CN213459775U - LED chip - Google Patents

Abstract

The patent discloses a LED chip, it includes: a high-thermal-conductivity substrate is adopted, and the high-thermal-conductivity substrate can be selected from materials such as molybdenum, copper molybdenum, silicon substrate and the like; the current blocking layer is arranged below the N electrode; the insulating passivation layer is arranged on the high-heat-conductivity substrate; the reflecting mirror layer comprises a P-surface reflecting mirror layer which is respectively arranged below the N electrode and above the substrate insulating passivation layer, and the area of the N electrode reflecting layer is subjected to advanced roughening treatment; the current diffusion layer is arranged on the P-surface reflector layer; the epitaxial layer structure comprises a P-type semiconductor material layer, a quantum well layer and an N-type semiconductor material layer which are arranged from bottom to top. The LED chip adopting the structure can improve the light output efficiency, improve the heat dissipation effect and prolong the service life of devices.

Description

LED chip

Technical Field

The patent relates to the technical field of semiconductors, in particular to a semiconductor light-emitting device, and especially relates to an LED chip.

Background

The light emitting diode is a commonly used light emitting device, emits light by energy released by recombination of electrons and holes, and is widely applied in the field of illumination. The light emitting diode can efficiently convert electric energy into light energy, and has wide application in modern society, such as illumination, flat panel display, medical devices and the like.

Traditional sapphire substrate is adorned chip just, after electron conversion is the photon, the photon is in the diffusion process, and partial photon is absorbed by the sapphire substrate to partial photon is sheltered from by opaque electrode, produces invalid light output, and then influences light output efficiency.

The traditional sapphire substrate is normally provided with the chip, in the electronic conversion process, partial electric energy is converted into heat energy, the heat conduction capability effect of the sapphire substrate is poor, and the service life of the chip is directly influenced.

In addition, in the conventional forward chip structure, when a metal electrode is prepared, the light output efficiency is greatly restricted by the image design and the area of the electrode, and the metal electrode is made of opaque materials, so that part of photons can be shielded by the P electrode.

Disclosure of Invention

This patent is just proposed based on prior art's above-mentioned demand, and the technical problem that this patent will be solved provides a LED chip, can improve light output efficiency to improve the radiating effect, increase the device life-span.

In order to solve the technical problem, the technical scheme provided by the patent comprises:

an LED chip, comprising: the high-thermal-conductivity substrate comprises a molybdenum substrate, a copper-molybdenum substrate and a silicon substrate; an electron blocking layer disposed under the N electrode; the passivation layer is arranged on the high-thermal-conductivity substrate; the reflecting mirror layer comprises a reflecting mirror layer arranged below the N electrode and a P-surface reflecting mirror layer arranged above the passivation layer; the current diffusion layer is arranged on the P-surface reflector layer and the upper surface of the N-type semiconductor material layer; the epitaxial layer structure comprises a P-type semiconductor material layer, a quantum well layer and an N-type semiconductor material layer which are arranged from bottom to top.

Preferably, the mirror is a total reflection mirror.

Preferably, a metal bonding layer is further disposed between the high thermal conductive substrate and the passivation layer.

Preferably, the epitaxial layer structure is an epitaxial layer structure of a gallium nitride system.

Preferably, the current diffusion layer is an ITO layer.

Preferably, the N electrode area mirror material is selected from insulating materials to form an electron blocking layer structure.

Preferably, the N electrode region includes a roughened structure.

This patent adopts above-mentioned technical scheme to have following effect: (1) the substrate is replaced by adopting bonding and stripping processes, the replaced substrate is made of the high-heat-conduction material 201, and the heat energy converted by the device in the working state is efficiently led out, so that the service life of the device is prolonged; (2) an omnidirectional reflector 203 is manufactured on the p-GaN surface, and an n electrode manufacturing area 302 adopts a roughening process and is used for manufacturing an omnidirectional reflector, so that a multi-angle omnidirectional reflection effect is formed; (3) the material of the radioactive mirror prepared in the N electrode area is selected from insulating materials to form an electrode barrier layer structure, so that the current crowding phenomenon is relieved. (4) Since most of the replaced high thermal conductivity substrate material has electrical conductivity, a passivation layer 202 is prepared on the contact substrate surface to prevent electrons from escaping from the substrate surface; (5) the current diffusion layer is prepared on the p-GaN surface, the ITO material is used in the invention, and the current diffusion layer can be prepared to increase the current diffusion capability.

Drawings

FIG. 1 is a schematic view of an epitaxial wafer structure in an embodiment of the present invention

FIG. 2 is a schematic view of the structure of the transfer and different active layers in the embodiment of this patent

FIG. 3 is a schematic view of the complete structure of an LED chip according to the embodiment of the present invention

Detailed Description

The following detailed description of the embodiments of the present patent refers to the accompanying drawings and is only for the purpose of illustrating preferred embodiments of the patent and is not to be construed as limiting the scope of the patent.

The present embodiment provides an LED chip, the structure of which is shown in fig. 3.

The chip is fabricated on the basis of the semiconductor epitaxial layer of fig. 1.

The semiconductor epitaxial wafer is a common structure in the prior art, and comprises a sapphire substrate, and a stress buffer layer (optional), an N-type semiconductor material layer, a quantum well layer and a P-type semiconductor material layer which are sequentially formed upwards on the sapphire substrate. The semiconductor epitaxial wafer is a basic structure for manufacturing various LED chips, and mainly has the function of providing a core PN junction structure of the semiconductor chip so as to generate light in a power-on state. In the present embodiment, the semiconductor epitaxial wafer preferably comprises a gallium nitride system semiconductor epitaxial wafer to meet the light emission requirements of various wavelengths. It will be appreciated by those skilled in the art that other systems of semiconductor materials may be used to implement the inventive concepts of the present patent.

In the present embodiment, the semiconductor epitaxial wafer described in the present embodiment does not include a sapphire substrate because the sapphire substrate 101 has poor thermal conductivity.

Instead, the substrate is replaced by a high thermal conductivity material substrate 201 from the original sapphire substrate by a substrate lift-off and bonding technique. The structure, location and manner of fabrication of the high thermal conductivity material substrate will be described in detail below.

Current diffusion layer 204

In this embodiment, the current diffusion layer 204 is formed on the P-type semiconductor material layer of the semiconductor epitaxial wafer, and in this embodiment, the current diffusion layer 204 is preferably made of ITO material or other transparent materials, and the current diffusion layer is prepared to increase the current diffusion capability.

Mirror layer

On the p-GaN surface, a reflector layer is manufactured on the current diffusion layer 203, and the reflector layer is an all-directional reflector layer; and the n electrode manufacturing area adopts a roughening process and an all-directional reflector, so that a multi-angle all-directional reflection effect is formed, and the reflector material adopts an insulating material, so that the effect of an electron blocking layer is achieved, and the current crowding phenomenon is prevented.

Passivation layer 202

Since most of the high thermal conductivity substrate material used in this embodiment has electrical conductivity, the passivation layer 202 is prepared on the contact substrate surface to prevent electrons from escaping from the substrate surface;

high thermal conductivity substrate 201

The heat conducting substrate 201 is a substrate made of a material with high heat conducting capacity, and can be made of substrate materials such as molybdenum, copper molybdenum, silicon and the like; the heat conducting substrate is arranged on the passivation layer, a bonding layer is preferably adopted in a hair extension mode, the bonding layer is arranged on the passivation layer, and then the bonding layer is bonded with the heat conducting substrate through a pressing process.

N electrode 302

The N electrode is arranged on the upper surface of the chip and is electrically connected with the N-type semiconductor material.

P electrode 301

The P-electrode 301 is electrically connected to the P-type semiconductor material.

By adopting the scheme, compared with the traditional chip with the normal mounting structure, the LED chip has obvious advantages of heat dissipation and current diffusion, can prolong the service life of the chip and can improve the optical power.

Compared with the traditional vertical structure, the current spreading layer is prepared to keep good electronic diffusion capacity, and the reflector is prepared by adopting a full-angle high-reflection material, so that the reflector has higher reflection capacity and extremely small light absorption compared with the traditional metal reflector. In addition, the coarsening and high-reflection material layer is adopted in the preparation of the n electrode area, and the novel structure can effectively reflect and output photons which cannot be output due to the shielding of electrode metal, so that the light output efficiency is improved.

According to another aspect of the present invention, the LED chip of the above-described structure can be manufactured as follows. See FIGS. 1-3

(1) An epitaxial wafer with an epitaxial layer material grown on a sapphire substrate is provided. The epitaxial material comprises a p-type gallium nitride layer, a quantum light emitting layer, an n-type gallium nitride layer, a buffer layer and the like from top to bottom, and the original sapphire substrate is a first substrate 101;

(2) a current diffusion layer 204 is manufactured on the surface of the p-type gallium nitride layer, and ITO or other transparent materials beneficial to current diffusion can be selected as materials;

(3) and carrying out an annealing process to enable the ITO and the gallium nitride to form better ohmic contact.

(4) Preparing an omnibearing reflecting mirror, preparing 203, and growing a total reflection ODR material by adopting an evaporation process;

(5) sequentially growing an insulating passivation layer 202, wherein insulating materials such as SiO2, Si3N4, SiON, Al2O3 and the like can be selected;

(6) evaporating and coating bonding metal material;

(7) the second substrate 201 is a substrate made of a material with high heat conductivity, and can be made of substrate materials such as molybdenum, copper molybdenum, silicon and the like;

(8) bonding with the second substrate 201 by using a pressing process;

(9) removing the original first substrate material by a stripping method (shown in fig. 2), wherein the stripping method can be wet etching stripping, laser stripping and other methods according to the second substrate material 201;

(10) respectively exposing the n-electrode area 302 and the p-electrode area 301 by using a photoresist by utilizing a photoetching technology, and manufacturing the n-electrode area and the p-electrode area twice;

(11) removing the exposed area by adopting a wet etching or dry etching process, and performing the etching twice, wherein the p electrode area 301 needs to be etched to the current diffusion layer 204 in the first etching process; etching the first electrode 302 for the second time until the n-type gallium nitride layer is etched;

(12) the n electrode area 302 is subjected to surface roughening by adopting a wet etching method, and a total reflector is prepared, wherein the reflector material is an insulating material;

(13) passivating and protecting the side wall, the non-n electrode 302 and the p electrode 301 by adopting a passivation layer deposition method;

(14) and depositing a metal material by adopting a metal evaporation method to finish the preparation of the electrode metal layer.

(15) And (3) cutting the wafer into single core particles through thinning and scratching processes to finish the preparation of the chip.

The above are preferred embodiments of the present patent, and the substitution, modification and deletion of the present patent under the inventive concept of the present patent should be included in the protection scope of the present patent as they do not depart from the inventive concept of the present patent.

Claims (7)

1. An LED chip, comprising:

the high-thermal-conductivity substrate comprises a molybdenum substrate, a copper-molybdenum substrate and a silicon substrate;

an electron blocking layer disposed under the N electrode;

the passivation layer is arranged on the high-thermal-conductivity substrate;

the reflecting mirror layer comprises a reflecting mirror layer arranged below the N electrode and a P-surface reflecting mirror layer arranged above the passivation layer;

the current diffusion layer is arranged on the P-surface reflecting mirror layer and the upper surface of the N-type semiconductor material layer;

the epitaxial layer structure comprises a P-type semiconductor material layer, a quantum well layer and an N-type semiconductor material layer which are arranged from bottom to top.

2. An LED chip according to claim 1, wherein said reflector is a total reflector.

3. The LED chip of claim 1, wherein a metal bonding layer is further disposed between the high thermal conductivity substrate and the passivation layer.

4. The LED chip of claim 1, wherein said epitaxial layer structure is an epitaxial layer structure of gallium nitride system.

5. The LED chip of claim 1, wherein said current spreading layer is an ITO layer.

6. The LED chip of claim 1, wherein said N electrode area reflector material is selected from insulating materials to form an electron blocking layer structure.

7. The LED chip of claim 6, wherein said N electrode region comprises a roughened structure.

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