CN204118111U

CN204118111U - A kind of Al2O3/SiON passivation layer structure of LED chip

Info

Publication number: CN204118111U
Application number: CN201420639117.XU
Authority: CN
Inventors: 王波; 郝锐; 叶国光; 易翰翔; 李方芳
Original assignee: Guangdong De Li Photoelectric Co Ltd
Current assignee: Guangdong De Li Photoelectric Co Ltd
Priority date: 2014-10-31
Filing date: 2014-10-31
Publication date: 2015-01-21
Anticipated expiration: 2024-10-31

Abstract

The utility model discloses a kind of Al2O3/SiON passivation layer structure of LED chip, comprise the n-type semiconductor layer grown successively on substrate, luminescent layer, p-type semiconductor layer and ITO conductive layer, n-type semiconductor layer is manufactured with n-type electrode, ITO conductive layer makes p-type electrode, it is characterized in that: the chip upper surface outside described n-type electrode, p-type electrode deposits Al2O3 layer and SiON layer successively.Al2O3/SiON passivation layer provided by the utility model is laminated construction, its growing method adopts two-step method, the first step first uses the homemade LP-MOCVD equipment growth Al2O3 film being exclusively used in grow oxide material, the material compactness of this metal organic chemical deposition method growth is good, crystal mass is high, can well control Al2O3 film growth rate, second step uses PECVD device growth SiON thin-film material, and double-layer structure plays the effect of electrode passivation and anti-reflection film raising light extraction efficiency respectively.

Description

A kind of Al2O3/SiON passivation layer structure of LED chip

Technical field

The utility model relates to the technical field of LED chip, particularly a kind of Al2O3 of LED chip /siON passivation layer structure and growing method thereof.

Background technology

Light-emitting diode (LED) becomes the main product in order to high-new energy development field under the active support of the government, and the plurality of advantages that it has, and volume is little, life-span long (50,000 hours), light efficiency are high, energy-conservation, has now been widely applied in daily life.LED chip surface to external world environment is very responsive, can adsorb other impurity thus reduce device performance, therefore often needing to deposit in wafer surface the contact that one deck insulating material comes isolated external environment and wafer surface, play passivation.In addition this passivation layer also needs the effect playing anti-reflection film, improves chip light-emitting efficiency, increases chip brightness.

What main flow LED chip all adopted in the market is the passivation layer of silica membrane (SiO2) as wafer, and is all adopt PECVD method to grow SiO2 film.As everyone knows, SiO2 well can not play passivation as passivation layer, this is because passivation layer deposition after electrode preparation, therefore growth temperature can not be too high, otherwise can affect electrode performance; Growth temperature is lower, and the SiO2 film adherability of deposition is poor, is easy to depart from chip surface, and dense materials also can reduce simultaneously, and pinhold density is large, has a significant impact chip performance.In sum, SiO2 passivating film well can not improve the photoelectric characteristic of LED chip.

Summary of the invention

For the deficiencies in the prior art, the utility model provides a kind of novel Al2O3/SiON laminated construction passivating film and its growing method to solve the problem that in existing chip processing procedure, passivation material compactness is low, Al2O3/SiON passivation layer provided by the utility model is a kind of laminated construction, succession is first grow Al2O3 film, then SiON rete is grown, jointly serve as the passivation layer structure of chip, simultaneously in new structure SiON material not only stickiness is good, compactness is good, pinhold density is little, and effectively can promote the light extraction efficiency of LED chip.

The technical solution of the utility model is: a kind of Al2O3/SiON passivation layer structure of LED chip, comprise the n-type semiconductor layer grown successively on substrate, luminescent layer, p-type semiconductor layer and tin indium oxide (ITO) transparency conducting layer, n-type semiconductor layer is manufactured with n-type electrode, ITO conductive layer makes p-type electrode, it is characterized in that: the chip upper surface outside described n-type electrode, p-type electrode deposits Al2O3 layer and SiON layer successively.

The optical thickness of described SiON layer is the odd-multiple of LED emission wavelength 1/4th, and the refractive index of SiON layer is n=(n _air× n _p-GaN) ^1/2.

Described Al2O3 layer and SiON layer constitute novel passivation layer, this passivation layer adopts two-step method growth, the first step first uses the homemade LP-MOCVD equipment growth Al2O3 film being exclusively used in grow oxide material, second step uses PECVD device growth SiON thin-film material, and double-layer structure plays electrode passivation respectively and anti-reflection film improves light extraction efficiency.

A growing method for the Al2O3/SiON passivation layer structure of LED chip, comprises the steps:

A, the LED chip after completing ITO etching is used acetone (ACE), isopropyl alcohol (IPA), deionized water carry out cleaning, drying;

B, the LED product after drying to be put in the MOCVD cavity of growth Al2O3 film, then MOCVD cavity is warmed up to 400-680 DEG C, pass into cavity Al source and O source, grow Al2O3 film and serve as electrode passivation layer;

C, use negative photoresist carry out PAD photoetching to Al2O3 film, form PAD figure on a photoresist;

D, use ICP equipment carry out dry etching to Al2O3 film, remove the Al2O3 film in PAD graphics field;

E, on the passivation layer etched away evaporation metal electrode, formed P, N electrode structure, then remove photoresist, and the chip after removing photoresist put into tube furnace annealing in process;

F, the LED chip preparing electrode is put into plasma reinforced chemical vapour deposition PECVD device cavity, pass into N2 preheating, then pass into the mist of silane, nitrous oxide (laughing gas) and the ammonia that diluted concentration is 2-3%, growth SiON anti-reflection film;

G, use wet-etching technology etch away the SiON on P, N electrode surface, and so far passivation layer growth is complete.

In described step B, Al2O3 film adopts the growth of MOCVD method, comprises following concrete steps:

B1, the LED chip that processing of step A is good is put into the reative cell of LP-MOCVD equipment, now chamber pressure is 20-100torr, graphite plate rotating speed is between 500-900 r/min, be heated within the scope of 400-680 DEG C under the reaction chamber atmosphere of N2, Ar or the two mist, process 5-15 min;

B2, pass in reative cell by Al source, O source, change chamber pressure is 17-45torr simultaneously, and start to grow Al2O3 film, growth rate is 0.5nm/min-10nm/min;

After B3, growth course terminate, chamber pressure is brought up to 50-100torr, increase the N2 flow passing into reaction chamber and reduce temperature by purging, wait LED chip to be removed.

In described step B2, the growing environment temperature of Al2O3 film is 450-650 DEG C, and growth pressure is 25-45torr, and growth thickness is 10nm-100nm, and graphite plate rotating speed is 500-900r/min.

In described step B2, the Al source passed into during growth Al2O3 film and the gas mole ratio of oxygen source are: VI/III between 100-3000.

In described step F, SiON film adopts the growth of PECVD method, comprises following concrete steps:

F1, LED product E step being completed electrode operation are put in the reaction chamber of plasma reinforced chemical vapour deposition (PECVD) equipment;

F2, use traffic are the N2 preheating 5-10min of 300-1000sccm, under the condition that N2 flow is constant, carry out plasma treatment 3-5min, and now radio-frequency power is 10-30W;

F3, then the mist of diluted silane, nitrous oxide (laughing gas) and ammonia is passed into PECVD cavity, growth SiON anti-reflection film.

In described step F, the optical thickness of SiON anti-reflection film is the odd-multiple of LED emission wavelength 1/4th, and its refractive index is n=(n _air× n _p-GaN) ^1/2.

Also comprise before described step G and use hmds (HMDS) as tackifier tackified finish to SiON film surface, then through coating positive photoresist, exposure, developing procedure.

The beneficial effects of the utility model are: the structure and the growing method that provide a kind of new passivation film, use the homemade LP-MOCVD being exclusively used in grow oxide material to grow Al2O3 film, the material compactness of this metal organic chemical deposition method growth is good, crystal mass is high, can well control Al2O3 film growth rate.Use the Al2O3 of mocvd method growth not only can complete coated whole LED wafer surface, and the MQW active region sidewalls exposed after being etched by ICP also covers completely, the whole LED of effective passivation, reduces the drain conditions of LED, improves its electrology characteristic.

Use PECVD method to grow SiON film after making P, N electrode, it is more even that cavity first can make LED wafer surface be heated with N2 preheating, and then can increase the adhesive force of SiON film on Al2O3 material with N2 plasma treatment crystal column surface.According to interfering the theory disappeared mutually, if SiON film will play the effect of anti-reflection film, PECVD deposit thickness is the odd-multiple of LED emission wavelength 1/4th, and the refractive index of film is n=(n _air× n _p-GaN) ^1/2, reduce the refringence between LED wafer superficial layer and outside air, increase the cirtical angle of total reflection, improve the light extraction efficiency of device.

Accompanying drawing explanation

Fig. 1 is the generalized section of LED chip described in the utility model.

Fig. 2 is the vertical view of LED chip described in the utility model.

In figure, 1-graph substrate, 2-N-GaN, 3-quantum well MQW luminescent layer, 4-P-GaN, 5-ITO conducting film, 6-Al2O3 passivating film, 7-SiON anti-reflection film, 8-P electrode, 9-N electrode, 10-Al2O3/SiON composite bed.

Embodiment

Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further details, in embodiment, LP-MOCVD used is the MOCVD device that self-control is exclusively used in grow oxide material, model is SCMD-600B, and plasma enhanced chemical vapor deposition PECVD used is commercially available model is Plasmalab800Plus.

As depicted in figs. 1 and 2, the Al2O3/SiON passivation layer structure of a kind of LED chip that the utility model provides, comprise graph substrate 1, GaN base epitaxial loayer, ITO conducting film 5, P electrode 8, N electrode 9 and Al2O3/SiON composite bed 10, wherein GaN base epitaxial loayer comprises N-GaN2, quantum well MQW luminescent layer 3 and P-GaN4, Al2O3/SiON composite bed 10 and comprises Al2O3 passivating film 6 and SiON anti-reflection film 7.The manufacture method of above-described embodiment is as follows:

1, clean GaN base epitaxial wafer, complete Mesa photoetching, ICP dry etch step, then chip is put into RPD equipment and deposit ito thin film 5, complete the lithography step of ito film layer 5 afterwards;

2, the LED chip in acetone (ACE), isopropyl alcohol (IPA), washed with de-ionized water step 1 is used, the LP-MOCVD being exclusively used in grow oxide material is put into after drying, temperature be 520 DEG C, pressure is 35torr, graphite plate rotating speed be 750r/min condition under growth thickness be the Al2O3 film 6 of 30nm, growth time 10min, cavity atmosphere is argon Ar;

3, take out LED chip after waiting for MOCVD cooling and carry out Pad photoetching, putting into ICP equipment afterwards uses chlorine to etch Al2O3 film 6 as active gases, after completing, taking-up chip carries out Plasma(plasma) sweep glue, drying step, evaporation P, N metal electrode, then removes photoresist and the chip after removing photoresist is put into tube furnace annealing in process;

4, by preparing P electrode 8, the LED chip of N electrode 9 puts into plasma reinforced chemical vapour deposition PECVD device cavity, pass into 400sccmN2 preheating 10min, then be starter 5min under the condition of 30W at radio-frequency power, then the mist of silane, nitrous oxide (laughing gas) and the ammonia that dilute strength is 2-3% is passed into grow SiON anti-reflection film 7, the flow of three kinds of gases is respectively 400sccm, 180sccm, 120sccm, deposit thickness is 1125, and refractive index is 1.58;

5, use wet-etching technology etches away the SiON film 7 on P, N electrode surface.

Namely the Al2O3/SiON passivation layer structure of LED chip described in the utility model is defined through above step.

Claims

1. the Al2O3/SiON passivation layer structure of a LED chip, comprise the n-type semiconductor layer grown successively on substrate, luminescent layer, p-type semiconductor layer and ITO conductive layer, n-type semiconductor layer is manufactured with n-type electrode, ITO conductive layer makes p-type electrode, it is characterized in that: the chip upper surface outside described n-type electrode, p-type electrode deposits Al2O3 layer and SiON layer successively.

2. the Al2O3/SiON passivation layer structure of LED chip according to claim 1, is characterized in that: the optical thickness of described SiON layer is the odd-multiple of LED emission wavelength 1/4th, and the refractive index of SiON layer is n=(n _air× n _p-GaN) ^1/2.