CN105374906A

CN105374906A - LED chip and preparation method thereof

Info

Publication number: CN105374906A
Application number: CN201410425629.0A
Authority: CN
Inventors: 刘英策; 胡红坡
Original assignee: GUANGDONG QUANTUM WAFER PHOTOELECTRIC TECHNOLOGY Co Ltd
Current assignee: GUANGDONG QUANTUM WAFER PHOTOELECTRIC TECHNOLOGY Co Ltd
Priority date: 2014-08-26
Filing date: 2014-08-26
Publication date: 2016-03-02

Abstract

The present application provides an LED chip structure and a preparation method thereof. The method comprises a step of roughening an epitaxial wafer and a step of flattening an electrode contact area. The structure comprises a substrate, a buffer layer, an N material layer, an MQW light emitting area and a coarsened P material which are orderly arranged from bottom to top, wherein a part of the surface of the P material has a flattened area, and a transparent conductive layer and an electrode are arranged in the flattened area.

Description

A kind of LED chip and preparation method thereof

Technical field

The present invention relates to and learn a skill in LED light, more specifically, relate to a kind of LED chip and preparation method thereof, wherein, the method particularly relates to alligatoring epitaxial wafer peace polarizing electrode contact zone.

Background technology

Light-emitting diode (LightEmittingDiode, LED) is the electroluminescent solid-state light source that a kind of low-voltage direct drives, and it has long-life, environmental protection, the advantage such as energy-conservation, thus is widely used, and every country is all being widelyd popularize.And can LED replace the key index that traditional lighting commercially occupies dominant position is its luminous efficiency, therefore, the large factory of each LED chip has all spent a large amount of human and material resources to research and develop the luminous efficiency how improving LED chip.

The nearest more than ten years, the technology improving luminous efficiency continues to bring out, such as PRough, ITOSputter, DBR, CBL, PadReflect etc.P type surface coarsening (PRough), because light extraction efficiency is high, and is widely used such as Taiwan wafer, Tai Gu by the large factory of each LED chip, grandly to reach.

A kind of manufacture method with the GaN base LED chip of p-GaN layer surface coarsening is disclosed in Chinese invention patent CN102157640, adopt metal organic chemical vapor deposition on sinking to the bottom, grow each layer, by after the evaporation of p-GaN surface, form CsCl nano island, and then etching, form the epitaxial wafer of surface coarsening.Chip structure after existing alligatoring as shown in Figure 6, wherein, 11-transparency conducting layer; 12-P type electrode; 13-P material; 14-MQW luminous zone; 15-N material; 16-resilient coating; 17-substrate; 18-N type electrode.Can improve LED chip luminous power and light extraction efficiency after alligatoring, but there is many problems in PRough processing procedure, due between its electrode and P-GaN due to more coarse, first, affect current spread, and then cause Vf higher; The second, when adopting reflection processing procedure, because the alligatoring between Pad and P-GaN can reduce reflectivity, and then electrode reflection processing procedure is weakened to the effect of luminance raising.

Summary of the invention

For overcoming above-mentioned defect of the prior art, the present invention proposes a kind of LED chip and preparation method thereof.

According to an aspect of the present invention, propose a kind of preparation method of LED chip, comprising: alligatoring epitaxial wafer; Peace polarizing electrode contact zone.

Wherein, the method comprises further: step 1, provide epitaxial wafer through alligatoring; Step 2, deposit on the P material layer of alligatoring epitaxial wafer one deck etching smoothing layer; Step 3, etching smoothing layer on arrange PR protective layer, wherein, expose the region need doing graduation; Step 4, utilize chemical solution or this structure of plasma etching, then spend glue and remove PR protective layer, erode the etching smoothing layer protected by PR with corrosive liquid; Step 5, arranges transparency conducting layer, then arranges electrode in graduation region.

According to a further aspect in the invention, propose a kind of LED chip structure, comprising: the substrate be Down-Up disposed in order, resilient coating, N material layer, MQW luminous zone and the P material through alligatoring; Wherein, there is graduation region in a surface part for P material, graduation region is arranged transparency conducting layer and electrode.

LED chip structure of the present invention's design and preparation method thereof, by the contact area between graduation asperities epitaxial wafer electrode and P-GaN, can solve the problem that alligatoring epitaxial wafer Vf is higher; And when making alligatoring epitaxial wafer adopt reflecting electrode processing procedure, overcome the on the low side and problem that light extraction efficiency that is that cause is lower of Pad reflectivity.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the alligatoring epitaxial wafer according to the application;

Fig. 2 be according to the deposition-etch smoothing layer of the application after schematic diagram;

Fig. 3 is the schematic diagram carrying out the chip structure after PR protection according to the application;

Fig. 4 be according to the application through over etching and remove the structural representation of protective layer;

Fig. 5 is the schematic diagram according to the layout transparency conducting layer of the application and the LED chip structure of electrode layer;

Fig. 6 is the schematic diagram of the alligatoring epitaxial slice structure of prior art.

Wherein, in this application: 1-substrate; 2-resilient coating; 3-N material; 4-MQW luminous zone; 5-P material; 6-etches smoothing layer; 7-PR photoresist; 8-graduation region; 9-electrode; 10-transparency conducting layer.

In order to the structure of embodiments of the invention clearly can be realized, specific size, structure and device are marked in the drawings, but this is only signal needs, be not intended to limit the invention in this specific dimensions, structure, device and environment, according to specific needs, these devices and environment can carry out adjusting or revising by those of ordinary skill in the art, and the adjustment carried out or amendment are still included in the scope of accompanying claim.

Embodiment

Below in conjunction with the drawings and specific embodiments, a kind of LED chip provided by the invention and preparation method thereof is described in detail.

In the following description, by description multiple different aspect of the present invention, but, for those skilled in the art, can only utilize some or all structure of the present invention or flow process to implement the present invention.In order to the definition explained, set forth specific number, configuration and order, but clearly, also can implement the present invention when there is no these specific detail.In other cases, in order to not obscure the present invention, will no longer be described in detail for some well-known features.

In first embodiment of the application, provide a kind of preparation method of LED chip, wherein, the method comprises alligatoring epitaxial wafer peace polarizing electrode contact zone.Wherein, further, this LED chip is preparation method comprise further: step 1, provide an alligatoring epitaxial wafer, as shown in Figure 1, wherein, substrate 1 is positioned at bottom, be disposed in order resilient coating 2, N material 3, MQW luminous zone 4 and P material 5, wherein, P material 5 is through the P material layer of alligatoring, this coarsening technique can be of the prior art any one.

The method comprises further: step 2, deposit on the P material layer 5 of alligatoring epitaxial wafer one deck etching smoothing layer 6.Be appreciated that due to the selection index system in deposition process, the surface after alligatoring deposits, the thickness of the region smoothing layer of its projection can be partially thin, and the region of depression can be partially thick, as shown in Figure 2.

The method comprises further: step 3, to carry out at needs the smoothing layer 6 that etches does PR protective layer 7 (as the signal of black block layer), and wherein, expose the region need doing graduation, this region is positioned at the side of smoothing layer, becomes ditching type, as shown in Figure 3.

The method comprises further: step 4, utilize chemical solution or this structure of plasma etching, and due to the protective effect of PR protective layer, the graduation region only exposed is etched, and other region is protected.Known further, due to the selectivity of etching, on the etching smoothing layer of alligatoring epitaxial wafer, its region etch speed protruded can be very fast, and sunk area etch rate is comparatively slow, and the rough region therefore exposed can etch graduation gradually.Finally, spend glue and remove PR protective layer, erode the etching smoothing layer protected by PR with corrosive liquid, as shown in Figure 4, the region merely through etching keeps graduation (graduation region 8), recovers alligatoring structure after remaining region is corroded.

The method also comprises: step 5, subsequently, arranges transparency conducting layer 10 thereon, then arranges electrode 9 in graduation region, as shown in Figure 5.

In second embodiment of the application, a kind of LED chip structure is provided, wherein, this structure comprise Down-Up be disposed in order substrate 1, resilient coating 2, N material layer 3, MQW luminous zone 4 and the P material 5 through alligatoring, there is graduation region 8 in a surface part for P material 5, graduation region is arranged transparency conducting layer 10 and electrode 9.

Wherein, this graduation region is formed by chemical solution or this region of plasma etching, due to the selectivity of etching, on the etching smoothing layer initially with alligatoring epitaxial wafer, its region etch speed protruded can be very fast, and sunk area etch rate is comparatively slow, the rough region therefore exposed can etch graduation gradually.

Finally it should be noted that, above embodiment is only in order to describe technical scheme of the present invention instead of to limit this technical method, the present invention can extend in application other amendment, change, application and embodiment, and therefore think that all such amendments, change, application, embodiment are all in spirit of the present invention and teachings.

Claims

1. a preparation method for LED chip, comprising:

Alligatoring epitaxial wafer; With

Graduation electrode contact district.

2. method according to claim 1, wherein, the method comprises further:

Step 1, provide epitaxial wafer through alligatoring;

Step 2, deposit on the P material layer of alligatoring epitaxial wafer one deck etching smoothing layer;

Step 3, etching smoothing layer on arrange PR protective layer, wherein, expose the region need doing graduation;

Step 4, utilize chemical solution or this structure of plasma etching, then spend glue and remove PR protective layer, erode the etching smoothing layer protected by PR with corrosive liquid, form graduation region;

Step 5, arranges transparency conducting layer, then arranges electrode in graduation region.

3. method according to claim 2, wherein, in step 1, the epitaxial wafer of this alligatoring is comprise the substrate being positioned at bottom, and the resilient coating be disposed in order, N material layer, MQW luminous zone and P material layer, wherein, P material layer is through the P material layer of alligatoring.

4. method according to claim 2, wherein, in step 2, the P material surface after alligatoring deposits, and the thickness of the region smoothing layer of its projection can be partially thin, and the region of depression can be partially thick.

5. method according to claim 2, wherein, in step 3, needs the region of graduation to be positioned at the side of smoothing layer, becomes ditching type.

6. method according to claim 2, wherein, in step 4, due to the selectivity of etching, on the etching smoothing layer of alligatoring epitaxial wafer, the region etch speed of protrusion can be fast, sunk area etch rate can be slow, makes the rough region exposed can etch graduation gradually.

7. method according to claim 5, wherein, in step 4, by removing etching smoothing layer, the region merely through etching keeps graduation, namely produces graduation region, recovers alligatoring structure after remaining region is corroded.

8. a LED chip structure, comprising:

The substrate be Down-Up disposed in order, resilient coating, N material layer, MQW luminous zone and the P material through alligatoring;

Wherein, there is graduation region in a surface part for P material, graduation region is arranged transparency conducting layer and electrode.

9. chip structure according to claim 8, wherein, this graduation region is formed by the etching smoothing layer on chemical solution or this region alligatoring of plasma etching P material layer; Wherein, the etching smoothing layer initially with alligatoring epitaxial wafer etches, its region etch speed protruded can be fast, and sunk area etch rate can be slow, makes the alligatoring region exposed to etch graduation.