Embodiment
The self-supporting substrate
Self-supporting substrate of the present invention comprises semiconductor layer and inorganic particulate.As shown in Figure 1, the self-supporting substrate that comprises semiconductor layer 22, inorganic particulate 28 is used to comprise in the manufacturing of compound semiconductor element of nitride semiconductor luminescent element 1 of n type contact layer 3, luminescent layer 4, p type contact layer 5, electrode 6,7 and so on, does not comprise the substrate of sapphire and so on.
[semiconductor layer]
Semiconductor layer is generally the III-V group-III nitride, preferably with In
xGa
yAl
zThe metal nitride of N (0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1, x+y+z=1) expression.The composition of semiconductor layer for example can utilize X-ray diffraction method to try to achieve, and perhaps can utilize SEM-EDX to analyze cut surface and try to achieve by cutting self-supporting substrate.
In addition, semiconductor layer for example also can contain and is useful on single or multiple lift (thick film layers, superlattice film layer etc.) or the resilient coating that necessary layer in the action that makes nitride semiconductor luminescent element becomes high-quality crystal.
[inorganic particulate]
Inorganic particulate is contained in the semiconductor layer, comprises the inorganic matter of oxide, nitride, carbide, boride, selenides, metal and so on.The content of inorganic matter with respect to inorganic particulate usually more than 50 quality %, preferred more than 90%, more preferably more than 95%.The composition of the inorganic particulate in the semiconductor layer can utilize the section of SEM-EDX analyzing semiconductor layer to try to achieve by cutting self-supporting substrate.
Oxide for example is silica, aluminium oxide, zirconia, titanium oxide, cerium oxide, zinc oxide, tin oxide and yttrium-aluminium-garnet (YAG).
As nitride, for example be silicon nitride, boron nitride.
Carbide for example is carborundum (SiC), boron carbide, diamond, graphite, fullerene.
Boride for example is zirconium boride (ZrB
2), chromium boride (CrB
2).
Sulfide for example is zinc sulphide, cadmium sulfide, calcium sulfide, strontium sulfide.
Selenides for example is zinc selenide, cadmium selenide.
Oxide, nitride, carbide, boride, sulfide, selenides also can partly replace the element of wherein contained element with other.As the examples of substances that element contained in the oxide is partly replaced with other elements, can enumerate as activator and contain the silicate of cerium or europium or the fluorophor of aluminate.
As metal, can enumerate silicon (Si), nickel (Ni), tungsten (W), tantalum (Ta), chromium (Cr), titanium (Ti), magnesium (Mg), calcium (Ca), aluminium (Al), gold (Au), silver (Ag), zinc (Zn).
No matter inorganic particulate is which kind of of the particle that is made of described a kind of inorganic matter or their mixture or the compound particle of having changed can.
Under the situation that inorganic particulate is made of a kind of inorganic matter, inorganic particulate preferably is made of oxide, more preferably is made of silica.As mixture, the combination of the oxide particle beyond preferred silicon oxide particle and the silica, the more preferably combination of silicon oxide particle and Titanium particles.As the compound particle of having changed, for example can enumerate the particle that on the particle that constitutes by nitride, has oxide.
Inorganic particulate preferably contains the mask material of the growth of semiconductor layer, further preferably has mask material on its surface.Exist on the surface of inorganic particulate under the situation of mask material, mask material preferably covers more than 30% of surface of inorganic particulate, more preferably covers more than 50%.Mask material for example is silica, zirconia, titanium oxide, silicon nitride, boron nitride, tungsten (W), molybdenum (Mo), chromium (Cr), cobalt (Co), silicon (Si), gold (Au), zirconium (Zr), tantalum (Ta), titanium (Ti), niobium (Nb), nickel (Ni), platinum (Pt), vanadium (V), hafnium (Hf), palladium (Pd), preferred silica.They both may be used alone, can also be used in combination.The composition of the mask material of inorganic particulate can pass through cutting semiconductor lamination element, utilizes SEM-EDX to analyze its section for inorganic particulate and tries to achieve.
The shape of inorganic particulate also can be spherical (for example section is for circular, oval-shaped), tabular (for example the aspect ratio L/T of length L and thickness T is 1.5~100.), (for example the ratio L/W of width W and length L is 1.5~100 to needle-like.) or unsetting (comprise the particle of various shapes, shape is skimble-scamble as a whole.), preferably spherical.The average grain diameter of inorganic particulate is generally more than the 5nm, more than the preferred 10nm, more than the further preferred 20nm, in addition usually below 50 μ m, below the preferred 10 μ m, further below the preferred 1 μ m.When containing average grain diameter in described scope during inorganic particulate, then can obtain becoming the self-supporting substrate of the semiconductor light-emitting elements of exhibit high brilliance.The shape of inorganic particulate and average grain diameter for example can utilize electron microscope to take the section of semiconductor layer by cutting self-supporting substrate, try to achieve according to the image of gained.
In order to improve exothermic character or rigidity, the self-supporting substrate also can the mounting support member.Supporting member for example is metal, macromolecule resin so long as the high material of exothermic character excellent material or rigidity gets final product.In addition, metal also can be the alloy of low-temperature alloy and so on.Macromolecule resin also can be thermosetting resin, ray hardening resin.Provide the example of the self-supporting substrate 22 that metallic plate 101 has been installed among Fig. 2 as supporting member.Provide the example of the self-supporting substrate 22 that semiconductor light-emitting elements usefulness package body 102 has been installed among Fig. 3 as supporting member.The thickness of self-supporting substrate is usually more than 3 μ m, preferably more than 10 μ m, usually below 500 μ m, preferably below 100 μ m, further preferably below 65 μ m, below 45 μ m.For the situation of the self-supporting substrate that supporting member is installed, in thickness, do not comprise the thickness of supporting member.
The manufacture method of self-supporting substrate
The manufacture method of self-supporting substrate of the present invention is included in substrate or the operation (a) of configuration inorganic particulate on the resilient coating arbitrarily.
Substrate for example is sapphire, SiC, Si, MgAl
2O
4, LiTaO
3, ZrB
2, CrB
2, preferred sapphire, SiC, Si.
The manufacture method of self-supporting substrate also can be included in the operation (s1) of grown buffer layer on the substrate.Resilient coating is normally with In
xGa
yAl
zThe III-V the group-III nitride of N (0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1, x+y+z=1) expression.No matter resilient coating is can more than 1 layer or 2 layers.The growth of resilient coating for example can utilize organic metal vapor phase growth (MOVPE), the directed outgrowth (MBE) of molecular ray, hydride vapor phase growth (HVPE), carries out under 400 ℃~700 ℃ temperature conditions.
The manufacture method of self-supporting substrate also can also be included in the In that grows on the resilient coating
xGa
yAl
zThe operation (s2) of N layer (0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1, x+y+z=1).
Inorganic particulate for example comprises the inorganic matter of oxide, nitride, carbide, boride, selenides, metal and so on.The content of inorganic matter with respect to inorganic particulate usually more than 50 quality %, preferred more than 90%, more preferably more than 95%.The composition of inorganic particulate can utilize chemical analysis, luminesceence analysis to wait and try to achieve.
Oxide for example is silica, aluminium oxide, zirconia, titanium oxide, cerium oxide, zinc oxide, tin oxide and yttrium-aluminium-garnet (YAG).
As nitride, for example be silicon nitride, boron nitride.
Carbide for example is carborundum (SiC), boron carbide, diamond, graphite, fullerene.
Boride for example is zirconium boride (ZrB
2), chromium boride (CrB
2).
Sulfide for example is zinc sulphide, cadmium sulfide, calcium sulfide, strontium sulfide.
Selenides for example is zinc selenide, cadmium selenide.
Oxide, nitride, carbide, boride, sulfide, selenides also can partly replace the element of wherein contained element with other.As the examples of substances that element contained in the oxide is partly replaced with other elements, can enumerate as activator and contain the silicate of cerium or europium or the fluorophor of aluminate.
As metal, can enumerate silicon (Si), nickel (Ni), tungsten (W), tantalum (Ta), chromium (Cr), titanium (Ti), magnesium (Mg), calcium (Ca), aluminium (Al), gold (Au), silver (Ag), zinc (Zn).
Inorganic particulate also can be the material that becomes described oxide, nitride, carbide, boride, sulfide, selenides, metal when heat treated, for example also can be silicon.Silicon is the inorganic nature key that has Si-O-Si as main framing, has the polymer of the structure of organic substituent in Si, when heat treated is about 500 ℃, then becomes silica.
As inorganic particulate, no matter use described a kind of inorganic matter, also be to use their mixture or which kind of of the compound particle of having changed can.The inorganic particulate that is made of a kind of inorganic matter preferably is made of oxide, more preferably is made of silica.As mixture, the combination of the oxide particle beyond preferred silicon oxide particle and the silica, the more preferably combination of silicon oxide particle and Titanium particles.As the compound particle of having changed, for example can enumerate the particle that on the particle that constitutes by nitride, has oxide.
Inorganic particulate preferably contains the mask material of the growth of semiconductor layer, further preferably has mask material on its surface.Exist on the surface of inorganic particulate under the situation of mask material, mask material preferably covers more than 30% of surface of inorganic particulate, more preferably covers more than 50%.Mask material for example is silica, zirconia, titanium oxide, silicon nitride, boron nitride, tungsten (W), molybdenum (Mo), chromium (Cr), cobalt (Co), silicon (Si), gold (Au), zirconium (Zr), tantalum (Ta), titanium (Ti), niobium (Nb), nickel (Ni), platinum (Pt), vanadium (V), hafnium (Hf), palladium (Pd), preferred silica.They both may be used alone, can also be used in combination.The inorganic particulate that has mask material on the surface for example can utilize following method modulation,, utilizes evaporation or sputter mask film covering material at particle surface that is, or at particle surface with compound hydrolysis etc.
The shape of inorganic particulate also can be spherical (for example section is for circular, oval-shaped), tabular (for example the aspect ratio L/T of length L and thickness T is 1.5~100.), (for example the ratio L/W of width W and length L is 1.5~100 to needle-like.) or unsetting (comprise the particle of various shapes, shape is skimble-scamble as a whole.), preferably spherical.So, the more preferably spherical silica of inorganic particulate.As spherical silica, consider from the viewpoint that can easily obtain the more unified particle of single dispersion and size ratio, recommend to use silica gel.Silica gel is the material that has disperseed silicon oxide particle in solvent (water etc.) with colloidal, can utilize to sodium metasilicate carry out ion-exchange method, the method for the organo-silicon compound hydrolysis of tetraethyl orthosilicate (TEOS) and so on is obtained.In addition, the average grain diameter of inorganic particulate is generally more than the 5nm, preferably more than 10nm, further more than the preferred 0.1 μ m, in addition usually below 50 μ m, below the preferred 10 μ m, further below the preferred 1 μ m.When containing the inorganic particulate of average grain diameter in described scope, then can obtain becoming the self-supporting substrate of the semiconductor light-emitting elements of exhibit high brilliance.
In addition, make under the situation of semiconductor light-emitting elements at the self-supporting substrate that uses gained, be made as λ (nm) at emission wavelength with semiconductor light-emitting elements, when the average grain diameter of inorganic particulate was made as d (nm), then the d/ λ of inorganic particulate is usually more than 0.01, and was preferred more than 0.02, more preferably more than 0.2, usually below 100, preferred below 30 in addition, more preferably below 3.0.
Average grain diameter is a volume average particle size of utilizing centrifugal settling method to measure.Average grain diameter also can be utilized the mensuration beyond the centrifugal settling method, for example dynamic light scattering method, Coulter counter method, laser diffractometry, electron microscope are measured, yet under this situation, can be used as correction, be scaled the volume average particle size of utilizing centrifugal settling method to measure.For example, try to achieve the average grain diameter of the particle that becomes standard, calculate their coefficient correlation with centrifugal settling method and other granulometry.Coefficient correlation preferably by for the different a plurality of standard particles of particle diameter, is calculated the coefficient correlation with respect to the volume average particle size of utilizing centrifugal settling method to measure, makes calibration curve and tries to achieve.If the use calibration curve then can be tried to achieve volume average particle size according to the average grain diameter that obtains with the determination method beyond the centrifugal settling method.
The configuration of inorganic particulate is for example used substrate is impregnated into method in the slip that contains inorganic particulate and medium; Or in that being carried out dry method after coating on the substrate or spraying, slip gets final product.Medium is water, methyl alcohol, ethanol, isopropyl alcohol, n-butanol, ethylene glycol, dimethyl acetamide, methyl ethyl ketone, methyl iso-butyl ketone (MIBK) etc., preferred water.Coating preferably utilizes spin coating method to carry out, if utilize this method, then can make the configuration density homogeneous of inorganic particulate.Drying also can use circulator to carry out.
Inorganic particulate can utilize following formula to try to achieve according to population P, the average grain diameter d of particle (area S) in the mensuration visual field of scan line electron microscope (SEM) when the substrate surface that has disposed inorganic particulate is observed in the top to the coverage rate of substrate.
Coverage rate (%)=((d/2)
2* π P100)/S
Under the situation that inorganic particulate is made of a kind of inorganic matter, inorganic particulate to the coverage rate of substrate usually more than 1%, preferred more than 30%, further preferred more than 50%, preferred below 90% usually below 95%, further preferred below 80%.
Owing to be easy to the epitaxial growth semiconductor layer and planarization, therefore as a rule inorganic particulate is disposed 1 layer on substrate, being disposed at more than 90% in 1 layer for example with inorganic particulate, as long as can the epitaxial growth semiconductor layer and planarization, then also can be more than 2 layers, both a kind of inorganic particulate can be disposed 2 layers at least, also can be with at least 2 kinds of inorganic particulates single layer configuration respectively.In combination as Titanium particles and silicon oxide particle, under the situation of at least 2 kinds of inorganic particulates of configuration, the inorganic particulate of initial configuration (for example titanium oxide) to the coverage rate of substrate usually more than 1%, preferred more than 30%, usually below 95%, preferred below 90%, further preferred below 80%.The inorganic particulate (for example silica) of second layer configuration later on to the coverage rate of substrate usually more than 1%, preferred more than 30%, further preferred more than 50%, preferred below 90% usually below 95%, further preferred below 80%.
Manufacture method of the present invention also is included in the operation (h) of grown semiconductor layer on the material that obtains in the operation (a).
As semiconductor layer, for example be with In
xGa
yAl
zThe III-V the group-III nitride of N (0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1, x+y+z=1) expression.Semiconductor layer both can be 1 layer, also can be more than 2 layers.
In addition, semiconductor layer no matter be formation face structure or that do not form the face structure which kind of can, yet under the high situation of the coverage rate of inorganic particulate, be preferably formed the face structure.The easy planarization of the semiconductor layer of formation face structure.
Under the situation of grown semiconductor layer, the preferred composition of the III-V nitride semiconductor layer depends on the particle diameter and the configuration status of inorganic particulate when forming the face structure, yet under the high situation of the coverage rate of inorganic particulate, preferred high usually A1 forms.But, at embeding layer is the GaN layer, or under the situation with AlGaN layer of comparing lower A1 composition with the A1 composition of face structure, when the A1 of the III-V nitride semiconductor layer composition becomes too high, then the lattice mismatch that produces between embeding layer and face structure will become greatly, has the situation that produces crack or dislocation on substrate.
Consider that from the viewpoint of the good crystal of the crystal mass that obtains not have the crack A1 of face structure forms and also can adjust accordingly with particle diameter, the configuration status of inorganic particulate, for example under the coverage rate of inorganic particulate was situation more than 50%, preferred growth was with formula: Al
dGa
1-dN[0<d<1] expression the face structure, more preferably grow with Al
dGa
1-dN[0.01 ≦ d ≦ 0.5] (AlN mixed crystal ratio is more than 1.0%, below 50%.) expression the face structure.
The long temperature of looking unfamiliar is usually more than 700 ℃, and is preferred more than 750 ℃, usually below 1000 ℃, preferred below 950 ℃ in addition.Under the situation of grown buffer layer, preferably between the growth temperature of the growth temperature of resilient coating and embeding layer, surface layer both can be 1 layer to the growth temperature of face structure, also can be more than 2 layers.
Growth for example utilizes the epitaxial growth method of organic metal vapor phase growth (MOVPE), the directed outgrowth (MBE) of molecular ray, hydride vapor phase growth (HVPE) and so on to get final product.
Utilizing MOVPE to come under the situation of growth regulation III-V family semiconductor layer, as long as to utilize carrier gas following III-th family raw material and V family raw material to be imported the method for reacting furnace.
The III-th family raw material for example is:
Trimethyl gallium [(CH
3)
3Ga below is called TMG.]、
Triethyl-gallium [(C
2H
5)
3Ga below is called TEG.] and so on formula:
R
1R
2R
3Ga
[R
1, R
2, R
3The expression low alkyl group.] expression trialkyl gallium;
Trimethyl aluminium [(CH
3)
3Al below is called TMA.]、
Triethyl aluminum [(C
2H
5)
3Al below is called TEA.]、
Triisobutyl aluminium [(i-C
4H
9)
3Al] and so on formula:
R
1R
2R
3Al
[R
1, R
2, R
3The expression low alkyl group.] expression trialkylaluminium;
Front three amine alane [(CH
3)
3N:AlH
3];
Trimethyl indium [(CH
3)
3In below is called TMI.]、
Triethylindium [(C
2H
5)
3In] and so on formula:
R
1R
2R
3In
[R
1, R
2, R
3The expression low alkyl group.] expression the trialkyl indium;
Diethyl inidum chloride [((C
2H
5)
2InCl] and so on the material that from the trialkyl indium, 1 to 2 alkyl is replaced with halogen atom;
Inidum chloride [InCl] and so on formula:
InX
The indium halide of [X is a halogen atom] expression etc.
They both may be used alone, can also be used in combination.
As the gallium source in the middle of the III-th family raw material, preferred TMG, as the aluminium source, preferred TMA, as the indium source, preferred TMI.
V family raw material for example can be enumerated ammonia, hydrazine, methyl hydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, tert-butylamine, ethylenediamine etc.They both may be used alone, can also be used in combination.In the middle of the V family raw material, preferred ammonia, hydrazine, more preferably ammonia.
N type dopant for example is Si, Ge.Can be used as raw material that n type dopant uses for example as silane, disilane, germane, tetramethyl germane.
P type dopant for example is Mg, Zn, Cd, Ca, Be, preferred Mg, Ca.Can be used as the Mg raw material that p type dopant uses and for example be bis-cyclopentadienyl magnesium [(C
5H
5)
2Mg], bis-methylcyclopentadienyl magnesium [(C
5H
4CH
3)
2Mg], two ethyl cyclopentadienyl group magnesium [(C
5H
4C
2H
5)
2Mg], the Ca raw material is bicyclic pentadiene calcium [(C
5H
5)
2Ca] and derivative, for example two methyl cyclopentadienyl calcium [(C
5H
4CH
3)
2Ca], two ethyl cyclopentadienyl group calcium [(C
5H
4C
2H
5)
2Ca], fluorine cyclopentadienyl group calcium [(C enjoys a double blessing
5F
5)
2Ca]; Two-1-naphthyl calcium and derivative thereof; Calcium carbide and derivative thereof, for example two (4,4-difluoro-3-butylene-1-yl)-calcium, xenyl acetenyl calcium.They can be used singly or in combination.
Atmosphere gas during growth and the carrier gas of raw material for example can be enumerated nitrogen, hydrogen, argon gas, helium, preferably enumerate hydrogen, helium.They both may be used alone, can also be used in combination.
Reacting furnace possesses supply pipeline and the microscope carrier (suscepter) that raw material is supplied with to reacting furnace from storage container usually.Microscope carrier is the device of heated substrate, is placed in the reacting furnace.In addition, grow equably in order to make semiconductor layer, microscope carrier as a rule forms the structure that utilizes the power rotation.Microscope carrier portion within it has the heater of infrared lamp and so on.Utilize heater, pass supply pipeline and raw material thermal decomposition on substrate of supplying with to reacting furnace, grown semiconductor layer on substrate.Unreacting material in the middle of the raw material that reacting furnace is supplied with is as a rule discharged to the outside from reacting furnace from exhaust line, is sent to emission-control equipment.
Utilizing HVPE to come under the situation of growth regulation III-V nitride semiconductor layer, as long as to utilize carrier gas following III-th family and V family raw material to be imported the method for described reacting furnace.
The III-th family raw material for example is by gallium metal and hydrogen chloride gas are at high temperature the reacted gallium chloride gas that generates, the inidum chloride gas that generates by indium metal and hydrogen chloride gas are at high temperature reacted.
V family raw material for example is an ammonia.
Carrier gas for example is nitrogen, hydrogen, argon gas, helium, preferred hydrogen, helium.They can use separately, perhaps are used in combination.
In addition, under the situation of utilizing MBE growth regulation III-V nitride semiconductor layer, as long as the growth of semiconductor layer is to utilize carrier gas following III-th family raw material and V family raw material to be imported the method for described reacting furnace.
The III-th family raw material for example is the metal of gallium, aluminium, indium and so on.
V family raw material for example is nitrogen or ammonia.
Carrier gas for example is nitrogen, hydrogen, argon gas, helium, preferred hydrogen, helium.They can use separately, perhaps are used in combination.
In the operation (b), as a rule, semiconductor layer begins growth with the place that does not have inorganic particulate as growth district, form the face structure then.
In addition, in the operation (b), also can be with the flattening surface of semiconductor layer, for example face structure that also can be by embedding substrate is with its planarization, the face structure of this substrate is that grown semiconductor layer obtains when forming the face structure by the promotion cross growth.Utilize this kind growth, the dislocation that has arrived face is just by to horizontal bending, and inorganic particulate is embedded in the semiconductor layer, and the crystal defect of semiconductor layer reduces.
In addition, come under the situation of grown buffer layer utilizing operation (s1), in operation (b), resilient coating is because of as the hydrogen of carrier gas, as the etching action that ammonia caused of raw material, has interstitial situation in the zone of inorganic particulate in the middle of resilient coating and substrate.
The thickness of the semiconductor layer that forms in the operation (b) is usually more than 3 μ m, more than the preferred 10 μ m, usually below 500 μ m, below the preferred 100 μ m, more preferably below the 65 μ m, below the preferred especially 45 μ m.
Manufacture method of the present invention also comprises the operation (c) that substrate is removed.
No matter remove and can utilize the method for in the semiconductor laminated substrate that obtains from operation (b) substrate being removed to carry out, be which kind of of approach of the chemistry of the approach that utilizes the physics of internal stress, external stress and so on, etching and so on carry out can.
Owing to for example can produce the thermal stress (internal stress) that the difference by the thermal coefficient of expansion of substrate and semiconductor layer causes, so remove and to be used in the method for cooling off behind the semiconductor layer of having grown in the operation (b) and to carry out.
Remove and also can utilize grinding, laser lift-off to carry out.In this method, also can be on semiconductor layer, fitted have the support substrate of rigidity after, grind etc.
In addition, remove also can utilize substrate or semiconductor layer are fixed, and the method that loose the opposing party applies external force is carried out.
In the manufacture method of the present invention, also can repeat operation (a) and reach (b).As operation (a), also can be configured the sub-operation (a1) of inorganic particulate, dispose the sub-operation (a2) of other inorganic particulate thereafter.Under this situation, used inorganic particulate for example is a titanium oxide in the sub-operation (a1), and used inorganic particulate for example is a silica in the sub-operation (a2).
In addition, as operation (b), other the operation (b2) of semiconductor layer of growth on the operation (b1) of grown semiconductor layer, the semiconductor layer on the material that also can carry out in operation (a), obtaining at gained.By repeating, just can obtain being suitable for showing the more self-supporting substrate of the manufacturing of the semiconductor light-emitting elements of high brightness.
Utilize Fig. 4 that the manufacture method of self-supporting substrate of the present invention is described.
Shown in Fig. 4 (a), configuration inorganic particulate 23 on the surperficial 21A of substrate 21.The configuration of inorganic particulate 23 can utilize substrate 21 is flooded in the slip that has disperseed inorganic particulate 23 in medium (water, methyl alcohol, ethanol, isopropyl alcohol, n-butanol, ethylene glycol, dimethyl acetamide, methyl ethyl ketone, methyl iso-butyl ketone (MIBK) etc.) and dry method as previously mentioned; Or slip is gone up coating or spraying and dry method to the surperficial 21A of substrate 21 carry out.
Then, the inorganic particulate 23 that is disposed on the substrate 21 is embedded ground, epitaxial growth the III on substrate 21-V group-III nitride semiconductor forms the III-V nitride semiconductor layer that contains inorganic particulate.Inorganic particulate 23 as a rule plays a role as the mask of the growth of the III-V group-III nitride semiconductor, does not exist the part of inorganic particulate 23 just to become growth district 21B.Shown in Fig. 4 (b), when for the epitaxial growth of the III-V group-III nitride semiconductor during base feed, then the III-V group-III nitride semiconductor is just grown from growth district 21B, when forming the face structure, inorganic particulate 23 is embedded the ground growth.Shown in Fig. 4 (c), promote cross growth ground to embed the face structure and planarization, growth regulation III-V nitride semiconductor layer 22B obtains the III-V group-III nitride semiconductor lamination substrate 22D.The crystal defect of the III of gained-V group-III nitride semiconductor lamination substrate 22D is reduced significantly.
In addition, as shown in Figure 5, also can be after having disposed inorganic particulate 24 on the III-V group-III nitride semiconductor lamination substrate 22B, with inorganic particulate 24 as mask and growth regulation III-V group-III nitride semiconductor forms the III-V nitride semiconductor layer 25.The III-V nitride semiconductor layer 25 both can non-impurity-doped, also can be doped with impurity.
Under the situation of growth regulation III-V group-III nitride semiconductor on the substrate 21 that has disposed inorganic particulate 23, shown in Fig. 4 (c), there is inorganic particulate 23 near interface at substrate 21 and the III-V nitride semiconductor layer 22C, specifically, inorganic particulate 23 is contained among the III-V nitride semiconductor layer 22B, and its part contacts with substrate 21 at the interface substrate 21 and the III-V nitride semiconductor layer 22B's.
Substrate 21 among the III-V group-III nitride semiconductor lamination substrate 22D and the adhesion of the III-V nitride semiconductor layer crystal layer 22B substrate when not having inorganic particulate 23 is with a little less than the adhesion of the III-V group-III nitride semiconductor crystal layer is compared.
When the III-V nitride semiconductor layer 22C thickening, then internal stress that produces based on the difference of the thermal coefficient of expansion of substrate 21 and the III-V group-III nitride semiconductor crystal layer 22B etc. or external stress just easily the concentrated area act on the interface of substrate 21 and the III-V nitride semiconductor layer 22C.Shown in Fig. 4 (d), for example these stress are as stress (shear stress etc.) effect between the two interface.When stress became greater than adhesion, then the interface of substrate 21 and the III-V nitride semiconductor layer 22C or near will the fracture and substrate 21 is removed obtained self-supporting substrate 22.The thickness of the III-V nitride semiconductor layer 22C is usually more than 3 μ m, more than the preferred 10 μ m, usually below 500 μ m, below the preferred 100 μ m, more preferably below the 65 μ m, below the preferred especially 45 μ m.
Under the situation that forms the face structure, also can on substrate, form resilient coating, dispose inorganic particulate thereon.Resilient coating for example is the mixed crystal of InN, AlN and GaN, so long as with formula In
xGa
yAl
zThe compound of N (x+y+z=1,0 ≦ x ≦ 1,0 ≦ y ≦ 1,0 ≦ z ≦ 1) expression gets final product.
Utilize Fig. 6, B-4 to describe for the manufacture method of the self-supporting substrate that comprises the operation that forms resilient coating.Shown in Fig. 6 (a) and (b), after having formed resilient coating 26 on the substrate 21, shown in Fig. 6 (c), configuration inorganic particulate 23 on resilient coating 26.
Then, inorganic particulate 23 is embedded ground epitaxial growth the III-V group-III nitride semiconductor on resilient coating 26.Shown in Fig. 6 (d), when for epitaxial growth the III-V group-III nitride semiconductor during base feed, then the III-V group-III nitride semiconductor will be when forming the face structure, inorganic particulate 23 is embedded the ground growth, shown in Fig. 6 (e), promote the cross growth of the III-V group-III nitride semiconductor, embed the face structure and planarization forms the III-V nitride semiconductor layer 22B.In addition, also can go up the III-V nitride semiconductor layer 25 that forms other at the III-V group-III nitride semiconductor lamination 22B as shown in Figure 7.Then, shown in Fig. 6 (f), utilize internal stress or external stress, substrate 21 is removed, or substrate 21 is removed with resilient coating 26 (omitting among Fig. 6 (f)) both sides, obtain the self-supporting substrate.
Semiconductor light-emitting elements
Semiconductor light-emitting elements of the present invention is the element that comprises described self-supporting substrate, conducting shell, luminescent layer and electrode, as a rule has dual heterostructure, on described self-supporting substrate, comprise n type conducting shell, luminescent layer and p type conducting shell successively, and comprise electrode.
N type conducting shell for example is by with formula In
xGa
yA1
zThe n type contact layer that the III-V group-III nitride of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression constitutes.Consider the n type carrier concentration preferred 1 * 10 of n type contact layer from the viewpoint of the operation voltage that reduces semiconductor light-emitting elements
18Cm
-3More than, 1 * 10
19Cm
-3Below.Consider that from improving crystalline viewpoint the amount of the In of n type contact layer is usually (being that x is below 0.05) below 5%, and is preferred below 1%, the amount of Al is usually (being that z is below 0.05) below 5%, and is preferred below 1%.N type contact layer more preferably is made of GaN.
Luminescent layer has by with formula In
xGa
yAl
zThe barrier layer of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression, with formula In
xGa
yAl
zThe quantum well layer structure of the formation of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression potential well layer.Quantum well structure both can be multiple, also can be substance.
P type conducting shell for example is by with formula In
xGa
yAl
zThe p type contact layer that the III-V group-III nitride of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression constitutes.Consider that from the viewpoint of the operation voltage that reduces semiconductor light-emitting elements the p type carrier concentration of p type contact layer is 5 * 10
15Cm
- 3More than, preferred 1 * 10
15Cm
-3More than, 5 * 10
19Cm
-3Below.Consider that from the viewpoint that reduces contact resistance the amount of the Al of p type contact layer is usually (being that x is below 0.05) below 5%, and is preferred below 1%.P type contact layer preferably is made of GaAlN, GaN, more preferably is made of GaN.
Electrode is n electrode, p electrode.The n electrode contacts with n type contact layer, for example is alloy or the compound that contains as main composition with at least a element of selecting in the group that is made of Al, Ti and V, preferred Al, TiAl, VAl.The p electrode contacts with p type contact layer, for example is NiAu, ITO.
Semiconductor light-emitting elements also can comprise with formula In between n N-type semiconductor N and luminescent layer
xGa
yAl
zThe layer that the III-V group-III nitride of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression constitutes.This layer both can be an individual layer, also can be by layer multilayer of forming or carrier concentration is different that constitutes.
In addition, semiconductor light-emitting elements also can be between luminescent layer and p type contact layer, comprises by with formula In
xGa
yAl
zThe III-V the group-III nitride of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression, the preferably layer that constitutes by AlGaN.The AlGaN layer both can be the p type, also can be the n type.At the AlGaN layer is that carrier concentration is 1 * 10 under the situation of n type
18Cm
-3Below, preferred 1 * 10
17Cm
-3Below, more preferably 5 * 10
16Cm
-3Below.
In addition, semiconductor light-emitting elements also can be between p type contact layer and AlGaN layer, comprise space charge density be lower than the AlGaN layer with formula In
xGa
yAl
zThe layer that the nitride of N (x+y+z=1,0 ≦ x<1,0<y ≦ 1,0 ≦ z<1) expression constitutes.
As shown in Figure 1, semiconductor light-emitting elements 1 is for example on the III that contains inorganic particulate 23-V group-III nitride self-supporting substrate 22, comprise n type contact layer 3, luminescent layer 4, p type contact layer 5 successively, n electrode 6 is formed on the n type contact layer 3, and n electrode 7 is formed on the p type contact layer 5.
As long as the formation of n type contact layer 3, luminescent layer 4, p type contact layer 5 utilizes MOVPE, HVPE, MBE etc., for example if MOVPE, then as long as self-supporting substrate 22 is placed in the reacting furnace, the doping of supplying with described organic metal raw material and use as required when regulating flow makes it growth with raw material, get final product by heat-treating.For example, the growth temperature of n type contact layer 3 is more than 850 ℃, below 1100 ℃, and the growth temperature of luminescent layer 4 is more than 600 ℃, below 1000 ℃, and the growth temperature of p type contact layer 5 is usually more than 800 ℃, below 1100 ℃.
Embodiment
The present invention is described in detail to utilize embodiment, yet the present invention is not limited to embodiment.
Embodiment 1
[manufacturing of self-supporting substrate]
As substrate 31, the sapphire that has used C face mirror ultrafinish.As the raw material of silicon oxide particle 32, used silica gel ((strain) Japanese catalyst system, SEAHOSTAR KE-W50 (trade name), average grain diameter 550nm).Numbering is based on shown in Figure 8.Substrate 31 is placed on the circulator, and coating dilution thereon is the silica gel of 10 weight %, and Rotary drying has disposed silicon oxide particle 32 on substrate 31.Observe with SEM, consequently, silicon oxide particle is a simple layer, substrate 31 be 36% by silicon oxide particle to the coverage rate on surface.
According to following explanation, utilize normal pressure MOVPE epitaxial growth the III-V nitride semiconductor layer, growth contains the III-V nitride semiconductor layer of silicon oxide particle 32.
Under 1 atmospheric pressure, the temperature of microscope carrier is made as 485 ℃, carrier gas is made as hydrogen, supply with carrier gas, ammonia and TMG, the thickness of having grown on
substrate 31 is about 500
GaN resilient coating 33.The temperature of microscope carrier is made as 900 ℃, supplies with carrier gas, ammonia and TMG, the not Doped
GaN layer 34 of on GaN
resilient coating 33, having grown.The microscope carrier temperature is made as 1040 ℃, furnace pressure power is dropped to 1/4 air pressure, supply with carrier gas, ammonia and TMG, the not Doped
GaN layer 34 of having grown.From 1040 ℃ cool to room temperature, the self-supporting substrate (GaN monocrystalline, the thickness: 45 μ ms) that by the III that contain silicon oxide particle 32-V nitride semiconductor layer constitute have been obtained thereafter.Separation is to produce at (face that links as shown in Figure 9, the part under the silicon oxide particle 32) between
substrate 31 and the
silicon oxide particle 32.
Embodiment 2
Except having used dilution is the silica gel of 13 quality %, carries out [manufacturing of the self-supporting substrate] identical operations with embodiment 1, has obtained the self-supporting substrate.Substrate be 55% by silicon oxide particle to the coverage rate on surface.The photo that has disposed the substrate of silicon oxide particle is shown among Figure 10.In this example, also be between substrate 31 and substrate 31 and silicon oxide particle 32, to have produced to separate.
Embodiment 3
[manufacturing of self-supporting substrate]
As substrate, the sapphire that has used C face mirror ultrafinish.As the raw material of silicon oxide particle, used silica gel (daily output chemical industry (strain) system, MP-1040 (trade name), average grain diameter 100nm).Substrate is placed on the circulator, and coating dilution thereon is the silica gel of 10 weight %, and Rotary drying has disposed silicon oxide particle on substrate.Substrate be 55% by silicon oxide particle to the coverage rate on surface.
According to following explanation, utilize normal pressure MOVPE epitaxial growth the III-V nitride semiconductor layer, growth contains the III-V nitride semiconductor layer of silicon oxide particle.
Under 1 atmospheric pressure, the temperature of microscope carrier is made as 485 ℃, carrier gas is made as hydrogen, supply with carrier gas, ammonia and TMG, the thickness of having grown on substrate is about 500
The GaN resilient coating.The temperature of microscope carrier is made as 800 ℃, supplies with carrier gas, ammonia, TMA and TMG, the not doped with Al GaN layer of on the GaN resilient coating, having grown.The microscope carrier temperature is made as 1040 ℃, furnace pressure power is dropped to 1/4 air pressure, supply with carrier gas, ammonia and TMG, the not Doped GaN layer of having grown.From 1040 ℃ cool to room temperature, the self-supporting substrate (GaN monocrystalline, the thickness: 12 μ ms) that by the III that contain silicon oxide particle-V nitride semiconductor layer constitute have been obtained thereafter.Separation produces between substrate and silicon oxide particle.
Embodiment 4
Except having used silica gel (daily output chemical industry (strain) system that silica concentration is adjusted to 40 quality %, MP-4540M (trade name), average grain diameter 450nm), make not beyond Doped GaN layer growth to the 40 μ m, carried out [manufacture method of self-supporting substrate] identical operations with embodiment 3, self-supporting substrate (GaN monocrystalline, thickness: 40 μ m) have been obtained by the III that contains silicon oxide particle-V nitride semiconductor layer formation.Substrate in this example be 71% by silicon oxide particle to the coverage rate on surface.In addition, separation produces between substrate and silicon oxide particle.
Embodiment 5
As substrate, the sapphire that has used C face mirror ultrafinish.As the raw material of inorganic particulate, (CI changes into (strain) system, Nanotek TiO to have used the titanium oxide slip
2(trade name), average grain diameter 40nm, dispersant: water) and silica gel (daily output chemical industry (strain) system, MP-1040 (trade name), average grain diameter 100nm).Substrate is placed on the circulator, and coating dilution thereon is the titanium oxide slip of 1 weight %, and Rotary drying has disposed Titanium particles on substrate.Substrate be 36% by Titanium particles to the coverage rate on surface.In addition, coating thereon is adjusted to the silica gel of 40 weight %, and Rotary drying has disposed silicon oxide particle on substrate.Substrate be 71% by silicon oxide particle to the coverage rate on surface.
According to following explanation, utilize normal pressure MOVPE epitaxial growth the III-V nitride semiconductor layer, growth contains the III-V nitride semiconductor layer of silicon oxide particle.
Under 1 atmospheric pressure, the temperature of microscope carrier is made as 485 ℃, carrier gas is made as hydrogen, supply with carrier gas, ammonia and TMG, the thickness of having grown on substrate is about 500
The GaN resilient coating.The temperature of microscope carrier is made as 800 ℃, supplies with carrier gas, ammonia, TMA and TMG, the not doped with Al GaN layer of on the GaN resilient coating, having grown.The microscope carrier temperature is made as 1040 ℃, furnace pressure power is dropped to 1/4 air pressure, supply with carrier gas, ammonia and TMG, the not Doped GaN layer of the
thickness 20 μ m that grown.From 1040 ℃ cool to room temperature, the self-supporting substrate (GaN monocrystalline, the thickness: 20 μ ms) that by the III that contain Titanium particles and silicon oxide particle-V nitride semiconductor layer constitute have been obtained thereafter.Separation produces between substrate and inorganic particulate.
Embodiment 6
[manufacturing of self-supporting substrate]
Made self-supporting substrate shown in Figure 6.
As substrate 21, the sapphire that has used C face mirror ultrafinish.On substrate 21, utilize normal pressure MOVPE under 1 atmospheric pressure, the temperature of microscope carrier is made as 485 ℃, carrier gas is made as hydrogen, supply with carrier gas, ammonia and TMG, epitaxial growth thickness be about the GaN resilient coating 26 of 60nm.
Substrate 21 is taken out from reacting furnace, be placed on the circulator, thereon, coating is with silica gel ((strain) Japanese catalyst system, SEAHOSTAR KE-W50 (trade name), average grain diameter 550nm) dilution is the liquid of 10 weight %, and Rotary drying has disposed silicon oxide particle 23 on GaN resilient coating 26.Observe with SEM, consequently, silicon oxide particle is a simple layer, GaN resilient coating 26 be 36% by silicon oxide particle to the coverage rate on surface.
Substrate 21 is placed reacting furnace,, utilize normal pressure MOVPE epitaxial growth the III-V nitride semiconductor layer, the III-V nitride semiconductor layer 22B that has grown and contained silicon oxide particle 23 according to following explanation.
Under 500Torr, the temperature of microscope carrier is made as 1020 ℃, carrier gas is made as hydrogen, supply with carrier, ammonia 4.0slm and TMG20sccm75 minute, the temperature of microscope carrier is made as 1120 ℃, supply with carrier gas, ammonia 4.0slm and TMG35sccm90 minute, then, in the 500Torr that keep-ups pressure, the microscope carrier temperature is made as 1080 ℃, carrier gas is made as hydrogen, supplies with carrier gas, ammonia 4.0slm and TMG50sccm360 minute, not Doped GaN layer 22B grown.From 1080 ℃ cool to room temperature, the self-supporting substrate (GaN monocrystalline, the thickness: 35 μ ms) that by the III that contain silicon oxide particle 23-V nitride semiconductor layer constitute have been obtained thereafter.Separation is to produce between the part of substrate 21 sides of substrate 21 and silicon oxide particle 23.
Comparative example 2
Except not disposing silicon oxide particle, carried out [manufacturing of self-supporting substrate] identical operations with embodiment 4.In this example, semiconductor layer 22B does not separate with substrate 21.
Embodiment 7
Made semiconductor light-emitting elements with layer structure shown in Figure 11.
[the semiconductor light-emitting elements manufacturing of substrate]
In [manufacturing of self-supporting substrate] of embodiment 1, after the growth of Doped GaN layer 34 not, cool to room temperature not, on Doped GaN layer 34 not, as n type contact layer, grown be about the GaN layer 35 of mixing Si of 3.5 μ m after, according to the following explanation GaN layer 37 of having grown.Reduce the reacting furnace temperature and be made as 780 ℃, with nitrogen and behind the GaN layer 36 of having grown as carrier gas, the GaN layer 37B of InGaN layer 37A, the 18nm of 5 3nm that alternatively grow.The GaN layer 37C of growth 18nm obtained luminescent layer 37 on InGaN layer 37A.
The Al of growth 25nm consists of 0.05 the AlGaN layer 38 of mixing Mg, and the reacting furnace temperature is brought up to 1040 ℃, supplies with carrier gas, ammonia, TMG and (C
5H
4C
2H
5)
2Mg (EtCp
2Mg) 30 minutes, the GaN layer 39 of mixing Mg of the 150nm that grown.With reacting furnace cool to room temperature, the self-supporting substrate and the III that comprise semiconductor layer-V group-III nitride semiconductor light-emitting component substrate 40 that by the III that contain silicon oxide particle 32-V nitride semiconductor layer constitute have been obtained thereafter.Separation is to produce between substrate 31 sides of substrate 31 and silicon oxide particle 32.
[formation of electrode]
On the GaN layer 39 of mixing Mg of the III-V group-III nitride semiconductor light-emitting component with substrate 40, utilize photoetching to form p electrode pattern, vacuum evaporation NiAu utilizes and peels off the formation electrode pattern, heat treatment, having obtained area is 3.14 * 10
-4Cm
2Ohm p electrode.Utilize photoetching to form mask pattern, carry out dry-etching, exposed the GaN layer 35 of mixing Si.After removing mask, on the dry-etching face, utilize photoetching to form n electrode pattern, vacuum evaporation Al, utilization is peeled off the formation electrode pattern and has been obtained the n electrode.
[evaluation of semiconductor light-emitting elements]
Semiconductor light-emitting elements to gained applies voltage, has studied the characteristics of luminescence under substrate condition.Emission wavelength is 400nm, and light is output as 10.2mW (forward current is 20mA).
Comparative example 3
Except not disposing silicon oxide particle, and utilize laser lift-off to remove beyond the substrate with substrate the semiconductor light-emitting elements, carry out [the semiconductor light-emitting elements manufacturing of substrate] identical operations with embodiment 7, obtained the semiconductor light-emitting elements substrate, then carry out and [formation of electrode] identical operations, obtained semiconductor light-emitting elements.For semiconductor light-emitting elements, use the condition identical to estimate with embodiment 7 [evaluation of semiconductor light-emitting elements], the result is, and emission wavelength is 440nm, and light is output as 4.0mW (forward current is 20mA).