Summary of the invention
The invention provides a kind of method of avoiding or reducing the V-type defective of blue-green light LED material, be applicable to metal organic chemical vapor deposition (MOCVD) on Sapphire Substrate in the epitaxial growth blue-green light LED process, avoid or reduce V-type defective and consequent reverse leakage current.
The object of the present invention is achieved like this: a kind of method of avoiding or reducing the V-type defective of blue-green light LED material, this material has Sapphire Substrate layer 1 successively, the GaN resilient coating 2 of low-temperature epitaxy, the n-GaN layer 3 of high growth temperature, In
yGa
1-yN/GaN multiple quantum well layer 5,0<y<0.5, p-Al
zGa
1-zN/p-GaN layer 6,0<z<1 is characterized in that: at the n-GaN of high growth temperature layer 3 and In
yGa
1-yBetween the N/GaN multiple quantum well layer 5, the n-type Al of growth is arranged
xGa
1-xN/GaN superlattice layer 8,0<x<1 wherein, growth temperature is between 1100 ℃-1200 ℃, and pressure is between 30Torr-100Torr, Al
xGa
1-xThe N layer thickness is between between the 1nm to 5nm, and the GaN layer thickness is between between the 1nm to 5nm, and periodicity is between 5 to 10, and doping content is 1 * 10
16Cm
-3To 1 * 10
18Cm
-3Between and weak n-type Doped GaN layer 9, growth temperature is 1150 ℃-1200 ℃, growth pressure is 30Torr to 80Torr, thickness is between 1nm to 50nm, doping content is 1 * 10
16Cm
-3To 5 * 10
17Cm
-3Between.
The aforesaid method of avoiding or reducing the V-type defective of blue-green light LED material is characterized in that: with high-purity hydrogen (H
2) or nitrogen (N
2) as carrier gas, with trimethyl gallium (TMGa), trimethyl aluminium (TMAl), trimethyl indium (TMIn) and ammonia (NH
3) respectively as Ga, Al, In and N source are with silane (SiH
4), two luxuriant magnesium (Cp
2Mg) as n, p type dopant, growth course comprises the steps:
1. at first with backing material sapphire Sapphire substrate layer 1 in temperature greater than 1100 ℃, carry out oxide layer desorption and clean the processing 1 to 10 minute in the nitrogen atmosphere;
2. temperature is dropped between 450 ℃ and 600 ℃, the thick low temperature GaN nucleating layer 2 of growth 20nm to 60nm, during this growth course, growth pressure is between 30Torr to 760Torr, and the V/III mol ratio is between 500-30000;
3. underlayer temperature is elevated between 1000 ℃-1200 ℃, low temperature GaN nucleating layer is carried out annealing in process in position, annealing time is between 10 seconds to 10 minutes;
4. after the annealing, between adjustment to 1000 ℃-1200 ℃, 1 to the 5 micron n type Doped GaN layer 3 of growing, growth pressure is between 30Torr to 760Torr, and the V/III mol ratio is between 300-3000, and doping content is 1 * 10
18Cm
-3To 1 * 10
20Cm
-3Between;
5. with adjustment between 1100 ℃-1200 ℃ of the higher temperature region, growth pressure is controlled at low pressure range from growing n-type doped with Al between the 30Torr to 100Torr
xGa
1-xN/GaN (0<x<1) superlattice layer 8 structures, wherein Al
xGa
1-xThe N layer thickness is between between the 1nm to 5nm, and the GaN layer thickness is between between the 1nm to 5nm, and periodicity is between 5 to 10, and doping content is 1 * 10
16Cm
-3To 1 * 10
18Cm
-3Between.
6. with adjustment between 1150 ℃-1200 ℃ of the higher scopes, growth pressure transfers between the low pressure range 30Torr to 80Tor, the weak n-type Doped GaN layer 9 of growth, thickness is between 1nm to 50nm, doping content is 1 * 10
16Cm
-3To 5 * 10
17Cm
-3Between.
7. with adjustment to 700 ℃-800 ℃, pressure transfers between the 30Torr to 760Torr, growth In
yGa
1-yN/GaN (0<y<0.5) multiple quantum well layer 5, wherein In
yGa
1-yN quantum well layer thickness is between between the 1nm to 3nm, and the GaN barrier layer thickness is between between the 3nm to 20nm, and the quantum well number is between 1 to 10; The growth temperature that GaN builds layer compares In
yGa
1-yThe high 0-100 of the growth temperature of N quantum well layer ℃, GaN builds and undopes in the layer or slight n-type doping, and doping content is 1 * 10
16Cm
-3To 5 * 10
17Cm
-3Between.
8. p-Al grows
zGa
1-zN/p-GaN layer 6 transfers to temperature between 800 ℃-1000 ℃, growth p-Al
zGa
1-zN layer (0<z<1), wherein Al
zGa
1-zThe N layer thickness is between between the 1nm to 50nm, and in this growth course, growth pressure is between 30Torr to 100Torr;
Temperature is transferred to 800 ℃-1000 ℃, and pressure transfers to 30Torr-200Torr, growth p-type Doped GaN, and doping content is between 1 * 10
19Cm
-3To 1 * 10
20Cn
-3Between, thickness is 100nm-300nm.
The grow method of blue-green light LED material and the difference and the advantage of existing blue-green light LED growth method of the present invention is: usual way is after step 4 or direct growth In
yGa
1-yThe N/GaN multiple quantum well layer or behind 700 ℃-800 ℃ growth one deck GaN regrowth In
yGa
1-yThe N/GaN multiple quantum well layer is beneficial to introduce more In component, and V-type generation of defects can't be avoided or reduce to these methods all; The present invention introduces step 5 and step 6 after step 4, changed the surface energy of growing surface, makes (1011
-)-crystal face no longer is the crystal face of surface energy minimum, thereby avoids or reduced V-type generation of defects.
Embodiment
Fig. 1 is the schematic diagram of existing blue-green light LED material structure 1, and wherein threading dislocation reaches by the V-type defective of its generation and also illustrates as figure.It is successively by Sapphire Substrate layer 1, the GaN resilient coating 2 of low-temperature epitaxy, the layer n-GaN 3 of high growth temperature, lower temperature Grown GaN layer 4, In
yGa
1-yN/GaN multiple quantum well layer 5, p-Al
zGa
1-zN/p-GaN layer 6 is formed.
The 1st, Sapphire Substrate layer sapphire is generally (0001) direction.The 2nd, the GaN resilient coating of low-temperature epitaxy, thickness is 30nm-40nm usually.Growth temperature is usually between 450 ℃-600 ℃.The 3rd, the n-GaN of high growth temperature, thickness are 1 micron-5 microns, and doping content is between 1 * 10
18Cm
-3To 1 * 10
20Cm
-3Between, growth temperature is that growth pressure is between 200Torr to 760Torr between 1000 ℃-1200 ℃.The 4th, lower temperature Grown GaN, growth temperature are between 700 ℃-800 ℃, and thickness is generally between 10nm-30nm, and pressure is between 400Torr-760Torr, with ensuing In
yGa
1-yN/GaN Multiple Quantum Well growth conditions is close.Here the lower growth temperature of selection is the interface in order to provide to help In atom growth efficiency, and selecting higher growth pressure is in order to help the uniformity of In atom interface distributions.Yet lower growth temperature and higher growth pressure help the growth of [10-11]-crystal face, cause V-type defective to form on the top of threading dislocation easily, thereby at In
yGa
1-yForm highdensity V-type defective in the N/GaN Multiple Quantum Well.The 5th, In
yGa
1-yN/GaN Multiple Quantum Well, growth temperature are between 700 ℃-800 ℃, and pressure is between 400Torr-760Torr, In
yGa
1-yN trap layer thickness is 1nm-3nm, and the GaN barrier layer thickness is 3nm-20nm, and the quantum well number is 1-10, and GaN builds and undopes in the layer or slight n-type doping, and concentration is 1 * 10
16Cm
-3To 5 * 10
17Cm
-3Between.The 6th, the Al that the p-type mixes
zGa
1-zThe GaN contact layer that N (0<z<1) electronic barrier layer and p-type mix, the Al that the p-type mixes
zGa
1-z(0<z<1) electronic barrier layer thickness is between 1nm-50nm, and growth temperature is 800 ℃-1000 ℃, and growth pressure is between 30Torr to 100Torr, and doping content is 1 * 10
19Cm
-3To 1 * 10
20Cm
-3Between; The GaN contact layer that the p-type mixes, growth temperature is 800 ℃-1000 ℃, and growth pressure is 30Torr to 200Torr, and doping content is between 1 * 10
19Cm
-3To 1 * 10
20Cm
-3Between, thickness is 100nm-300nm.
Fig. 2 is existing the 2nd kind of blue-green light LED structural representation, and wherein threading dislocation reaches by the V-type defective of its generation and also illustrates as figure.It successively by it successively by Sapphire Substrate layer 1, the GaN resilient coating 2 of low-temperature epitaxy, the layer n-GaN 3 of high growth temperature, condition of high voltage is the weak doping n-GaN layer 7 of growth down, In
yGa
1-yN/GaN multiple quantum well layer 5, p-Al
zGa
1-zN/p-GaN layer 6 is formed.
Sapphire Substrate layer 1 is to the layer n-GaN 3 of high temperature growth, In
yGa
1-yN/GaN multiple quantum well layer 5 is to p-Al
zGa
1-zIdentical among N/p-GaN layer 6 and Fig. 1.
The 7th, condition of high voltage is the n-GaN layer of the weak doping of growth down, and growth temperature is between 1000 ℃-1100 ℃, and thickness is generally between 10nm-100nm, and pressure is between 400Torr-760Torr.Here selecting higher growth pressure is in order to obtain an interface that evenness is high, to help the uniformity that the In atom distributes.Yet higher growth pressure helps (1011
-The growth of)-crystal face causes V-type defective to form on the top of threading dislocation easily, thereby at In
yGa
1-yForm the V-type defective of higher density in the N/GaN Multiple Quantum Well.
Fig. 3 is the blue-green light LED structural representation of the embodiment of the invention, and wherein threading dislocation is also illustrated as figure.It is successively by Sapphire Substrate layer 1, the GaN resilient coating 2 of low-temperature epitaxy, the layer n-GaN 3 of high growth temperature, n-type Al
xGa
1-xN/GaN superlattice layer 8, the weak n-type Doped GaN layer 9 of growing under the low pressure condition, In
yGa
1-yN/GaN multiple quantum well layer 5, p-Al
zGa
1-zN/p-GaN layer 6 is formed.
Sapphire Substrate layer 1 is to the layer n-GaN 3 of high temperature growth, In
yGa
1-yN/GaN multiple quantum well layer 5 is to p-Al
zGa
1-zIdentical among N/p-GaN layer 6 and Fig. 1.
The 8th, higher temperature and lower pressure be the n-type Al of growth down
xGa
1-xThe N/GaN superlattice layer, 0<x<1 wherein, growth temperature is between 1100 ℃-1200 ℃, and pressure is between 30Torr-100Torr, Al
xGa
1-xThe N layer thickness is between between the 1nm to 5nm, and the GaN layer thickness is between between the 1nm to 5nm, and periodicity is between 5 to 10, and doping content is 1 * 10
16Cm
-3To 1 * 10
18Cm
-3Between.The 9th, higher temperature and lower pressure be the weak n-type Doped GaN of growth down, and growth temperature is 1150 ℃-1200 ℃, and growth pressure is 30Torr to 80Torr, and thickness is between 1nm to 50nm, and doping content is 1 * 10
16Cm
-3To 5 * 10
17Cm
-3Between.Here n-type Al
xGa
1-xThe introducing of the weak n-type Doped GaN layer 9 of growing under N/GaN superlattice layer 8 and the low pressure condition and select higher growth temperature and lower growth pressure has changed the free energy of growing surface, has suppressed (1011
-The growth of)-crystal face is avoided or has reduced V-type defective forming on the top of threading dislocation, thereby at In
yGa
1-yForm more low-density V-type defective in the N/GaN Multiple Quantum Well.
Embodiment 1
At first with backing material sapphire Sapphire substrate layer 1 in temperature greater than 1100 ℃, carry out oxide layer desorption and clean the processing 1 to 10 minute in the nitrogen atmosphere;
Temperature is dropped to 500 ℃, the thick low temperature GaN nucleating layer (the GaN resilient coating 2 of low-temperature epitaxy) of growth 25nm, during this growth course, growth pressure is at 200Torr, and the V/III mol ratio is 5000;
Underlayer temperature is elevated to 1100 ℃, low temperature GaN nucleating layer is carried out annealing in process in position, annealing time was at 1 minute; After the annealing, with adjustment to 1100 ℃, the 4 microns n type Doped GaN layers of growing (the layer n-GaN3 of high growth temperature), growth pressure is at 200Torr, and the V/III mol ratio is 3000, and doping content is 1 * 10
19Cm
-3
To 1120 ℃ of higher temperature region, growth pressure is controlled at 75Torr growing n-type doped with Al with adjustment
xGa
1-xN/GaN (x=0.2) superlattice layer 8 structures, wherein Al
0.2Ga
0.8N layer thickness 2nm, GaN layer thickness 4nm, periodicity is 5, doping content is 8 * 10
17Cm
-3Between;
Adjustment is arrived higher 1150 ℃, and growth pressure is 75Torr, the weak n-type Doped GaN layer 9 of growth, and thickness is 20nm, doping content is 3 * 10
17Cm
-3
With adjustment to 720 ℃, pressure transfers to 400Torr, growth In
yGa
1-yN/GaN (y=0.2) multiple quantum well layer 5, wherein In
0.2Ga
0.8N quantum well layer thickness is 2nm, and the GaN barrier layer thickness is 5nm, and the quantum well number is 5; The growth temperature that GaN builds layer compares In
yGa
1-yThe growth temperature of N quantum well layer is high 80 ℃, and GaN builds the slight n-type of layer and mixes, and doping content is 3 * 10
17Cm
-3
Growth p-Al
zGa
1-zN/p-GaN layer 6 transfers to temperature between 900 ℃, growth p-Al
zGa
1-zN layer (z=0.1), wherein Al
0.1Ga
0.9The N layer thickness is between 3nm, and in this growth course, growth pressure is at 100Torr;
Temperature is transferred to 900 ℃, and pressure transfers to 200Torr, growth p-type Doped GaN, and doping content is 2 * 10
19Cm
-3, thickness is 200nm.
The grow method of blue light-emitting diode material of the present invention has changed the surface energy of growing surface, makes (1011
-)-crystal face no longer is the crystal face of surface energy minimum, thereby avoids or reduced V-type generation of defects.V-type defect concentration is generally 1 * 10 in the existing blue light-emitting diode structure
9Cm
-2-1 * 10
10Cm
-2V-type defect concentration can be reduced to 1 * 10 in the blue light-emitting diode structure of the present invention
7Cm
-2-1 * 10
8Cm
-2Existing blue light-emitting diode structure direction leakage current is generally 1 microampere when-10V; Blue light-emitting diode structure direction leakage current of the present invention is generally less than 0.1 microampere when-10V.
Embodiment 2
At first with backing material sapphire Sapphire substrate layer 1 in temperature greater than 1100 ℃, carry out oxide layer desorption and clean the processing 1 to 10 minute in the nitrogen atmosphere;
Temperature is dropped to 500 ℃, the thick low temperature GaN nucleating layer (the GaN resilient coating 2 of low-temperature epitaxy) of growth 25nm, during this growth course, growth pressure is at 200Torr, and the V/III mol ratio is 5000;
Underlayer temperature is elevated to 1100 ℃, low temperature GaN nucleating layer is carried out annealing in process in position, annealing time was at 1 minute; After the annealing, with adjustment to 1050 ℃, the 4 microns n type Doped GaN layers of growing (the layer n-GaN 3 of high growth temperature), growth pressure is at 200Torr, and the V/III mol ratio is 3000, and doping content is 1 * 10
19Cm
-3
To 1120 ℃ of higher temperature region, growth pressure is controlled at 75Torr growing n-type doped with Al with adjustment
xGa
1-xN/GaN (x=0.1) superlattice layer 8 structures, wherein Al
0.2Ga
0.8N layer thickness 2nm, GaN layer thickness 4nm, periodicity is 8, doping content is 8 * 10
17Cm
-3Between;
Adjustment is arrived higher 1150 ℃, and growth pressure is 75Torr, the weak n-type Doped GaN layer 9 of growth, and thickness is 20nm, doping content is 3 * 10
17Cm
-3
With adjustment to 720 ℃, pressure transfers to 400Torr, growth In
yGa
1-yN/GaN (y=0.4) multiple quantum well layer 5, wherein In
0.4Ga
0.6N quantum well layer thickness is 3nm, and the GaN barrier layer thickness is 5nm, and the quantum well number is 6; The growth temperature that GaN builds layer compares In
yGa
1-yThe growth temperature of N quantum well layer is high 50 ℃, and GaN builds the slight n-type of layer and mixes, and doping content is 3 * 10
17Cm
-3
Growth p-Al
zGa
1-zN/p-GaN layer 6 transfers to temperature between 900 ℃, growth p-Al
zGa
1-zN layer (z=0.1), wherein Al
0.1Ga
0.9The N layer thickness is between 3nm, and in this growth course, growth pressure is at 100Torr;
Temperature is transferred to 900 ℃, and pressure transfers to 200Torr, growth p-type Doped GaN, and doping content is 2 * 10
19Cm
-3, thickness is 200nm.
The grow method of green light LED material of the present invention has changed the surface energy of growing surface, makes (1011
-)-crystal face no longer is the crystal face of surface energy minimum, thereby avoids or reduced V-type generation of defects.V-type defect concentration is generally 1 * 10 in the existing green light LED structure
9Cm
-2-1 * 10
10Cm
-2V-type defect concentration can be reduced to 1 * 10 in the green light LED structure of the present invention
7Cm
-2-1 * 10
8Cm
-2Existing green light LED structure direction leakage current is generally 1 microampere when-10V; Green light LED structure direction leakage current of the present invention is generally less than 0.1 microampere when-10V.
Embodiment 3
At first with backing material sapphire Sapphire substrate layer 1 in temperature greater than 1100 ℃, carry out oxide layer desorption and clean the processing 1 to 10 minute in the nitrogen atmosphere;
Temperature is dropped to 500 ℃, the thick low temperature GaN nucleating layer (the GaN resilient coating 2 of low-temperature epitaxy) of growth 25nm, during this growth course, growth pressure is at 200Torr, and the V/III mol ratio is 5000;
Underlayer temperature is elevated to 1100 ℃, low temperature GaN nucleating layer is carried out annealing in process in position, annealing time was at 1 minute; After the annealing, with adjustment to 1050 ℃, the 4 microns n type Doped GaN layers of growing (the layer n-GaN 3 of high growth temperature), growth pressure is at 200Torr, and the V/III mol ratio is 3000, and doping content is 1 * 10
19Cm
-3
To 1120 ℃ of higher temperature region, growth pressure is controlled at 75Torr growing n-type doped with Al with adjustment
xGa
1-xN/GaN (x=0.1) superlattice layer 8 structures, wherein Al
0.2Ga
0.8N layer thickness 2nm, GaN layer thickness 4nm, periodicity is 6, doping content is 8 * 10
17Cm
-3Between;
Adjustment is arrived higher 1150 ℃, and growth pressure is 75Torr, the weak n-type Doped GaN layer 9 of growth, and thickness is 20nm, doping content is 3 * 10
17Cm
-3
With adjustment to 720 ℃, pressure transfers to 400Torr, growth In
yGa
1-yN/GaN (y=0.3) multiple quantum well layer 5, wherein In
0.4Ga
0.6N quantum well layer thickness is 3nm, and the GaN barrier layer thickness is 5nm, and the quantum well number is 6; The growth temperature that GaN builds layer compares In
yGa
1-yThe growth temperature of N quantum well layer is high 50 ℃, and GaN builds the slight n-type of layer and mixes, and doping content is 3 * 10
17Cm
-3
Growth p-Al
zGa
1-zN/p-GaN layer 6 transfers to temperature between 900 ℃, growth p-Al
zGa
1-zN layer (z=0.1), wherein Al
0.1Ga
0.9The N layer thickness is between 3nm, and in this growth course, growth pressure is at 100Torr;
Temperature is transferred to 900 ℃, and pressure transfers to 200Torr, growth p-type Doped GaN, and doping content is 2 * 10
19Cm
-3, thickness is 200nm.
The grow method of blue or green light-emitting diode material of the present invention has changed the surface energy of growing surface, makes (1011
-)-crystal face no longer is the crystal face of surface energy minimum, thereby avoids or reduced V-type generation of defects.V-type defect concentration is generally 1 * 10 in the existing blue or green light-emitting diode structure
9Cm
-2-1 * 10
10Cm
-2V-type defect concentration can be reduced to 1 * 10 in the blue or green light-emitting diode structure of the present invention
7Cm
-2-1 * 10
8Cm
-2Existing blue or green light-emitting diode structure direction leakage current is generally 1 microampere when-10V; The blue or green light-emitting diode structure direction of the present invention leakage current when-10V usually less than 0.1 microampere.