CN106206901A - LED chip and manufacture method thereof - Google Patents

Abstract

The invention provides an LED chip and a manufacturing method thereof. The LED chip includes a substrate, an N-type semiconductor layer on the substrate, a light-emitting layer, a P-type semiconductor layer, and an N-type semiconductor layer and a P-type semiconductor layer respectively. Electrically connected N electrodes and P electrodes, the LED chip includes an N-type mesa etched to the N-type semiconductor layer and a number of N-type electrode grooves, the side walls of the N-type electrode grooves and the top of the P-type semiconductor layer are provided The insulating medium layer of the N-type electrode groove, the first transparent conductive layer connecting the bottom of the N-type electrode groove and the N-type semiconductor layer is formed on the insulating medium layer, and the first N electrode is provided on the N-type mesa A second N electrode is provided on the first transparent conductive layer in the N-type electrode slot, and the first N electrode and the second N electrode are electrically connected through the first transparent conductive layer. The current density distribution in the LED chip of the invention is uniform, the luminous performance of the LED chip is improved, the area of the active layer is effectively increased, and the luminous efficiency of the chip is improved.

Description

LED chip and manufacturing method thereof

technical field

The invention relates to the field of semiconductor chips, in particular to an LED chip and a manufacturing method thereof.

Background technique

A light-emitting diode (Light-Emitting Diode, LED) is a semiconductor electronic component that can emit light. This electronic component appeared as early as 1962. In the early days, it could only emit red light with low luminosity. Later, other monochromatic light versions were developed. Today, the light that can be emitted has covered visible light, infrared rays and ultraviolet rays, and the luminosity has also increased to a considerable extent. of luminosity. Because of its energy saving, environmental protection, safety, long life, low power consumption, low heat, high brightness, waterproof, miniature, shockproof, easy dimming, concentrated beam, easy maintenance, etc., it can be widely used in various indications, displays, decorations , backlight, general lighting and other fields.

The structure of the traditional LED chip mainly includes: horizontal structure and vertical structure, in which the two electrodes of the vertical structure LED chip are on the upper and lower sides of the LED, the P electrode is on the p-type gallium nitride side of the LED epitaxial layer, and the N electrode is on the LED chip. The n-type gallium nitride side of the epitaxial layer makes the current flow vertically through the LED epitaxial layer, and only one electrode on the light emitting surface of the chip is shaded. The two electrodes of the LED chip with a lateral structure are on the same side of the LED chip, the P electrode is in the p-type GaN region of the LED epitaxial layer, and the N electrode is distributed in the n-type GaN region exposed by etching. P and N electrodes are not equidistantly distributed, resulting in uneven current distribution in the n-type GaN and p-type GaN layers, thereby affecting luminous efficiency.

In addition, as shown in FIG. 1, in the traditional horizontal structure LED chip, the N electrodes 81' and 82' are distributed in the n-type GaN region exposed by etching, because the epitaxial layer needs to etch a larger area (the entire n-type region), Since the P electrodes 91 ′, 92 ′ and N electrodes 81 ′, 82 ′ are distributed on the light emitting surface of the LED chip, the effective area of light emitting is reduced, so the light emitting efficiency is low.

Contents of the invention

The object of the present invention is to provide an LED chip and a manufacturing method thereof, which can increase the luminous area of the chip and improve luminous efficiency.

In order to achieve the above object, the technical solutions provided by the embodiments of the present invention are as follows:

An LED chip comprising a substrate, an N-type semiconductor layer on the substrate, a light-emitting layer, a P-type semiconductor layer, and an N electrode electrically connected to the N-type semiconductor layer and the P-type semiconductor layer, respectively. P electrode, the LED chip includes an N-type mesa and a number of N-type electrode grooves etched to the N-type semiconductor layer, and an insulating medium across the N-type electrode groove is provided on the side wall of the N-type electrode groove and above the P-type semiconductor layer layer, the first transparent conductive layer connecting the bottom of the N-type electrode groove and the N-type semiconductor layer is formed on the insulating medium layer, the first N electrode is arranged on the N-type mesa, and the N-type electrode groove A second N electrode is provided on the first transparent conductive layer, and the first N electrode and the second N electrode are electrically connected through the first transparent conductive layer.

As a further improvement of the present invention, a second transparent conductive layer is provided on the P-type semiconductor layer outside the insulating medium layer, and the P electrode is located on the second transparent conductive layer, through which the second transparent conductive layer and the P Type semiconductor layer is electrically connected.

As a further improvement of the present invention, the N electrodes are distributed around the P electrodes.

As a further improvement of the present invention, the P electrodes include a first P electrode and a second P electrode laterally extending from the first P electrode.

As a further improvement of the present invention, both the first N-electrode and the second N-electrode are disposed on side portions of the LED chip.

As a further improvement of the present invention, the first N electrode and the second N electrode are arranged equidistantly from the P electrode.

As a further improvement of the present invention, the cross section of the N-type electrode groove is circular, rectangular, regular polygonal or irregular.

Correspondingly, a manufacturing method of an LED chip is characterized in that the manufacturing method comprises:

A substrate is provided, and an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer are epitaxially grown on the substrate in sequence;

Etching the epitaxial layer to the N-type semiconductor layer to form N-type mesa and several N-type electrode grooves;

preparing an insulating dielectric layer above the sidewall of the N-type electrode groove and the P-type semiconductor layer;

Prepare the first transparent conductive layer on the insulating medium layer, the first transparent conductive layer covers the bottom of the N-type electrode groove and is electrically connected with the N-type semiconductor layer, and prepares the second transparent conductive layer on the area outside the insulating medium layer on the P-type semiconductor layer. conductive layer;

The first N electrode is prepared on the N-type mesa, the second N electrode is prepared on the first transparent conductive layer in the N-type electrode groove, and the P electrode is prepared on the second transparent conductive layer.

As a further improvement of the present invention, the cross section of the N-type electrode groove is circular, rectangular, regular polygonal or irregular.

Compared with the prior art, the present invention has the following advantages:

The N electrode is distributed around the P electrode, and the electrode structure is symmetrical. When the voltage is applied to the LED chip, the current flow between the N electrode and the P electrode is scattered, which avoids the current flow between the electrodes in the prior art. In the case of a large difference in current density distribution within the layer, the current density distribution of the active layer is uniform, which improves the luminous performance of the LED chip;

The distribution of chip bonding points is reasonable, and flip-chip eutectic welding can be used to improve chip reliability;

In the N-electrode area, only the N-type mesa and the N-type electrode groove are etched away, and the active layer in the rest of the N-electrode area remains, which effectively increases the area of the active layer and greatly improves the luminous efficiency of the chip.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of a planar structure of an LED chip in the prior art;

2a and 2b are schematic diagrams of the cross-sectional structure and planar structure of the LED chip in the first embodiment of the present invention, respectively;

3a to 3e are process steps diagrams of the method for preparing the LED chip in the second embodiment of the present invention.

detailed description

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described The embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

The invention discloses an LED chip, which comprises a substrate, an N-type semiconductor layer on the substrate, a light-emitting layer, a P-type semiconductor layer, and an N electrode electrically connected to the N-type semiconductor layer and the P-type semiconductor layer respectively. and P electrodes, the LED chip includes an N-type mesa etched to the N-type semiconductor layer and a number of N-type electrode grooves, and an insulating dielectric layer across the N-type electrode grooves is provided on the side walls of the N-type electrode grooves and above the P-type semiconductor layer , the first transparent conductive layer connecting the bottom of the N-type electrode groove and the N-type semiconductor layer is formed on the insulating medium layer, the first N electrode is arranged on the N-type mesa, and the first transparent conductive layer in the N-type electrode groove A second N-electrode is provided on it, and the first N-electrode and the second N-electrode are electrically connected through the first transparent conductive layer.

In addition, a second transparent conductive layer is provided on the P-type semiconductor layer outside the insulating medium layer, the P electrode is located on the second transparent conductive layer, and is electrically connected to the P-type semiconductor layer through the second transparent conductive layer.

Correspondingly, the present invention also discloses a method for manufacturing an LED chip, comprising:

A substrate is provided, and an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer are epitaxially grown on the substrate in sequence;

Etching the epitaxial layer to the N-type semiconductor layer to form N-type mesa and several N-type electrode grooves;

preparing an insulating dielectric layer above the sidewall of the N-type electrode groove and the P-type semiconductor layer;

Prepare the first transparent conductive layer on the insulating medium layer, the first transparent conductive layer covers the bottom of the N-type electrode groove and is electrically connected with the N-type semiconductor layer, and prepares the second transparent conductive layer on the area outside the insulating medium layer on the P-type semiconductor layer. conductive layer;

The first N electrode is prepared on the N-type mesa, the second N electrode is prepared on the first transparent conductive layer in the N-type electrode groove, and the P electrode is prepared on the second transparent conductive layer.

The present invention will be further described below in combination with specific embodiments.

Referring to Figures 2a and 2b, the LED chip in the first embodiment of the present invention includes from bottom to top:

Substrate 10, the substrate can be sapphire, Si, SiC, GaN, ZnO, etc.;

N-type semiconductor layer 20, the N-type semiconductor layer can be N-type GaN, etc.;

A light emitting layer 30, the light emitting layer can be GaN, InGaN or InGaN/GaN multi-quantum well active layer, etc.;

P-type semiconductor layer 40, the P-type semiconductor layer can be P-type GaN, etc.;

The P electrode 90 and the N electrode 80 , the P electrode 90 is electrically connected to the P-type semiconductor layer 40 , and the N electrode 80 is electrically connected to the N-type semiconductor layer 20 .

Wherein, an N-type mesa 21 is formed by etching on the N-type semiconductor layer 20, and a number of N-type electrode grooves 50 etched to the N-type semiconductor layer are also formed on the periphery of the epitaxial layer of the LED chip. The mesa region and the region extending from the N-type mesa along the periphery of the LED chip and covering the N-type electrode groove 50 .

The insulating dielectric layer 60 is at least provided on the sidewall of the N-type electrode groove 50 and the region above the P-type semiconductor layer 40 across the N-type electrode groove 50. As shown in FIG. The area other than the bottom of the electrode groove 50 is provided with an insulating dielectric layer 60, and the material of the insulating dielectric layer is selected from one or more of SiO ₂ , Si ₃ N ₄ , SiON, etc. In this embodiment, an insulating layer 60 is used. The dielectric layer is used as an example for illustration. In other implementation manners, multiple layers of insulating dielectric layers may also be formed by multi-step deposition to improve insulation performance.

The first transparent conductive layer 71 is arranged on the top of the insulating medium layer 60 and the bottom of the N-type electrode groove 50, and the first transparent conductive layer 71 is only electrically connected with the N-type semiconductor layer 20 at the bottom of the N-type electrode groove 50 to conduct each N-type electrode slot 50 .

The second transparent conductive layer 72 is located outside the insulating medium layer 60 above the P-type semiconductor layer 40 , and the second transparent conductive layer 72 and the first transparent conductive layer 71 are separated from each other above the P-type semiconductor layer 40 .

The first transparent conductive layer and the second transparent conductive layer in this embodiment are ITO transparent conductive layers, and in other embodiments, they can also be ZITO, ZIO, GIO, ZTO, FTO, AZO, GZO, In ₄ Sn ₃ O ₁₂ , NiAu and other transparent conductive layers. The first transparent conductive layer and the second transparent conductive layer may be a single transparent conductive layer, or may be a combination of multiple transparent conductive layers.

The P electrode 90 is located on the second transparent conductive layer 72, and it includes a first P electrode 91 and a second P electrode 20 extending laterally from the first P electrode 91. The first P electrode 91 and the second P electrode 92 pass through the second P electrode respectively. The transparent conductive layer 72 is electrically connected to the P-type semiconductor layer 40 .

The N electrode 80 includes a first N electrode 81 disposed on the N-type mesa 21 , and a second N electrode 82 located at the bottom of the N-type electrode groove 50 and electrically connected to the first transparent conductive layer 71 . The first N-electrode 81 is located on the N-type mesa 21 and is directly electrically connected to the N-type semiconductor layer 20. The second N-electrode 82 is located in the N-type electrode groove 50 and passes through the first transparent conductive layer 71 at the bottom of the N-type electrode groove 50. It is electrically connected with the N-type semiconductor layer 20 . In addition, the adjacent second N electrodes, the second N electrodes and the first N electrodes are electrically connected to each other through the first transparent conductive layer 71 .

The material of the P electrode (the first P electrode and the second P electrode) and the N electrode (the first NID electrode and the second N electrode) in this embodiment can be selected from one of Ti, Cr, Au, Ni, and Al. or a combination of several.

As shown in FIG. 2b, the N electrodes 80 in this embodiment are distributed around the P electrodes 90, wherein the first N electrodes 81 and the second N electrodes 82 are both arranged on the side parts of the LED chip, and the first N electrodes 81 are located on the sides of the LED chips. On one side of the chip, the second N electrodes 82 are evenly distributed along the periphery of the LED chip on both sides of the first N electrode 81 . The P electrodes include a circular first P electrode 91 and a vertically elongated second P electrode 92 , and the first N electrode 81 and the second N electrode 82 are equidistant from the P electrode 90 .

In this embodiment, the N electrodes are distributed around the P electrodes. When a voltage is applied to the LED chip, the current flow between the N electrodes and the P electrodes is scattered, which avoids the current flow between the electrodes in the prior art being too concentrated, which causes the injection of active In the case of a large difference in current density distribution within the layer, the current density distribution of the active layer is uniform, which improves the luminous performance of the LED chip.

In addition, only the N-type mesa and the N-type electrode groove are etched away in the N-electrode region, while the active layer in the rest of the N-electrode region remains, which effectively increases the area of the active layer and greatly improves the luminous efficiency of the chip.

It should be understood that the cross-section of the N-type electrode groove in this embodiment is circular, and in other embodiments, the cross-section of the N-type electrode groove can also be a rectangle, a regular polygon or an irregular shape, etc., which will not be repeated here. Give examples one by one.

Referring to Figures 3a to 3e and shown in Figure 2b, the method for manufacturing an LED chip in the second embodiment of the present invention specifically includes the following steps:

As shown in FIG. 3a, a substrate 10 is provided, and an N-type semiconductor layer 20, a light-emitting layer 30, and a P-type semiconductor layer 40 are epitaxially grown on the substrate 10. Preferably, the substrate 10 in this embodiment is a sapphire substrate , the N-type semiconductor layer 20 is N-type GaN, the light-emitting layer 30 is an InGaN/GaN multi-quantum well active layer, and the P-type semiconductor layer 40 is P-type GaN;

As shown in FIG. 3b, the epitaxial layer is etched to the N-type semiconductor layer to form an N-type mesa 21 and a number of N-type electrode grooves 50;

As shown in FIG. 3c, an insulating dielectric layer 60 is prepared on the sidewall of the N-type electrode groove 50 and above the P-type semiconductor layer, and the insulating dielectric layer is selected from one or more of SiO ₂ , Si ₃ N ₄ , SiON, etc.;

As shown in FIG. 3d, a first transparent conductive layer 71 is prepared on the insulating medium layer 60. The first transparent conductive layer 71 covers the bottom of the N-type electrode groove 50 and is electrically connected to the N-type semiconductor layer 20. On the P-type semiconductor layer 40 Prepare the second transparent conductive layer 72 in the area other than the upper insulating dielectric layer 60, the first transparent conductive layer and the second transparent conductive layer are ITO, ZITO, ZIO, GIO, ZTO, FTO, AZO, GZO, In ₄ Sn ₃ O _12. NiAu, etc.;

Referring to FIG. 3e and shown in FIG. 2b, a first N electrode 81 is prepared on the N-type mesa 21, a second N electrode 82 is prepared on the first transparent conductive layer 71 in the N-type electrode groove 50, and a second N electrode 82 is prepared on the second transparent conductive layer 71. A first P electrode 91 and a second P electrode 92 are prepared on the layer 72, and the materials of the P electrode and the N electrode are selected from one or more of Ti, Cr, Au, Ni, and Al.

Compared with the prior art, the present invention has the following beneficial effects:

The N electrode is distributed around the P electrode, and the electrode structure is symmetrical. When the voltage is applied to the LED chip, the current flow between the N electrode and the P electrode is scattered, which avoids the current flow between the electrodes in the prior art. In the case of a large difference in current density distribution within the layer, the current density distribution of the active layer is uniform, which improves the luminous performance of the LED chip;

The distribution of chip bonding points is reasonable, and flip-chip eutectic welding can be used to improve chip reliability;

In the N-electrode area, only the N-type mesa and the N-type electrode groove are etched away, and the active layer in the rest of the N-electrode area remains, which effectively increases the area of the active layer and greatly improves the luminous efficiency of the chip.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (9)

1. A kind of LED chip, described LED chip comprises substrate, is positioned at the N-type semiconductor layer on the substrate, light-emitting layer, P-type semiconductor layer, and the N-type semiconductor layer and the N-type semiconductor layer electrically connected with P-type semiconductor layer respectively The electrode and the P electrode are characterized in that the LED chip includes an N-type mesa etched to the N-type semiconductor layer and a number of N-type electrode grooves, the side walls of the N-type electrode grooves and the top of the P-type semiconductor layer are provided The insulating medium layer of the type electrode groove, the first transparent conductive layer connecting the bottom of the N-type electrode groove and the N-type semiconductor layer is formed on the insulating medium layer, and the first N electrode is provided on the N-type mesa, A second N electrode is provided on the first transparent conductive layer in the N-type electrode groove, and the first N electrode and the second N electrode are electrically connected through the first transparent conductive layer. 2. The LED chip according to claim 1, wherein a second transparent conductive layer is provided on the P-type semiconductor layer outside the insulating medium layer, and the P electrode is located on the second transparent conductive layer , electrically connected to the P-type semiconductor layer through the second transparent conductive layer. 3. The LED chip according to claim 1, wherein the N electrodes are distributed around the P electrodes. 4. The LED chip according to claim 3, wherein the P-electrode comprises a first P-electrode and a second P-electrode extending laterally from the first P-electrode. 5 . The LED chip according to claim 3 , wherein the first N electrode and the second N electrode are both disposed on side portions of the LED chip. 6 . The LED chip according to claim 5 , wherein the first N electrode and the second N electrode are arranged equidistantly from the P electrode. 7 . The LED chip according to claim 1 , wherein the cross-section of the N-type electrode groove is circular, rectangular, regular polygonal or irregular. 8. A method for manufacturing the LED chip according to any one of claims 1 to 7, wherein the method for manufacturing comprises: A substrate is provided, and an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer are epitaxially grown on the substrate in sequence; Etching the epitaxial layer to the N-type semiconductor layer to form N-type mesa and several N-type electrode grooves; preparing an insulating dielectric layer above the sidewall of the N-type electrode groove and the P-type semiconductor layer; Prepare the first transparent conductive layer on the insulating medium layer, the first transparent conductive layer covers the bottom of the N-type electrode groove and is electrically connected with the N-type semiconductor layer, and prepares the second transparent conductive layer on the area outside the insulating medium layer on the P-type semiconductor layer. conductive layer; The first N electrode is prepared on the N-type mesa, the second N electrode is prepared on the first transparent conductive layer in the N-type electrode groove, and the P electrode is prepared on the second transparent conductive layer. 9 . The method for manufacturing an LED chip according to claim 8 , wherein the cross-section of the N-type electrode groove is in the shape of a circle, a rectangle, a regular polygon or an irregular shape.