阅读说明：本技术 发光二极管及制作方法 (Light emitting diode and manufacturing method thereof ) 是由 贾月华 彭钰仁 王笃祥 于 2021-06-10 设计创作，主要内容包括：本发明公开发光二极管,包括：半导体外延叠层,包含第一导电类型半导体层、有源层和第二导电类型半导体层,具有相对的第一表面和第二表面；透光性电介质层,位于所述半导体外延叠层的第二表面侧,具有多个开口贯穿所述透光性电介质层,形成多个贯穿孔；欧姆接触层,填充所述透光性电介质层的贯穿孔；粘附层,位于所述透光性电介质层远离半导体外延叠层的一侧；金属反射层,位于所述粘附层远离半导体外延叠层的一侧；其特征在于：所述欧姆接触层和粘附层之间含有防金属扩散层,可防止欧姆接触层中的金属往所述粘附层扩散,防止发光二极管的电压升高,欧姆接触层填充透光性电介质层的贯穿孔,可防止键合层的孔洞产生,提升发光二极管的打线良率。(The invention discloses a light emitting diode, comprising: a semiconductor epitaxial stack including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having opposite first and second surfaces; a light-transmitting dielectric layer located on a second surface side of the semiconductor epitaxial stack and having a plurality of openings penetrating the light-transmitting dielectric layer to form a plurality of through holes; an ohmic contact layer filling the through hole of the light-transmissive dielectric layer; the adhesive layer is positioned on one side, far away from the semiconductor epitaxial lamination, of the light-transmitting dielectric layer; the metal reflecting layer is positioned on one side of the adhesion layer, which is far away from the semiconductor epitaxial lamination layer; the method is characterized in that: the metal diffusion prevention layer is arranged between the ohmic contact layer and the adhesion layer, so that metal in the ohmic contact layer can be prevented from diffusing to the adhesion layer, the voltage of the light-emitting diode is prevented from rising, the ohmic contact layer is filled in the through hole of the light-transmitting dielectric layer, holes in the bonding layer can be prevented from being generated, and the routing yield of the light-emitting diode is improved.)

1. A light emitting diode, comprising:

the semiconductor epitaxial lamination comprises a first conduction type semiconductor layer, an active layer and a second conduction type semiconductor layer, and is provided with a first surface and a second surface which are opposite, wherein the first surface is a light-emitting surface;

a light-transmitting dielectric layer located on a second surface side of the semiconductor epitaxial stack and having a plurality of openings penetrating the light-transmitting dielectric layer to form a plurality of through holes;

an ohmic contact layer filling the through hole of the light-transmissive dielectric layer and contacting the first conductivity type semiconductor layer;

the adhesive layer is positioned on one side, far away from the semiconductor epitaxial lamination, of the light-transmitting dielectric layer;

the metal reflecting layer is positioned on one side of the adhesion layer, which is far away from the semiconductor epitaxial lamination layer;

the method is characterized in that: and a metal diffusion prevention layer is arranged between the ohmic contact layer and the adhesion layer.

2. The led of claim 1, wherein: the metal diffusion prevention layer is positioned in the through hole of the light-transmitting dielectric layer.

3. The led of claim 1, wherein: the light-transmitting dielectric layer fills the through hole of the light-transmitting dielectric layer and partially extends out of the through hole.

4. The led of claim 1, wherein: the ohmic contact layer and the adhesion layer contain the same metal atoms.

5. The led of claim 1, wherein: the metal atoms in the metal diffusion prevention layer have lower mobility than the metal atoms in the ohmic contact layer.

6. The led of claim 1, wherein: the metal diffusion prevention layer is one or a combination of more of Pt, Ti, Ni and Cr.

7. The led of claim 1, wherein: the thickness of the light-transmitting dielectric layer is greater than that of the ohmic diffusion layer.

8. The led of claim 1, wherein: the thickness of the metal diffusion prevention layer is 30 nm-120 nm.

9. The led of claim 1, wherein: the ohmic contact layer is a combination of one or more materials of conductive metal compounds, wherein the conductive metal is Au, Ag or Al, and the other material at least comprises Zn, Be, Ge and Ni.

10. The led of claim 1, wherein: the thickness of the light-transmitting dielectric layer is 100 nm-500 nm.

11. The led of claim 1, wherein: the adhesion layer is a material which has good adhesion between the light-transmitting dielectric layer and the metal reflection layer and has high light transmittance.

12. The led of claim 1, wherein: the adhesion layer is IZO or ITO.

13. The led of claim 1, wherein: the thickness of the adhesion layer is 2-10 nm.

14. The led of claim 1, wherein: the light-transmitting dielectric layer is of a single-layer or multi-layer structure and is composed of at least one of nitride, oxide or fluoride.

15. The led of claim 1, wherein: the metal reflective layer has a reflectance of 70% or more.

16. The led of claim 1, wherein: the metal reflecting layer is formed by at least one metal or alloy of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf.

17. The led of claim 1, wherein: the light emitting wavelength of the light emitting diode is red light or infrared light.

18. The led of claim 1, wherein: the semiconductor epitaxial stack of the light emitting diode further includes a recess that is open from the second surface side and extends through the active layer to the bottom near the first surface side.

19. An illumination device, characterized by: a light emitting diode comprising any one of claims 1 to 18.

20. A method for manufacturing a light emitting diode comprises the following steps:

(1) providing a semiconductor epitaxial lamination layer, wherein the semiconductor epitaxial lamination layer comprises a first conduction type semiconductor layer, an active layer and a second conduction type semiconductor layer, the semiconductor epitaxial lamination layer is provided with a first surface and a second surface which are opposite, and the first surface is a light emitting surface;

(2) forming a light-transmissive dielectric layer on a second surface side of the semiconductor epitaxial stack, and forming a plurality of openings in the light-transmissive dielectric layer to penetrate the light-transmissive dielectric layer and form a plurality of through holes;

(3) forming an ohmic contact layer in the through hole of the light-transmitting dielectric layer;

(4) forming a metal diffusion prevention layer on the ohmic contact layer;

(5) forming an adhesion layer on one side of the light-transmitting dielectric layer far away from the semiconductor epitaxial lamination layer;

(6) and forming a metal reflecting layer on one side of the adhesion layer far away from the semiconductor epitaxial lamination layer.

Technical Field

The invention relates to a light emitting diode, belonging to the technical field of semiconductor optoelectronic devices.

Background

A Light Emitting Diode (LED) has the advantages of high Light Emitting intensity, high efficiency, small volume, and long service life, and is considered as one of the most potential Light sources. In recent years, LEDs have been widely used in daily life, for example, in the fields of illumination, signal display, backlight, vehicle lights, and large screen display, and these applications also put higher demands on the brightness and light emitting efficiency of LEDs.

Existing light emitting diodes include a horizontal type and a vertical type. The vertical type light emitting diode is obtained by a process of transferring the semiconductor epitaxial stack onto another substrate such as a silicon, silicon carbide or metal substrate and removing the original epitaxially grown substrate, and can effectively improve the technical problems of light absorption, current crowding or poor heat dissipation caused by the epitaxially grown substrate, compared with the horizontal type. The substrate is generally transferred by a bonding process, and the bonding is mainly performed by metal-metal high-temperature high-pressure bonding, that is, a metal bonding layer is formed between one side of the semiconductor epitaxial lamination and the substrate. The other side of the semiconductor epitaxial lamination layer provides a light-emitting side, a wire electrode is arranged on the light-emitting side to provide current injection or outflow, and a substrate below the semiconductor epitaxial lamination layer provides current outflow or inflow, so that the light-emitting diode with current passing through the semiconductor epitaxial lamination layer vertically is formed.

In order to improve the light extraction efficiency, a metal reflective layer and a transparent dielectric layer are usually designed on one side of a metal bonding layer to form an ODR reflective structure, so as to reflect the extracted light on one side of the metal bonding layer to the light extraction side, thereby improving the light extraction efficiency. The ohmic contact layer is manufactured on the opening of the light-transmitting dielectric layer, and the adhesion layer is arranged between the light-transmitting dielectric layer and the metal reflection layer, so that the problem of poor adhesion of the light-transmitting dielectric layer and the metal reflection layer is solved.

The chip structure has the problem of high voltage due to the fact that substance diffusion exists between the ohmic contact layer and the adhesion layer, and therefore ohmic contact between the ohmic contact layer and the semiconductor epitaxial lamination layer is affected.

Disclosure of Invention

In order to solve the problems, the invention can prevent the metal in the ohmic contact layer from diffusing to the adhesion layer by forming the metal diffusion prevention layer between the ohmic contact layer and the adhesion layer, thereby solving the problem of the voltage rise of the light-emitting diode caused by the influence of the ohmic contact layer and the ohmic contact of the semiconductor epitaxial lamination layer due to the diffusion of the metal in the ohmic contact layer to the adhesion layer.

To achieve the above object, the present invention provides a light emitting diode, including: the semiconductor epitaxial lamination comprises a first conduction type semiconductor layer, an active layer and a second conduction type semiconductor layer, and is provided with a first surface and a second surface which are opposite, wherein the first surface is a light-emitting surface; a light-transmitting dielectric layer located on a second surface side of the semiconductor epitaxial stack and having a plurality of openings penetrating the light-transmitting dielectric layer to form a plurality of through holes; an ohmic contact layer filling the through hole of the light-transmissive dielectric layer; the adhesive layer is positioned on one side, far away from the semiconductor epitaxial lamination, of the light-transmitting dielectric layer; the metal reflecting layer is positioned on one side of the adhesion layer, which is far away from the semiconductor epitaxial lamination layer; the method is characterized in that: and a metal diffusion prevention layer is arranged between the ohmic contact layer and the adhesion layer.

Preferably, the metal diffusion prevention layer is located in a through hole of the light-transmissive dielectric layer.

Preferably, the metal diffusion preventing layer fills the through hole of the light-transmitting dielectric layer and partially extends out of the through hole.

Preferably, the ohmic contact layer and the adhesion layer contain the same metal atom composition.

Preferably, the metal atoms in the metal diffusion prevention layer have lower mobility than the metal atoms in the ohmic contact layer.

Preferably, the metal diffusion prevention layer is a combination of one or more of Pt, Ti, Ni and Cr.

Preferably, the thickness of the light transmissive dielectric layer is greater than the thickness of the ohmic diffusion layer.

Preferably, the thickness of the metal diffusion prevention layer is 30 nm-120 nm.

Preferably, the ohmic contact layer is a combination of one or more materials of a conductive metal compound, wherein the conductive metal is Au, Ag or Al, and the other material at least comprises Zn, Be, Ge, Ni.

Preferably, the thickness of the light-transmitting dielectric layer is 100nm to 500 nm.

Preferably, the adhesion layer is a material having good adhesion between the light-transmitting dielectric layer and the metal reflection layer and high light transmittance.

Preferably, the adhesion layer is IZO or ITO.

Preferably, the thickness of the adhesion layer is 2-10 nm.

Preferably, the light-transmitting dielectric layer is a single-layer or multi-layer structure and is composed of at least one of nitride, oxide or fluoride.

Preferably, the metal reflective layer has a reflectance of 70% or more.

Preferably, the metal reflective layer is formed of a metal or an alloy of at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf.

Preferably, the light emitting wavelength of the light emitting diode is red light or infrared light.

Preferably, the light emitting diode further includes a first electrode on the light emitting surface and a second electrode electrically connected to the metal layer.

Preferably, a substrate is further disposed below the metal reflective layer, the substrate is a conductive substrate, and the substrate is located between the metal reflective layer and the second electrode.

Preferably, the semiconductor epitaxial stack of the light emitting diode further includes a plurality of recesses which are open from the second surface side and extend through the active layer to the bottom near the first surface side.

The invention also provides a lighting device, which is characterized in that: comprising a light emitting diode according to any of the preceding claims.

The invention also provides a manufacturing method of the light-emitting diode, which comprises the following steps:

(1) providing a semiconductor epitaxial lamination layer, wherein the semiconductor epitaxial lamination layer comprises a first conduction type semiconductor layer, an active layer and a second conduction type semiconductor layer, the semiconductor epitaxial lamination layer is provided with a first surface and a second surface which are opposite, and the first surface is a light emitting surface;

(2) forming a light-transmissive dielectric layer on a second surface side of the semiconductor epitaxial stack, and forming a plurality of openings in the light-transmissive dielectric layer to penetrate the light-transmissive dielectric layer and form a plurality of through holes;

(3) forming an ohmic contact layer in the through hole of the light-transmitting dielectric layer to be in contact with the first conductivity type semiconductor layer;

(4) forming a metal diffusion prevention layer on the ohmic contact layer;

(5) forming an adhesion layer on one side of the light-transmitting dielectric layer far away from the semiconductor epitaxial lamination layer;

(6) and forming a metal reflecting layer on one side of the adhesion layer far away from the semiconductor epitaxial lamination layer.

Preferably, the method for manufacturing the light emitting diode further includes forming a first electrode on the light emitting surface and forming a second electrode on the metal reflective layer.

Preferably, the metal diffusion prevention layer is a combination of one or more of Pt, Ti, Ni and Cr.

Preferably, the thickness of the metal diffusion prevention layer is 30 nm-120 nm.

Advantageous effects

Through the structure and the method design of the invention, the following technical effects can be realized:

the method comprises the following steps that 1, a metal diffusion prevention layer is added between an ohmic contact layer and an adhesion layer, so that metal in the ohmic contact layer can be prevented from diffusing to the adhesion layer, and the problem that the ohmic contact between the ohmic contact layer and a semiconductor epitaxial lamination is influenced to cause the voltage of a light emitting diode to be increased due to the fact that the metal in the ohmic contact layer diffuses to the adhesion layer can be solved;

2. the ohmic contact layer and the metal diffusion prevention layer are filled in the through hole of the light-transmitting dielectric layer, so that the flatness of the interface of the metal reflecting layer can be ensured, the emissivity of the light-emitting diode is improved, and the light-emitting efficiency of the light-emitting diode is improved;

3. the ohmic contact layer and the metal diffusion preventing layer are filled in the through hole of the light-transmitting dielectric layer, so that the generation of holes when the semiconductor epitaxial lamination is bonded to the substrate can be reduced, and the routing yield of the light-emitting diode is improved.

Additional features and advantages of the invention 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 invention. The objectives and other advantages of the invention 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 invention will be described in connection with certain exemplary implementations and methods of use, it will be understood by those skilled in the art that it is not intended to limit the invention 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 invention as defined by the appended claims.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. Furthermore, the drawing figures are for a descriptive summary and are not drawn to scale.

Fig. 1 is a schematic cross-sectional view of a light emitting diode according to embodiment 1.

Fig. 2 is a schematic top view of the light emitting diode according to embodiment 1.

Fig. 3 is a schematic cross-sectional view of another light emitting diode according to embodiment 1.

Fig. 4 is a schematic view of an epitaxial structure provided in the manufacturing process mentioned in embodiment 2, the epitaxial structure including a semiconductor epitaxial stack.

Fig. 5 is a schematic view of forming a transparent dielectric and forming a through-hole to expose the second surface side of the semiconductor epitaxial stack provided in the manufacturing process mentioned in embodiment 2.

Fig. 6 is a schematic structural view of the ohmic contact layer and the metal diffusion preventing layer formed by the through hole of the transparent dielectric layer provided in the manufacturing process described in embodiment 2.

Fig. 7 is a schematic structural diagram of forming an adhesion layer on a transparent dielectric layer provided in the manufacturing process mentioned in embodiment 2.

Fig. 8 is a schematic view of a structure obtained by transferring a semiconductor epitaxial stack provided in the manufacturing process mentioned in embodiment 2 to a base plate through a bonding process and removing a growth substrate.

Fig. 9 is a schematic view of a structure obtained after a first electrode is formed on a second conductivity type semiconductor layer in the manufacturing process mentioned in embodiment 2.

Fig. 10 is a schematic cross-sectional view of a light emitting diode according to embodiment 3.

Fig. 11 is a schematic cross-sectional view of a light emitting diode according to embodiment 4.

Fig. 12 is a schematic cross-sectional view of a light emitting diode according to embodiment 5.

Element numbering in the figures: 10: growing a substrate; 100: a substrate; 101: a metal bonding layer; 102: a metal reflective layer; 103: an adhesive layer; 104: a light-transmitting dielectric layer; 105: an ohmic contact layer; 106: a metal diffusion prevention layer; 107: a first conductive type semiconductor layer; 108: an active layer; 109: a second conductive type semiconductor layer; 110: a first electrode; 110 a: a pad electrode; 110 b: an extension electrode; 111: a second electrode; 112: an insulating layer; 113: a second metal layer; s1: a first surface of a semiconductor epitaxial stack; s2: a second surface of the semiconductor epitaxial stack; v1: an opening of the light-transmissive dielectric layer.

Modes for carrying out the invention

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.

Example 1

The invention provides a light emitting diode, which comprises the following stacked layers as shown in a schematic cross-sectional view in fig. 1: 100: a substrate; 101: a metal bonding layer; 102: a metal reflective layer; 103: an adhesive layer; 104: a light-transmitting dielectric layer; 105: an ohmic contact layer; 106: a metal diffusion prevention layer; 107: a first conductive type semiconductor layer; 108: an active layer; 109: a second conductive type semiconductor layer; 110: a first electrode; 111: a second electrode.

The details of each structural stack are described below.

The substrate 100 is a conductive substrate, and the conductive substrate may be silicon, silicon carbide, or a metal substrate, and the metal substrate is preferably a copper, tungsten, or molybdenum substrate. The thickness of the substrate 100 is preferably 50 μm or more in order to be able to support the semiconductor epitaxial stack with sufficient mechanical strength. In addition, in order to facilitate machining of the substrate 100 after bonding to the semiconductor epitaxial stack, the thickness of the substrate 100 is preferably not more than 300 μm. In this embodiment, the substrate 100 is preferably a silicon substrate.

The metal bonding layer 101 is a bonding metal material used when the semiconductor epitaxial stack side is adhered to the substrate 100, such as a metal of gold, tin, titanium, nickel, platinum, and the like, and the metal bonding layer 101 may have a single-layer structure or a multi-layer structure, and may be a combination of a plurality of materials.

The metal reflective layer 102 is on the upper side of the metal bonding layer 101 and closer to the side of the semiconductor epitaxial stack, and the metal reflective layer 102 has a metal reflectance of 70% or more, and is formed of a metal or an alloy containing at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf. In this embodiment, the metal reflective layer 102 is preferably Au. The metal reflective layer 102 can reflect light emitted from the semiconductor epitaxial stack toward the substrate 100 back to the semiconductor epitaxial stack and emit the light from the light-emitting side. The light emitting surface of the light emitting diode is located on a side of the second conductive type semiconductor layer 109 away from the active layer 108.

A transparent dielectric layer 104 between the first conductivity type semiconductor layer 107 and the adhesion layer 103 for providing ohmic contact position at one side of the semiconductor epitaxial stack, and therefore, it is necessary to select an insulating material having a high resistance value such as fluoride or oxide or nitride, specifically, ZnO, SiO₂、SiO_x、SiO_xN_y、Si₃N₄、Al₂O₃、TiO_xAt least one of MgF or GaF. The transparent dielectric layer 104 is located on a side of the first conductive type semiconductor layer 107 away from the active layer 108, and the transparent dielectric layer 104 is further configured to reflect the optical radiation of the active layer 108 back to the semiconductor epitaxial stack or to emit light from the sidewall, so that a low refractive index material is preferably selected to increase the probability of reflection of the optical radiation when the optical radiation passes through the semiconductor epitaxial stack to the surface of the transparent dielectric layer 104, the refractive index is preferably 1.5 or less, such as silicon oxide, and the thickness of the transparent dielectric layer 104 is preferably 100nm or more, for example, 100 to 500nm, more preferably, 100 to 400nm, or more preferably, 150 to 400 nm. The light transmittance of the light-transmissive dielectric layer 104 is at least 70%, preferably 80% or more, and more preferably 90% or more.

More preferably, the transparent dielectric layer 104 is a single layer or multiple layers of different materials or is formed by repeatedly stacking two kinds of insulating layer materials with different refractive indexes. More preferably, the optical thickness of the light-transmissive dielectric layer is in a range of an integer multiple of (light emission wavelength/4). A series of openings V1 penetrating the transparent dielectric layer 104 are formed in the transparent dielectric layer 104, and as shown in fig. 2, a plurality of through holes are formed, the horizontal cross-sectional shape of the openings may be circular, elliptical or polygonal, and the horizontal width of the transparent dielectric layer 104 is preferably 2 to 10 μm.

The ohmic contact layer 105 may be further included between the metal reflective layer 102 and the transparent dielectric layer 104, the ohmic contact layer 105 may fill at least a partial region of the plurality of through holes of the transparent dielectric layer 104, and the ohmic contact layer 105 may form ohmic contact with the first conductive type semiconductor layer 107 through the plurality of through holes to uniformly transfer current from the metal reflective layer 103 and the metal bonding layer 102 to the semiconductor epitaxial stack, so that the ohmic contact layer 105 covers at least the plurality of through hole regions, and does not cover a side contacting the first conductive type semiconductor layer 107 in a full-surface manner. The ohmic contact layer 105 uses a light transmitting conductive metal. The light-transmitting conductive metal is preferably an alloy material, such as gold zinc, gold germanium, gold nickel germanium, or gold beryllium, and the ohmic contact layer 105 may have a single-layer or multi-layer structure. In this embodiment, the ohmic contact layer 105 is preferably gold zinc.

The metal reflective layer 102 and the transparent dielectric layer 104 form an ODR reflective structure, so that light emitted from the semiconductor epitaxial stack toward the substrate 100 returns to the semiconductor epitaxial stack and is emitted from the light emitting side, thereby improving the light emitting efficiency.

The adhesion layer 103 is formed on one side of the transparent dielectric layer 104 away from the semiconductor epitaxial stack, and the adhesion layer 103 is a transparent conductive material, such as IZO or ITO, and more preferably a material having good adhesion between the transparent dielectric layer 104 and the metal reflective layer 102, such as gold or silver.

It is more preferred that the thickness of the adhesion layer 103 is at most one fifth of the thickness of the light-transmissive dielectric layer 104, or in particular that the thickness of the adhesion layer is at most 10nm, at least 1 nm. A range above this thickness will destroy the reflectivity of the light transmissive dielectric layer 104, resulting in severe light absorption. Values below this thickness range result in poor adhesion. The light transmittance of the adhesion layer 103 such as IZO or ITO is generally lower than that of the light transmissive dielectric layer 104. The adhesive layer of this thickness range is a continuous film layer or more preferably a discrete layer.

Diffusion occurs when the metal in the ohmic contact layer 105 is in direct contact with the adhesion layer 103, for example, the ohmic contact layer 105 is AuZn, and the adhesion layer 103 is IZO or ITO, wherein the metal Zn of the ohmic contact layer 105 diffuses into the adhesion layer 103, thereby affecting ohmic contact between the ohmic contact layer 105 and the first conductive type semiconductor layer 107, and thus causing the voltage of the semiconductor light emitting diode to increase.

In order to block the metal of the ohmic contact layer 105 from diffusing into the adhesion layer 103, the light emitting diode in this embodiment includes a metal diffusion preventing layer 106, the metal diffusion preventing layer 106 is located between the ohmic contact layer 105 and the adhesion layer 103, and the metal atoms of the metal diffusion preventing layer 106 have lower mobility than the metal atoms of the ohmic contact layer 105, so that the metal diffusion preventing layer 106 can block the diffusion of the metal atoms of the ohmic contact layer 105.

In some embodiments, the metal diffusion layer 106 is located in the through hole of the transparent dielectric layer 104, as shown in fig. 1, the surfaces of the metal diffusion prevention layer 106 and the transparent dielectric layer 104 away from the semiconductor epitaxial stack are substantially flush, which can ensure the flatness of the subsequent metal reflective layer 102, thereby improving the reflectivity of the metal reflective layer 102, and thus improving the reflectivity of the light emitting diode.

In some embodiments, the metal diffusion barrier 106 fills the through-hole of the transparent dielectric layer 104 and partially extends out of the through-hole, as shown in fig. 3.

The metal diffusion prevention layer 106 is a combination of one or more of Pt, Ti, Ni, and Cr. The thickness of the metal diffusion preventing layer 106 is 30nm to 120nm, preferably 50nm to 100 nm.

The semiconductor epitaxial stack has a first surface S1 and a second surface S2 opposite to the first surface S1, and a sidewall connecting the first surface S1 and the second surface S2. The semiconductor epitaxial lamination is obtained through MOCVD or other growth modes, and is a semiconductor material capable of providing conventional radiation such as ultraviolet, blue, green, yellow, red, infrared light and the like, specifically can be a material of 200-950 nm, such as common nitride, specifically is a gallium nitride-based semiconductor epitaxial lamination, and the gallium nitride-based epitaxial lamination is commonly doped with elements such as aluminum, indium and the like and mainly provides radiation of 200-550 nm wave bands; or common aluminum gallium indium phosphide-based or aluminum gallium arsenic-based semiconductor epitaxial lamination, and mainly provides radiation with a wave band of 550-950 nm.

The semiconductor epitaxial stack mainly includes a first conductive type semiconductor layer 107, a second conductive type semiconductor layer 109, and an active layer 108 located between the first conductive type semiconductor layer 107 and the second conductive type semiconductor layer 109. The first and second conductive type semiconductor layers 107 and 109 may be doped n-type or p-type to achieve at least the supply of electrons or holes, respectively. The n-type semiconductor layer may be doped with an n-type dopant such as Si, Ge, or Sn, and the p-type semiconductor layer may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. The first conductive type semiconductor layer 107, the active layer 108, and the second conductive type semiconductor layer 109 may be made of material such as aluminum gallium indium nitride, gallium nitride, aluminum indium phosphide, aluminum gallium indium phosphide, gallium arsenide, or aluminum gallium arsenide. The first conductive type semiconductor layer 107 or the second conductive type semiconductor layer 109 includes a capping layer for supplying electrons or holes therein, and may include other layer materials such as a current spreading layer, a window layer, an ohmic contact layer, etc., which are differently arranged in multiple layers according to doping concentration or composition content. The active layer 108 is a region for providing light radiation by recombination of electrons and holes, and the active layer 108 may be a periodic structure of a single quantum well or a multiple quantum well, and different materials may be selected according to the emission wavelength. By adjusting the composition ratio of the semiconductor material in the active layer 108, light of different wavelengths is desirably radiated. In the present embodiment, the semiconductor epitaxial stacked layer is preferably composed of an AlGaInP-based material.

The first electrode 110 is disposed on the light-emitting side of the semiconductor epitaxial stack. In some embodiments, the first electrode 110 includes a pad electrode 110a and an extension electrode 110b, wherein the pad electrode 110a is mainly used for external wire bonding during packaging. The pad electrode 110a can be designed into different shapes, such as a cylinder or a square or other polygonal shape, according to the actual bonding requirement. The extension electrode 110b may be formed in a predetermined pattern shape, and the extension electrode 110b may have various shapes, particularly, a stripe shape.

The light emitting diode further includes a second electrode 111, and the second electrode 111 is formed on the back surface side of the substrate 100 in this embodiment. The substrate 100 of the present embodiment is a conductive supporting substrate, and the first electrode 110 and the second electrode 111 are formed on both sides of the substrate 100 to realize vertical current flow through the semiconductor epitaxial stack, thereby providing uniform current density.

The first electrode 110 and the second electrode 111 are preferably made of a metal material. The first electrode 110, at least the pad electrode portion 110a and the extension electrode portion 110b, may further include a metal material that enables good ohmic contact with the semiconductor epitaxial stack.

Example 2

The following describes in detail the manufacturing process of the light emitting diode of example 1.

As shown in fig. 4, a semiconductor epitaxial stack is first provided, which includes a first conductivity type semiconductor layer 107, a second conductivity type semiconductor layer 109, and an active layer 108 located between the first conductivity type semiconductor layer 107 and the second conductivity type semiconductor layer 109, and has a first surface S1 and a second surface S2 opposite to each other, wherein the first surface S1 is a light emitting surface.

The method specifically comprises the following steps: a growth substrate 10, preferably a gallium arsenide substrate, is provided, on which growth substrate 10a semiconductor epitaxial stack is epitaxially grown by an epitaxial process, such as MOCVD, comprising a first conductivity type semiconductor layer 107, a second conductivity type semiconductor layer 109 and an active layer 108 located between first conductivity type semiconductor layer 107 and second conductivity type semiconductor layer 109. When the first conductive type semiconductor layer 107 is a p-type semiconductor, the second conductive type semiconductor layer 109 may be an n-type semiconductor of different conductivity, and conversely, when the first conductive type semiconductor layer 107 is an n-type semiconductor, the second conductive type semiconductor layer 109 may be a p-type semiconductor of different conductivity. The active layer 108 may be a neutral, p-type, or n-type conductivity semiconductor. When a current is applied through the semiconductor epitaxial stack, the active layer 108 is excited to emit light. In this embodiment, the first conductive type semiconductor layer 107 is preferably a p-type semiconductor layer. The semiconductor epitaxial stack is preferably an AlGaInP-based material, and the active layer radiates red or infrared light.

As shown in fig. 5, next, a transparent dielectric layer 104 is formed on the first conductivity type semiconductor layer 107 on the side away from the active layer 108, and in this embodiment, the transparent dielectric layer 104 is preferably SiO₂Or MgF₂(ii) a The thickness of the transparent dielectric layer 104 is preferably 100nm or more, for example, 100 to 500nm, more preferably 100 to 400nm, or even more preferably 150 to 400 nm. Through a mask and etching process, openings are formed in the light-transmissive dielectric layer 104 to expose the second surface side of the semiconductor epitaxial stack, and a plurality of through holes are formed.

As shown in fig. 6, the ohmic contact layer 105 is formed in the through hole of the transparent dielectric layer 104, and a light transmissive conductive metal is used for the ohmic contact layer 105. The light transmission conductive metal is preferably an alloy material, such as gold zinc, gold germanium nickel or gold beryllium. In this embodiment, the ohmic contact 105 is preferably gold zinc. The thickness of the ohmic contact layer 105 is 80 to 400nm, preferably 150nm or more, and more preferably 200nm or more. Then, a metal diffusion prevention layer 106 is formed on the ohmic contact layer 105, and the material of the metal diffusion prevention layer 106 is one or a combination of Pt, Ti, Ni and Cr. Preferably, the thickness of the metal diffusion layer 106 of the ohmic contact prevention layer is 30nm to 120 nm. Preferably, the surface of the light-transmitting dielectric layer 104 and the surface of the metal diffusion prevention layer 106 are substantially flush, which can ensure the flatness of the metal reflection layer 102, thereby improving the reflectivity of the metal reflection layer 102 and the light emitting efficiency of the light emitting diode.

As shown in fig. 7, an adhesion layer 103 is formed on a side of the transparent dielectric layer 104 away from the active layer 108, wherein the adhesion layer 103 is made of IZO or ITO, and in this embodiment, the adhesion layer 103 is preferably made of IZO and has a thickness of 10nm or less, preferably 2 to 10 nm.

As shown in fig. 8, a metal reflective layer 102 is then formed on the adhesion layer 103, where the metal reflective layer is preferably Au or Ag, and in this embodiment, the metal reflective layer is preferably Au; arranging a bonding layer 101 on one side of the metal reflecting layer 102, and bonding a substrate 100 through a bonding process; next, the growth substrate 10 is removed by a wet etching process, and the structure shown in fig. 8 is obtained;

next, as shown in fig. 9, a first electrode 110 is formed on the second conductive type semiconductor layer 109, the first electrode 110 includes a main electrode 110a and an extension electrode 110b of a wire bonding portion, wherein the main electrode 110a and the extension electrode 110b respectively provide a wire bonding position and a horizontal current spreading.

Finally, a rear electrode 111 was formed on the rear surface side of the substrate 100, and a light-emitting diode as shown in fig. 1 was obtained.

According to the invention, the metal diffusion prevention layer 106 is added between the ohmic contact layer 105 and the adhesion layer 103, so that the metal in the ohmic contact layer 105 can be prevented from diffusing to the adhesion layer 103, and the problem of voltage rise of the light emitting diode caused by the influence of the ohmic contact layer 105 and the ohmic contact of the semiconductor epitaxial lamination due to the fact that the metal in the ohmic contact layer 105 diffuses to the adhesion layer 103 can be solved. Meanwhile, the ohmic contact layer 105 and the metal diffusion prevention layer 106 fill the through hole of the light-transmitting dielectric layer 104, so that the flatness of the interface of the metal reflection layer 102 can be ensured, the reflectivity of the light-emitting diode is improved, and the light-emitting efficiency of the light-emitting diode is improved; the generation of holes when the semiconductor epitaxial lamination is bonded to the substrate 100 can be reduced, and the wire bonding yield of the light-emitting diode is improved.

Example 3

In order to further improve the efficiency of the light emitted from the light-emitting surface of the light emitted from the active layer 108, as compared with the light-emitting diode shown in fig. 1 in embodiment 1, as shown in fig. 10, the first surface S1 of the semiconductor epitaxial stacked layer has a roughened structure.

Example 4

As a modification of the structure shown in fig. 1, as shown in fig. 11, the first electrode 110 and the second electrode 111 are led out from the second surface S2 side of the semiconductor epitaxial stack and electrically connected to the outside.

Specifically, as shown in fig. 11, the structure includes a semiconductor epitaxial stack in which a first conductivity type semiconductor layer 107, an active layer 108, and a second conductivity type semiconductor layer 109 are stacked layer by layer, a first surface S1 of the semiconductor epitaxial stack is a light exit surface, a second surface S2 side of the semiconductor epitaxial stack is the first conductivity type semiconductor layer 107, and the semiconductor epitaxial stack has a plurality of independent recesses extending from the second surface side to penetrate through the active layer 108 to the bottom to be in contact with the second conductivity type semiconductor layer 109, the horizontal width of the recesses is 1 μm or more, and the area of the recesses occupying the second surface side is 1 to 20%.

The transparent dielectric layer 104 and the adhesion layer 103 are formed at least on the second surface S1 side of the semiconductor epitaxial stack, wherein the transparent dielectric layer 104 may also extend to the sidewall surface covering the plurality of recesses, the transparent dielectric layer 104 has a plurality of openings on the second surface S2 side of the semiconductor epitaxial stack to form a plurality of through holes, and the metal reflection layer 102 is located on the surface side of the adhesion layer. The light transmissive dielectric layer 104 exposes the locations of the plurality of recesses. The ohmic contact layer 105 fills the through hole of the translucent dielectric layer, and directly contacts the second surface S2 side of the semiconductor epitaxial stack. The metal diffusion prevention layer 106 is positioned between the adhesion layer 103 and the ohmic contact layer 105, and can prevent the metal of the ohmic contact layer 105 from diffusing into the adhesion layer 103, so that the problem of the voltage rise of the light emitting diode caused by the influence of the metal in the ohmic contact layer 105 diffusing into the adhesion layer 103 on the ohmic contact of the ohmic contact layer 105 and the semiconductor epitaxial lamination layer can be solved. There is also an insulating layer 112 on the surface side of the metal reflective layer, the material of the insulating layer 112 may be oxide or nitride or fluoride, such as silicon oxide, silicon nitride, and in some embodiments, the insulating layer 112 may also extend to cover the sidewall of the recess, exposing the bottom of the recess.

The insulating layer 112 has a second metal layer 113 on its surface, and the second metal layer 113 fills the plurality of openings of the semiconductor epitaxial stack through the recesses to the bottom in contact with the second conductivity-type semiconductor layer 109.

The metal reflective layer 102 further includes a portion of the surface exposed to provide the first electrode 109, the second metal layer 113 further includes a portion of the surface exposed to provide the second electrode 110, and the first electrode 109 and the second electrode 110 are located on the same side of the periphery of the semiconductor epitaxial stack for external wire bonding.

The second metal layer 113 further has a substrate 100 on one side, the substrate is a conductive or non-conductive substrate, and the second metal layer 113 further includes a bonding layer for bonding the substrate.

Example 5

As an alternative example of embodiment 4, as shown in fig. 12, in which the substrate 100 is a conductive substrate, the second electrode 111 is provided on the back side of the conductive substrate 100 for external electrical connection.

It should be noted that the above-mentioned embodiments are only for illustrating the present invention, and not for limiting the present invention, and those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention, so that all equivalent technical solutions also belong to the scope of the present invention, and the scope of the present invention should be defined by the claims.