A kind of method that improves antistatic ability of GaN-based light-emitting diode
Technical field
The invention belongs to the gallium nitride based light emitting diode preparing technical field, particularly a kind of method that improves antistatic ability of GaN-based light-emitting diode.
Background technology
Current semiconductor lighting technology based on gallium nitride based light emitting diode (LED) is permeated to aspect of social life, as Landscape Lighting, and special lighting, and the LCD backlight source lighting etc.But the defective intrinsic owing to III-nitride is many, and dislocation density is big, problems such as quality of materials difference, and it is poor to have caused based on the semiconductor lighting device antistatic effect of III-nitride, has limited it and has further entered high-end applications market.Semiconductor lighting wants to enter general illumination, and except efficient need improve constantly, it also was a very urgent demand that antistatic effect improves.
At present at the problem of GaN base LED antistatic effect difference, people have proposed a lot of solutions, such as adding Zener diode when the encapsulation, and static electrification ring etc. during operation, and in material structure, add low-doped current extending etc.But, owing to these methods or by external means led chip is carried out electrostatic protection, lower the static injury, also increased the LED cost of manufacture simultaneously; Or by current expansion, rather than, only improve the LED antistatic effect to a certain extent fundamentally to the raising of crystal mass, also exist more serious accumulation of static electricity injury, so there is following defective in said method:
1, increase the LED cost of manufacture;
2, antistatic effect waits to improve;
3, there is more serious accumulation of static electricity injury.
Summary of the invention
(1) technical problem that will solve
In view of this, main purpose of the present invention is to provide a kind of method that improves antistatic ability of GaN-based light-emitting diode, by between involuntary Doped GaN and Doped GaN, inserting one aluminium gallium nitride alloy/gallium nitride superlattice insert layer, the stress that brings because of lattice mismatch in modulation and the release epitaxial loayer, and make the dislocation in the GaN epitaxial loayer turn to, merge, the density of threading dislocation in the epitaxial loayer of reduction subsequent growth, solve the ropy problem of epitaxial material, reach and improve quality of materials, improve the purpose of the antistatic effect of light-emitting diode.
(2) technical scheme
For achieving the above object, the invention provides a kind of method that improves antistatic ability of GaN-based light-emitting diode, comprising:
Select a substrate;
Growth one gallium nitride nucleating layer on this substrate;
The involuntary doped gallium nitride layer of growth on this gallium nitride nucleating layer;
Growth one aluminium gallium nitride alloy/gallium nitride superlattice insert layer on this involuntary doped gallium nitride layer;
The gallium nitride layer that growth N type mixes on this aluminium gallium nitride alloy/gallium nitride superlattice insert layer;
Growing aluminum nitride gallium indium multiple quantum well light emitting layer on the gallium nitride layer that this N type mixes;
The aluminum indium gallium nitride layer that growing P-type mixes on this aluminum indium gallium nitride multiple quantum well light emitting layer, this aluminum indium gallium nitride layer is the aluminum indium gallium nitride sandwich construction of individual layer or different component and thickness; And
The gallium nitride layer that growing P-type mixes on the aluminum indium gallium nitride layer that this P type mixes.
In the such scheme, described substrate is sapphire, carborundum, silicon, GaAs, zinc oxide or lithium aluminate.Perhaps, described substrate is a planar substrate, perhaps produces rule or erose graph substrate on the surface, and the characteristic size of graph substrate is as follows: the figure bottom size is 0.1-10 μ m, and the figure spacing is 0.1-5 μ m, and the figure height is 0.1-5 μ m.
In the such scheme, the described gallium nitride nucleating layer of growing on substrate adopts metallo-organic compound physical vapor epitaxy, and growth temperature is 500-600 ℃, and growth pressure is 10000-90000Pa, and growth thickness is 0.01-0.1 μ m.
In the such scheme, in the step of the described involuntary doped gallium nitride layer of growing on the gallium nitride nucleating layer, growth temperature is 900-1200 ℃, and growth pressure is 10000-60000Pa, and growth thickness is 1-5 μ m.
In the such scheme, in the step of the described one aluminium gallium nitride alloy/gallium nitride superlattice insert layer of on involuntary doped gallium nitride layer, growing, growth temperature is 1000-1100 ℃, growth pressure is 5000-40000Pa, the thickness of every pair of superlattice unit is 0.001-0.1 μ m, the superlattice logarithm is that 1-100 is right, and these superlattice are that the n type mixes or are non-doping that n type doping elements is a silicon.
In the such scheme, in the step of the described gallium nitride layer that growth N type mixes on aluminium gallium nitride alloy/gallium nitride superlattice insert layer, growth temperature is 1000-1100 ℃, and growth pressure is 10000-60000Pa, and growth thickness is 1-5 μ m, and its n type doped chemical is Si.
In the such scheme, described on the gallium nitride layer that the N type mixes in the step of growing aluminum nitride gallium indium multiple quantum well light emitting layer, aluminum indium gallium nitride multiple quantum well light emitting layer is Ga
1-xIn
xN/Al
xIn
yGa
1-x-yN multiple quantum well light emitting layer, growth temperature are 650-900 ℃, and growth pressure is 20000-60000Pa, the Al of Multiple Quantum Well
xIn
yGa
1-x-yThe N potential barrier thickness is 0.005-0.05 μ m, Ga
1-xIn
xN quantum well thickness is 0.001-0.01 μ m, and wherein the logarithm of Multiple Quantum Well is that 1-30 is right.
In the such scheme, in the step of the described aluminum indium gallium nitride layer that growing P-type mixes on aluminum indium gallium nitride multiple quantum well light emitting layer, the Al that the aluminum indium gallium nitride layer that the P type mixes mixes for the p type
xIn
yGa
1-x-yThe N layer, 0≤x≤1,0≤y≤1 wherein, growth temperature is 900-1100 ℃, and pressure is 5000-40000Pa, and this aluminum indium gallium nitride layer is a monolayer material, or the Al of different component
xIn
yGa
1-x-yThe N laminated construction; For monolayer material, its thickness is 0.005-0.1 μ m; For laminated construction, its thickness in monolayer is 0.001 μ m-0.1 μ m, and the laminated construction logarithm is 2 to 30 pairs; The foreign atom of this aluminum indium gallium nitride layer is magnesium or zinc.
In the such scheme, in the step of the gallium nitride layer that growing P-type mixes on the aluminum indium gallium nitride layer that the P type mixes, growth temperature is 800-1100 ℃, and pressure is 10000-60000Pa, and growth thickness is 0.1-1 μ m.
(3) beneficial effect
From technique scheme as can be seen, the present invention has following beneficial effect:
1, utilize the present invention, owing to fundamentally improved the quality of materials of each layer of LED, so can well improve the antistatic effect of LED.
2, utilize the present invention and since fundamentally improve the quality of materials of quality of materials, the especially luminous zone of each layer of LED, so this LED structure has good reduction accumulation of static electricity injury.
3, utilize the present invention,,, help in the back road of LED processing procedure, reducing cost so do not need external means owing to be to improve by the quality of materials of LED own to improve antistatic effect.
Description of drawings
Fig. 1 is the method flow diagram of raising antistatic ability of GaN-based light-emitting diode provided by the invention;
Fig. 2 is the transmission electron microscope pattern according to embodiment of the invention AlGaN/GaN superlattice insert layer;
Fig. 3 is the antistatic test result of GaN base LED that adopts the AlGaN/GaN superlattice according to the embodiment of the invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.
Key of the present invention is to set about from epitaxial growth mechanism and the control of epitaxial loayer dislocation, by introducing the distribution that aluminium gallium nitride alloy/gallium nitride superlattice change dislocation in the epitaxial loayer, make it turn to, merge, and then the dislocation density in the GaN material of reduction subsequent growth, improve quality of materials, improve the antistatic effect of light-emitting diode.
The method of this raising antistatic ability of GaN-based light-emitting diode provided by the invention, by between involuntary Doped GaN and Doped GaN, inserting one aluminium gallium nitride alloy/gallium nitride superlattice insert layer, lattice match and stress in the modulation epitaxial loayer, make the dislocation in the GaN epitaxial loayer turn to, merge, thereby the density of threading dislocation in the epitaxial loayer of reduction subsequent growth, improve quality of materials, improve the antistatic effect of light-emitting diode.
As shown in Figure 1, Fig. 1 is the method flow diagram of raising antistatic ability of GaN-based light-emitting diode provided by the invention, and this method comprises: select a substrate; Growth one gallium nitride nucleating layer on this substrate; The involuntary doped gallium nitride layer of growth on this gallium nitride nucleating layer; Growth one aluminium gallium nitride alloy/gallium nitride superlattice insert layer on this involuntary doped gallium nitride layer; The gallium nitride layer that growth N type mixes on this aluminium gallium nitride alloy/gallium nitride superlattice insert layer; Growing aluminum nitride gallium indium multiple quantum well light emitting layer on the gallium nitride layer that this N type mixes; The aluminum indium gallium nitride layer that growing P-type mixes on this aluminum indium gallium nitride multiple quantum well light emitting layer, this aluminum indium gallium nitride layer is the aluminum indium gallium nitride sandwich construction of individual layer or different component and thickness; And the gallium nitride layer that growing P-type mixes on the aluminum indium gallium nitride layer that this P type mixes.
Wherein, described substrate is sapphire, carborundum, silicon, GaAs, zinc oxide or lithium aluminate.Perhaps, described substrate is a planar substrate, perhaps produces rule or erose graph substrate on the surface, and the characteristic size of graph substrate is as follows: the figure bottom size is 0.1-10 μ m, and the figure spacing is 0.1-5 μ m, and the figure height is 0.1-5 μ m.
The described gallium nitride nucleating layer of growing on substrate adopts metallo-organic compound physical vapor epitaxy, and growth temperature is 500-600 ℃, and growth pressure is 10000-90000Pa, and growth thickness is 0.01-0.1 μ m.
In the step of the described involuntary doped gallium nitride layer of growing on the gallium nitride nucleating layer, growth temperature is 900-1200 ℃, and growth pressure is 10000-60000Pa, and growth thickness is 1-5 μ m.
In the step of the described one aluminium gallium nitride alloy/gallium nitride superlattice insert layer of on involuntary doped gallium nitride layer, growing, growth temperature is 1000-1100 ℃, growth pressure is 5000-40000Pa, the thickness of every pair of superlattice unit is 0.001-0.1 μ m, the superlattice logarithm is that 1-100 is right, these superlattice are that the n type mixes or are non-doping that n type doping elements is a silicon.
In the step of the described gallium nitride layer that growth N type mixes on aluminium gallium nitride alloy/gallium nitride superlattice insert layer, growth temperature is 1000-1100 ℃, and growth pressure is 10000-60000Pa, and growth thickness is 1-5 μ m, and its n type doped chemical is Si.
Described on the gallium nitride layer that the N type mixes in the step of growing aluminum nitride gallium indium multiple quantum well light emitting layer, aluminum indium gallium nitride multiple quantum well light emitting layer is Ga
1-xIn
xN/Al
xIn
yGa
1-x-yN multiple quantum well light emitting layer, growth temperature are 650-900 ℃, and growth pressure is 20000-60000Pa, the Al of Multiple Quantum Well
xIn
yGa
1-x-yThe N potential barrier thickness is 0.005-0.05 μ m, Ga
1-xIn
xN quantum well thickness is 0.001-0.01 μ m, and wherein the logarithm of Multiple Quantum Well is that 1-30 is right.
In the step of the described aluminum indium gallium nitride layer that growing P-type mixes on aluminum indium gallium nitride multiple quantum well light emitting layer, the Al that the aluminum indium gallium nitride layer that the P type mixes mixes for the p type
xIn
yGa
1-x-yThe N layer, 0≤x≤1,0≤y≤1 wherein, growth temperature is 900-1100 ℃, and pressure is 5000-40000Pa, and this aluminum indium gallium nitride layer is a monolayer material, or the Al of different component
xIn
yGa
1-x-yThe N laminated construction; For monolayer material, its thickness is 0.005-0.1 μ m; For laminated construction, its thickness in monolayer is 0.001 μ m-0.1 μ m, and the laminated construction logarithm is 2 to 30 pairs; The foreign atom of this aluminum indium gallium nitride layer is magnesium or zinc.
In the step of the gallium nitride layer that growing P-type mixes on the aluminum indium gallium nitride layer that the P type mixes, growth temperature is 800-1100 ℃, and pressure is 10000-60000Pa, and growth thickness is 0.1-1 μ m.
In the method for the raising antistatic ability of GaN-based light-emitting diode that present embodiment provides, used epitaxial device is the business PC that German AIXTRON company produces, and model is Crius 31x2 '.Used group V source is ammonia (NH
3), III family metal organic source material is trimethyl gallium (TMGa) and trimethyl indium (TMIn), except growth multiquantum well region N
2The carrier gas of doing the outer remainder layer of carrier gas is H
2, p type and n type impurity are respectively Mg, Si.
At first, behind the MOCVD growth apparatus of packing on 2 inches the Sapphire Substrate, be warmed up to 1100 ℃ of high-temperature bakings earlier, reative cell cools to 560 ℃ of growing low temperature aluminum indium gallium nitride nucleating layers then, the flow of trimethyl gallium is 75 standard ml/min, ammonia flow is 15 standard liter/min, and growth time is 100-200 second, and chamber pressure is 60000Pa.The nucleation and closure that heat up afterwards and carry out GaN successively, the about 2 μ m of the involuntary Doped GaN layer of growing, growth Si doped n type AlGaN/GaN superlattice, wherein Al content is 0.05-0.2, the Si doping content is 1 * 10
18-1 * 10
19Gm
-3, AlGaN and GaN bed thickness are 0.003-0.01 μ m; The GaN layer 2 μ m of growing n-type doping afterwards; Next cool to 700-900 ℃, and system is switched to N
2Atmosphere, pressure are 40000Pa, growing gallium nitride indium/aluminum indium gallium nitride multiple quantum well light emitting district; Again switch atmosphere to H
2, temperature is elevated to the sandwich construction of 1000 ℃ of growth Mg doped p type aluminum indium gallium nitrides and gallium nitride, grows 5 pairs altogether, and aluminum indium gallium nitride thickness and gallium nitride thickness are 0.005 μ m.The Mg doped p of growing afterwards type gallium nitride layer 0.1-0.2 μ m has promptly finished the growth of complete light emitting diode construction.
Fig. 2 shows the transmission electron microscope pattern according to embodiment of the invention AlGaN/GaN superlattice insert layer, and Fig. 3 shows the antistatic test result of GaN base LED that adopts the AlGaN/GaN superlattice according to the embodiment of the invention.AlGaN/GaN insert layer of the present invention has effectively reduced the dislocation density in the GaN layer of subsequent growth, improved quality of materials, improved the antistatic effect of LED device, as shown in Figure 3, be prepared into the led chip of using backlight of 0.25mm * 0.6mm, its Human Body Model's antistatic effect surpasses 6000V.
Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.