CN102969413A - Manufacturing method of laser-induced air-gap light emitted diode - Google Patents

Abstract

A method for manufacturing a laser-induced air-gap light-emitting diode, comprising the following steps: Step 1: Take a substrate, and use a laser to form a regular mesh air gap within 30um from the upper surface of the substrate; Step 2: Use The MOCVD method sequentially grows the nucleation layer, the N-type doped layer, the multi-quantum well light-emitting layer, the P-type doped layer, and the ITO layer; Step 3: Using photolithography, one side of the ITO layer is etched downward, The etching depth reaches the N-type doped layer to form a mesa; step 4: prepare a P-type electrode on the unetched side of the ITO layer; step 5: prepare an N-type electrode on the mesa.

Description

Fabrication method of laser-induced air-gap light-emitting diode

technical field

The invention belongs to the technical field of semiconductors, in particular to a method for manufacturing a laser-induced air-gap light-emitting diode.

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.

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: CN101110392A). 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 scan the inside of the LED sapphire substrate to obtain criss-cross air gaps, which changes the light path of the light emitted by the LEDs in the air gaps, greatly improving the extraction efficiency of the LEDs. 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 method for manufacturing a laser-induced air-gap light-emitting diode, which scans the inside of the light-emitting diode sapphire substrate in the process of making the light-emitting diode chip to obtain criss-cross air gaps, so that the light-emitting diode The emitted light changes in the light path of the air gap, which greatly improves the extraction efficiency of the light emitting diode. The external quantum efficiency of the light-emitting diode is improved, and it is especially suitable for the production of large-scale power crystal grains.

In order to achieve the above object, the present invention provides a method for manufacturing a laser-induced air-gap light-emitting diode, comprising the following steps:

Step 1: Take a substrate, and use a laser to form a regular mesh air gap inside 30um from the upper surface of the substrate;

Step 2: sequentially grow a nucleation layer, an N-type doped layer, a multi-quantum well light-emitting layer, a P-type doped layer, and an ITO layer on the substrate by MOCVD;

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

Step 4: preparing a P-type electrode on the unetched side of the ITO layer;

Step 5: Prepare N-type electrodes on the table.

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 specific technical content of the present invention, below in conjunction with embodiment and accompanying drawing detailed description as follows, wherein:

Fig. 1 is a structural sectional view of the present invention.

Detailed ways

Please refer to Fig. 1, the present invention provides a method for manufacturing a laser-induced air-gap light-emitting diode, comprising the following steps:

Step 1: Take a substrate 21. The material of the substrate 21 is sapphire, Si, SiC, GaAs or glass. A laser is used to form a regular mesh air gap inside the upper surface of the substrate 21 at a distance of 30um. The inside of the substrate 21 is acted on by a laser to form regular or irregular air gaps; the air gap width is 100nm-5um, the air gap length is 500nm-5um, and the air gap distance is 3um-10um. Wherein the air gap of the substrate 21 is arranged in a single layer or in multiple layers;

Wherein the laser may be a nanosecond laser, a picosecond laser or a femtosecond laser. The laser wavelength can be 266nm, 355nm, 532nm or 1064nm.

Step 2: sequentially grow on the substrate 21 by MOCVD method: nucleation layer 22, n-type doped layer 23, the material of the n-type doped layer 23 is n-GaN, n-type GaN is doped with Si, with a thickness of 1-5um. The material of the multi-quantum well light-emitting layer 24 is InGaN/GaN, the thickness is 50-500 nm, and the period number of the multi-quantum well light-emitting layer 24 is 1-100. The material of the p-type doped layer 25 is p-type GaN, which is doped with Mg, and has a thickness of 200-500 nm. The material of the ITO layer 26 is 95% InO ₂ , 5% SnO ₂ , and the thickness is 10-1000nm.

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'; the etching depth cannot penetrate the N-type doped layer 23, the depth reaches the middle of the thickness of the N-type doped layer 23.

Step 4: Prepare a P-type electrode 27 on the unetched side of the ITO layer 26; the material of the P-type electrode is Cr/Pt/Au, and the thickness is:

Step 5: Prepare an N-type electrode 28 on the mesa 23'. The N-type electrode material is Cr/Pt/Au, and the thickness is:

The above description is only an embodiment of the present invention, and does not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to the present invention. Within the scope of the technical solution, the protection scope of the present invention should be determined by the claims.

Claims (5)

1. A method for making a laser-induced air-gap light-emitting diode, comprising the steps of: Step 1: Take a substrate, and use a laser to form a regular mesh air gap inside 30um from the upper surface of the substrate; Step 2: sequentially grow a nucleation layer, an N-type doped layer, a multi-quantum well light-emitting layer, a P-type doped layer, and an ITO layer on the substrate by MOCVD; Step 3: Using photolithography, etch one side of the ITO layer downward, and the etching depth reaches the N-type doped layer to form a mesa; Step 4: preparing a P-type electrode on the unetched side of the ITO layer; Step 5: Prepare N-type electrodes on the table. 2. The manufacturing method of laser-induced air-gap light-emitting diodes according to claim 1, wherein the material of the lateral photonic crystal substrate is sapphire, Si, SiC, GaAs or glass. 3. The manufacturing method of laser-induced air-gap light-emitting diode according to claim 1, wherein the inside of the substrate is acted on by laser to form regular or irregular air gaps; the air gap width is 100nm-5um, and the air gap length is 500nm -5um, the air gap distance is 3um-10um. 4. The method for manufacturing a laser-induced air-gap light-emitting diode according to claim 1, wherein the air gap of the substrate is arranged in a single layer or in multiple layers. 5. The manufacturing method of laser-induced air-gap light-emitting diode according to claim 1, wherein the laser is a nanosecond laser, a picosecond laser or a femtosecond laser, and the laser wavelength is 266nm, 355nm, 532nm or 1064nm.

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