layer can be SiO 2 、SiN x 、Al 2 O 3 And the like.
The insulating layer has a first opening and a second opening, and a first pad electrode 109 and a second pad electrode 110 are disposed on an upper portion of the insulating layer 108. The first pad electrode 109 may be electrically connected to the first contact electrode 106 through the first opening of the insulating layer 108. The second pad electrode 110 may be electrically connected to the second contact electrode 107 through the second opening. The first opening and the second opening may have a circular shape, and in some other embodiments, the first opening and the second opening may have a square shape, or the like, and the shape and the number of each opening are not particularly limited, and only one opening may be provided, and if a plurality of openings are provided, the current may be more uniformly dispersed. In addition, in some other embodiments, in the case where a plurality of openings are provided, each opening may be distributed at equal intervals or non-equal intervals according to actual needs, which is not limited to the embodiments disclosed in the present disclosure. In some embodiments, the first pad electrode 109 includes a stack of Ti, al, pt, au, ni, sn or an alloy of any combination thereof or any combination thereof. In some embodiments, the second pad electrode 110 includes a stack of Ti, al, pt, au, ni, sn or an alloy of any combination thereof or any combination thereof. The thickness of the first pad electrode 109 and the second pad electrode 110 is 1 to 5 μm, preferably 3 to 4 μm.
By arranging the composite ohmic contact layer 105, the light absorption problem of the traditional ohmic contact layer can be reduced and a relatively flat and stable ohmic contact interface can be obtained, so that the photoelectric performance and the luminous efficiency of the light-emitting diode are improved.
Examples
The process for manufacturing the light emitting diode of the above embodiment 1 will be described in detail.
Referring to fig. 4, a semiconductor epitaxial stack is formed on a growth substrate 10, and may be grown by various methods known in the art, such as organometallic chemical vapor deposition (Metal Organic Chemical VaporDeposition, MOCVD), molecular beam epitaxy (Molecular Beam Epitaxy, MBE) or hydride vapor phase epitaxy (Hydride Vapor Phase Epitaxy, HVPE). The growth substrate 10 is a gallium arsenide substrate. The semiconductor epitaxial stack is a material of gallium arsenide (GaAs) series, and includes a first conductivity type semiconductor layer 102, a second conductivity type semiconductor layer 104, and an active layer 103 between the first conductivity type semiconductor layer 102 and the second conductivity type semiconductor layer 104; and a composite ohmic contact layer 105 on a side of the second conductive type semiconductor layer remote from the active layer.
Referring to fig. 5, the roughened surface is formed on the surface of the first conductive type semiconductor layer 102 by roughening treatment, and the method for forming the roughened surface is not particularly limited, and for example, etching or mechanical polishing may be used. A bonding layer 101 is deposited on the roughened surface of the first conductivity type semiconductor layer 102, and the surface of the bonding layer 101 is polished, wherein the bonding layer 101 is preferably silicon dioxide.
Referring to fig. 6, a semiconductor epitaxial layer stack is bonded to a substrate 100 through a bonding layer 101, wherein the substrate 100 is a sapphire substrate; the growth substrate 10 is then removed.
Referring to fig. 7, defining a photoresist pattern on the surface of the semiconductor epitaxial stacked layer, removing the second conductivity type semiconductor layer 104 and the active layer 103 in a partial area of the surface of the composite ohmic contact layer 105 until a part of the first conductivity type semiconductor layer 102 is exposed, forming a first mesa S1, and then forming a first contact electrode 106 and a second contact electrode 107 on the first mesa and the composite ohmic contact layer;
referring to fig. 8, an insulating layer 108 is deposited, wherein the insulating layer 108 completely covers the surface of the semiconductor epitaxial stack, the sidewalls of the semiconductor epitaxial stack, and the exposed surface of the bonding layer 101.
Then, a first opening and a second opening are formed in the insulating layer 108 over the first conductive type semiconductor layer 102 and the second conductive type semiconductor layer 104, respectively, and the first pad electrode 109 and the second pad electrode 110 are prepared and electrically connected to the first conductive type semiconductor layer 102 and the composite ohmic contact layer 105 through the corresponding first opening and second opening, respectively, to obtain the light emitting diode shown in fig. 1.
By arranging the composite ohmic contact layer 105, the light absorption problem of the traditional ohmic contact layer can be reduced and a relatively flat and stable ohmic contact interface can be obtained, so that the photoelectric performance and the luminous efficiency of the light-emitting diode are improved.
Examples
The present embodiment provides a light emitting device, as shown in fig. 9, which includes a die attach substrate 200 and a light emitting diode on the die attach substrate 200. The light emitting diode may be the light emitting element provided in embodiment 1 of the present application. The die attach substrate 200 may be a ceramic substrate, a printed circuit board, or the like. The die bonding substrate 200 has a die bonding region thereon, the die bonding regions are arranged according to a specific logic design sequence, the light emitting diode is located on the die bonding region of the die bonding substrate 200, and a metal connection layer 201, such as a tin connection layer, is disposed therebetween. The light-emitting device can be used in the fields of lamps, display screens and the like.
The light-emitting diode in the light-emitting device can reduce and solve the light absorption problem of the traditional ohmic contact layer by arranging the composite ohmic contact layer 105, and can obtain a smoother and stable ohmic contact interface at the same time, thereby improving the photoelectric performance and the light-emitting efficiency of the light-emitting diode.
In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present application may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.
Although terms such as a substrate, a growth substrate, a semiconductor epitaxial stack, a first conductivity type semiconductor layer, a light emitting layer, a second conductivity type semiconductor layer, a first contact electrode, a first pad electrode, a second contact electrode, a second pad electrode, an insulating layer, a bonding layer, and the like are more used herein, the possibility of using other terms is not excluded. These terms are used merely for convenience in describing and explaining the nature of the application; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present application; the terms first, second, and the like in the description and in the claims of embodiments of the application and in the above-described figures, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims (18)

1. The light emitting diode includes;
the semiconductor epitaxial lamination is provided with a first surface and a second surface which are opposite, the semiconductor epitaxial lamination sequentially comprises a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer along the direction from the first surface to the second surface, and a composite ohmic contact layer is arranged on one side of the second conductive type semiconductor far away from the active layer;
the direction of the composite ohmic contact layer from the first surface to the second surface at least comprises a first sub-layer and a second sub-layer, and the band gap width of the composite ohmic contact layer is larger than 1.8eV.
2. A light emitting diode according to claim 1 wherein: the first sub-layer has a bandgap width that is less than a bandgap width of the second sub-layer.
3. A light emitting diode according to claim 1 wherein: the material of the first sub-layer is Al x1 Ga 1- x1 As, wherein 0.5.ltoreq.X 1<1。
4. A light emitting diode according to claim 1 wherein: the thickness of the first sub-layer is 100-300nm, and the doping concentration of the second sub-layer is 1×10 17 cm -3 ~1×10 19 cm -3 。
5. A light emitting diode according to claim 1 wherein; the material of the second sub-layer is Al x2 Ga y2 InP where 0.ltoreq.x2.ltoreq.1 or 0.ltoreq.y2.ltoreq.1.
6. A light emitting diode according to claim 1 wherein: the thickness of the second sub-layer is 5-50nm, and the doping concentration of the second sub-layer is 1 multiplied by 10 18 cm -3 ~ 1×10 22 cm -3 。
7. A light emitting diode according to claim 1 wherein: the composite ohmic contact layer is of a patterned structure.
8. A light emitting diode according to claim 1 wherein: the light emitting diode further includes first and second contact electrodes electrically connected to the first conductive type semiconductor layer and the composite ohmic contact layer, respectively.
9. A light emitting diode according to claim 8 wherein: the light emitting diode further includes first and second pad electrodes electrically connected to the first and second contact electrodes.
10. A light emitting diode according to claim 8 wherein: the second contact electrode comprises at least three elements of Au, ge and Ni and alloys thereof.
11. A light emitting diode according to claim 10 wherein: the second contact electrode further comprises Pt and Ti.
12. A light emitting diode according to claim 10 wherein: and the interface of the second contact electrode and the composite ohmic contact layer contains Ni element.
13. A light emitting diode according to claim 9 wherein: the semiconductor device further includes an insulating layer having a first opening and a second opening, and the first and second pad electrodes are electrically connected to the first and second contact electrodes through the first and second openings.
14. A light emitting diode according to claim 9 wherein: the first pad electrode and the second pad electrode include Ti, al, pt, au, ni, sn, in or an alloy of any combination thereof or a laminate of any combination thereof.
15. A light emitting diode according to claim 8 wherein: the thickness of the first contact electrode and the second contact electrode is 0.5-3 mu m.
16. A light emitting diode according to claim 9 wherein: the thickness of the first pad electrode and the second pad electrode is 1-5 μm.
17. A light emitting diode according to claim 1 wherein: the light emitting diode radiates light with the wavelength of 550-950 nm.
18. A light emitting device, characterized in that: the light emitting device comprising the light emitting diode according to any one of claims 1 to 17.
CN202310859619.7A 2023-07-13 2023-07-13 Light emitting diode and light emitting device Pending CN116646432A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310859619.7A CN116646432A (en) 2023-07-13 2023-07-13 Light emitting diode and light emitting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310859619.7A CN116646432A (en) 2023-07-13 2023-07-13 Light emitting diode and light emitting device

Publications (1)

Publication Number Publication Date
CN116646432A true CN116646432A (en) 2023-08-25

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