CN205028916U

CN205028916U - LED epitaxial structure

Info

Publication number: CN205028916U
Application number: CN201520770301.2U
Authority: CN
Inventors: 郑树文; 韩振伟; 何苗; 李述体
Original assignee: South China Normal University
Current assignee: South China Normal University
Priority date: 2015-09-29
Filing date: 2015-09-29
Publication date: 2016-02-10
Anticipated expiration: 2025-09-29

Abstract

The utility model provides a LED epitaxial structure, this structure includes from bottom to top: substrate, nucleation layer, the gaN layer of not adulterateing, n type gaN layer, luminescent layer, electron barrier and p type gaN layer, its characteristics lie in: the electron barrier comprises alxGa1 -xN layer, multicycle gaNInyGa1 -yN superlattice structure layer and alzGa1 -zN layer. The utility model discloses can effectively hinder grade electronic and leak, radiative recombination probability between reinforcing electron and the hole, and then improve LED's the internal quantum efficiency and the output of light to and reinforcing LED's antistatic effect. The utility model discloses accessible atomic layer epitaxy technique is prepared, can extensively be used for LED device field as a LED epitaxial structure.

Description

A kind of LED epitaxial structure

Technical field

This novel practical relates to the growth technology field of semiconductor photoelectric device, particularly a kind of LED epitaxial structure.

Background technology

Take LED as the forth generation light source of representative, because having, structure is little, fail safe good, and the high and energy-conservation plurality of advantages such as obviously of luminous efficiency, has become the best light source selection of alternative conventional illumination sources., current business-like white LED light source, mainly by sending blue light on the epitaxial structure of GaN base LED, and sends gold-tinted by the fluorescent material of blue-light excited YAG, two mixture of colours thus obtain white light.Thus, the epitaxial structure design of GaN base LED is very important, and the blue light how obtaining high-luminous-efficiency from epitaxial structure is particularly important.The design breaking through conventional blu-ray LED epitaxial structure is not enough, and the growth quality improving LED epitaxial structure is forward position key technology work very important at present.

Traditional GaN base LED epitaxial structure is generally grow into stratum nucleare, layer of undoped gan, n-type GaN layer, multiple quantum well light emitting, AlGaN barrier and p-type GaN layer on a sapphire substrate successively.Because traditional LED structure only adopts single AlGaN electronics barrier, so the resistance shelves scarce capacity to electronics, cause electronics to reveal obviously, cause the Net long wave radiation recombination rate in LED component internal electron hole low, thus cause LED internal quantum efficiency and light output efficiency not high.

The ESD(ElectroStaticdischarge of current LED component, static discharge) main method of protecting is quality by improving LED epitaxial structure, and in LED epitaxial structure, add Zener diode or increase current extending and realize.Such as Chinese invention patent prospectus CN101335313 discloses a kind of N-shaped nitride layer plain nitride layer of middle insertion of LED structure in (publication date on December 31st, 2008) or insert plain nitride layer between N-shaped nitride layer and luminescent layer, its new LED epitaxial structure formed just is equivalent to add an electric capacity, thus improves the barrier propterty of ESD.

Utility model content

Technical problem to be solved in the utility model is to provide a kind of LED epitaxial structure, and this structure can improve the luminous efficiency of LED and strengthen the protective capacities of ESD.

For solving the problems of the technologies described above, a kind of LED epitaxial structure of the present utility model, comprise from bottom to top: GaN nucleating layer, layer of undoped gan, n-type GaN layer, multiple quantum well light emitting layer, electronics barrier and p-type GaN layer, its feature is: described electronics barrier is by Al _xga _1-xn layer, multicycle GaN/In _yga _1-yn super lattice structure layers and Al _zga _1-zn layer (referred to as A-SL-A layer) is formed; Wherein, 0<x≤0.8,0<y≤0.2,0<z≤0.5.

Further, the Al in described electronics barrier _xga _1-xn layer growth on the luminescent layer of LED epitaxial structure, multiply periodic GaN/In _yga _1-yn superlattice structure layer growth is at Al _xga _1-xon N layer, Al _zga _1-zn layer growth is at multiply periodic GaN/In _yga _1-yin N super lattice structure layers

Key features of the present utility model is the electronics barrier inserting A-SL-A structure between multiple quantum well light emitting layer and p-type GaN layer.The structure of described electronics barrier is Al _xga _1-xn layer growth, on the luminescent layer of LED epitaxial structure, then grows multiply periodic GaN/In _yga _1-yn super lattice structure layers, finally grows Al _zga _1-zn layer.Described multicycle GaN/In _yga _1-yn super lattice structure layers, its periodicity is 2 to 15, and each cycle comprises GaN layer and In successively _yga _1-yn material layer, each GaN layer and In _yga _1-ythe thickness of N material layer is 1nm to 6nm.Al in described electronics barrier _xga _1-xn layer and Al _zga _1-zthe maximum ga(u)ge of N layer is all no more than 20nm.

The beneficial effects of the utility model are: by inserting the electronics barrier of A-SL-A structure between multiple quantum well light emitting layer and p-type GaN layer, can effectively electronics be limited in luminescent layer, strengthen the probability of the radiation recombination in luminous zone electronics and hole, and then improve the luminous efficiency of LED.On the other hand, the electronics barrier of A-SL-A structure joins in LED epitaxial structure, is just equivalent in LED structure, add multiple electric capacity, so LED just can be made to have better against esd ability.

Accompanying drawing explanation

Fig. 1 is the utility model LED epitaxial structure schematic diagram;

Fig. 2 is the schematic diagram of electronics barrier in the utility model LED epitaxial structure;

Fig. 3 is the operating current of embodiment in the utility model LED epitaxial structure and interior quantum luminous efficiency result figure;

Fig. 4 is operating current and the optical output power result figure of embodiment in the utility model LED epitaxial structure.

In figure: 1 is substrate; 2 is nucleating layer; 3 is layer of undoped gan; 4 is n-type GaN layer; 5 is multiple quantum well light emitting layer; 6 is A-SL-A electronics barrier; 61 is Al _xga _1-xn layer; 62 is GaN layer; 63 is In _yga _1-yn layer; 64 is Al _zga _1-zn layer; 7 is p-type GaN layer.

Embodiment

Below in conjunction with accompanying drawing, embodiment of the present utility model is described further, but execution mode of the present utility model is not limited thereto.

In this embodiment, LED epitaxial structure is at sapphire (Al ₂o ₃) first substrate grows the GaN material nucleating layer that a layer thickness is about 25nm, be then about 1um layer of undoped gan at nucleating layer surface-borne thickness, (thickness is 2um, and concentration is about 5 × 10 then to grow the n-type GaN layer of Si Doped GaN successively ¹⁸cm ^-3), 6 cycle In _0.15ga _0.85multiple quantum well light emitting layer (the In of N/GaN _0.15ga _0.85n and GaN thickness is respectively 2.5nm and 10nm), electronics barrier (Al _xga _1-xthe x of N is 0.15, In _yga _1-yy in N is 0.03, Al _zga _1-zz in N layer is 0.15, and each layer thickness is all 1nm, GaN/In _yga _1-ythe periodicity of N superlattice structure is 9), and the p-type GaN layer of Mg Doped GaN (thickness is about 0.3um, and concentration is 7 × 10 ¹⁷cm ^-3).What this epitaxial structure adopted is atomic-layer epitaxial growth method, can be the methods such as MOCVD or MBE.

Carry out photoelectric properties analysis to the LED epitaxial structure of this embodiment, the analysis result obtained is shown in shown in Fig. 3 and Fig. 4.Learnt by Fig. 3, novel GaN base LED epitaxial structure of the present invention has better internal quantum efficiency, especially under larger operating current (200mA), still keep lower decay (only 2.1%), the electronics barrier that display the present embodiment adopts can limit the leakage of electronics very well.And the internal quantum efficiency of traditional GaN base LED epitaxial structure is lower, under 200A operating current, luminous efficiency decay is very fast, reaches 21.2%.Learnt by Fig. 4, the LED epitaxial structure of the present embodiment has higher optical output power (cutting into 300um × 300um scale chips to carry out test and comparison to LED) than traditional structure.

In addition, by carrying out against esd performance test to the LED epitaxial structure of the utility model embodiment, under the antistatic pattern test of human body (testing 3 times, every minor tick 1 second), when reverse voltage reaches 2500V, the reverse current value of epitaxial structure is still O.And traditional GaN base LED epitaxial structure reaches about 1500V at reverse voltage just there will be larger reverse current value, namely epitaxial structure has been damaged, and such comparative test illustrates that the LED epitaxial structure of the present embodiment has better against esd ability.

The thickness, technological parameter etc. of above embodiment are signal, any change that those of ordinary skill in the art go out under the prerequisite not violating inventive concept and spirit or modification, all should regard as within protection scope of the present invention.Such as, as more example, when other conditions are constant, make the Al in electronics barrier _xga _1-xthe x of N is 0.8, In _yga _1-yy in N is 0.2, Al _zga _1-zz in N layer is 0.5, and each layer thickness is all 1nm, GaN/In _yga _1-ythe periodicity of N superlattice structure is 3), by same method of testing, in the scope of aforementioned definition, the conclusion identical with above-mentioned example can be drawn all equally.

Claims

1. a LED epitaxial structure, is included in GaN nucleating layer, layer of undoped gan, n-type GaN layer, multiple quantum well light emitting layer, electronics barrier and p-type GaN layer that substrate grows successively, it is characterized in that: described electronics barrier is by Al _xga _1-xn layer, multicycle GaN/In _yga _1-yn super lattice structure layers and Al _zga _1-zn layer is formed; Wherein, 0<x≤0.8,0<y≤0.2,0<z≤0.5.

2. LED epitaxial structure according to claim 1, is characterized in that the Al in electronics barrier _xga _1-xn layer growth on the luminescent layer of LED epitaxial structure, multiply periodic GaN/In _yga _1-yn superlattice structure layer growth is at Al _xga _1-xon N layer, Al _zga _1-zn layer growth is at multiply periodic GaN/In _yga _1-yin N super lattice structure layers.

3. LED epitaxial structure according to claim 1 and 2, is characterized in that described multicycle GaN/In _yga _1-yn super lattice structure layers, its periodicity is 2 to 15, and each cycle comprises GaN layer and In successively _yga _1-yn material layer, each GaN layer and In _yga _1-ythe thickness of N material layer is 1nm to 6nm.

4. LED epitaxial structure according to claim 3, is characterized in that Al _xga _1-xn layer and Al _zga _1-zthe thickness of N layer is all no more than 20nm.