CN1973063B - Monocrystals of nitride containing gallium and its application - Google Patents
Monocrystals of nitride containing gallium and its application Download PDFInfo
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- CN1973063B CN1973063B CN2005800188221A CN200580018822A CN1973063B CN 1973063 B CN1973063 B CN 1973063B CN 2005800188221 A CN2005800188221 A CN 2005800188221A CN 200580018822 A CN200580018822 A CN 200580018822A CN 1973063 B CN1973063 B CN 1973063B
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Abstract
Bulk mono-crystalline gallium-containing nitride, grown on the seed at least in the direction essentially perpendicular to the direction of the seed growth, essentially without propagation of crystalline defects as present in the seed, having the dislocation density not exceeding 10<4>/cm<2> and considerably lower compared to the dislocation density of the seed, and having a large curvature radius of the crystalline lattice, preferably longer than 15m, more preferably longer than 30m, and most preferably of about 70m, considerably longer than the curvature radius of the crystalline lattice ofthe seed.
Description
Technical field
Theme of the present invention is the monocrystals of nitride containing gallium that is used as epitaxial substrate in the process that obtains nitride semiconductor structure, and by using flux method and ammonia process to prepare the method for monocrystals of nitride containing gallium.
The nitride (IUPAC, 1989) that contains XIII family element is the valuable materials that is used for optoelectronics industry.
Monocrystals of nitride containing gallium is considered to be used for the best substrate of cvd nitride gallium epitaxial film, and its energy gap can be used for producing laser diode (LD) and emission blue light diode (LED).Yet, must satisfy so that its condition that can be used as epitaxial substrate is the low-dislocation-density of its high crystalline quality and monocrystalline.
The monocrystals of nitride containing gallium that obtains by existing method does not satisfy these requirements as yet.Yet, to research and the technical progress in this field of expectation demand promotion of the material of suitable quality.
Background technology
The author of WO 02/101120 discloses on crystal seed from containing the supercritical solution crystalline method of the preferred ammonia of nitrogenate solvent.By this method, can obtain having the mass parameter higher than industrial substrate is the dislocation desity monocrystals of nitride containing gallium lower than these substrates, and it can obtain by vapour deposition process, for example HVPE and MOCVD or MBE.Demonstrate high dilatation by the monocrystalline that obtains as the method for learning from the disclosure of WO 02/101120.Because the equilibrium response of crystallisation process makes than the industrial material in each research centre, the whole world, can be from containing the monocrystalline that the overcritical solution that contains the gallium solvent obtains very high crystalline quality.The major advantage of WO 02/101120 technology is to guarantee the pressure and temperature scope that suits wherein to contain gallium nitride from the process based on recrystallization the supercritical solution of nitrogenate solvent.
In other research-and-development activity outside WO 02/101120 method, a large amount of factors that have a limited influence for the practical application of this method are confirmed and are overcome the obstruction that is run into gradually, are included in the technology and equipment aspect.Some obstructions are: the limited availability of desired purity raw material, suitable crystalline seed quality, the selection of suitable mineralizer and the control of single crystal growth rate.
Also known synthetic other method that contains gallium nitride, for example HNP.By these methods, obtain having the algan single crystal that contains of very high crystalline quality and low-dislocation-density.Unfortunately, because the crystal that obtains thus has not satisfied size and irregular shape, so far, it can't be as the epitaxial substrate material in industrial production LED, LD and other semiconductor structure.And processing parameter especially needs to use very high pressure, and significant limitation obtains the crystal of desired size by this method on technical scale.
Studies show that of this paper utilizes flux method to contain the resulting result likely of gallium nitride from the gallium melt growth under nitrogen atmosphere.These methods are industrial attractive, because use low relatively pressure and temperature.
The basic parent material that is used for the open method of WO 02/101120, promptly experience the raw material of recrystallization and crystal seed by according to will be placed on from the mono-crystal gallium nitride of gas phase heterogeneous crystal seed especially the HVPE method on the sapphire obtain.Because the lattice parameter difference of heterogeneous crystal seed and gained monocrystals of nitride containing gallium, and because the difference of two kinds of materials aspect thermal expansion, the monocrystals of nitride containing gallium that obtains by the HVPE method, preferred gallium nitride single crystal have irregular crystalline texture, and it shows in the small curvature radius of gained monocrystals of nitride containing gallium for example.Containing the process of gallium nitride from the overcritical ammonia solution recrystallization monocrystalline that contains, crystal defect in the single crystal gan layer that the use of this monocrystalline such as crystalline seed causes obtaining on this crystal seed and dislocation desity enlarge.In addition, on the crystal seed of orientation, observe at the gallium end of the crystal seed growth conditions different with the nitrogen end face perpendicular to the wafer form of gallium nitride crystal lattice c axle.
The author of WO 03/035945 discloses can be by covering crystalline seed with having the ELOG structure that is easy to laterally promptly towards the surface of a axle growth that contains the gallium nitride lattice, promptly, effectively improve the quality of crystalline seed according to the epitaxial substrate quality improvement method that obtains by method of vapor-phase growing.Yet, consider the random alignment of crystal defect and surface dislocation, on the crystal seed that is coated with the ELOG structure, can on enough degree, eliminate the degree of expansion of the crystal defect of main substrate, described main substrate obtains by the HVPE method, and single crystal gan layer is from depositing on it based on the supercritical solution that contains ammonia solvent.Separate by the band that is grown directly upon on the main substrate on the surface that is easy to transverse growth of arranging with small distance mutually.Must be noted that at this, do not consider that multiple the and optional deposition of ELOG structure on crystalline seed mainly is because expensive.
Summary of the invention
First purpose of the present invention provides the monocrystals of nitride containing gallium that is grown on the crystal seed, it does not expand the crystal defect that exists in the crystal seed substantially, and guarantees to have the crystallinity of raising and the dislocation desity of minimizing from the epitaxial substrate of monocrystals of nitride containing gallium.
Second purpose of the present invention provides more long-life semiconductor structure, and described semiconductor structure is deposited on the epitaxial substrate of new improvement.
The 3rd purpose of the present invention provides a kind of method for preparing monocrystals of nitride containing gallium by flux method and ammonia process.
The unexpected discovery of the inventor can realize above-mentioned purpose by preparation in accordance with the present invention, and described method guarantees that monocrystals of nitride containing gallium has desired size, geometric parameter and required crystalline quality.As a result, can obtain having the arbitrary orientation and enough epitaxial substrate of high crystalline quality.
According to the present invention, at least along the direction growth that is basically perpendicular to the seeded growth direction, it does not expand the crystal defect that exists in the crystal seed to monocrystals of nitride containing gallium substantially, it is characterized in that on crystal seed, and its dislocation desity is no more than 10
4/ cm
2And the lattice that significantly is lower than the dislocation desity of crystal seed and has larger radius of curvature, be preferably greater than 15m, more preferably greater than 30m, most preferably be about 70m, it is significantly greater than the lattice radius-of-curvature of crystal seed.
According to the present invention, monocrystals of nitride containing gallium is grown along the direction that is basically perpendicular to the seeded growth direction on crystal seed at least, it does not expand the crystal defect that exists in the crystal seed substantially, its have preferably be lower than 40 second of arcs (for Cu K α 1) from the FWHM of (0002) planar X ray rocking curve and significantly be lower than the FWHM of crystal seed, have the larger radius of curvature lattice simultaneously, be preferably greater than 15m, more preferably greater than 30m, most preferably be about 70m, it is significantly greater than the lattice radius-of-curvature of crystal seed.
Preferably be doped with to build and/or receptor type and/or magnetic type doping agent according to monocrystalline of the present invention, concentration is 10
17/ cm
3-10
21/ cm
3, and comprise n-type, p-type or compensation (semi-insulating) material.
Preferably, monocrystalline according to the present invention is grown under following environment and condition, and wherein perpendicular to the c axle, the growth velocity that especially is parallel on the direction of a axle is equal to or higher than in the growth velocity that is parallel on the monocrystalline c direction of principal axis.
According to monocrystalline of the present invention gallium nitride single crystal preferably.
According to the present invention, can prepare the wafer of arbitrary orientation with phase shape or non-polar plane, it is as monocrystalline according to the present invention or cut from this monocrystalline and obtain, and cutting is carried out on the required direction with respect to the single crystal growing direction.
Descend according to preferred its surface dislocation density of wafer of the present invention, because cutting is carried out being basically parallel on the single crystal growing direction.
Preferably have apolar surfaces according to wafer of the present invention, it is suitable for other processing.
Preferably have polar surfaces according to wafer of the present invention, it is suitable for other processing.
According to the present invention, wafer can be used as the substrate of the next self-contained XIII family element nitride of epitaxial deposition semiconductor structure.
The present invention also comprises the substrate of the next self-contained XIII family element nitride of epitaxial deposition semiconductor structure, it can be used as that monocrystalline according to the present invention obtains or according to wafer of the present invention, particularly, it is suitable for producing the semiconductor structure that needs nitride, described nitride has enough low surface dislocation density, especially in XIII family element-terminated side, also has the 100mm of being not less than
2, preferably be not less than 450mm
2Epitaxial surface.
The present invention also is included in the semiconductor structure that obtains on the substrate.
Because solution produced according to the present invention, thereby the monocrystals of nitride containing gallium that can guarantee homogeneous gan especially, it has the crystallization parameters and the excellent low surface dislocation density of the excellence that satisfies the optoelectronics industry requirement.
Monocrystalline according to the present invention contains gallium nitride and has Commonly Used Size, regular shape, has outstanding crystal property simultaneously, is fit to the technical requirements of optoelectronics industry.
In concrete preferred embodiment of the present invention, monocrystals of nitride containing gallium has theoretical conduction parameter.This feature that gets the epitaxial substrate of self-contained gallium nitride monocrystalline can change laser structure and the quantity that significantly improves this structure on each substrate.
Simultaneously, should be emphasized that solution according to the present invention also is preferred on cost.
Description of drawings
Fig. 1 illustrates the synoptic diagram that is used for containing by the flux method growing single-crystal crucible of gallium nitride, Fig. 2 is illustrated in the time dependent figure of temperature among the embodiment 4-9, Fig. 3 illustrates the sectional view that is used for overcritical autoclave that contains the ammonia solution growth method and stove group and Fig. 4 and illustrates and obtain the skeleton view that monocrystalline according to the present invention contains the equipment of gallium nitride.
Specific embodiments
In the following description, following term and definition should have following implication, except as otherwise noted.
Autoclave regardless of its form, comprises enclosed reaction vessel, wherein carries out the crystallization process from fluid phase under aforementioned temperature and the pressure range.In order to contain crystallization the ammonia solution, be to use the device shown in Fig. 7 and 8 easily, further concrete hereinafter the discussion from overcritical.
Containing gallium nitride is the compound that contains at least one a gallium atom and a nitrogen-atoms in its structure.It include but not limited to binary compound-GaN, and ternary compound-AlGaN, InGaN or quaternary compound AlInGaN are in any case preferably comprise the gallium of the main part that all is higher than the hotchpotch contents level.Composition with respect to other element of gallium can improve until the selected crystallization technique of its non-contravention in its structure.
Crystallization direction c, a or m are meant hexagonal c, a or m direction, have following Miller's indices: c-[0001],
Be meant by the flux method crystallization from melt crystallization.
Containing gallium material is to contain gallium nitride or its precursor.As raw material, can use the GaN that obtains by any means, for example, case of flux methods, HNP method, HVPE method.In addition, can use the polycrystal GaN that obtains by gallium and the overcritical reaction that contains ammonia solution.
HVPE method (halogenide vapour phase epitaxy) refers to the technology of vapour deposition epitaxial film, and wherein (under the situation of XIII family element nitride) uses XIII family's element halide and ammonia as substrate.
MBE (molecular beam epitaxy) method is meant by obtain the method for the epitaxial film of atomic thickness from so-called " molecular beam " molecule deposition on substrate.
MOCVD method (metal organic chemical vapor deposition) refers to the method for vapour deposition epitaxial film, and wherein (under the situation of gan) uses ammonia and organo-metallic gallium compound as substrate.
Liquid phase crystallization method in this application is meant overcritical contain ammonia solution or scorification crystallization.
The flux method that obtains crystalline composition is meant a group of methods, wherein because the chemical reaction between metal (melt) and the nitrogenous gas (particularly, can be the mixture of gaseous nitrogen or nitrogen and ammonia) obtains described trinitride.Melt comprises gallium and fusing assistant.Certainly, this method is carried out under suitable temperature and pressure.Under the situation as the sodium of well known flux, the representative temperature of this method is about 600-800 ℃, and typical pressure is about 5MPa.
Mineralizer is to introduce one or more I family element ions to the overcritical ammonia solvent that contains, and supports to contain the gallium nitride dissolved substances.
The overcritical ammonia solvent that contains is at least by being used for dissolving the supercritical solvent that the ammonia that contains gallium material is formed, and it contains one or more supports and contains gallium nitride dissolved I family's element (basic metal) ion.Overcritically contain derivative and/or its mixture, the especially hydrazine that ammonia solvent also can contain ammonia.
The overcritical ammonia solution that contains is meant by making and contains gallium material and be dissolved in the overcritical solution that ammonia solvent obtains that contains.
Monocrystals of nitride containing gallium refers to contain the single crystalline substrate of gallium nitride form, thereon can by MOCVD send out or epitaxial growth method for example HVPE obtain photoelectric device for example photodiode (LED) or laser diode (LD).
Crystal face C, A or M are meant the surface of C, A or the M face of hexagonal lattice, have following Miller index: c-[0001], a-[1120], m-[1100].These Surface Vertical are in the crystallization direction (c, a and m) of correspondence.
But polarity or nonpolar other finished surface-be meant the surface that is fit to epitaxial deposition of nitride layers, can produce at least one photoelectric device thereon.This surface should have the size that is enough to by the method extension of MOCVD, MBE method or other epitaxial deposition of nitride layers, is preferably greater than 10mm
2, most preferably greater than 100mm
2
Polarity or nonpolar crystal surface: in the XIII of wurtzite structure family element nitride crystal, the crystal face (with containing these planar planes of crystal) that is parallel to the crystal c axle is called apolar surfaces, and is called polar surfaces perpendicular to the crystal face (with containing these planar planes of crystal) of crystal c axle.
Contain the gallium nitride precursor and be and contain gallium and optional I family element (basic metal), II family element (alkaline-earth metal), XIII family element (family number according to IUPAC 1989), nitrogen and/or hydrogen and gallium, its alloy or the material or the mixture of metallic compound, hydride, acid amides, imide, amino-imide and trinitride of containing at least, it can form and dissolve in as the defined overcritical gallium compound that contains in the ammonia solvent hereinafter.
Supersaturation: if contain the concentration of soluble gallium compounds in the ammonia solution and be higher than the solubleness that contains gallium nitride under specific physical and chemical condition, so for can be defined as poor between actual concentrations and the solubleness in the overcritical supersaturation that contains ammonia solution that contains gallium nitride under this condition overcritical.When dissolving contains gallium nitride in closed system, for example can obtain hypersaturated state by improving temperature or reducing pressure.
Diffusion process among the application is meant crystal growing process, and wherein the migration between raw material and the crystal seed is undertaken by diffusion substantially.
Convection process among the application is meant crystal growing process, and wherein the migration between raw material and the crystal seed is undertaken by convection current substantially.
Solubleness: our experiment shows, can realize equilibrium state under the sufficiently high temperature and pressure between solid (containing gallium nitride) and supercritical solution.Therefore, the solubleness that contains gallium nitride can be defined as the equilibrium concentration of the soluble gallium compounds that obtains in containing the above-mentioned dissolution process of gallium nitride.In this process, equilibrium concentration is that solubleness can be controlled by the composition, temperature and/or the pressure that change solvent.
The dissolving that contains gallium material is meant that described raw material gallium compound is dissolved in and forms for example reversible or irreversible process of gallium title complex in the supercritical solvent.The gallium title complex is a chemical complex, and the gallium atom that wherein is in the center is by NH
3 -Type dentate or derivatives thereof is as NH
2 -, NH
2-Deng surround.
Be meant in spontaneous crystallization at selective crystallization on the crystal seed and do not have or the spontaneous crystallization degree that takes place can ignore the time crystallisation process that on seed surface, takes place.This process is for realizing that the bulk-shaped monocrystal that purpose of the present invention promptly obtains to contain gallium nitride is indispensable, and this also is a staple of the present invention simultaneously.
Contain ammonia solution spontaneous crystallization and refer to that any position contains any unwanted nucleation and growth process of gallium nitride crystalline in autoclave except on the seed surface from supersaturation is overcritical.This definition is also included within the growth on the seed surface, and wherein growing crystal has the orientation that is different from this crystal seed.
Melt among the application is meant the mixture of molten metal.
XIII family element-terminated side (terminated side), Ga end face, N end face: in having the crystal of wurtzite structure, people can distinguish the crystallization direction (crystallographic axis) that is expressed as a, perpendicular to another crystallization direction-c of a.In having the XIII family element nitride crystal of wurtzite structure, be incoordinate perpendicular to the crystal face (C-face) of c axle.Traditionally they are called XIII family element-terminated side and nitrogen end face or have XIII family element polarity or nitrogen polar surface.Particularly, under the situation of mono-crystal gallium nitride, people can distinguish gallium end face (Ga-face) and nitrogen end face (N-face).These masks have different chemistry and physical properties (for example easy etching or thermostability).In vapour phase epitaxy method, settled layer on XIII family element-terminated side.
The temperature and pressure of reaction: in the embodiment of this specification sheets, when autoclave does not promptly have the overcritical measurement of high pressure temperature in the kettle of having carried out when containing ammonia solution when being empty.Therefore, the temperature value of being quoted among this embodiment is not an actual temperature value of implementing described process in supercritical state.Pressure is directly measured or is calculated based on the physics and the chemical data that contain ammonia solvent under selected technological temperature and autoclave volume.In case of flux methods, measure the temperature of autoclave inside, crucible outside.Yet the temperature value that provides among the application should be very near the actual temperature value that is included in the melt in the crucible.
Fusing assistant is meant the material that adds reaction environment in case of flux methods, and it helps reactant to remain liquid phase in whole process.
Contain the chemical transport of gallium nitride in supercritical solution be meant comprise contain the dissolving of gallium material in supercritical solution, soluble gallium compounds in this solution circulation and contain gallium nitride from supersaturation supercritical solution crystalline successive processes.Usually, chemical transport can be by other chemistry between the temperature difference, pressure reduction, concentration difference XOR dissolved raw material and the crystallized product or physical difference and is caused.According to the present invention, monocrystals of nitride containing gallium can obtain by the dissolving of autoclave and the chemical transport between the crystallizing field, and the temperature difference shown in described chemical transport passes through between two districts realizes, and the temperature of crystallizing field should be higher than the temperature of dissolve area.
The temperature and pressure coefficient of solubleness (TCS and PCS): the negative temperature coefficient of solubleness is meant that solubleness is the decreasing function of temperature if all other parameters remain unchanged.Equally, the positive temperature coefficient of solubleness is meant that solubleness is the increasing function of temperature if all other parameters remain unchanged.We studies show that, contain gallium nitride at least in 300 ℃～550 ℃ temperature ranges and under the pressure of 100MPa～550Mpa and reveal negative temperature coefficient (negative TCS) and thrust coefficient (positive PCS) at the overcritical solubility table that contains in the ammonia solvent.
Transverse growth in the present patent application is meant in the crystal seed upper edge perpendicular to the block growth of the direction of the inceptive direction of seeded growth.Opposite with ELOG (epitaxial lateral overgrowth), transverse growth is clear and definite macroscopic (order of magnitude of seed sized or even bigger).And the crystalline ridge (projection) of transverse growth on the direction of the inceptive direction that is parallel to seeded growth obviously exceeds the ridge of used crystal seed.Under ELOG (epitaxial lateral overgrowth) situation, this two classes ridge is equal substantially.
ELOG (epitaxial lateral overgrowth) is that wherein crystal is grown on specific substrate by gas phase or the overcritical crystal growth that contains ammonia solution.Under the situation of gallium nitride, on the surface of substrate, produce the matrix (several microns high and several microns wide) of the parallel ridges thing (ridges) on surface with the transverse growth of being easy to.Usually, gallium nitride is grown in the c direction.Produce convex protrusion and be easy to the surface of transverse growth consistent along the m direction then with the A face.In this case, transverse growth is restricted to several or tens microns, in case and the interval between the convex protrusion by the pulling crystal outgrowth that becomes, it just finishes.Then, the main growth of bulk crystals is carried out along the c direction.Can prevent that by this way some dislocations that are present in the substrate are penetrated in the crystal that lifts.
Crystal seed is by containing the key that the ammonia solution crystallization obtains required bulk gallium-containing nitride monocrystalline from overcritical.Consider that the crystal seed quality is the fact of key of the crystalline quality of bulk gallium-containing nitride monocrystalline, the crystal seed of selecting to be used for this process should have high as far as possible quality.Also can use various structures or wafer with modified surface.For example have some spaces enough far away, be arranged on the initial substrate and the surface tissue that is easy to the horizontal outgrowth of crystallization nitride can be used as crystal seed (ELOG structure).Can utilize the whole bag of tricks to produce crystal seed, for example by vapor phase growth, as HVPE, MOCVD or MBE.
In using WO 02/101120 aspect the disclosed method by analysis the experience of himself, and by the test verify for the feasibility report that contains gallium nitride that obtains the monocrystalline form, the inventor finds that monocrystals of nitride containing gallium grows with different rates under varying environment, and in addition on each direction of hexagonal wurtzite type lattice with the different rates growth, wherein make gan and other contain the gallium nitride crystallization.This information directly contains the gallium nitride shape based on what obtained by spontaneous crystallization in obtaining the process of this type of nitride single-crystal.
As disclosed among the WO 02/101120, obtaining spontaneous crystallization by this method is that fact proved of six policy shapes exists preferred growth for the lattice c axle that contains gallium nitride.
Known low temperature and the low pressure flux method that in nitrogen atmosphere, obtains GaN from Ga-Na and Ga-Li.Because desired preferred pressure and temperature parameter in these methods, make the present inventor to as allow these parameters with from contain gallium nitride solution overcritical-preferably containing ammonia-environment, to obtain the method for potential method of raw material and the possible crystalline seed that is used for crystallisation process interested.
Yet the process that obtains gan from the Ga-Na alloy melt is difficult technically, this be since sodium to the reactivity of moisture, under processing condition sodium vapor high pressure and cause in the distillation of the colder part of reactor deposition.Sodium is difficult to this method industrialization as these character of fusing assistant are feasible.
Youting Song et al. has reported in Journal of Crystal growth 247 (2003) 275-278 and has utilized lithium as the GaN crystallization (temperature about 800 ℃ of fusing assistant by flux method, pressure 0.2MPa, process duration 120-180 hour).This report proof uses lithium can obtain GaN under not fiercer condition as fusing assistant, yet the crystal amount of spontaneous formation is still unsatisfactory.
Obtaining the glidant technology application facet of raw material and crystal seed, observation of carrying out and experience show that the glidant method can obtain having the spontaneous gallium nitride crystal that contains of the hexagonal wafer form of high-crystallinity and low surface dislocation density.The crystal shape of spontaneous formation (not having crystal seed) shows under processing condition, exists on perpendicular to the direction that contains gallium nitride lattice c axle preferably to contain the gallium nitride growth.
As in the flux method, this research allows crystal to grow on the direction perpendicular to the c axle, for can on perpendicular to the direction of c axle, carrying out crystal growth, though restricted dimensionally and may be very slow by present method from overcritical originally studies show that also of method that contains ammonia solution growth.
This means by containing the gallium nitride monocrystalline that contains that the ammonia solution growth method obtains and determined by size, shape and seed orientation on the one hand, determine by process duration in the system and raw material shelf time on the other hand from overcritical.
For above-mentioned observation, gallium nitride single crystal growing to the small part that contains according to known method occurs on the direction near the direction of growth of the crystal seed that obtains by identical or different method, and this means unfortunately at the deposition monocrystalline and contains expanding to small part of the crystal defect that is present in the gallium nitride layer in the crystal seed.
Recently have been found that can obtain that mass parameter is higher than kind of brilliant parameter substantially by the condition of selecting to contain the gallium nitride crystallisation process contain the gallium nitride crystal.At this moment, when concern guaranteed to contain the gallium nitride appropriate size, the inventor paid general attention and obtains the crystal seed of suitable dimension.
Can obtain by in described process, on required direction, controlling single crystal growing according to monocrystals of nitride containing gallium of the present invention, described process be included in perpendicular on the direction of single crystal growing from the step of liquid growth, wherein said monocrystalline comes self-contained gallium nitride during obtaining phase.
The liquid growth monocrystalline can utilize under 300 ℃-950 ℃ temperature by flux method guarantees that system carries out for the fusing assistant of liquid phase.
From the optional Ga-Li melt growth that comprises additional flux X, X is preferably selected from Bi, In, K, Na, Pb, Rb, Sb, Sn and Te by flux method, and the mol ratio of X: Ga: Li is 0.5: 1.0: 1.5-1.5: 1.0: 2.5.
Preferably, utilize flux method, under 700 ℃ of-850 ℃ of temperature, under the 2.0-2.5Mpa pressure and optional add crystallization and contain gallium nitride and grow.
Preferably, be heated to temperature required melt mutually in, use the protective atmosphere of the preferred argon gas of rare gas element.Then, argon gas is added system, and thermograde is being remained in the melt scope and when crystal seed places cold zone, on crystal seed, carry out single crystal growing.
What recommend is that after finishing crystal growth by flux method, melt should begin slow cooling, is cooled fast to envrionment temperature subsequently.
Preferably, in inert gas atmosphere, can utilize fusing assistant, surpass 700 ℃ by heating until melt temperature and obtain heterogeneous Ga melt, then by stablizing melt, changing atmosphere and under stable condition, carry out crystal growth subsequently by the nitrogen that representative gases is replaced into pressure 2.0-2.5MPa, and after finishing growth, can be under processing condition the gained crystal is taken out from melt gradually or can make all substances cooling as mentioned above, come separating obtained monocrystalline by dissolving solid-state melt at last.
When heating Li-Ga melt in the zone, thermograde is remained near the melt, and crystal seed is placed the cooling zone.
It should be noted that in diffusion process the Heating Zone Temperature in the inert gas atmosphere keeps below subsurface region and is higher than the base area, and after atmosphere is changed over nitrogen, the reverse temperature gradient.
Scheme as an alternative, in convection process, use other raw material-as the interior nitrogenous source in the melt-for containing lithium, gallium or comprising the element nitride crystal form of the metal of Bi, In, K, Na, Pb, Rb, Sb, Sn or Te as additional flux, and make additional raw material become liquid phase by as mentioned above all substances being heated to medial temperature, exceed tens degrees centigrade temperature and the zone of placing other raw material is reached.
Preferably, in two kinds of flux methods, the temperature difference between the zone remains on tens degrees centigrade level.
According to the present invention, the liquid growth monocrystalline can also be undertaken by the growth method in the supercritical solution of nitrogen-containing solvent, preferably contains in the ammonia solution overcritical.
According to present method, what system comprised crystal form contains the preferred crystalline composition of gallium material, I family element and/or its mixture and/or its compound, especially contain nitrogen and/or hydrogen, preferred trinitride, optionally add II family element and/or its compound that forms mineralizer, and mineralizer is used as with ammonia and contains ammonia solvent.The required crystallization that contains gallium nitride on the seed surface, be higher than and/or be lower than under the temperature and pressure of material dissolution temperature and pressure and carrying out.There are two humidity provinces.Raw material is at dissolve area, and at least a crystal seed is at crystallizing field, and dissolve area is positioned at the crystallizing field top, carries out mass transfer from dissolve area to crystallizing field.
Preferably, the temperature difference between dissolve area and the crystallizing field is 1 ℃-150 ℃, preferred 10 ℃-100 ℃, and the temperature of crystallizing field is not less than 350 ℃, preferably is not less than 400 ℃, most preferably is 500 ℃-550 ℃.
Preferably obtain by growing on perpendicular to the direction of single crystal growing direction according to monocrystals of nitride containing gallium of the present invention, described monocrystalline is from containing gallium nitride based on the overcritical identical monocrystalline of chemical constitution that contains the growth method of ammonia solution.
Preferably, can obtain by the growth of control monocrystalline on required direction according to monocrystals of nitride containing gallium of the present invention, this is because at least one containing from the lithium base in the gallium melt along the direction growth perpendicular to monocrystalline c axle, and at least onely contain in the ammonia solution along direction growth perpendicular to monocrystalline c axle overcritical, wherein each all uses raw material and crystal seed in mutually, optional repeat on and at the growth phase on the c direction of principal axis, until at least one obtains the monocrystalline of desired size along it perpendicular to the c direction of principal axis.
Preferably, be used to obtain according to the crystal seed of monocrystals of nitride containing gallium of the present invention for orientation perpendicular to the wafer form of monocrystalline c axle contain the gallium nitride form, it obtains by the gas phase crystallization method, it has and is not more than 10
8/ cm
2Surface dislocation density, and at first this crystal seed is coated with what be parallel to desired thickness on the monocrystalline c direction of principal axis and contains the gallium nitride layer, and obtains 10 by the overcritical growth method that contains ammonia solution
4/ cm
2-10
6/ cm
2Surface dislocation density, carry out the wafer growth by flux method on perpendicular to the direction of monocrystalline c axle subsequently, then can be on perpendicular to the wafer of monocrystalline c axle growth deposition another contain the gallium nitride layer, grow towards the c axle from the overcritical ammonia solution that contains simultaneously.
The gallium nitride that contains that obtains by the HNP method has low-down surface dislocation density, it can be used as crystal seed, then by flux method required direction-perpendicular to the c axle-direction on grow, and along the original shape that depends on crystal seed on the direction of its c axle by the overcritical method that contains ammonia solution growth, and after obtaining the monocrystalline of desired size, cut the wafer of required orientation from it, afterwards, can repeat fluxing agent growth stage and/or the overcritical ammonia solution growth phase that contains.
In addition, the gallium nitride monocrystalline that contains of the hexagonal wafer form that is obtained by spontaneous crystallization by flux method can be used as crystal seed.Subsequently, carry out the growth of described crystal seed by the overcritical ammonia solution growth method that contains along the c direction of principal axis, and after obtaining the monocrystalline of desired size, cut the wafer of required orientation from it, afterwards, can repeat fluxing agent growth stage and/or the overcritical ammonia solution growth phase that contains.
According to another preferred embodiment of the present invention, can obtain monocrystals of nitride containing gallium by the growth of control monocrystalline on required direction, it comprises that at least one is being parallel on the monocrystalline c direction of principal axis at the overcritical growth step that utilizes raw material and crystal seed in the ammonia solution that contains perpendicular to the axial growth step of monocrystalline c and at least one.
Usually, in order to obtain, will contain the gallium nitride wafer as crystal seed by what the HVPE method obtained according to monocrystals of nitride containing gallium of the present invention.
Yet, preferably, to contain the gallium nitride monocrystalline as crystal seed, it is the wafer with at least one non-polar plane, obtain obtaining for monocrystalline or by the monocrystalline that obtains from the gas phase crystallization process, or more preferably obtain by the overcritical ammonia solution growth method that contains, on perpendicular to the direction of monocrystalline c axle, carry out the wafer growth by flux method and/or the overcritical ammonia solution growth method that contains afterwards.
Can mix to body and/or acceptor and/or magnetic type doping agent according to monocrystals of nitride containing gallium of the present invention, concentration is 10
17/ cm
3-10
21/ cm
3The result who contains gallium nitride that mixes according to the present invention is n-type, p-type or compensation (semi-insulating) material.
Preferably, be the gan form according to monocrystals of nitride containing gallium of the present invention.
Preferably, the suitable dimension that is used to obtain the crystal seed of monocrystals of nitride containing gallium is by making the crystal seed experience contain gallium nitride lattice c axle and the initial procedure of growth is guaranteed perpendicular to containing on the gallium nitride lattice c direction of principal axis alternately being parallel to.
Flux method by the Ga-Li melt is being parallel on the c direction of principal axis alternately growth and is carrying out in a predetermined direction alternating growth perpendicular to the c direction of principal axis with by the overcritical ammonia solution method that contains.As selection, use one of these methods, and in follow-up phase, alternately manifest the aufwuchsplate on the required direction, on perpendicular to the direction that reduces direction, grow simultaneously.
Contain the growth of gallium nitride monocrystalline on required direction and be disclosed among the publication WO03/035945 as reducing.
Contain gallium nitride to confirm to obtain the monocrystalline that based single crystal contains the very high crystalline quality of gallium nitride wafer according to the test result of monocrystalline of the present invention, described wafer obtains by method of vapor-phase growing especially HVPE method, supposes to grow on the direction perpendicular to the c axle in obtaining the subsequent step of method that monocrystalline according to the present invention contains gallium nitride.The wafer that obtains like this has very large radius-of-curvature, and greater than 15m, more preferably greater than 30m, most preferably more than 70m, and the radius-of-curvature of the monocrystalline that obtains on the direction identical with the seeded growth direction has the representative value of about 2-15m.At this moment, be preferably according to the FWHM of monocrystalline of the present invention and be lower than 40 second of arcs.
GaN shows good solubility in overcritical NH3, supposes to introduce for example NaNH of basic metal or its compound
2Or KNH
2Based on the test that the inventor carries out, solubility with pressure rises and descends with temperature.According to these relations, can implement according to process of the present invention and obtain required crystal.
Raw material places the upper area of reactor.This zone remain on reactor lower part zone differing temps scope under, wherein settle at least one single crystal seed.
Particularly, the negative temperature coefficient of GaN solubleness means because thermograde in process environments, make can cause from as the top cold zone of the dissolve area of crystalline composition form raw material to gan chemical transport as the high-temperature zone, bottom of crystallizing field.
As the use of crystalline composition in the GaN recrystallization process of preferred feedstock is preferred, and this is because it can guarantee that required being easy to of technology dissolved and the gallium amount of solubilized form progressively.
As mentioned above, contain from overcritical that the crystalline crystal seed can obtain by any means the ammonia solution.Preferably, use the GaN that derives from the HVPE method, the GaN monocrystalline that can obtain having big relatively surface wafer form by this method.Utilize these crystal seeds, the monocrystals of nitride containing gallium that obtains according to the present invention has low-down dislocation desity, but they are extremely thin simultaneously.Material according to the invention is the best materials of the substrate of epitaxial deposition of semiconductor layers.At this moment, can adopt aforesaid method to prepare the crystal seed that is used for subsequent process.
As for mineralizer, can use basic metal, alkali metal compound, particularly contain the mixture of those and they of nitrogen and hydrogen.Basic metal can be selected from Li, Na, K, Rb and Cs, and their compound can be selected from hydride, acid amides, imide, amino-imide, nitride and trinitride.
Be used to obtain the ion that the supercritical environment that contains ammonia solution according to the adding alkalimetal ion of bulk gallium nitride single crystal of the present invention can also comprise the soluble form of other metal ion of specially introducing and other element, to improve the performance of gained mono-crystal gallium nitride.But this environment also contains with raw material to be introduced and be discharged into impurity at random the environment from the element of application apparatus in treating processes.Can be by utilizing highly purified reagent or the reagent of additional purification reduces the content of impurity at random for arts demand.Impurity from equipment also can be controlled by the choice structure material according to the used principle of those skilled in the art.
Preferably, crystal according to the present invention perpendicular to or be parallel to control growing on the required direction of c axle by following examples in specifically described method carry out, its graph of a relation by temperature and treatment time represents, as shown in drawings.As shown in Figure 2, keep below dissolve area from the overcritical temperature that contains the crystallization phases of ammonia solution, upper area (hereinafter describing in detail) as Fig. 3 and 4 concise and to the point autoclave dissolve areas of describing wherein in whole crystallisation cycle process, keeps constant level with temperature.
Under these conditions, because the interregional temperature difference and thermograde make raw material dissolve at dissolve area, and convection current causes the chemical transport between the zone, when containing ammonia solution and reaching supersaturation, on the crystal seed of crystallizing field, carry out the crystallization of GaN when overcritical with respect to GaN.
Containing ammonia solution when growth from overcritical, interregional temperature approach can change at wide region, is preferably formed several degrees centigrade-tens degrees centigrade.In addition, according to the present invention, can during process, change the interregional temperature difference.Like this, can control the growth velocity and the quality of gained monocrystals of nitride containing gallium.
In addition, can improve primary process, for example by periodically-varied temperature in All Ranges, but the temperature of crystallizing field must always be higher than the temperature of dissolve area.
The inventor studies the optimization that is used to control the flux process that contains the gallium crystal growth, uses molybdenum crucible as shown in Figure 1, is placed in the high-temperature reactor with controlled atmosphere, is adjusted to be operated in and boosts down, and be equipped with strip heater.In Fig. 1, crucible
AThe Li-Ga melt is housed, and described melt contains above-mentioned additional flux (being selected from Bi, In, K, Na, Pb, Rb, Sb, Sn and Te).At crucible
AThe bottom, the crystallization raw material of GaN form is arranged, it is interior nitrogenous source.Specified phase in process is introduced crystal seed
B, and can it be sunk to melt or take out from melt by the unshowned mechanism of accompanying drawing.Two kinds of orientations of crystalline seed show in the zone of growing on the crystal seed and can be orientated in crucible in a different manner.
Grow and the reactor of various structures, to carry out from the overcritical ammonia solution that contains.In following examples, use the autoclave that schematically is shown in Fig. 3 and Fig. 4
1Autoclave
1The device of baffle forms is equipped with
2, it is equipped with has heating
5And/or refrigerating unit
6Two stoves
3With
4Device
2Can be the horizontal baffle form or have the center and/or the baffle plate of opening on every side
7, described barrier partitions autoclave
1In the top dissolve area
8With the lower junction crystalline region
9Autoclave
1The temperature value in Zhong Ge district is in 100 ℃ of-800 ℃ of scopes, and temperature can be set in stove by the control device (not shown)
3With
4In.At autoclave
1In, dissolve area
8At horizontal baffle or baffle plate
7Top and raw material
10Place this zone.And crystallizing field
9At horizontal baffle or baffle plate
7The below.In this zone, place at least one crystal seed
11Crystal seed
11Placement location be lower than the point of crossing of the reflux fluid that rises and descend.
Monocrystals of nitride containing gallium according to the present invention is characterised in that it has extremely low surface dislocation density.It can contain the 0.1ppm or bigger of having an appointment-even greater than the basic metal of 1.0ppm content, even greater than the basic metal of 10ppm, described basic metal is introduced system (depending on the Method type that the control crystal is grown on required direction) as fusing assistant or mineralizer.For the basic metal that has the several ppm of 0.1ppm-according to GDMS (glow discharge mass spectrometry) curve display of product sample of the present invention.In addition, some transition metal (Fe, Cr, Ni, Co, Ti, Mn) that are present in the reaction environment provide measurable signal.In order to contrast, the similar curve display of GaN crystalline that obtains by the HVPE method exists content to be lower than the potassium of 0.1ppm.And the transition metal curve exists with noise level, and there are these elements of extremely low amount in this to this proof at the GaN crystal that obtains by the HVPE method.
According to the test of carrying out in advance, the inventor determine the GaN monocrystalline on crystal seed from the Ga-Li melt growth that has above-mentioned additional flux with from the overcritical control condition that contains the method for ammonia solution growth.The same positive checking of these conditions contains the nitride of other XIII family element, and the mixed nitride thing that contains gallium and other XIII family element.Because the lattice parameter of gan, aluminium and indium is similar, therefore can come the part substituted by gallium with aluminium and/or indium in containing in the gallium nitride of obtaining according to the present invention.
In following examples, be described in more detail the present invention.
Embodiment 1 (flux method)
The mixture of gallium and lithium is placed the high-temperature reactor (Fig. 1) of molybdenum crucible (A), and the crucible volume is 250cm
3The additional flux that will be selected from Bi, In, K, Na, Pb, Rb, Sb, Sn and Te equally adds system, makes that the mol ratio of X in the experiment of carrying out in advance: Ga: Li is 0.5: 1.0: 1.5-1.5: 1.0: 2.5.With extremely about 780 ℃ of mixture heating up, the result obtains having the X that provides: Ga: the alloy of the aforementioned metal of Li mol ratio in argon (Ar) atmosphere.After one day, atmosphere is changed into nitrogen (N2) under the 2.3MPa pressure.Subsequently the pressure and temperature condition in the reactor was kept several days.Subsequently, the monocrystalline of beginning on crystal seed (B) contains the process of growth of gallium nitride, and crystal seed (B) is basically perpendicular to the single-crystal wafer form of crystal c axle and has 0.24-4cm for orientation
2Long-pending perpendicular to the cross-sections surfaces of c axle.The process of growth time length under the processing condition is 1-2 week.Then reactor is slowly cooled off, further (fast) is cooled to room temperature (RT) subsequently.As selection, crystal seed is slowly pulled out from the fused alloy under processing condition.The result of processing, observing seed surface long-pending (at crystal c-planar survey) increases about 20%.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 2 (diffusion flux method)
The mixture of gallium and lithium is placed the high-temperature reactor (Fig. 1) of molybdenum crucible (A), and the crucible volume is 250cm
3The additional flux that will be selected from Bi, In, K, Na, Pb, Rb, Sb, Sn and Te equally adds system, makes that the mol ratio of X in the experiment of carrying out in advance: Ga: Li is 0.5: 1.0: 1.5-1.5: 1.0: 2.5.In argon (Ar) atmosphere with mixture heating up to about 780 ℃ medial temperature, wherein the temperature on crucible top is lower than tens degrees centigrade of medial temperatures, the temperature of crucible bottom is higher than tens degrees centigrade of medial temperatures simultaneously.As a result, obtain having the X that provides: Ga: the alloy of the aforementioned metal of Li mol ratio.After one day, change into nitrogen (N under the 2.3MPa pressure with the thermograde in crucible counter-rotating and with atmosphere
2).Subsequently the pressure and temperature condition in the reactor was kept several days.Subsequently, the monocrystalline of beginning on crystal seed (B) contains the process of growth of gallium nitride, and crystal seed (B) is basically perpendicular to the single-crystal wafer form of crystal c axle for orientation and has the cross-sections surfaces perpendicular to the c axle of 0.24-4cm2 long-pending.The process of growth time length under the processing condition is 1-2 week.Then reactor is slowly cooled off, further (fast) is cooled to room temperature (RT) subsequently.As selection, crystal seed is slowly pulled out from the fused alloy under processing condition.The result of processing, observing seed surface long-pending (at crystal c-planar survey) increases about 10%.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 3 (convection current flux method)
The mixture of gallium and lithium is placed the high-temperature reactor (Fig. 1) of molybdenum crucible (A), and the crucible volume is 250cm
3The additional flux that will be selected from Bi, In, K, Na, Pb, Rb, Sb, Sn and Te equally adds system, makes that the mol ratio of X in the experiment of carrying out in advance: Ga: Li is 0.5: 1.0: 1.5-1.5: 1.0: 2.5.In addition, raw material (C) is placed the crucible bottom.With mixture heating up, until reaching about 780 ℃ medial temperature, wherein the temperature on crucible top is lower than tens degrees centigrade of medial temperatures in argon (Ar) atmosphere, and the temperature of crucible bottom is higher than tens degrees centigrade of medial temperatures simultaneously.As a result, obtain having the X that provides: Ga: the alloy of the aforementioned metal of Li mol ratio.After one day, atmosphere is changed into nitrogen (N under the 2.3MPa pressure
2).Subsequently the pressure and temperature condition in the reactor was kept several days.Subsequently, the monocrystalline of beginning on crystal seed (B) contains the process of growth of gallium nitride, and crystal seed (B) is as the single-crystal wafer form of gained among the embodiment 1 and has 0.24-4cm
2Long-pending perpendicular to the cross-sections surfaces of c axle.Crystal seed places the top of crucible.The process of growth time length under the processing condition is 1-2 week.Then reactor is slowly cooled off, further (fast) is cooled to room temperature (RT) subsequently.As selection, crystal seed is slowly pulled out from the fused alloy under processing condition.The result of processing, observing seed surface long-pending (at crystal c-planar survey) increases about 25%.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 4 (containing the ammonia solution crystallization) from overcritical
According to the disclosure of WO 02/101120, will contain gallium material, crystal seed, mineralizer and ammonia and charge into 600cm
3The dissolve area of autoclave in (Fig. 3 and Fig. 4).Crystal seed is a gallium nitride single crystal, for as the single-crystal wafer form of gained among the embodiment 1 and have 0.24-4cm
2Long-pending perpendicular to the cross-sections surfaces of c axle.Sodium Metal 99.5 is as mineralizer.Raw material places dissolve area, and crystal seed is placed in crystallizing field (Fig. 3).T in crystallizing field
2T in=550 ℃ and the dissolve area
1Carry out the crystallisation process on the crystal seed under=500 ℃ the constant temperature.This temperature distribution in the autoclave keeps 16 days (Fig. 2).Under this condition, the autoclave internal pressure is about 390MPa.The result of process, observe raw material dissolve area be partly dissolved and each crystal seed two sides at crystallizing field on the growing single-crystal gallium nitride layer.The total thickness of recrystallization layer (measuring along the crystal c axle) is about 1200 μ m (on each crystal seed).The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 5 (containing the ammonia solution crystallization) from overcritical
Carry out the step described in the embodiment 4, just sodium Metal 99.5 replaced to-a) metallic lithium, b) sodiumazide or c) Sodium Bromide is as mineralizer.After handling 16 days, observe the single crystal gan layer of on each crystal seed two sides of crystallizing field, growing.The total thickness of recrystallization layer (measuring along the crystal c axle) is respectively about a) 380 μ m, b) 840 μ m and c) 530 μ m.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 6 (containing the ammonia solution crystallization) from overcritical
Carry out the step described in the embodiment 4, and used crystal seed have the orientation be basically perpendicular to the single-crystal wafer form of crystal c axle and have 0.24-4cm
2Long-pending perpendicular to the cross-sections surfaces of c axle, and these wafers have square shape or equilateral triangle shape.The result of process, observe raw material dissolve area be partly dissolved and each crystal seed at crystallizing field on the face that is parallel to the crystal c axle and crystal C face on the growing single-crystal gallium nitride layer.The total thickness of recrystallization layer (measuring along the crystal c axle) is about 2mm (on each crystal seed).The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 7 (containing the ammonia solution crystallization) from overcritical
Carry out the step described in the embodiment 6, just sodium Metal 99.5 is replaced to Sodium Bromide as mineralizer.Seeding crystals has six faces and is parallel to the hexagon shape of crystal c axle and has 0.24-4cm for being orientated the single-crystal wafer form that is basically perpendicular to the crystal c axle
2Long-pending perpendicular to the cross-sections surfaces of c axle.After handling 16 days, observation is being parallel to the single crystal gan layer of growing on all faces of c axle on each crystal seed of crystallizing field.The total thickness of recrystallization layer (measuring along the crystal c axle) is respectively about 1100 μ m.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 8 (containing the ammonia solution crystallization) from overcritical
Carry out the step described in the embodiment 4, just in crystallisation process, the temperature of crystallizing field is T
2The temperature T of=500 ℃ and dissolve area
1=450 ℃.Used crystal seed has orientation and is basically perpendicular to the single-crystal wafer form of crystal c axle and has 0.24-4cm
2Long-pending perpendicular to the cross-sections surfaces of c axle, and these wafers have square shape or equilateral triangle shape, and at least one face is parallel to crystalline A face.The result of process observes raw material and is partly dissolved and the growing single-crystal gallium nitride layer at dissolve area, goes up on the thickness of the about 400 μ m of growth and two the C faces at each crystal seed at the face that is parallel to the crystal c axle on each crystal seed (measuring perpendicular to the crystal c axle) and grows.The total thickness of recrystallization layer (measuring along the crystal c axle) is about 700 μ m on each crystal seed.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
Embodiment 9 (containing the ammonia solution crystallization) from overcritical
Carry out the step described in the embodiment 6,, reach the temperature T of crystallizing field respectively in system just in the recrystallization stage
2The temperature T of=550 ℃ and dissolve area
1After=500 ℃ the target temperature, with the temperature T of dissolve area
1500 ℃ of-450 ℃ of temperature range intercycle variations, simultaneously with the temperature T of crystallizing field
2550 ℃ of-500 ℃ of temperature range intercycle variations, always temperature is higher to make crystallizing field.Like this, perpendicular to obtaining stimulating with the crystal growth that is parallel to the c axle.After handling 16 days, observe on all faces that are parallel to the c axle on each crystal seed of crystallizing field and the single crystal gan layer of growing on the crystalline C face.The total thickness of recrystallization layer (measuring along the axle perpendicular to the crystal c axle) is about 900 μ m, and the total thickness of recrystallization layer (measuring along the crystal c axle) also is about 900 μ m.The GaN monocrystalline that storage obtains during the course is to be used for further measurement and to use.
The crystal that evaluation obtains in embodiment 1-9.These crystal have high crystalline quality, low-level lattice imperfection (the long radius-of-curvature of wafer), and preferably the HWHM value of waving the X ray curve by (0002) is lower than 60 second of arcs, is lower than 40 second of arcs in preferred embodiment (embodiment 6).The inventor finds that the single crystal growing technology that is proposed is not limited to have on the equipment and material of the lower substantially possibility that obtains large size single crystal.
Appropriate combination (alternately preferred) is used perpendicular to c axle (embodiment 1-3 and 6-9) and is parallel to c axle (embodiment 4-6 and 8-9) growing gallium nitride, and allowing to obtain volume is 2.5cm
3With C face top surface area be about 5cm
2Contain the gallium nitride monocrystalline.Because high crystalline quality and size, this crystal can cut into wafer, and is used as the substrate of nitride based optoelectronic semiconductor component subsequently.This wafer can have arbitrary orientation and have polarity or non-polar plane.Can on required direction, cut with respect to single crystal growing.Particularly, orientation guarantees additionally to reduce surface dislocation density towards the cutting of single crystal growing substantially.
Claims (28)
1. monocrystals of nitride containing gallium, it at least along the direction growth that is basically perpendicular to the seeded growth direction, does not expand the crystal defect that is present in the crystal seed substantially on crystal seed, and its dislocation desity is no more than 10
4/ cm
2And significantly be lower than the dislocation desity of crystal seed and have lattice radius-of-curvature greater than 15m, it is significantly greater than the lattice radius-of-curvature of crystal seed.
2. according to the monocrystals of nitride containing gallium of claim 1, it is characterized in that the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 30m.
3. according to the monocrystals of nitride containing gallium of claim 1, it is characterized in that the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 70m.
4. monocrystals of nitride containing gallium, it is grown along the direction that is basically perpendicular to the seeded growth direction on crystal seed at least, substantially do not expand the crystal defect that is present in the crystal seed, its have for Cu K α 1 be lower than 40 second of arcs from the halfwidth of (0002) planar X ray rocking curve and significantly be lower than the halfwidth of crystal seed, have the lattice radius-of-curvature greater than 15m simultaneously, it is significantly greater than the lattice radius-of-curvature of crystal seed.
5. according to the monocrystals of nitride containing gallium of claim 4, it is characterized in that the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 30m.
6. according to the monocrystals of nitride containing gallium of claim 4, it is characterized in that the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 70m.
7. according to the monocrystals of nitride containing gallium of claim 1 or 4, it is characterized in that be doped with to build and/or receptor type and/or magnetic type doping agent, concentration is 10
17/ cm
3-10
21/ cm
3, and comprise n-type, p-type or compensation semi insulating material.
8. according to the monocrystals of nitride containing gallium of claim 1 or 4, its growing environment and condition are for to be equal to or higher than the growth velocity that is being parallel on the monocrystalline c direction of principal axis perpendicular to the growth velocity on the direction of c axle.
9. according to the monocrystals of nitride containing gallium of claim 1 or 4, its growing environment and condition are for to be equal to or higher than the growth velocity that is being parallel on the monocrystalline c direction of principal axis along the growth velocity on the direction of a axle.
10. according to the monocrystals of nitride containing gallium of claim 1 or 4, it is a gallium nitride single crystal.
11. the wafer of an arbitrary orientation, it has polarity or apolar surfaces, as obtaining according to the monocrystalline of claim 1 or from described monocrystalline cutting, carries out on the required direction with respect to the single crystal growing direction and cut.
12. the wafer according to claim 11 is characterized in that, owing to cut into slices being basically parallel on the single crystal growing direction, makes its surface dislocation density additionally reduce.
13. the wafer according to claim 10 or 11 is characterized in that, it has the apolar surfaces that can further process.
14. the wafer according to claim 10 or 11 is characterized in that, it has the polar surfaces that can further process.
15. according to the wafer of claim 10 purposes as the substrate of making by XIII family element nitride that is used for the epitaxial deposition semiconductor structure.
16. a substrate that is used for the epitaxial deposition semiconductor structure of being made by XIII family element nitride, it obtains as the monocrystalline according to claim 1 or according to the wafer of claim 10 or 11, its epitaxial surface is not less than 100mm
2
17. the substrate according to claim 16 is characterized in that, described epitaxial surface is not less than 450mm
2
18. the substrate according to claim 16 or 17 is characterized in that, described substrate is fit to the semiconductor structure of the nitride of the enough low surface dislocation density of manufacturing needs.
19. the substrate according to claim 18 is characterized in that, described substrate is adapted at the semiconductor structure that the element-terminated side manufacturing of XIII family needs the nitride of enough low surface dislocation density.
20. a semiconductor structure, it is deposited on according on each the substrate among the claim 16-19.
21. a method for preparing monocrystals of nitride containing gallium, described monocrystals of nitride containing gallium at least along the direction growth that is basically perpendicular to the seeded growth direction, are not expanded the crystal defect that is present in the crystal seed substantially on crystal seed, its dislocation desity is no more than 10
4/ cm
2And significantly be lower than the dislocation desity of crystal seed and have lattice radius-of-curvature greater than 15m, it is significantly greater than the lattice radius-of-curvature of crystal seed,
Described method is included in a step perpendicular to growth monocrystals of nitride containing gallium on the direction of crystal seed C axle; With
Another step of growth monocrystals of nitride containing gallium on crystal seed C direction of principal axis.
22. the method for preparing monocrystals of nitride containing gallium according to claim 21 is characterized in that, the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 30m.
23. the method for preparing monocrystals of nitride containing gallium according to claim 21 is characterized in that, the lattice radius-of-curvature of described monocrystals of nitride containing gallium is greater than 70m.
24. the method for preparing monocrystals of nitride containing gallium according to claim 21 is characterized in that, a described step be included in perpendicular on the direction of crystal seed C axle by flux method growth monocrystals of nitride containing gallium.
25. the method for preparing monocrystals of nitride containing gallium according to claim 21 is characterized in that, described another step is included on the crystal seed C direction of principal axis by from the overcritical ammonia solution crystallization monocrystals of nitride containing gallium of growing that contains.
26. according to the method for preparing monocrystals of nitride containing gallium of claim 21, wherein flux method is used for the monocrystals of nitride containing gallium of growing on the A of crystal seed or M direction of principal axis.
27. according to the method for preparing monocrystals of nitride containing gallium of claim 21, a wherein said step and described another step are carried out repeatedly.
28. according to the method for preparing monocrystals of nitride containing gallium of claim 24 or 26, wherein said flux method is the method for metal liquid mixture growth monocrystals of nitride containing gallium from containing lithium and gallium and being selected from the additional flux of Bi, In, Pb, Rb, Sb, Sn and Te.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PLP368483 | 2004-06-11 | ||
| PL04368483A PL368483A1 (en) | 2004-06-11 | 2004-06-11 | Monocrystals of nitride containing gallium and its application |
| PLP-368483 | 2004-06-11 | ||
| PLP368781 | 2004-06-25 | ||
| PL04368781A PL368781A1 (en) | 2004-06-25 | 2004-06-25 | Gallium containing nitride monocrystal and its application |
| PLP-368781 | 2004-06-25 | ||
| PCT/JP2005/011093 WO2005121415A1 (en) | 2004-06-11 | 2005-06-10 | Bulk mono-crystalline gallium-containing nitride and its application |
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| Publication Number | Publication Date |
|---|---|
| CN1973063A CN1973063A (en) | 2007-05-30 |
| CN1973063B true CN1973063B (en) | 2010-09-15 |
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| CNB200580019026XA Expired - Fee Related CN100485888C (en) | 2004-06-11 | 2005-06-10 | High electron mobility transistor (HEMT) made of group XIII element nitride layers and manufacturing method thereof |
| CN2005800188221A Expired - Fee Related CN1973063B (en) | 2004-06-11 | 2005-06-10 | Monocrystals of nitride containing gallium and its application |
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| EP2267197A1 (en) * | 2009-06-25 | 2010-12-29 | AMMONO Sp.z o.o. | Method of obtaining bulk mono-crystalline gallium-containing nitride, bulk mono-crystalline gallium-containing nitride, substrates manufactured thereof and devices manufactured on such substrates |
| PL224995B1 (en) | 2010-04-06 | 2017-02-28 | Inst Wysokich Ciśnień Polskiej Akademii Nauk | Substrate for epitaxial growth |
| JP6106932B2 (en) * | 2012-03-19 | 2017-04-05 | 株式会社リコー | Group 13 nitride crystal and group 13 nitride crystal substrate |
| EP2888390A1 (en) * | 2012-08-24 | 2015-07-01 | Sixpoint Materials Inc. | A bismuth-doped semi-insulating group iii nitride wafer and its production method |
| EP3247824A1 (en) * | 2015-01-22 | 2017-11-29 | SixPoint Materials, Inc. | Seed selection and growth methods for reduced-crack group iii nitride bulk crystals |
| DE112016005022T5 (en) * | 2015-11-02 | 2018-08-02 | Ngk Insulators, Ltd. | EPITAXIAL SUBSTRATE FOR SEMICONDUCTOR ELEMENTS, SEMICONDUCTOR ELEMENTS AND PRODUCTION PROCESS FOR EPITAXIAL SUBSTRATES FOR SEMICONDUCTOR ELEMENTS |
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2004
- 2004-06-11 PL PL04368483A patent/PL368483A1/en not_active Application Discontinuation
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| Song Y等.Bulk GaN single crystals: growth conditions by flux method.Journal of Crystal Growth247 3-4.2003,247(3-4),275-278. |
| Song Y等.Bulk GaN single crystals: growth conditions by flux method.Journal of Crystal Growth247 3-4.2003,247(3-4),275-278. * |
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| Publication number | Publication date |
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| CN100485888C (en) | 2009-05-06 |
| CN1973063A (en) | 2007-05-30 |
| PL368483A1 (en) | 2005-12-12 |
| CN1965399A (en) | 2007-05-16 |
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