2455results about "From condensed vapors" patented technology

Crystal growth systems with a baffle are provided. In one example, a crystal growth system for growing crystalline material, the crystalline material including silicon carbide, includes a seed holder configured to hold a silicon carbide seed crystal. The seed crystal provides a growth surface for growth of the silicon carbide crystalline material. The system includes a crucible at least partially defining a crystal growth chamber. The system includes a source material. The system includes one or more baffles within the crystal growth chamber and spaced apart from the source material. The one or more baffles include one or more apertures defined through the one or more baffles. The baffle includes a long dimension that is non-perpendicular to the growth surface of the seed crystal.

The invention belongs to the technical field of semiconductors, and particularly relates to a gradient transition composite tantalum carbide coating and a preparation method thereof.The gradient transition composite tantalum carbide coating is located on the surface of a graphite substrate material and sequentially comprises a pyrolytic carbon coating, a tantalum carbide-pyrolytic carbon composite coating and a tantalum carbide coating from inside to outside; wherein the thermal expansion coefficient of the pyrolytic carbon coating is 2.5-4.5 * 10 <-6 > / K, the thermal expansion coefficient of the composite coating is 4.5-6.0 * 10 <-6 > / K, and the thermal expansion coefficient of the tantalum carbide coating is 6.1-8.0 * 10 <-6 > / K. According to the gradient transition structure of the coating, the problem that thermal expansion coefficients between the coating and a base body are not matched is solved, the thermal shock resistance of the coating is effectively improved, meanwhile, the pinning effect can be achieved, the adhesive force between the coatings is enhanced, and the service life of a product is prolonged; compared with a single tantalum carbide coating, crack accumulation and through holes cannot be generated.

The invention belongs to the technical field of silicon carbide single crystal materials, and particularly relates to a growth device of large-size silicon carbide single crystals and a preparation method of the silicon carbide single crystals, porous graphite cylinders are arranged in a powder area of the growth device of the large-size silicon carbide single crystals, and the porous graphite cylinders are distributed along the edge of the powder area to the center in a stepped mode. The height is gradually increased from the edge to the center; a plurality of layers of stacked graphite pore plates are arranged at the top of the powder area, the upper end parts of the porous graphite cylinders are flush with the upper surfaces of the corresponding layers of graphite pore plates, and the porous graphite cylinders penetrate through the graphite pore plates, so that a continuous gas phase transmission channel from the powder area to the crystal growth area is formed. According to the invention, the plurality of porous graphite cylinders are arranged in the silicon carbide raw material area in a stepped manner, so that the temperature field distribution of the raw material area is stabilized, the gas phase layout is optimized, impurities in gas phase components are filtered, and the defects of microtubes, inclusions, dislocation and the like in crystals are improved.

An epitaxial nitride ferroelectric device and method of operation are provided. The device includes a substrate and a heterostructure supported by the substrate. The heterostructure includes a semiconductor layer supported by the substrate and a ferroelectric III-nitride alloy layer supported by the semiconductor layer. The ferroelectric III-nitride alloy layer includes a group IIIB element. The device further includes first and second contacts in electrical communication with the ferroelectric III-nitride ferroelectric alloy layer and the semiconductor layer, respectively. The polarity of a poling voltage applied between the first and second contacts is adapted to establish a state of ferroelectric polarization in the ferroelectric III-nitride alloy layer.

The invention relates to the field of silicon carbide crystal growth, in particular to a high-efficiency silicon carbide single crystal growth method which comprises the following steps: (S.1) providing a reverse thermal field environment of which the temperature is sequentially reduced from top to bottom in the vertical direction; (S.2) heating the silicon carbide powder so as to generate silicon carbide sublimation gas; (S.3) the silicon carbide sublimation gas is introduced into the thermal field environment along with the carrier gas, so that the silicon carbide sublimation gas is layered under screening of the carrier gas, and a silicon-rich atmosphere located at the top of the thermal field environment and a supersaturated atmosphere located at the bottom of the thermal field environment are obtained; and (S.4) contacting the supersaturated atmosphere with a seed crystal arranged at the bottom of the thermal field environment so as to grow the silicon carbide single crystal on the surface of the seed crystal. Through the reverse thermal field design, carrier gas screening layering and carbon powder dynamic compensation mechanism, the problems that in traditional silicon carbide single crystal growth, silicon gas phase enrichment inhibits the crystallization rate, and defects are caused by unbalance of the stoichiometric ratio are systematically solved.

The invention discloses a preparation device and method for growing a large-size silicon carbide single crystal. A raw material gas phase in a high-temperature area is transmitted to the surface of a seed crystal in a low-temperature area for crystal growth by using a physical gas phase transmission method; the device comprises a furnace chamber, a movable sectional type heating system, a thermal insulation material, a graphite crucible, porous graphite, a seed crystal unit, a crystal growth induction forming device and an electric field device. The method comprises the following steps: installing a seed crystal unit in a crucible filled with silicon carbide powder, placing the crucible in a heater, and carrying out a crystal growth stage to prepare the silicon carbide single crystal. The whole growth process of the crystal is in a constant temperature state, thermal stress caused by the temperature difference between the growth end and the seed crystal end and the temperature difference between the crystal edge and the crystal center in the top end seed crystal method crystal growth process is avoided, the dislocation defect of the crystal is reduced, and finally the high-quality silicon carbide single crystal is obtained. And the production cost is reduced.

A silicon carbide source material structure for use in a sublimation system for growing single crystal silicon carbide is provided. The silicon carbide source material structure may comprise a first layer and a second layer, the first layer being different from the second layer in at least one property.

The invention provides a vertical structure ultraviolet photoelectric detector and a preparation method thereof. The ultraviolet photoelectric detector is of a vertical structure, the design facilitates light absorption of the ultraviolet photoelectric detector, the light utilization rate of the ultraviolet photoelectric detector is improved, and compared with a horizontal structure, the transmission distance is shortened, and the cost is low; the ultraviolet photoelectric detector provided by the invention has a relatively high switching ratio of light and dark current and relatively small dark current, and also has a very high response speed under the condition of keeping the switching ratio of light and dark current and the dark current; a PN junction is formed between the nickel oxide hole transport layer and the beta-phase gallium oxide single crystal, so that the ultraviolet photoelectric detector has self-driving performance; in the manufacturing process, the substrate is used as a supporting frame, and the extraction electrode is packaged in one step through the conductive adhesive tape, so that 3-5 photoetching steps of a traditional horizontal structure are omitted, the process is simplified, and the process manufacturing is simpler.

The invention discloses a preparation method and application of a high-quality single primitive cell thickness chromium-antimony magnetic film, and the method comprises the steps: placing a strontium titanate substrate in a cavity of molecular beam epitaxial growth equipment, and carrying out the degassing and high-temperature annealing of the strontium titanate substrate under an ultra-vacuum condition until regular steps appear on the surface of the strontium titanate substrate; and with a chromium source and an antimony source as evaporation sources, growing the chromium-antimony magnetic thin film on the pretreated substrate by adopting a molecular beam epitaxy growth technology. The thin film prepared by the method has extremely remarkable magnetic anisotropy, the easy magnetization axis of the thin film is in the out-of-plane direction, and the magnetization intensity difference in the in-plane direction and the out-of-plane direction is obvious; in addition, the thin film has ferromagnetism, and the coercive field is gradually reduced along with temperature rise; in addition, the film also has stable magnetic properties, and shows the characteristic that the Curie temperature is higher than room temperature. And meanwhile, the preparation method has the advantages of accurately controlling the layer number of the thin film and realizing high-quality growth, and an ideal magnetic thin film material is provided for development of a new generation of semiconductor devices.

The invention provides a silicon carbide crystal growth process which comprises the following steps: A) dividing the interior of a crucible into seven loading areas, namely an F area, a D area, a B area, an A area, a C area, an E area and a G area which are adjacent in sequence by adopting graphite partition plates, filling silicon carbide powder in each loading area, and placing the graphite partition plates perpendicular to the bottom surface of the crucible; the particle size of the silicon carbide powder is 10-80 meshes; and B) fixing a seed crystal on the top of the crucible filled with the silicon carbide powder, and growing the silicon carbide crystal by adopting a PVT method. By optimizing the charging process, the uniformity and the utilization rate of sublimation gas of the powder in the growth process can be improved, the stability of a temperature field in a furnace is facilitated, the probability of crystal phase change is reduced, crystal defects (phase change, polycrystal, dislocation and the like) are reduced, and thus the crystal quality is improved.

Silicon carbide single crystal substrate (100), wherein the silicon carbide single crystal substrate (100) has a diameter of not less than 100 mm, the silicon carbide single crystal substrate (100) has an oxygen concentration of no more than 1 × 10 17 cm -3 exhibits the silicon carbide single crystal substrate (100) has a dislocation density of no more than 2 × 10 4 cm -2 exhibits, and the silicon carbide single crystal substrate (100) has a stacking fault area ratio of no more than 2.0%.

The invention provides an anti-ferroelectric lanthanum ferrite, bismuth ferrite and strontium titanate superlattice film with high energy storage density as well as a preparation method and application thereof. The anti-ferroelectric lanthanum ferrite, bismuth ferrite and strontium titanate superlattice film with high energy storage density comprises a substrate layer, a bottom electrode layer and a plurality of stacked relaxation ferroelectric layers, wherein the bottom electrode layer and the multiple stacked relaxation ferroelectric layers are sequentially arranged on the substrate layer; each relaxor ferroelectric layer sequentially comprises a first functional layer, a second functional layer and a third functional layer from bottom to top; the first functional layer comprises LaFeO3, the second functional layer comprises BiFeO3, and the third functional layer comprises SrTiO3. The anti-ferroelectric lanthanum ferrite, bismuth ferrite and strontium titanate superlattice thin film with the high energy storage density has small electric leakage performance and high polarization value, and more excellent energy storage performance is achieved.

The invention relates to the technical field of silicon carbide single crystal growth, in particular to a high-purity semi-insulating silicon carbide single crystal for an optical element and a growth process thereof.The growth process includes the steps that S1, silicon carbide powder, a graphite crucible and the like are assembled to form a thermal field device, the thermal field device is placed in an induction furnace, room-temperature furnace washing treatment and low-temperature furnace washing treatment are sequentially carried out, and the silicon carbide powder is obtained; carrying out thermal field impurity removal treatment; s2, assembling the silicon carbide seed crystal and the impurity-removed thermal field device, raising the temperature in the induction furnace, conveying high-purity argon or mixed gas of high-purity argon and high-purity hydrogen into the induction furnace, and performing crystal growth; s3, after crystal growth is finished, high-temperature and high-pressure annealing treatment is carried out firstly, then furnace cooling treatment is carried out, and the high-purity semi-insulating silicon carbide crystal ingot for the optical element is obtained. The silicon carbide crystal ingot with excellent light transmission performance and high resistivity is obtained by selecting specific raw materials, reasonably designing an assembly mode and combining processes of thermal field impurity removal, high-temperature and high-pressure annealing and the like.

A silicon carbide source material structure for use in a sublimation system for growing crystalline silicon carbide is provided. The silicon carbide source material structure includes a composite shaped solid. The composite shaped solid may be made by casting, extrusion, 3D printing, graphite conversion, or other suitable process.

The invention discloses a method for bonding diamond and gallium nitride, which comprises the following steps of: preparing monocrystal diamond and a GaN epitaxial wafer, etching the GaN epitaxial wafer to form a layered stepped structure, bombarding GaN by using Ar ion beams to activate the surface of the GaN, depositing an intermediate layer on the surface, thinning the intermediate layer until the middle GaN part is exposed after the deposition is completed, polishing after the thinning is completed, and finally, carrying out the bonding of the diamond and the gallium nitride. The method comprises the following steps: respectively soaking GaN and monocrystal diamond in an acidic solution and an alkaline solution, enabling the GaN and the monocrystal diamond to be in contact with each other after soaking, applying pressure, performing high-temperature annealing for bonding, and then removing a substrate of a GaN epitaxial wafer to finally obtain the GaN / diamond. Through the layered stepped structural design, the bonding of diamond and GaN can be realized, the interface thermal resistance can be effectively reduced, the contact area is obviously increased, the heat dissipation of a GaN device can be more uniform and sufficient, and the problem of difference of thermal expansion coefficients is solved.

A physical vapor transport system with improved hot zone package alignment includes a first video pyrometer to view a center of a first hot zone at a first end of the hot zone package to measure a first temperature of the hot zone package and provide a first video feed showing instantaneous positions of the hot zone package as it is rotated. A second video pyrometer views a second hot zone viewport at a second end of the hot zone package to measure a second temperature of the center of the hot zone package and provide a second video feed showing instantaneous positions of the hot zone package as it is rotated. A controller processes the temperature measurements and video feeds and adjusts the system components or settings to correct for mis-alignment of the hot zone package.

The invention discloses a super-large-scale silicon single crystal growth method based on a high-temperature superconducting magnetic control technology, and relates to the technical field of silicon single crystal growth, and the method comprises the following steps: setting and calibrating an initial magnetic field intensity, and combining a gradient graphite felt heat conductivity coefficient function to optimize temperature field uniformity; a dynamic magnetic field regulation and control mechanism is introduced in the melt stage, melt convection is inhibited through flow velocity-magnetic field joint control, and oxygen concentration monitoring is synchronized; a multi-physics coupling simulation and multi-objective optimization algorithm is adopted in the crystal growth stage, the magnetic field intensity, the heating power and the crystal pulling parameters are adjusted in real time, and the oxygen content and the growth rate are balanced; and the tail stress is relieved through a gradient field reduction technology, and finally, the low-defect and high-uniformity silicon single crystal is obtained. Melt flow and temperature field uniformity are accurately regulated and controlled through a high-temperature superconducting magnetic control technology, dynamic monitoring and a multi-target optimization algorithm are combined, the growth quality of silicon single crystals is remarkably improved, the defect rate and energy consumption are reduced, and meanwhile efficient and stable production of large-size crystals is achieved.

The invention discloses a method for preparing a high-quality one-dimensional iron-antimony nanowire by utilizing a molecular beam epitaxial growth technology and application, and belongs to the technical field of semiconductor materials. According to the method, a strontium titanate single crystal is used as a substrate, and the substrate is pretreated under an ultrahigh vacuum condition until regular steps are formed on the surface of the substrate; then an iron source and an antimony source are used as evaporation sources, an ultrahigh vacuum environment and precise temperature control are combined, and the high-quality one-dimensional iron-antimony nanowire is prepared on the pretreated substrate through the molecular beam epitaxial growth technology. The prepared nanowires are uniformly distributed on the surface of the substrate, the height is 8.03 nm, and the width is 2.7 nm. A scanning tunnel spectrum result shows that the energy gap of the iron-antimony nanowire is obviously increased relative to that of an iron-antimony thin film, and the adjustability of the semiconductor band gap is shown. The method has remarkable advantages in the aspect of accurately controlling and preparing narrow-band-gap semiconductor nanowires with uniform sizes and nanometer widths, and an excellent material basis is provided for research and development of new-generation semiconductor devices.

The invention provides a SiC crystal with a facet at an edge, a wafer thereof and a semiconductor device, and relates to the technical field of silicon carbide wafers. The SiC crystal contains a facet region and a non-facet region; the facet area is located on the outer circumferential end face of the SiC crystal, the distance between the edge, away from the outer circumferential end face, of the facet area and the outer circumferential end face does not exceed 3% of the diameter of the SiC crystal, and the SiC crystal is obtained through direct growth by adopting a PVT method and is not subjected to subsequent processing. According to the SiC crystal disclosed by the invention, the facet area is fixed at the edge position of the crystal, and the facet area is removed in the subsequent crystal processing process, so that no facet area exists on the whole crystal and a wafer processed along with the crystal at a relatively low cutting loss rate.

An object of the present invention is to provide a novel technique capable of manufacturing a large-diameter AlN substrate.The present invention is a method for manufacturing an AlN substrate, including a crystal growth step S30 of forming an AlN layer 20 on a SiC underlying substrate 10 having through holes 11. In addition, the present invention is a method for forming an AlN layer including the through hole formation step S20 of forming the through holes 11 in the SiC underlying substrate 10 before forming the AlN layer 20 on the SiC underlying substrate 10.

The invention provides a seed layer for preparing a preferred orientation crystal film and the crystal film, lanthanide series metal salt is selected as an initial raw material of the seed layer, the initial raw material is adopted to prepare a solution, the prepared solution is filtered to obtain a seed layer solution, the seed layer solution is subjected to spin coating or ink jet printing on a substrate, and heat treatment is performed to obtain the seed layer. According to the seed layer for preparing the preferred orientation crystal film and the preferred orientation crystal film, the high-quality single crystal film is prepared under simple and convenient conditions, and the seed layer and the preferred orientation crystal film have wide application prospects in the fields of information storage, intelligent sensing, biomedical treatment, energy and the like.

The invention provides a combined crucible and an oxide crystal growth method.The combined crucible is used for oxide crystal growth and comprises a first ceramic crucible, a second ceramic crucible, a third ceramic crucible and a fourth ceramic crucible, the graphite layer is arranged in the first ceramic crucible; the second ceramic crucible comprises a second containing space with the top open and the bottom closed, and the second ceramic crucible is arranged in the graphite layer. The combined crucible is designed by adopting an iridium-free scheme, so that the cost of the crucible can be greatly reduced.

The invention relates to porous tantalum carbide prepared by using a molten salt method and a preparation method and application thereof.The preparation method comprises the steps that molten salt and a solid-phase sintering method are combined, firstly, a porous carbon-based material (such as porous graphite) is metalized to form porous tantalum by using excessive molten tantalum precursor powder (such as tantalum oxide); then tantalum atoms thermally move, diffuse and permeate into crystal lattices of carbon materials such as graphite, high-purity and high-porosity porous tantalum carbide is obtained, and a part of carbon cores exist in the porous tantalum carbide; and finally, removing carbon in a heat treatment furnace to obtain the high-purity and high-porosity porous tantalum carbide. Compared with the prior art, the porous tantalum carbide prepared by the method has the advantages of higher corrosion resistance, reproducibility, higher porosity and no gap blockage phenomenon.

The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof, and relates to the technical field of semiconductors. The light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, a non-doped GaN layer, an N-type GaN layer, an electron dredging layer, a multi-quantum well layer, an electron blocking layer and a P-type GaN layer which are stacked on the substrate in sequence, the electron dredging layer comprises a first sub-layer, a second sub-layer, a third sub-layer and a fourth sub-layer which are sequentially stacked, the first sub-layer is a Si3N4 layer, the second sub-layer comprises an AlGaN layer, a first InGaN layer and a first GaN layer which are periodically and alternately stacked, the third sub-layer comprises a second GaN layer and a second InGaN layer which are periodically and alternately stacked, and the fourth sub-layer is a Si3N4 layer. And the fourth sub-layer comprises an AlInGaN layer, a third InGaN layer and a third GaN layer which are periodically and alternately stacked. According to the invention, while the electronic expansibility is improved, excessive electrons are prevented from entering the multi-quantum well layer to generate electron overflow.

The invention provides a preparation method and a preparation device of a silicon carbide epitaxial wafer. The preparation method comprises the following steps: providing a substrate, and placing the substrate in an epitaxial reaction cavity; the substrate is heated, the distance between the substrate and a heating heat source is controlled to be H mm, and the reaction temperature in the epitaxial reaction cavity is T DEG C; introducing carrier gas, a growth source and a doping source, and preparing an epitaxial layer on the surface of the substrate to obtain a silicon carbide epitaxial wafer; wherein the distance H mm and the reaction temperature T DEG C meet the condition that (T-1500) / H is larger than or equal to 5.5 and smaller than or equal to 7. By controlling the distance between the substrate and a heating heat source, the airflow and the temperature field on the surface of the substrate are adjusted, the temperature difference between the center and the edge of the wafer is reduced, and the triangular defects on the surface of the wafer are reduced; meanwhile, the distance between the substrate and the heating heat source is matched with the temperature in the epitaxial reaction cavity, the growth rate of the epitaxial layer can be ensured, triangular defects are reduced, meanwhile, step defects are avoided, and therefore the overall quality of the epitaxial wafer is improved.

Various forms of Mga(Six(GeySn1-y)1-x)Ob are disclosed. In some aspects, an epitaxial layer comprises single crystal Mga(Six(GeySn1-y)1-x)Ob, wherein 1.5≤a≤2.5, 3≤b≤5, 0≤x≤1, and 0≤y≤1; wherein the single crystal Mga(Six(GeySn1-y)1-x)Ob has a crystal symmetry compatible with a substrate or an underlying layer on which the single crystal Mga(Six(GeySn1-y)1-x)Ob is grown. In some aspects, a semiconductor structure includes an epitaxial layer comprising single crystal Mga(Six(GeySn1-y)1-x)Ob, wherein 1.5≤a≤2.5, 3≤b≤5, 0≤x≤1, and 0≤y≤1; The semiconductor structure also includes a substrate or an underlying layer on which the single crystal Mga(Six(GeySn1-y)1-x)Ob is grown; wherein the single crystal Mga(Six(GeySn1-y)1-x)Ob has a crystal symmetry compatible with the substrate or the underlying layer.

The invention discloses a cleaning device for a graphite disc in the semiconductor industry, and relates to the technical field of semiconductor epitaxy, the cleaning device comprises an upper substrate and a graphite disc, and the graphite disc is arranged on one side of the upper substrate. According to the invention, deposited particles on the graphite disc can be cleaned in time after the graphite disc process production is completed, so that the use frequency of the graphite disc is improved, the efficiency of an epitaxial process is improved, and meanwhile, the influence of graphite disc deposits on the wafer performance when the graphite disc is repeatedly used is also reduced.

The present invention relates to the field of the preparation of silicon carbide crystals, and in particular to a device and method for the diameter expansion growth of a silicon carbide crystal. The device comprises a graphite diameter expansion device comprising a porous graphite diameter expansion ring. The porous graphite diameter expansion ring serves as a gas channel and is used for releasing an accumulated growth atmosphere during the diameter expansion growth of the silicon carbide crystal. The porous graphite diameter expansion ring not only ensures the smoothness of gas exhaust, but also solves the problem of polycrystalline silicon carbide growing on an edge of a silicon carbide seed crystal hindering the diameter expansion of the silicon carbide crystal. In addition, in the axial direction of the graphite diameter expansion device and in a direction away from the silicon carbide seed crystal, the porosity of the porous graphite diameter expansion ring gradually decreases, so that the growth atmosphere in a graphite crucible is controlled to ensure that the growth atmosphere can be discharged in time when the growth atmosphere is excessive in the early stage, and the discharge amount is reduced when the growth atmosphere in the later growth stage is insufficient, thus increasing the growth rate of the silicon carbide crystal. In addition, hard graphite felt is arranged around the diameter expansion device to serve as a heat insulation material, so that a rational temperature gradient of silicon carbide crystal growth is maintained.

A crystal growth method and system, an apparatus, and a storage medium. The crystal growth method comprises: determining a parameter set of a crystal growth device in a target heat, wherein the parameter set comprises at least one target parameter, and the target parameter is a parameter, affecting crystal growth, in the crystal growth device; acquiring a first temperature measurement value of a first temperature measurement point of the crystal growth device in a target time period of the target heat; and on the basis of the target parameter and the first temperature measurement value, by means of a crystal plane temperature determination model, determining a simulated crystal plane temperature corresponding to the first temperature measurement value.

An object of the present invention is to provide a novel technology capable of achieving high-quality SiC seed crystal, SiC ingot, SiC wafer and SiC wafer with an epitaxial film. The present invention, which solves the above object, is a method for producing a SiC seed crystal for growth of a SiC ingot, the method including a heat treatment step of heat-treating a SiC single crystal in an atmosphere containing Si element and C element. As described above, by heat-treating the SiC single crystal in an atmosphere containing the Si element and the C element, it is possible to produce a high-quality SiC seed crystal in which strain and crystal defects are suppressed.