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86results about How to "Improve defect density" patented technology

Growth of GaAs epitaixial layers on Si substrate by using a novel GeSi buffer layer

This invention provides a process for growing Ge epitaixial layers on Si substrate by using ultra-high vacuum chemical vapor deposition (UHVCVD), and subsequently growing a GaAs layer on Ge film of the surface of said Ge epitaixial layers by using metal organic chemical vapor deposition (MOCVD).
The process comprises steps of, firstly, pre-cleaning a silicon wafer in a standard cleaning procedure, dipping it with HF solution and prebaking to remove its native oxide layer. Then, growing a high Ge-composition epitaixial layer, such as Si0.1Ge0.9 in a thickness of 0.8 μm on said Si substrate by using ultra-high vacuum chemical vapor deposition under certain conditions. Thus, many dislocations are generated and located near the interface and in the low of part of Si0.1Ge0.9 due to the large mismatch between this layer and Si substrate.
Furthermore, a subsequent 0.8 μm Si0.05Ge0.95 layer, and/or optionally a further 0.8 μm Si0.02Ge0.98 layer, are grown. They form strained interfaces of said layers can bend and terminate the propagated upward dislocation very effectively. Therefore, a film of pure Ge is grown on the surface of said epitaixial layers. Finally, a GaAs epitaixial layer is grown on said Ge film by using MOCVD.
Owner:NAT CHIAO TUNG UNIV

Method for increasing uniformity of on-chip n-type doping concentration of silicon carbide epitaxial wafer

ActiveCN103614779ADoping Concentration Uniformity OptimizationEnlarge selection windowPolycrystalline material growthAfter-treatment detailsSilanesGas phase
The invention relates to a method for increasing the uniformity of on-chip n-type doping concentration of a silicon carbide epitaxial wafer. According to the method, a chemical vapor deposition growth technology serves as basis; a silicon surface silicon carbide substrate with the deviation (11-20) direction of 4 degrees or 8 degrees is adopted; silane and propane serve as growth sources; hydrogen chloride serves as an auxiliary gas for inhibiting gas phase nucleation of a silicon component; hydrogen serves as a carrier gas and a diluent gas; nitrogen serves as an n-type doping agent. A small amount of process gas silane or propane is added into a base air floatation gas and is pushed by the air floatation gas serving as a carrier gas to the edge of the substrate to finely adjust the carbon silicon ratio of the edge of the substrate, so that the doping efficiency of the n-type doping source on the edge of the substrate is changed, the doping concentration deviation of the edge point and the central point of the epitaxial wafer caused by non-linear exhausting is effectively reduced, and the uniformity of the on-chip doping concentration of the epitaxial wafer is effectively optimized on the premise of not changing key process parameters. The selection window of the key process parameters is enlarged and technical support is provided for the growth of a high-quality silicon carbide epitaxial material.
Owner:NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD

Epitaxial growth method for reducing interface thermal resistance of gallium nitride high-electron-mobility field-effect transistor

The invention relates to an epitaxial growth method for reducing interface thermal resistance of a gallium nitride high-electron-mobility field-effect transistor. An epitaxial material is grown through a vapor phase epitaxial growth method of metal organic matter chemical vapor deposition and the like. A gallium nitride epitaxial wafer comprises a substrate, a lower aluminium nitride nucleating layer, an upper aluminium nitride nucleating layer, a gallium nitride transition layer, a gallium nitride buffer layer, a barrier layer and a cap layer from the bottom up in sequence. The carrier gasesused in the growing process of the lower aluminium nitride nucleating layer and the upper aluminium nitride nucleating layer are hydrogen and nitrogen respectively. The carrier gas used in the growingprocess of the gallium nitride transition layer is nitrogen. The carrier gas used in the growing process of the gallium nitride buffer layer is hydrogen or a mixture of hydrogen and nitrogen. Throughthe carrier gas conversion process, the method reduces defect density in the aluminum nitride nucleating layer and the gallium nitride layer, improves interface quality of the aluminum nitride nucleating layer and the gallium nitride layer, and effectively reduces the interface thermal resistance of the gallium nitride high-electron-mobility field-effect transistor.
Owner:NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD

Seawater corrosion resistant ultra-low carbon bainite steel and preparation method thereof

The invention discloses seawater corrosion resistant ultra-low carbon bainite steel and a preparation method thereof. The bainite steel comprises the following components in percentage by weight: 0.02 to 0.05 percent of C, 1.0 to 1.5 percent of Mn, less than 0.006 percent of S, 0.24 to 0.40 percent of Si, 0.04 to 0.09 percent of P, 0.05 to 0.2 percent of Ni, 0.3 to 0.5 percent of Cu, 0.03 to 0.04 percent of Nb, 0.2 to 0.4 percent of Mo, 0.002 to 0.005 percent of B, less than 0.08 percent of Al, less than or equal to 0.06 percent of Cr and the balance of Fe; and the tissue is granular bainite. The preparation method comprises the following steps of: smelting molten steel with vacuum and casting the molten steel to form ingots, roughly rolling the ingots in an austenite recrystallization area after soaking treatment, then finely rolling the ingots in an austenite non-recrystallization area, cooling the rolled ingots to between 450 and 500 DEG C with water after rolling, and cooling the rolled ingots in the air to room temperature. The seawater corrosion resistant ultra-low carbon bainite steel has good comprehensive mechanical property, low raw material cost, simple production process and good seawater corrosion resistance based on excellent mechanical property and welding property.
Owner:NORTHEASTERN UNIV +1

Group III nitride crystals usable as group III nitride substrate, method of manufacturing the same, and semiconductor device including the same

The present invention provides a method of manufacturing Group III nitride crystals that are of high quality, are manufactured highly efficiently, and are useful and usable as a substrate that is used in semiconductor manufacturing processes. The method of manufacturing Group III nitride crystals includes: forming a first layer made of a semiconductor that is expressed by a composition formula of AlsGatIn1-s-tN (where 0≦s≦1, 0≦t≦1, and s+t≦1); forming a second layer by bringing the surface of the first layer into contact with a melt in an atmosphere including nitrogen, wherein the second layer includes greater defects in a crystal structure, such as a dislocation density for example, than those of the first layer, and the melt includes alkali metal and at least one Group III element selected from the group consisting of gallium, aluminum, and indium; and forming a third layer through crystal growth in the melt in an atmosphere including nitrogen, wherein the third layer is made of a semiconductor that is expressed by a composition formula of AluGavIn1-u-vN (where 0≦u≦1, 0≦v≦1, and u+v≦1), and the third layer has less defects in a crystal structure, such as a dislocation density for example, than those of the second layer.
Owner:PANASONIC CORP +1

Growth of GaAs expitaxial layers on Si substrate by using a novel GeSi buffer layer

This invention provides a process for growing Ge epitaixial layers on Si substrate by using ultra-high vacuum chemical vapor deposition (UHVCVD), and subsequently growing a GaAs layer on Ge film of the surface of said Ge epitaixial layers by using metal organic chemical vapor deposition (MOCVD). The process comprises steps of, firstly, pre-cleaning a silicon wafer in a standard cleaning procedure, dipping it with HF solution and prebaking to remove its native oxide layer. Then, growing a high Ge-composition epitaixial layer, such as Si0.1Ge0.9 in a thickness of 0.8 μm on said Si substrate by using ultra-high vacuum chemical vapor deposition under certain conditions. Thus, many dislocations are generated and located near the interface and in the low of part of Si0.1Ge0.9 due to the large mismatch between this layer and Si substrate. Furthermore, a subsequent 0.8 μm Si0.05Ge0.95 layer, and / or optionally a further 0.8 μm Si0.02Ge0.98 layer, are grown. They form strained interfaces of said layers can bend and terminate the propagated upward dislocation very effectively. Therefore, a film of pure Ge is grown on the surface of said epitaixial layers. Finally, a GaAs epitaixial layer is grown on said Ge film by using MOCVD.
Owner:NAT CHIAO TUNG UNIV

Crystal growth furnace for preparing single crystal by PVT method and application thereof

The invention discloses a crystal growth furnace for preparing single crystals through a PVT method and an application of the crystal growth furnace, which belong to the field of semiconductor material preparation. The crystal growth furnace for preparing the single crystals by the PVT method comprises a crucible, a heat preservation structure, a furnace body and a heating coil which are arrangedfrom inside to outside, and further comprises a seed crystal column arranged in the crucible. The side wall of the crucible comprises an interlayer, the interlayer comprises an inner side wall and anouter side wall, the porosity of the inner side wall is higher than that of the outer side wall, and the interlayer forms a raw material cavity; the extension directions of the seed crystal column andthe central axis of the crucible are approximately the same, and a crystal growth cavity is formed between the seed crystal column and the inner surface of the inner side wall; the heating coil induces and heats the side wall of the crucible, so that the raw materials in the raw material cavity penetrate through the inner side wall after sublimation, and are conveyed to the surface of the seed crystal column in the crystal growth cavity along the radial gas phase for crystal growth. The crystal growth furnace can be used for efficiently and quickly preparing the silicon carbide single crystalwith extremely low defect density and the substrate of the silicon carbide single crystal, so that a technical foundation is laid for large-scale commercialization of high-quality and low-cost silicon carbide substrates.
Owner:SICC CO LTD

Gallium-source reactor

The invention provides a gallium-source reactor. The gallium-source reactor at least comprises a reaction layer, a first air inlet pipeline located on the top end of the reaction layer, and a first air outlet pipeline located on the bottom end of the reaction layer, wherein the bottom end of the first air inlet pipeline extends into the reaction layer and is arranged close to the bottom end of the reaction layer, and the top end of the first air outlet pipeline extends into the reaction layer and is arranged close to the top end of the reaction layer. According to the invention, since the bottom end, extending into the reaction layer, of the first air inlet pipeline is arranged close to the bottom end of the reaction layer and the top end, extending into the reaction layer, of the first air outlet pipeline is arranged close to the bottom end of the reaction layer, hydrogen chloride gas enters the reaction layer from the first air inlet pipeline; then since liquid metallic gallium totally soaks the bottom end of the first air inlet pipeline, the hydrogen chloride gas passes through the liquid metallic gallium and reacts with the liquid metallic gallium; eventually produced gallium chloride flows out from the first air outlet pipeline; and thus, the hydrogen chloride gas is allowed to fully react with metal gallium.
Owner:镓特半导体科技(上海)有限公司
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