WO2016015445A1

WO2016015445A1 - Led chip and manufacturing method therefor

Info

Publication number: WO2016015445A1
Application number: PCT/CN2014/095920
Authority: WO
Inventors: 王磊; 朱琳; 王强
Original assignee: 无锡华润华晶微电子有限公司
Priority date: 2014-07-28
Filing date: 2014-12-31
Publication date: 2016-02-04
Also published as: CN105449068A

Abstract

Provided are an LED chip and a manufacturing method therefor. The method comprises: a substrate (11); an epitaxial layer (12) located on the substrate (11); a transparent electrode layer (13) located on the epitaxial layer (12); at least two grooves (A) penetrating through the transparent electrode layer (13) along a longitudinal direction, with the bottom thereof being located in the epitaxial layer (12), and arranged along the edge of the transparent electrode layer (13); an insulating layer (14), lining the side walls of the grooves and located on the transparent electrode layer (13) at the edge of a notch; an N-type electrode (15) located on the insulating layer (14); and a P-type electrode (16) located on the transparent electrode layer (13), wherein distances from the P-type electrode (16) to various N-type electrodes (15) are all equal. By means of the present invention, by setting N-type electrodes of an LED chip to surround a P-type electrode at equal distances, when the LED chip operates, flow directions of the current between the N-type electrodes and the P-type electrode are relatively dispersive, which can make the current intensity distribution relatively uniform, thereby improving light-emitting efficiency of the LED chip.

Description

LED chip and manufacturing method thereof

Cross-reference to related applications

This patent application claims priority from Chinese patent application filed on July 28, 2014, the application number is 201410362471.7, the applicant is Wuxi Huarun Huajing Microelectronics Co., Ltd., and the invention name is "an LED chip and its manufacturing method". The entire content of this application is hereby incorporated by reference.

Technical field

Embodiments of the present invention relate to the field of semiconductor technologies, and in particular, to an LED chip and a method of fabricating the same.

Background technique

Light Emitting Diode (LED) has the advantages of small volume, long life, fast response, high degree of controllability, good stability, low power consumption, no heat radiation, no mercury, and other toxic substances. Its application and promotion has been very rapid since its launch.

With the application and promotion of LEDs, the development of LED-related technologies has also advanced by leaps and bounds. At present, the structure of the LED chip can be divided into a vertical structure, a formal structure and a flip-chip structure. The flip-chip LED chip has good heat dissipation performance, so it has attracted the attention of technicians. In the prior art, when the LED chip is operated, the current flow between the P-type electrode and the N-type electrode is concentrated, resulting in uneven current density distribution, thereby affecting the luminous efficiency of the LED chip.

Summary of the invention

In view of this, an embodiment of the present invention provides an LED chip and a manufacturing method thereof to solve the problem that the current distribution between the P-type electrode and the N-type electrode is relatively concentrated when the LED chip is operated, and the current density distribution is uneven. Technical problem.

In a first aspect, an embodiment of the present invention provides an LED chip, including:

Substrate

An epitaxial layer, the epitaxial layer being on the substrate;

a transparent electrode layer, the transparent electrode layer is located on the epitaxial layer;

At least two grooves extending longitudinally through the transparent electrode layer and a bottom portion in the epitaxial layer, the grooves being distributed at edges of the transparent electrode layer;

An insulating layer, the insulating layer is lined on the sidewall of the trench and on the transparent electrode layer at the edge of the slot;

An N-type electrode, the N-type electrode being on the insulating layer;

a P-type electrode, the P-type electrode being located on the transparent electrode layer, wherein distances of the P-type electrode to each of the N-type electrodes are equal.

Further, the epitaxial layer includes an N-type GaN layer, an n-GaN or GaN multiple quantum well active layer, and a P-type GaN layer, wherein the N-type GaN layer is on the substrate, and the InGaN or GaN is more A quantum well active layer is on the N-type GaN layer, and the P-type GaN layer is on the InGaN or GaN multiple quantum well active layer.

Further, a bottom of the trench is located in the N-type GaN layer; the N-type electrode is in direct contact with the N-type GaN layer.

Further, the groove has a cross section of one of a circle, a rectangle, and a square; the number of the grooves is 4, 5, 6, 7, or 8.

Further, the material of the transparent electrode layer is ITO, ZnO, or Ni and Au alloy; the material of the insulating layer is one of SiO ₂ , Si ₃ N ₄ , SiON; the N-type electrode and the The material of the P-type electrode is one of Ti, Cr, Pt, Au, Ni, Al, Be, and Ge.

Further, the grooves are evenly distributed along the edges of the transparent electrode layer.

Further, the LED chip is soldered on a circuit board by flip-chip eutectic soldering, wherein the circuit board includes a substrate and a positive electrode and a negative electrode on the substrate, and the positive electrode is spaced apart from the negative electrode;

The P-type electrode is located on the positive electrode, and the N-type electrode is located on the negative electrode.

In a second aspect, an embodiment of the present invention further provides a method for fabricating an LED chip, including:

Forming an epitaxial layer on the substrate;

Forming a transparent electrode layer on the epitaxial layer;

Forming at least two grooves extending longitudinally through the transparent electrode layer and having a bottom portion in the epitaxial layer, wherein the grooves are distributed at edges of the transparent electrode layer;

Forming an insulating layer on the sidewall of the trench and on the transparent electrode layer at the edge of the slot;

Forming an N-type electrode on the insulating layer;

A P-type electrode is formed on the transparent electrode layer, wherein distances of the P-type electrode to each of the N-type electrodes are equal.

Further, forming an epitaxial layer on the substrate includes sequentially forming an N-type GaN layer, an InGaN or GaN multiple quantum well active layer, and a P-type GaN layer on the substrate.

Further, a bottom of the trench is formed in the N-type GaN layer; the N-type electrode is in direct contact with the N-type GaN layer.

The LED chip provided by the embodiment of the present invention and the manufacturing method thereof are provided by disposing at least two slots in the LED chip that pass through the transparent electrode layer in the longitudinal direction and the bottom portion is located in the epitaxial layer, wherein the slots are distributed along the edge of the transparent electrode layer, An insulating layer is disposed on the sidewall of the trench and on the transparent electrode layer at the edge of the slot, and an N-type electrode is disposed on the insulating layer and a P-type electrode is disposed on the transparent electrode layer, wherein the P-type electrode is connected to each of the N-type electrodes The distances are equal, so that the N-type electrode to the P-type electrode are equidistant and surround it. When the LED chip is operated, the current flow between the N-type electrode and the P-type electrode is relatively dispersed, and the current density distribution can be relatively uniform. Thereby, the luminous efficiency of the LED chip can be improved.

DRAWINGS

Other features, objects, and advantages of the present invention will become more apparent from the Detailed Description of Description

1 is a cross-sectional view of an LED chip according to a first embodiment of the present invention;

2 is a top plan view of an LED chip according to Embodiment 1 of the present invention;

3 is a cross-sectional view showing a connection between an LED chip and a circuit board according to Embodiment 1 of the present invention;

4 is a schematic flow chart of a method for fabricating an LED chip according to Embodiment 2 of the present invention.

The technical features indicated by the reference numerals in the figures are:

10, LED chip; 11, substrate; 12, epitaxial layer; 121, N-type GaN layer; 122, InGaN or GaN multiple quantum well active layer; 123, P-type GaN layer; 13, transparent electrode layer; Layer; 15, N-type electrode; 16, P-type electrode; A, slot; 20, circuit board; 21, substrate; 22, positive electrode;

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should also be noted that, for ease of description, only some, but not all, of the present invention are shown in the drawings.

Embodiment 1

Embodiment 1 of the present invention provides an LED chip. 1 is a schematic cross-sectional view of an LED chip according to a first embodiment of the present invention. As shown in FIG. 1, the LED chip 10 includes: a substrate 11; an epitaxial layer 12, the epitaxial layer 12 is located on the substrate 11, a transparent electrode layer 13, and the transparent electrode layer 13 is located at the epitaxial layer. 12; at least two slots (shown in area A surrounded by a broken line in the figure), the slots along the longitudinal direction Passing through the transparent electrode layer 13 and the bottom is located in the epitaxial layer 12, the groove is distributed along the edge of the transparent electrode layer 13; the insulating layer 14 is lined on the sidewall of the groove And a transparent electrode layer 13 on the edge of the notch; an N-type electrode 15 on the insulating layer 14; and a P-type electrode 16 on the transparent electrode layer 13 wherein the distance from the P-type electrode 16 to each of the N-type electrodes 15 is equal.

It should be noted that the material of the substrate 11 may be sapphire. The "longitudinal direction" passing through the transparent electrode layer 13 in the longitudinal direction is a direction from the transparent electrode layer 13 to the epitaxial layer 12 and perpendicular to the surface of the transparent electrode layer 13. Further, the structure of the LED chip shown in FIG. 1 is only a specific example of the present invention, and the structure of the LED chip is not limited herein.

It should also be noted that the distance between the N-type electrode 15 and the P-type electrode 16 refers to the distance between the N-type electrode portion and the P-type electrode 16 in the groove because the N-type electrode of the portion is directly connected to the epitaxial layer. 12 contact (since the bottom of the trench is located in the epitaxial layer 12), a voltage difference is formed between the portion of the N-type electrode and the P-type electrode 16 when the LED chip 10 is in operation, thereby enabling the LED chip to emit light. Therefore, the distance between the N-type electrode 15 and the P-type electrode 16 can also be regarded as the distance between the groove and the P-type electrode 16. On the one hand, the N-type electrodes located at the edge of the groove can be used to protect the insulating layer 14, and on the other hand, the N-type electrodes 15 can be electrically connected to each other to provide an operating voltage together during operation.

Specifically, the transparent electrode layer 13 and the epitaxial layer 12 may be etched in the longitudinal direction by an etching process to form a trench, wherein the bottom of the trench is located in the epitaxial layer 12, that is, the trench passes through the transparent electrode layer 13, but is not worn. Over the epitaxial layer 12. And the formed grooves are distributed along the edges of the transparent electrode layer 13. The insulating layer 14 is lined on the sidewall of the trench and on the transparent electrode layer 13 at the edge of the slot and forms an N-type electrode 15 on the insulating layer 14, that is, the N-type electrode 15 corresponds to the slot one by one, that is, the N-type electrode The number of 15 is the same as the number of grooves, so that the N-type electrode 15 is also distributed along the edge of the transparent electrode layer 13, but is electrically insulated from the transparent electrode layer 13 by the insulating layer 14. Preferably, when the N-type electrode 15 is fabricated, all of the N-type electrodes 15 can be Electrically connected, it is relatively convenient to provide an operating voltage for the N-type electrode 15. Further, the material for electrically connecting all of the N-type electrodes 15 is the same as that of the N-type electrode, which simplifies the process flow and reduces the cost.

Referring to FIG. 1, after forming a P-type electrode 16 having the same distance from each of the N-type electrodes 15 on the transparent electrode layer 13, an N-type electrode 15 is formed around the P-type electrode 16 and each of the N-type electrodes 15 to the P-type electrode is formed. The LED chips 10 are equally spaced apart by 16. Further, in the present invention, the number of slots is required to be at least two (as described above, the number of formed N-type electrodes 15 is the same as the number of slots), so that the N-type electrode 15 can well surround P. Type electrode 16. When an operating voltage is applied to the LED chip 10, the current flow between the N-type electrode 15 and the P-type electrode 16 is relatively dispersed, thereby avoiding a relatively concentrated current flow between the N-type electrode and the P-type electrode in the prior art, and the current can be made. The density distribution is relatively uniform, so that the luminous efficiency of the LED chip can be improved. Optionally, the grooves are evenly distributed along the edge of the transparent electrode layer 13. Thus, after the N-type electrode 15 and the P-type electrode 16 are formed, the N-type electrode 15 surrounds the P-type electrode 16 and is uniformly distributed around the P-type electrode 16, so that between the N-type electrode 15 and the P-type electrode 16 The current flow is more dispersed, which makes the current density distribution more uniform, so that the luminous efficiency of the LED chip can be better improved.

2 is a top plan view of an LED chip according to Embodiment 1 of the present invention. Referring to FIG. 2, the N-type electrode 15 surrounds the P-type electrode 16, and all of the N-type electrodes 15 are electrically connected. It should be noted that FIG. 2 is only one specific example of the LED chip. The shape of the surface of the LED chip shown in FIG. 2 is a square. In actual design, the shape of the surface of the LED chip may also be a rectangle, a circle, a hexagon, or the like. In addition, the shape of the P-type electrode 16 is not limited herein as long as the distances from the P-type electrode 16 to the respective N-type electrodes 15 are equal. In addition, the number of the slots shown in FIG. 2 is eight, and the slots are evenly distributed along the edges of the transparent electrode layer 13. In actual design, the number of slots may be at least two according to the situation, and the present invention Here, the shape of the surface of the LED chip and the number of slots and the groove along the transparent electrode The distribution of the layer 13 is not limited.

It should be noted that, in FIG. 2, the portion between the adjacent N-type electrodes 15 is the same as the material of the N-type electrode and realizes electrical connection between the adjacent N-type electrodes 15. As described above, the portion that electrically connects the N-type electrodes 15 can provide an operating voltage for the N-type electrode 15 more conveniently when the LED chip is in operation.

Further, the epitaxial layer 12 includes an N-type GaN layer 121, an InGaN or GaN multiple quantum well active layer 122, and a P-type GaN layer 123, wherein the N-type GaN layer 121 is located on the substrate 11, The InGaN or GaN multiple quantum well active layer 122 is located on the N-type GaN layer 121, and the P-type GaN layer 123 is located on the InGaN or GaN multiple quantum well active layer 122. It should be noted that the N-type GaN layer 121, the InGaN or GaN multiple quantum well active layer 122, and the P-type GaN layer 123 may be sequentially formed on the substrate 11 by a chemical vapor deposition process.

The structure of the epitaxial layer 12 is closely related to the working principle of the LED chip 10. When the LED chip 10 is not biased, a PN junction is formed between the N-type GaN layer 121 and the P-type GaN layer 123, and the terminal voltage of the PN junction forms a certain barrier, which prevents the N-type GaN layer 121 from being formed. Electrons (majority carriers in the N-type GaN layer 121) diffuse into the P-type GaN layer 123 and holes in the P-type GaN layer 123 (majority carriers in the P-type GaN layer 123) are directed to the N-type GaN layer 121. diffusion. When the LED chip is applied with a forward bias voltage, that is, the operating voltage, the barrier formed by the PN structure is lowered, and the majority carriers in the N-type GaN layer 121 and the P-type GaN layer 123 are diffused toward each other due to the electron mobility ratio. The mobility of the holes is much larger, so that a large amount of electrons are diffused into the P-type GaN layer 123, constituting the injection of minority carriers in the P-type GaN layer 123. These electrons from the N-type GaN layer 121 are recombined with the holes in the P-type GaN layer 123, and the energy obtained by the recombination is released in the form of light energy, thereby enabling the LED chip 10 to emit light.

Further, the bottom of the trench is located in the N-type GaN layer 121; the N-type electrode 15 is in direct contact with the N-type GaN layer 121. Thus, the N-type electrode 15 can apply a voltage to the N-type GaN layer 121. And with the cooperation of the P-type electrode 16, the LED chip 10 can operate normally.

Alternatively, the groove may have a cross section of one of a circle, a rectangle, and a square.

Optionally, the material of the transparent electrode layer 13 may be ITO (Indium Tin Oxide), ZnO or Ni and Au alloy.

Optionally, the material of the insulating layer 14 may be one of SiO ₂ , Si ₃ N ₄ , and SiON.

Optionally, the materials of the N-type electrode 15 and the P-type electrode 16 may each be one of Ti, Cr, Pt, Au, Ni, Al, Be, and Ge.

Optionally, the number of the slots may be 4, 5, 6, 7, or 8.

Referring to FIG. 1, since the P-type electrode 16 is located at the top of the LED chip 10 and has a light blocking effect, light generated in the epitaxial layer 12 of the LED chip 10 is reflected by the P-type electrode 16 and only a small amount of light is emitted from the N-type. A gap between the electrode 15 and the P-type electrode 16 is emitted. Since the substrate 11 and the epitaxial layer 12 are both transparent, the generated light and the light reflected by the P-type electrode 16 can be emitted through the epitaxial layer 12 and the substrate 11 and the bottom of the LED chip 10, and thus, in practical applications, The LED chip 10 in FIG. 1 needs to be inverted, that is, the LED chip 10 needs to adopt a flip-chip structure.

3 is a cross-sectional view showing the connection of an LED chip and a circuit board according to Embodiment 1 of the present invention. Further, referring to FIG. 3, the LED chip 10 is soldered on the circuit board 20 by flip-chip eutectic soldering, wherein the circuit board 20 includes a substrate 21 and a positive electrode 22 and a negative electrode 23 on the substrate 21, and The positive electrode 22 is spaced apart from the negative electrode 23; the P-type electrode 16 of the LED chip 10 is located on the positive electrode 22, and the N-type electrode 15 of the LED chip 10 is located on the negative electrode 23.

The LED chip 10 is soldered on the circuit board 20 by a flip-chip eutectic soldering process. When the LED chip 10 is in operation, the operating voltage can be supplied through the circuit board 20, which can improve the reliability of the LED chip. Preferably, the LED chip can be soldered to the circuit board including the heat sink by flip-chip eutectic soldering, which can better improve the stability and reliability of the LED chip.

The LED chip provided in Embodiment 1 of the present invention has at least two slots disposed in the LED chip through the transparent electrode layer in the longitudinal direction and at the bottom in the epitaxial layer, wherein the slots are distributed along the edge of the transparent electrode layer, on the sidewall of the slot An insulating layer is disposed on the transparent electrode layer at the edge of the notch, and an N-type electrode is disposed on the insulating layer and a P-type electrode is disposed on the transparent electrode layer, wherein the distance between the P-type electrode and each of the N-type electrodes is equal The N-type electrode to the P-type electrode are equidistant and surround the periphery thereof. When the LED chip is operated, the current flow between the N-type electrode and the P-type electrode is relatively dispersed, so that the current density distribution is relatively uniform, thereby improving The luminous efficiency of the LED chip; in addition, the LED chip is soldered on the circuit board by flip-chip eutectic soldering, and the reliability of the LED chip can also be improved.

Embodiment 2

Embodiment 2 of the present invention provides a method for fabricating an LED chip. The LED chip described in the first embodiment can be fabricated by the method for fabricating the LED chip in the embodiment, and the manufacturing process is compatible with the existing process. In this embodiment, for a detailed description of the concept and a detailed description of the working principle, refer to the first embodiment, and details are not described herein again.

4 is a schematic flow chart of a method for fabricating an LED chip according to Embodiment 2 of the present invention. As shown in FIG. 4, the manufacturing method of the LED chip of this embodiment includes:

Step 301, forming an epitaxial layer on the substrate;

In this step, further, forming an epitaxial layer on the substrate includes sequentially forming an N-type GaN layer, an InGaN or GaN multiple quantum well active layer, and a P-type GaN layer on the substrate.

Step 302, forming a transparent electrode layer on the epitaxial layer;

Step 303, forming at least two grooves that pass through the transparent electrode layer in the longitudinal direction and have a bottom portion in the epitaxial layer, wherein the grooves are distributed at the edges of the transparent electrode layer;

In this step, further, the bottom of the trench is formed in the N-type GaN layer.

Step 304, forming an insulating layer on the sidewall of the trench and on the transparent electrode layer at the edge of the slot;

Step 305, forming an N-type electrode on the insulating layer;

In this step, further, the N-type electrode is in direct contact with the N-type GaN layer.

Step 306, forming a P-type electrode on the transparent electrode layer, wherein the distance from the P-type electrode to each of the N-type electrodes is equal.

A method for fabricating an LED chip according to Embodiment 2 of the present invention, wherein at least two grooves are formed in the LED chip through the transparent electrode layer in the longitudinal direction and the bottom portion is located in the epitaxial layer, wherein the grooves are distributed along the edge of the transparent electrode layer, An insulating layer is formed on the sidewall of the trench and on the transparent electrode layer at the edge of the slot, and an N-type electrode is formed on the insulating layer and a P-type electrode is formed on the transparent electrode layer, wherein the P-type electrode is applied to each of the N-type electrodes The distances are equal, so that the N-type electrode to the P-type electrode are equidistant and surround it. When the LED chip is operated, the current flow between the N-type electrode and the P-type electrode is relatively dispersed, and the current density distribution can be relatively uniform. Thereby, the luminous efficiency of the LED chip can be improved.

Note that the above are only the preferred embodiments of the present invention and the technical principles applied thereto. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various modifications, changes and substitutions may be made without departing from the scope of the invention. Therefore, the present invention has been described in detail by the above embodiments, but the present invention is not limited to the above embodiments, and other equivalent embodiments may be included without departing from the inventive concept. The scope is determined by the scope of the appended claims.

Claims

An LED chip, comprising:

Substrate

An epitaxial layer, the epitaxial layer being on the substrate;

a transparent electrode layer, the transparent electrode layer is located on the epitaxial layer;

At least two grooves extending longitudinally through the transparent electrode layer and a bottom portion in the epitaxial layer, the grooves being distributed at edges of the transparent electrode layer;

An insulating layer, the insulating layer is lined on the sidewall of the trench and on the transparent electrode layer at the edge of the slot;

An N-type electrode, the N-type electrode being on the insulating layer;

a P-type electrode, the P-type electrode being located on the transparent electrode layer, wherein distances of the P-type electrode to each of the N-type electrodes are equal.
The LED chip according to claim 1, wherein the epitaxial layer comprises an N-type GaN layer, an InGaN or GaN multiple quantum well active layer, and a P-type GaN layer, wherein the N-type GaN layer is located in the On the substrate, the InGaN or GaN multiple quantum well active layer is on the N-type GaN layer, and the P-type GaN layer is on the InGaN or GaN multiple quantum well active layer.
The LED chip according to claim 2, wherein a bottom of the trench is located in the N-type GaN layer;

The N-type electrode is in direct contact with the N-type GaN layer.
The LED chip according to claim 1, wherein the groove has a cross section of one of a circle, a rectangle, and a square;

The number of the grooves is four, five, six, seven or eight.
The LED chip according to claim 1, wherein the transparent electrode layer is made of ITO, ZnO or Ni and an Au alloy;

The material of the insulating layer is one of SiO 2 , Si 3 N 4 , and SiON;

The material of the N-type electrode and the P-type electrode is one of Ti, Cr, Pt, Au, Ni, Al, Be, and Ge.
The LED chip according to claim 1, wherein the groove is evenly distributed along an edge of the transparent electrode layer.
The LED chip according to any one of claims 1 to 6, wherein the LED chip is soldered on a circuit board by flip-chip eutectic soldering, wherein the circuit board includes a substrate and is located on the substrate a positive electrode and a negative electrode, and the positive electrode is separated from the negative electrode;

The P-type electrode is located on the positive electrode, and the N-type electrode is located on the negative electrode.
A method for manufacturing an LED chip, comprising:

Forming an epitaxial layer on the substrate;

Forming a transparent electrode layer on the epitaxial layer;

Forming at least two grooves extending longitudinally through the transparent electrode layer and having a bottom portion in the epitaxial layer, wherein the grooves are distributed at edges of the transparent electrode layer;

Forming an insulating layer on the sidewall of the trench and on the transparent electrode layer at the edge of the slot;

Forming an N-type electrode on the insulating layer;

A P-type electrode is formed on the transparent electrode layer, wherein distances of the P-type electrode to each of the N-type electrodes are equal.
The method of fabricating an LED chip according to claim 8, wherein forming an epitaxial layer on the substrate comprises: sequentially forming an N-type GaN layer, an InGaN or GaN multiple quantum well active layer, and a P-type on the substrate. GaN layer.
The method of fabricating an LED chip according to claim 9, wherein a bottom of the trench is formed in the N-type GaN layer;

The N-type electrode is in direct contact with the N-type GaN layer.