41results about How to "Reduce the difficulty of growing" patented technology

The invention relates to a double-sided bonding long-wavelength vertical cavity surface emitting laser (VCSEL) and a manufacturing method thereof. The laser comprises an N electrode (1), an N-type GaAs substrate (2), an N-type GaAs/AlGaAs material series lower distributed Bragg reflector (DBR) (3), an InP based strained quantum well active area (4), a GaAs/AlGaAs material series upper DBR (5), a SiO2 mask (8), a P electrode (9) and a light-exiting window (10), wherein the upper DBR (5) consists of a P-type DBR (6) and an intrinsic DBR (7). The structure and the method overcome the defects of smaller refractive index difference, poor thermal conductivity and poor electrical conductivity of DBR materials of the conventional VCSEL, not only can realize good current limit, but also can reducethe absorption consumption and the growth difficulty of the materials and omit the step of secondary epitaxial process.

The invention provides an epitaxial growth method of a purple-light LED. The suitable wavelength range of the method is 365-420 nm, the growth difficulty of the purple-light LED can be greatly lowered, meanwhile, the radiation power of the purple-light LED can be increased and the reliability of purple-light LED devices is effectively improved. In the epitaxial growth method, an n-type AlGaN/GaN super lattice structure is adopted, potential-barrier-layer AlGaN and potential-well-layer GaN are doped alternately periodically, and therefore concentration of n-type carriers can be concentrated; the concentration of different layers change periodically, and periodic conductance changes enable currents to be diffused better; meanwhile, the conductance changing area is widened, so that the transmitting effect of an electric leakage channel with linear defects is weakened, forward voltage can be lowered, and ESD can be improved.

The invention provides a quadruple-junction cascading solar battery which comprises an InP substrate layer, and an InGaAs sub-battery, a first tunnel junction, an InGaAsP sub-battery, a second tunnel junction, a gradual transition layer, a GaAs sub-battery, a third tunnel junction, a GaInP sub-battery and a GaAs contact layer that are arranged on the substrate layer sequentially. The invention further provides a fabrication method of the quadruple-junction cascading solar battery, which comprises the step of allowing the InGaAs sub-battery, the first tunnel junction, the InGaAsP sub-battery, the second tunnel junction, the gradual transition layer, the GaAs sub-battery, the third tunnel junction, the GaInP sub-battery and the GaAs contact layer to be grown on the InP substrate layer.

The invention discloses an epitaxial growth method with a p-layer special doped structure. According to the method, when a p-type layer of an LED (Light Emitting Diode) is grown, double-element doping of a GaN/AlGaN superlattice structure is adopted, that is, a small amount of silane is doped when doping magnesium. The silane is doped as a donor, however, due to the small amount of the doped silane, the lattice imperfection caused by the doped magnesium can be remarkably improved, a self-compensation effect is reduced, the crystal quality is improved, non-composite imperfection centers are reduced, a small number of scattering centers are caused, the carrier mobility and the ionization efficiency of an accepter are improved, and in addition, as the growing temperature of AlGaN is high, such doping is beneficial for improving the doping concentration of magnesium, the doping effect of the p-layer is improved, and the overall lighting efficiency of the LED is greatly improved. Due to improvement of the crystal quality and the improvement of barrier layer conductivity, the current expansion capability is improved, and the reliability of the LED device is also improved.

The invention discloses a preparation method of a rare earth substituted yttrium iron garnet crystal. The method includes the steps of: respectively weighing Y2O3, Re2O3 and Fe2O3 in molar ratio according to Y(3-x)RexFe5O12, conducting grinding and briquetting, and then carrying out solid-phase reaction to obtain a polycrystalline material block; crushing and grinding the polycrystalline materialblock, and adding a fluxing agent to obtain a mixed material; putting the mixed material into a crucible, putting the crucible into a crystal growth furnace, performing heating to a set temperature, and conducting heat preservation to obtain a high-temperature solution; then changing the relative positions of the crucible and a heating coil to enable the crucible to gradually move to a low-temperature area until the high-temperature solution is completely crystallized, stopping moving, and performing cooling to room temperature to obtain a crystal ingot; and removing the fluxing agent by adopting mechanical stripping or solution corrosion method to obtain the crystal. By means of the fluxing agent, the method provided by the invention effectively lowers the crystal growth temperature and reduces energy consumption, provides a driving force for crystal growth through vertical movement, promotes the growth of crystals, and can acquire the large-size blocky crystal.

The invention relates to a method for preparing a transmissive AlGaN ultraviolet photocathode based on substrate peeling, comprising the following steps: 1) preparing a material; 2) sequentially carryout high-temperature baking, nucleate layer growth and high-quality GaN release layer growth; 3) growing a p-type Mg doped AlGaN photoemissive layer with high aluminum content; 4) bon that quartz window material on the surface of the AlGaN; 5) that GaN lay is thoroughly decomposed by use a laser decomposition technology, and the substrate is stripped; 6) activating surface of the AlGaN by Cs or Cs/O layer. 1) GaNis taken as that buffer lay of the ultraviolet photoelectric cathode instead of AlN, so that the growth difficulty of the buffer layer is reduce, the crystal quality of the p-type AlGaN emitting layer is improved, and the photocathode with higher sensitivity is prepared; 2) that lase decomposition technology of the buffer lay is adopted to fully decompose the GaN layer and realizethe substrate peeling off, thereby avoiding the absorption of the ultraviolet incident light by the substrate and the buff layer and ensuring the efficient detection of the ultraviolet light by the photoemission layer; 3) the substrate peeled off by the laser can be used repeatedly and economically.

The present invention provides a 795nm quantum well laser based on an AlGaAs/GaInP active region. The epitaxial structure comprises a substrate, a buffer layer, an N-type lower limit layer, a lower waveguide layer, a quantum well layer, an upper waveguide layer, and P-type upper limit layer and an ohmic contact layer from the bottom to the top. The upper waveguide layer and the lower waveguide layer are made of an aluminum-free material gallium indium phosphate, the quantum well layer is made of an aluminum gallium arsenide material, and a wide waveguide semi-aluminum-free active region is formed by the waveguide layers and the quantum well layer. According to the 795nm quantum well laser, the special requirements of a pump laser with the application of a small and simplified self-doubledlaser crystal can be satisfied, at the same time, the influence of the roughness of a growth interface and an episodic field at a cavity surface on the service and reliability of the laser can be reduced effectively by an optimized laser structure.

The invention discloses a method for growing yttrium iron garnet crystals by adopting a composite fluxing agent. The yttrium iron garnet (Y3Fe5O12, YIG for short) crystal is an important magneto-optical material and is prepared by the following steps: accurately weighing, mixing, grinding and sintering raw materials to obtain a polycrystal material, crushing the polycrystal material, adding the composite fluxing agent, carrying out ball milling to obtain a mixed material, filling a crucible with the mixed material, heating the crucible filled with the material to a set temperature, keeping thematerial at the temperature to obtain high-temperature molten crystal solution, then carrying out slow cooling until the solution in the crucible is completely cooled and crystallized, conducting cooling to room temperature to obtain a crystal ingot, and removing the fluxing agent by adopting a mechanical stripping and chemical corrosion method to finally obtain the crystal. According to the invention, through the lead-free composite fluxing agent, environmental pollution caused by lead and the corrosion to a platinum crucible are greatly reduced, the growth temperature of the crystal is effectively reduced, and the bulk single crystal with a larger size can be obtained.

The invention belongs to the technical field of multiple quantum wells of nanometer arrays, and discloses an InGaN/GaN nano-pillar multiple quantum well grown on a strontium tantalum lanthanum aluminate substrate and a preparation method thereof. The InGaN/GaN nano-pillar multiple quantum well grown on a strontium tantalum lanthanum aluminate substrate comprises an AlN nucleation layer grown on a La<0.3> Sr<1.7>AlTaO<6> substrate, a GaN nano-pillar template grown on the AlN nucleation layer, an AlN/GaN super lattice layer grown on the nano-pillar template, and an InGaN/GaN nano-pillar multiple quantum well grown on the AlN/GaN super lattice layer. A nano-pillar array prepared is size-controllable and of uniform orientation. The obtained multiple quantum well has low defect density and excellent electrical and optical properties.

A selective epitaxial method for integrated photoelectric device and self-aligned template converter includes such steps as growing buffering layer, lower limitting layer and active layer on the surface of substrate, selectively growing upper limitting layer and vertical wedge waveguide by SiO2 mask, preparing ridge waveguide or burried waveguide as required, and epitaxial growth of indium phosphide layer and ohm contact layer, and preparing p/n electrodes.

The invention discloses a Si-based vertical cavity surface emitting chip. The structure consists from bottom to top of an n-type electrode, a substrate, a buffer layer, a lower distributed Bragg reflector located on the substrate, active area located on the lower distributed Bragg reflector, an upper distributed Bragg reflector located on the active area, a p-type electrode located on the upper distributed Bragg reflector, and a SiO2 confinement layer located around a cylindrical mesa. In the invention, a silicon-doped (AlxGa1-x)2O3, (AlyGa1-y)2O3 stacked structure is prepared on an n-type silicon substrate as the lower distributed Bragg reflector, rare earth-doped Ga2O3 is used as an n-type luminous material, and a GaAs, AlGaAs or InP, InGaAsP stacked structure is used as the upper distributed Bragg reflector. As a silicon-based vertical cavity surface emitting light source according to the invention, the characteristics of high thermal stability, high chemical stability, simple preparation method and high reliability are gained.

The invention provides a method for improving the reliability of a gate oxide layer of a peripheral circuit area of a flash memory. The method includes the following steps that: oxidation treatment is performed on a nitrogen containing region of the top of a semiconductor substrate at the peripheral circuit area; and the nitrogen containing region is converted into an oxide layer, and the oxide layer is removed, and therefore, a nitrogen-free semiconductor substrate surface of the peripheral circuit area is exposed; and a gate oxide layer is grown on the nitrogen-free semiconductor substrate surface. With the method adopted, when an MOS device is manufactured in the peripheral circuit area in a subsequent process, the nitrogen containing region of the top of the semiconductor substrate is removed, and therefore, the growth difficulty of the gate oxide layer on the surface of the semiconductor substrate can be lowered, and especially, the growth capacity of the gate oxide layer on the semiconductor substrate at corners of an isolation structure can be improved, and the integrity and uniformity of gate oxide layer growth can be increased, and the reliability of the gate oxide layer of the MOS device can be improved; and the oxidation treatment mentioned in the invention is performed at room temperature or low temperature, and therefore, thermal budget in the prior art can be decreased, and device doping profile shift can be avoided. The method is advantageous in convenient implementation and simple operation.

The invention discloses a preparation method of zirconium oxide crystal, and belongs to the field of preparation of metal oxide functional materials. Yttrium oxide and zirconium oxide are mixed in proportion and ground into uniform powder, the cubic zirconium oxide crystal is prepared through a cold crucible method, then reduction treatment is conducted, and the black cubic zirconium oxide crystal can be obtained. The material can realize large-size rapid crystallization growth and is suitable for large-scale production, the crucible material can be recycled as a raw material and the cost is saved, and the obtained crystal has a large crystal size and a high crystallinity.

The invention discloses a preparation method for a GaInP/GaAs dual-junction solar cell. The preparation method comprises: step A, a first transition layer GaP grows on a substrate; step B, a second transition layer Ga(1-x)InxP grows on the first transition layer GaP; step C, a GaAs bottom cell grows on the second transition layer Ga(1-x)InxP; and step D, a GaInP top cell grows on the GaAs bottom cell, wherein the content of indium in the second transition layer Ga(1-x)InxP is adjusted to realize matching of the lattice constant of the second transition layer Ga(1-x)InxP with the lattice constant of the GaAs bottom cell. According to the preparation method, the GaP and the Ga(1-x)InxP are used as transition layers and transition of the lattice constant of the second transition layer Ga(1-x)InxP to the lattice constant of the GaAs bottom cell is realized, so that lattice constant matching is realized and thus an objective of growing and preparing a GaInP/GaAs dual-junction solar cell is achieved.

The invention belongs to the technical field of crystal preparation, and particularly discloses a method for growing uranium dioxide crystals by using a borate fluxing agent, which comprises the following steps: (1) mixing and grinding a fluxing agent Li5U (BO3)3 with Li2CO3, H3BO3 and UO2 powder in a stoichiometric ratio for 3 hours; (2) putting the mixed powder in the step (1) into a platinum crucible, and sintering at a three-stage temperature; (3) mixing fluxing agents Li5U (BO3) 3 and UO2 according to the molar ratio of 83 mol%: 1; preparing 17mol% of raw materials, fully mixing and grinding, loading into a platinum crucible, introducing Ar/5% H2, putting into a tubular resistance furnace, heating to 1235 DEG C, dissolving UO2 by using a Li5U(BO3) 3 fluxing agent, enabling the systemto reach a molten state, and slowly cooling to reach supersaturation to drive the crystal to grow, thereby obtaining the UO2 crystal. The scheme is mainly used for preparing the uranium dioxide crystal, and the problem that the ultrahigh-melting-point uranium dioxide crystal is difficult to grow by an existing melt method is solved.

The invention provides a high-strain semiconductor structure and a preparation method thereof, and in a composite active layer of the high-strain semiconductor structure, the indium content in a first component gradient layer is smaller than the indium content in a quantum well layer and larger than the indium content in a first barrier layer. The indium content in the second component gradient layer is smaller than the indium content in the quantum well layer and larger than the indium content in the second barrier layer; the indium component content in a plurality of first sub-gradient layers in the first component gradient layer meets a progressive increase area of a Gaussian function along with the increase of the number of the first sub-gradient layers, and the indium component content in a plurality of second sub-gradient layers in the second component gradient layer meets a progressive decrease area of the Gaussian function along with the increase of the number of the second sub-gradient layers; the content of indium in the first stress compensation layer and the second stress compensation layer is zero; and the quantum well layer, the first component gradient layer and the second component gradient layer are used for laser light. The process difficulty and complexity of the high-strain semiconductor structure are reduced, and the growth quality is improved.