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98results about How to "Reduce incorporation" patented technology

Co-precipitation method for preparing rare earth cerium ion-doped yttrium aluminum garnet fluorescent powder

InactiveCN101851510AReduce the chance of adulteration of impuritiesPrecise control of chemical calculations is easyLuminescent compositionsIonYttrium
The invention discloses a co-precipitation method for preparing rare earth cerium ion-doped yttrium aluminum garnet fluorescent powder and relates to fluorescent powder. The method comprises the following steps of: dissolving yttrium oxide powder in excessive concentrated sulfuric acid and mixing dissolved yttrium oxide with solution of cerous nitrate and solution of aluminum nitrate to prepare metal ion solution, wherein the ratio of Y<3+> to Ce<3+> to Al<3+> is 2.94:0.06:5; adding the metal ion solution into a precipitator to obtain a co-precipitate; cleaning, filtering and drying the co-precipitate to obtain a precursor; pre-sintering the precursor to obtain pre-sintered powder; and calcining the pre-sintered powder to obtain the rare earth cerium ion-doped yttrium aluminum garnet fluorescent powder. In the used co-precipitation method, mixing is performed under the ionic condition, so the mixing is more uniform compared with that of a mechanical mixing method, impurity doping possibility is reduced, accurate control of chemical calculation becomes easier and granularity can be controlled according to a reaction condition. The precipitator and the like are preferably selected and the co-precipitation method is implemented to form a pure YAG phase at the temperature of 1,100 DEG C, which is about 500 DEG C lower than that of a conventional high temperature solid phase reaction method.
Owner:XIAMEN UNIV

Aluminium nitride single crystal growth device dispensing with seed crystal bonding technology and method

The invention discloses an aluminium nitride single crystal growth device dispensing with a seed crystal bonding technology and a process and relates to the semiconductor manufacture technology. The aluminium nitride single crystal growth device comprises a heating system, an infrared temperature measurement system, seed crystals, a growth crucible, a crucible partition and a double-layered nestedcrucible, wherein the heating system is arranged on the outermost side; a temperature difference exists between the bottom and the top of the crucible; the crucible is arranged in a heat insulation material; the seed crystals are placed at the bottom of the crucible; the double-layered nested crucible is vertically placed on the upper side of the crucible partition and comprises an inner-layer crucible and an outer-layer crucible; the heights of the walls of the inner-layer crucible and the outer-layer crucible are kept the same; and a gap between the side walls of the inner-layer crucible and the outer-layer crucible is filled with high-purity aluminium nitride powder. Doping of aluminium nitride single-crystal impurity elements can be reduced, the crystal quality is improved, the single-crystal usable area is increased, the aluminium nitride single crystal growth device is simple and easy to use, facilitates low-cost preparation of aluminium nitride single crystals, and can preventgrowth of the aluminium nitride single crystals from being influenced by the seed crystal bonding technology.
Owner:PEKING UNIV

Non-polar patterned AlN/sapphire composite substrate and manufacturing method thereof

The invention discloses a non-polar patterned AlN/sapphire composite substrate and a manufacturing method thereof. The structure thereof comprises a r-plane patterned sapphire substrate, a sapphire pattern, a mask layer and an AlN covering layer. The sapphire pattern is a part of the r-plane patterned sapphire substrate, and is an asymmetric conical or pyramidal structure, that is, inclines towarda [1101] crystal orientation. The structure can effectively solve a problem that crystal quality is difficult to improve since growth rates along different directions are different during epitaxial growth of non-polar III-nitride. The AlN covering layer is formed by direct reaction with NH3 while the sapphire substrate is decomposed under high temperature in an NH3 atmosphere. The composite substrate provided by the invention can effectively reduce combination of O-containing impurities in an epitaxial growth process of the III-nitride, and can also obtain a dense high-quality non-polarity AlN covering layer on the surface of the sapphire substrate on the premise of not consuming an Al source, and has important significance on growing the high-quality non-polar III-nitrides and related devices on the substrate.
Owner:SOUTHEAST UNIV

Method for preparing epitaxial wafer of light-emitting diode and epitaxial wafer

The invention discloses a method for preparing an epitaxial wafer of a light-emitting diode and the epitaxial wafer and belongs to the field of light-emitting diode fabrication. A gallium source is intermittently introduced into a reaction chamber and an aluminum source is continuously introduced into the reaction chamber, the intermittent introduction of the gallium source allows an appropriate amount of gallium atoms to exist in the reaction chamber, the appropriate amount of gallium atoms act as an activator, the quality of an obtained AlGaN buffer sub layer is good, a AlN buffer sub layeris welled matched with the AlGaN buffer sub layer with appropriate amount of gallium atoms, and the quality of the AlN buffer sub layer grown on the AlGaN buffer sub layer is improved. When the AlN buffer sub layer is grown, due to the gas phase reaction between an ammonia gas and the aluminum source, a part of the reactants generated by the reaction are incorporated into the AlN buffer sub layer,and the quality of the AlN buffer sub layer is affected. The ammonia gas is intermittently introduced, the reduction of the ammonia gas can inhibit the gas phase reaction between aluminum and the ammonia gas, a reactant of the ammonia gas and aluminum source reaction growth is reduced and is combined into the AlN buffer sub layer, and finally the crystal quality of the epitaxial wafer is improved.
Owner:HC SEMITEK CORP

Grower for effectively restraining gallium oxide crystal defects

The invention discloses a grower for effectively restraining gallium oxide crystal defects. The grower comprises a plurality of thermal field components in a formed single crystal furnace, and the thermal field components are horizontally and concentrically mounted. A heating body and an iridium crucible are embedded into the center of a thermal field and heated by round induction coils, the heating body and the iridium crucible are separated, and a clearance is reserved between the heating body and the iridium crucible. Each thermal field component comprises a zirconia inner heat preservation barrel for supporting an iridium reflecting screen, an upper heat preservation component covering the iridium reflecting screen, a middle heat preservation component surrounding the zirconia inner heat preservation barrel, and a lower heat preservation component surrounding the iridium crucible and the heating body, and seed rod inlets are reserved in the upper heat preservation component. According to design of the grower, losses of the iridium crucible can be reduced, the content of impurity elements in crystals can be effectively restrained, therefore, the defects in the crystals can be restrained well, the service life of the crucible can be prolonged, and a foundation is laid for achieving mass production of gallium oxide single crystals with high quality and low cost.
Owner:CHINA ELECTRONICS TECH GRP NO 46 RES INST

Production method for polyamide

The present invention is directed to a process for producing a polyamide, which process includes directly melt-polymerizing a diamine component including 70 mol % or more of p-xylylenediamine and a dicarboxylic acid component including 70 mol % or more of a C6 to C18 aliphatic dicarboxylic acid, in the absence of solvent in a batch-type reactor equipped with a stirring blade, the process including: (1) reacting the diamine component with the dicarboxylic acid component under a pressure condition of 0.2 to 0.5 MPa (Abs); (2) maintaining a vapor phase section of a reaction tank of the reactor at 200° C. or higher during reaction; (3) stirring the contents of the reaction tank, from the start of adding the diamine component until after completion of the addition and before the start of pressure falling, such that the stirring-related Froude number represented by a specific formula is adjusted to 0.0002 to 0.15; and (4) employing a stirring blade having no structural body in the horizontal direction or having a structural body in the horizontal direction, which body does not come into contact with the interface between the reaction mixture and the vapor phase section during stirring. In the polyamide production process, deposition of solid matter in the reaction tank vapor section and in a vapor pipe is suppressed, and incorporation into the product of unmelted solid matter originating from the deposits is reduced.
Owner:MITSUBISHI GAS CHEM CO INC
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