CN102593301A - Light emitting diode with coarsened side surface and manufacturing method thereof - Google Patents

Abstract

A light-emitting diode with roughened sides, comprising: a substrate, the side of which is roughened; a nucleation layer, which is fabricated on the substrate with roughened sides; an N-type doped layer, which is fabricated On the nucleation layer, the N-type doped layer has a mesa; a multi-quantum well light-emitting layer is fabricated on the other side of the N-type doped layer mesa, and the multi-quantum well light-emitting layer is grown alternately in 10 cycles GaN/InGaN; a P-type doped layer fabricated on the MQW light-emitting layer; an ITO layer fabricated on the P-type doped layer; a P-type metal electrode fabricated on the ITO layer On: an N-type metal electrode fabricated on the mesa of the doped layer. The invention can improve the light extraction efficiency, so that the external quantum efficiency of the light-emitting diode is improved, and is especially suitable for the production of large-sized power crystal grains.

Description

Light-emitting diode with roughened sides and manufacturing method thereof

technical field

The invention belongs to the technical field of semiconductors, in particular to a light-emitting diode with roughened sides and a manufacturing method thereof.

Background technique

Because light-emitting diodes have the advantages of energy saving, environmental protection, and long life, in the next few years, light-emitting diodes may replace traditional lighting fixtures such as incandescent lamps and fluorescent lamps, and enter thousands of households.

FIG. 1 shows a prior art light-emitting diode without side roughening, and its luminous efficiency is low.

At present, nitride-based light-emitting diode materials are mainly heteroepitaxially grown on substrates such as sapphire, silicon, and silicon carbide. Due to the large difference between the refractive index of gallium nitride material and air, the light total reflection effect that occurs at the escape interface makes the light extraction of light-emitting diode devices very limited. T.Fujii, Y.Gao, et al. in Appl.Phys.Lett.84 (2004) 855. proposed a gallium nitride-based light-emitting diode surface roughening technology to improve the extraction efficiency of light-emitting diodes. After that, surface roughening is a commonly used key technology to improve the light extraction efficiency of LEDs. However, the previous surface roughening technology mainly focused on the surface roughening of p-type gallium nitride, the surface roughening of the indium tin oxide transparent conductive layer, the back roughening of the sapphire substrate, and the side roughening of the gallium nitride epitaxial layer. The roughening treatment of the light-emitting surface of the side wall of the diode sapphire substrate is not involved. In addition, Japan Hamamatsu Photonics Co., Ltd. proposed a laser processing method for low-damage laser cutting silicon wafers in 2007 (application number: 200710147746.5, publication number: CN 101110392A). However, it does not mention the influence of the roughened sapphire surface of the GaN LED device on the extraction efficiency of the LED.

This technology uses laser processing technology to process the side of the sapphire substrate of the light-emitting diode to obtain a rough sapphire side structure, which greatly improves the extraction efficiency of the light-emitting diode. This technology has obvious advantages, which greatly optimizes the process and greatly reduces the production cycle and cost.

Contents of the invention

The main purpose of the present invention is to provide a light-emitting diode with a side structure and a manufacturing method thereof, which is a method for roughening the sidewall of a gallium nitride-based light-emitting diode substrate in the process of making a light-emitting diode chip, which can greatly improve the light output. The efficiency improves the external quantum efficiency of light-emitting diodes, and is especially suitable for the production of large-scale power crystal grains.

To achieve the above object, the present invention provides a light-emitting diode with roughened sides, comprising:

a substrate, the sides of the substrate are roughened;

a nucleation layer fabricated on the side-roughened substrate;

An N-type doped layer made on the nucleation layer, the N-type doped layer has a table;

A multi-quantum well light-emitting layer, which is fabricated on the other side of the N-type doped layer mesa, the multi-quantum well light-emitting layer is gallium nitride/indium gallium nitrogen alternately grown in 10 cycles;

A P-type doped layer fabricated on the multi-quantum well light-emitting layer;

An ITO layer, which is fabricated on the P-type doped layer;

A P-type metal electrode made on the ITO layer;

An N-type metal electrode is fabricated on the mesa of the doping layer.

Compared with the prior art, the present invention provides that only appropriate processing is added in the cutting process with chip technology, which is simple and easy to operate, and can greatly improve the light extraction efficiency, so that the external quantum efficiency of light-emitting diodes is improved, and is especially suitable for large-sized power-type crystal grains production.

Description of drawings

In order to further illustrate the technical content of the present invention, the present invention will be further described below in conjunction with accompanying drawing and embodiment, wherein:

FIG. 1 is a schematic structural view of a conventional light-emitting diode;

Fig. 2 is the first embodiment of the present invention, showing a schematic diagram of the roughened structure of the side of the substrate, and the roughened figure is a triangular structure;

Fig. 3 is a second embodiment of the present invention, showing a schematic view of the roughened structure of the side of the substrate, and the roughened figure is a circular structure;

Fig. 4 is a third embodiment of the present invention, showing a schematic view of the structure of the side of the substrate after roughening, and the roughened pattern is a discontinuous structure;

Fig. 5 is a fourth embodiment of the present invention, showing a schematic view of the roughened structure of the side of the substrate, and the roughened pattern is a continuous structure;

Fig. 6 is a fifth embodiment of the present invention, showing a schematic diagram of the structure of the side of the substrate after roughening, the roughened pattern is a continuous structure, and the substrate is an inverted trapezoid;

Fig. 7 is a sixth embodiment of the present invention, showing a schematic view of the roughened structure of the side of the substrate, the roughened pattern is a discontinuous structure, and the substrate is semicircular or hemispherical;

Detailed ways:

Please refer to Fig. 2, the present invention provides a light emitting diode with a side structure, including:

A substrate 21. The side surface of the substrate 21 is roughened. The roughened side surface can reduce the total reflection effect of light inside the LED device and improve the light extraction efficiency of the device. The material of the substrate 21 is sapphire, Si, SiC, GaAs or glass, and the shape of the substrate 21 is rectangle, inverted trapezoid, semicircle or hemisphere. A light-emitting diode with roughened sides, wherein the side of the substrate 21 is roughened to form a continuous roughened surface or a discontinuous roughened surface.

A nucleation layer 22 made on the substrate 21 with roughened sides;

An N-type doped layer 23 is fabricated on the nucleation layer 22, the N-type doped layer 23 has a mesa 23', wherein the depth of the mesa 23' of the doped layer 23 is less than the thickness of the doped layer 23.

A multi-quantum well light-emitting layer 24, which is made on the other side of the N-type doped layer 23 mesa 23', the multi-quantum well light-emitting layer 24 is gallium nitride/indium gallium nitrogen alternately grown in 10 cycles; wherein The material of the core layer 22 , the N-type doped layer 23 and the P-type doped layer 24 is GaN.

A P-type doped layer 25, which is made on the multi-quantum well light-emitting layer 24;

An ITO layer 26, which is fabricated on the P-type doped layer 25, wherein the ITO layer 26 is conducive to current expansion, improves the injection efficiency of electrons and the internal quantum efficiency of the device.

A P-type metal electrode 27, which is made on the ITO layer 26;

An N-type metal electrode 28 is fabricated on the mesa 23' of the doped layer 23, and the prepared P-type metal electrode 27 and N-type metal electrode 28 can be connected to an external power supply.

Wherein the above-mentioned rectangular, inverted trapezoidal, semicircular or hemispherical side of the substrate 21, after the roughening treatment, can be a continuous roughened surface or a discontinuous roughened surface, and its shape can be triangular or rhombus , circle or polygon.

Please refer to FIG. 2 again. The present invention provides a method for manufacturing a light-emitting diode with a side structure, which includes the following steps:

Step 1: Take a substrate 21, and roughen the side of the substrate 21 to form a continuous roughened surface or a discontinuous roughened surface, wherein the material of the roughened substrate 21 is sapphire, Si, SiC , GaAs or glass, the shape of the substrate 21 is rectangular, inverted trapezoidal, semicircular or hemispherical, wherein the sidewall of the substrate 21 is roughened, and the laser is used to form an induced shape on the sidewall surface of the substrate 21, after etching The liquid etches out triangles, rhombuses, circles or polygons. The roughened side can reduce the total reflection effect of light inside the LED device and improve the light extraction efficiency of the device.

Step 2: On the substrate 21, the nucleation layer 22, the N-type doped layer 23, the multi-quantum well light-emitting layer 24, the P-type doped layer 25 and the ITO layer 26 are sequentially grown by the MOCVD method, wherein the nucleation layer 22, the N The materials of the P-type doped layer 23 and the P-type doped layer 24 are GaN, and the multi-quantum well light-emitting layer 24 is GaN/InGaN grown alternately in 10 periods.

Step 3: using photolithography, etch one side of the ITO layer 26 downward, and the etching depth reaches the N-type doped layer 23 to form a mesa 23';

Step 4: Prepare a P-type metal electrode 27 on the unetched side of the ITO layer 26, prepare an N-type metal electrode 28 on the mesa 23', and prepare the P-type metal electrode 27 and N-type metal electrode 28. Connect to an external power source.

Wherein the above-mentioned rectangular, inverted trapezoidal, semicircular or hemispherical side of the substrate 21, after the roughening treatment, can be a continuous roughened surface or a discontinuous roughened surface, and its shape can be triangular or rhombus , circle or polygon.

Example 1:

As shown in FIG. 2 , it is basically consistent with the foregoing content, which shows that the roughened side surface of the substrate 201 is a triangular structure.

Example 2:

As shown in FIG. 3 , it is basically consistent with the above content, which shows that the roughened side of the substrate 201 is a circular structure.

Example 3:

As shown in FIG. 4 , which is basically consistent with the foregoing content, it shows that the roughened shape of the side surface of the substrate 201 is a discontinuous roughened structure.

Example 4:

As shown in FIG. 5 , it is basically consistent with the aforementioned content, which shows that the roughened shape of the side surface of the substrate 201 is a continuous roughened structure.

Example 5:

As shown in FIG. 6 , which is basically consistent with the aforementioned content, it shows that the roughened shape of the side surface of the substrate 201 is an inverted trapezoidal discontinuous roughened structure.

Embodiment 6:

As shown in FIG. 7 , which is basically consistent with the foregoing content, it shows that the shape of the side surface roughening of the substrate 201 is a circular or hemispherical discontinuous roughening structure.

The above examples are only used for illustrating the present invention, rather than limiting the present invention, and those of ordinary skill in the art can also make various transformations or changes without departing from the spirit and scope of the present invention; therefore, All equivalent technical solutions should also belong to the category of the present invention and should be defined by each claim.

Claims (10)

1. the light-emitting diode of a side alligatoring comprises:

One substrate, the side of this substrate are through roughening treatment, and the side of substrate after the roughening treatment is triangle, rhombus, circle or polygon;

One nucleating layer, it is produced on the substrate of side alligatoring;

One N type doped layer, it is produced on the nucleating layer, and this N type doped layer has a table top;

One multiple quantum well light emitting layer, it is produced on the opposite side of N type doped layer table top, and this multiple quantum well light emitting layer is the gallium nitride/indium gallium nitrogen of 10 cycle alternating growths;

One P type doped layer, it is produced on the multiple quantum well light emitting layer;

One ITO layer, it is produced on the P type doped layer;

One P type metal electrode, it is produced on the ITO layer;

One N type metal electrode, it is produced on the table top of doped layer.

2. the light-emitting diode of side according to claim 1 alligatoring, wherein the material of the substrate of surface coarsening is sapphire, Si, SiC, GaAs or glass, this substrate be shaped as rectangle, trapezoidal, semicircle or hemisphere.

3. the light-emitting diode of side structure according to claim 2 wherein after the roughening treatment of the side of this substrate, forms continuous coarse surface or discontinuous coarse surface.

4. the light-emitting diode of side structure according to claim 1, wherein the material of nucleating layer, N type doped layer and P type doped layer is GaN.

5. the light-emitting diode of side structure according to claim 1, wherein the degree of depth of the table top of N type doped layer is less than the thickness of N type doped layer.

6. the manufacture method of the light-emitting diode of a side structure comprises the steps:

Step 1: get a substrate, roughening treatment is carried out in the side of this substrate, forms continuous coarse surface or discontinuous coarse surface;

Step 2: on substrate, adopt the MOCVD method to grow into stratum nucleare, N type doped layer, multiple quantum well light emitting layer, P type doped layer and ITO layer successively;

Step 3: adopt the method for photoetching, etching under the side direction on the ITO layer, etching depth arrives in the N type doped layer, forms table top;

Step 4: do not preparing P type metal electrode on the side of etching on the ITO layer;

Step 5: preparation N type metal electrode on table top.

7. the manufacture method of the light-emitting diode of side structure according to claim 6, wherein the material of the substrate of surface coarsening is sapphire, Si, SiC, GaAs or glass, this substrate be shaped as rectangle, trapezoidal, semicircle or hemisphere.

8. the manufacture method of the light-emitting diode of side structure according to claim 6, wherein the material of nucleating layer, N type doped layer and P type doped layer is GaN.

9. the manufacture method of the light-emitting diode of side structure according to claim 6, wherein this multiple quantum well light emitting layer is the gallium nitride/indium gallium nitrogen of 10 cycle alternating growths.

10. the manufacture method of the light-emitting diode of side structure according to claim 6, wherein substrate sidewall alligatoring is to form in the sidewall surfaces of substrate with laser to induce shape, erodes away triangle, rhombus, circle or polygon through corrosive liquid.

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