64results about How to "Improve doping uniformity" patented technology

The invention discloses a preparation method for high-purity flaky alumina, belonging to the technical field of preparation of special powder. The preparation method comprises the following steps: with high-purity aluminum isopropoxide with a purity of 99.999%, pure water and isopropanol as main raw materials and ammonium bifluoride or ammonium fluoride as a crystal morphology controlling agent, dissolving the high-purity aluminum isopropoxide in isopropanol to prepare a solution A; preparing a solution B from pure water, isopropanol and ammonium bifluoride; then gradually adding the solution A into the solution B drop by drop at a certain addition speed; carrying out a reaction under the conditions of heating and stirring so as to produce hydrated alumina; and then successively carrying out filtering, drying and roasting so as to obtain the high-purity flaky alumina. The high-purity flaky alumina prepared by using the method has crystal grain thickness of no more than 1.0 [mu]m, a radial size of 5 to 20 [mu]m, a smooth surface, a flaky shape, no agglomeration and crystal twinning, and good dispersibility, and can be used in fields like cosmetics, pearlescent pigment, high-grade coatings and fine ceramics.

The invention provides a graphene coating type doping method, which comprises the following steps: Step 1, preparing a doping coating solution; Step 2, coating the doping solution on the target substrate surface; The cloth liquid substrate is heated for polymerization and curing to form a doped coating; step 4, soak the doped coating with deionized water and dry it; step 5, transfer and cover graphene on the doped coating to form A composite structure composed of the first doped coating and graphene in sequence. Further, the above step 1 to step 4 can also be repeated on the composite structure to form a second layer of doped coating. The beneficial effects of the present invention are: adopting coating doping process, the thickness of the doped coating is uniform and controllable, suitable for large-area "roll-to-roll" production; in addition, the doped coating itself is stable, and is located between the graphene and the target substrate Between, the doping effect is stable and long-lasting.

The invention provides a lithium cobalt oxide material and a preparation method thereof as well as an anode material. The lithium cobalt oxide material is mainly prepared from an element M doped lithium cobalt oxide particle and a coating which coats the surface of the lithium cobalt oxide particle; the molecular formula of the lithium cobalt oxide particle is LiaCo1-bMbO2, wherein a is not less than 0.95 but not more than 1.15; b is not less than 0.003 but not more than 0.01; M is at least one or several of Mg, Al, Ti, Zr, Ni, Mn, Cr, Mo, W and a rare earth element; the coating is selected from one or a mixture of ZnO and SnO2, and has a weight which is 0.5wt% to 5 wt%, preferably 1wt% to 5wt%, preferably 2wt% to 5wt% and preferably 2wt% to 4wt%, of that of the lithium cobalt oxide particle. By using the lithium cobalt oxide material, the problems that the rate capability and the cycle performance of an existing material are poor under high pressure are solved.

A kind of foam material made from metal adulterated by low-density poly-4-methyl-pentylene and its preparation are disclosed. It is produced by: blending with the dissolvent / non-solvent system and metal power, heating and melting, forming the dispersive system including the metal power through stirring, dispersing the metal power using supersonic wave, putting in the poly-4-methyl-pentylene, shifting it into die after heated and dissolved, lower the temperature at a fixed rate, getting the need shapes from the solid mixture after condensation, vacuum drying or supercritical extraction. Its advantages include: good doped uniformity, large content of the doped element, realizable to adulterate one element or several elements.

The invention discloses a preparation method of a fluorine-doped lithium-rich manganese-based positive electrode material. The lithium-rich manganese-based positive electrode material has a chemical general formula of xLi2MnO3.(1-x) LiMO<2-y>F<2y>, wherein x is larger than or equal to 0.1 and smaller than or equal to 0.9, y is larger than 0 and smaller than or equal to 0.05, and M is one or more of Ni, Co, Mn, Cr, Fe, Ti, Mo, Ru, V, Nb, Zr and Sn. The preparation method comprises the following steps of: preparing a fluorine-doped lithium-rich manganese-based precursor through a precipitation reaction by adopting soluble metal salt, a precipitator, a soluble fluorine-containing compound and water; and uniformly mixing the fluorine-doped lithium-rich manganese-based precursor with a lithium salt, and carrying out presintering and high-temperature sintering to obtain the fluorine-doped lithium-rich manganese-based positive electrode material. According to the method, the soluble fluorine-containing compound is used as a fluorine source, fluorine doping is synchronously realized during coprecipitation of the lithium-rich manganese-based precursor, the doping uniformity is relatively good, and the cycle performance of the doped lithium-rich material is greatly improved.

The invention discloses a method for preparing a single-core MgB2 superconducting line/strip. The method comprises the steps that (1) mixed powder is prepared; (2) high-energy ball milling is conducted on the mixed powder, so that precursor powder is obtained; (3) the precursor powder is contained in a composite metal tube, so that a filled tube composite body is manufactured; (4) rotary forging and drawing are conducted, so that a single-core line is obtained; (5) vacuum sintering is conducted, so that the single-core MgB2 superconducting line is obtained or after the single-core line is rolled into a strip, vacuum sintering is conducted on the strip, so that the single-core MgB2 superconducting strip is obtained. According to method for preparing the single-core MgB2 superconducting line/strip, firstly, heat treatment with high temperature is conducted on powder raw materials, it can be guaranteed that TiB2 generated after a reaction is evenly distributed on a crystal boundary, and therefore the critical current density of the MgB2 superconducting line/strip can be increased easily; secondly, due to the fact that crystal grains are further refined through high-energy ball mining, the density of a superconducting core wire is increased easily and the connectivity of MgB2 crystal grains is improved easily; thirdly, more crystal boundaries formed by grain refinement can form a pinning center, and therefore the critical current density of the line/strip is increased further.

The invention provides a lightly-doped substrate, a substrate with a selective emitter, and a solar cell and a preparation method and application thereof. The lightly-doped substrate comprises a P type silicon wafer layer, an N type silicon layer, a first phosphorosilicate glass layer, an oxide layer and a second phosphorosilicate glass layer which are connected in sequence. According to the invention, in the subsequent heavy doping process of the lightly-doped substrate, the doping uniformity of a doping source on the surface of a silicon wafer can be improved, and the square resistance valueof a heavy doped region can be reduced, so that the silver-silicon contact resistance is reduced; the preparation method of the lightly-doped substrate is simple, easy to implement and suitable for industrial large-scale production and application; and the phosphorus content of the heavily-doped region in the substrate with the selective emitter prepared by the lightly-doped substrate is relatively high, the sheet resistance of the heavily doped region is relatively low and uniform, and the prepared solar cell has relatively high light conversion efficiency.

The application discloses a low-resistivity P-type 4HSiC single crystal and a preparation method thereof, wherein silicon carbide growth simulation software is adopted to simulate the crystal growth process of a physical vapor transport method, and the temperatures of all points in a crucible, the material transport flow line, the residual material shape, the crystallinity and the like which cannot be monitored are obtained, and then the temperature field, thermal diffusion, material transmission and surface kinetics in the model can be acquired according to the material transmission path and the SiC powder state diagram at each preset time node in the growth process of the SiC single crystal and the temperature field diagram in the crucible; finally, the simulation result is analyzed, wherein the growth temperature and the growth pressure and the placement position of the Al source releaser in the crucible are selected, and actual growth on the p-type 4HSiC single crystal is carried out by utilizing a PVT single crystal growth furnace, so that the doping uniformity can be improved, and the P-type 4HSiC single crystal with good quality is obtained.

The invention provides a preparation method of a vertical-gate semiconductor device. The preparation method comprises the following steps: providing a substrate; forming a trench in the substrate, wherein the trench defines a photodiode region and a floating diffusion region; forming a first polycrystalline silicon layer in the trench, wherein the first polycrystalline silicon layer covers the inner wall of the trench and extends to cover the surface of the substrate; performing a first ion implantation process on the first polycrystalline silicon layer; forming a second polycrystalline silicon layer in the trench, wherein the trench is filled with the second polycrystalline silicon layer, and the second polycrystalline silicon layer covers the first polycrystalline silicon layer; and performing a second ion implantation process on the second polycrystalline silicon layer and the first polycrystalline silicon layer. According to the invention, the phenomenon of non-uniform electrical performance of an image sensor is improved.

The invention discloses a method for inducing high-concentration movable holes in GaN material by using a fluorine ion implantation method, a hole quantum well and a two-dimensional hole gas (2DHG) are formed, the high efficiency p-type doping of GaN material is realized, Unlike the traditional p-doping principle, This method is mainly realized by adjusting the relative position between the valence band of F + and Fermi level, The device structure comprises a substrate, an n-type gallium nitride semiconductor layer (containing fluorine ion implantation) on a substrate, A metal electrode is arrange on that n-type gallium nitride semiconductor layer. The invention utilize F + with strong electronegativity of ion implantation to induce high-concentration 2DHG in the gallium nitride to providemovable holes, which is compatible with the prior silicon technology, and the concentration and depth of the implanted fluorine ion can be precisely regulated, and the preparation process is simple and the cost is low.

The embodiment of the invention provides a preparation method of a ferroelectric film, a ferroelectric memory and a preparation method of the ferroelectric memory. The preparation method of the ferroelectric film comprises the following steps that atomic layer deposition is carried out by taking a main element source as a reaction precursor, main elements are deposited on the surface of a substrate, and most free bonding points on the surface of the substrate are absorbed by controlling the deposition time; then inert gas is used as purification gas for performing clearing and purging on a chamber; then atomic layer deposition is carried out by taking a doping element source as a reaction precursor, so that doping elements adsorb residual free bonding points on the surface of the substrate; inert gas is used as purification gas for clearing and purging; at the moment, the two precursors exist on the surface of the substrate at the same time, and then are subjected to oxidation treatment together by using oxidizing gas; then inert gas is used as purification gas for clearing and purging; and the steps are repeated to obtain the ferroelectric film with the target thickness. Accordingto the method provided by the embodiment, better low-concentration uniform doping can be realized.

The invention relates to a high-content element uniformly-doped lithium cobalt oxide precursor and a preparation method thereof, the structural formula of the lithium cobalt oxide precursor is CoxMyO4, x is more than or equal to 0.95 and less than 1, y is more than 0 and less than or equal to 0.05, M represents a doped metal, the crystal system is a cubic system, the space group is F-43m, the unit cell parameter a value of the lithium cobalt oxide precursor is between 8.07 and 8.12, and the unit cell parameter b value of the lithium cobalt oxide precursor is more than 0 and less than 1. The true density is between 6.02 g/cm < 3 > and 6.10 g/cm < 3 >.

The invention discloses a high-performance Cr3+ and Nd3+ compositely doped GSGG laser ceramic and a preparation method of the ceramic. The preparation method comprises the following steps that high-purity Cr3O3, Nd2O3, Gd2O3, Sc2O3 and Ca2O3 powder is taken as the raw materials, the raw materials are compounded according to the stoichiometric ratio of the raw materials, a nitrate solution is formed after uniform mixing, the raw materials are injected into the nitrate solution by one step with ammonium hydroxide as a precipitant, at the same time, full stirring is performed, and a sediment solution is formed by aging; the sediment solution is filtered, washed and dried to obtain a precursor powder body, calcination is performed at the temperature of 800 DEG C to 1,100 DEG C in the air atmosphere, and a Cr3+ and Nd3+: GSGG nano-powder body is obtained; the nano-powder body is subjected to isostatic cool pressing after being dry-pressed, vacuum sintering is performed, a sample is taken out and ground and polished after furnace temperature is cooled to the room temperature, and the Cr3+ and Nd3+: GSGG laser ceramic is obtained. Compared with single crystals of the system, the preparation technology is simple, and the comprehensive performance of the material can be improved.

The invention discloses a gallium and scandium co-doping zinc oxide scintillation single crystal and a preparation method thereof. ZnO and GaXScY of the gallium and scandium co-doping zinc oxide scintillation single crystal contain two doped ions which are Ga3+ and Sc3+, wherein the final doping concentration X of Ga3+ in the zinc oxide scintillation single crystal is 1-1000 ppm, and the final doping concentration Y of Sc3+ in the zinc oxide scintillation single crystal is 10-10000 ppm. According to the preparation method, zinc oxide serves as a raw material, and the gallium and scandium co-doping zinc oxide scintillation single crystal is generated by adopting a hydrothermal method. The gallium and scandium co-doping zinc oxide scintillation single crystal is excellent in scintillation and physical performance, and large-size high-quality single crystal is obtained easily through growth.

The invention provides a vertical pulling method for monocrystalline silicon. The method includes the following steps: providing a silicon sheet with the surface grown deuterium doped silicon nitride;performing mixing fusion on the silicon sheet and a polysilicon fragment; performing seed crystal melting; and adopting the vertical pulling method with a magnetic field to form a monocrystalline silicon ingot. The invention also provides a formation method of a wafer, and the monocrystalline silicon ingot prepared by the vertical pulling method is used as an original material to form the wafer.The concentrations of nitrogen and deuterium of a silicon single-crystal bar can be accurately controlled and the good doping uniformity is obtained by the vertical pulling method for monocrystallinesilicon.

The invention relates to a method for enhancing the ohmic contact of a gallium oxide semiconductor device. The method comprises the following steps of defining a pattern of which an ohmic contact region needing to be enhanced on the upper surface of a gallium oxide substrate by adopting a photoetching process, exposing the region, and shielding the residual region by using a photoresist; injectingthe doping ions into the upper surface of the substrate; removing the photoresist on the upper surface of the gallium oxide substrate; performing heat treatment; defining and forming a pattern of a metal electrode region by adopting the photoetching process, exposing the region, and shielding other regions by using the photoresist; forming a metal electrode on the upper surface of the gallium oxide substrate; removing the photoresist on the upper surface of the gallium oxide substrate; carrying out the fast annealing treatment. According to the method for enhancing the ohmic contact of the gallium oxide semiconductor device, the doping range, the concentration and the depth of the ohmic contact region can be accurately controlled, the preparation process is simple, the ohmic contact of the gallium oxide semiconductor device can be effectively enhanced in combination with thermal annealing treatment after injection, and the gallium oxide semiconductor device with good ohmic contact isformed.

The invention discloses a method for improving the doping uniformity of a semiconductor laser, and the method comprises the steps: placing a substrate on a pedestal of epitaxial growth equipment, and enabling the edge, facing the surface of the pedestal, of the substrate not to be in contact with the surface, facing the substrate, of the pedestal; sequentially growing an n-type epitaxial layer, an active layer and a p-type epitaxial layer on the surface, deviating from a base, of a substrate, introducing a growth condition sensitive doping source required for growing the p-type epitaxial layer from two or three gas paths of epitaxial growth equipment, and vertically arranging the two or three gas paths. By implementing the invention, the contact between the substrate and the base is changed, so that the contact between the edge of the substrate and the edge of the base becomes poor, the temperature uniformity of the surface of the substrate can be effectively adjusted, and the influence of the temperature on the non-uniform doping of the doping source can be reduced; moreover, two or three paths of doping sources sensitive to the growth condition are simultaneously introduced, so that the doping uniformity of the doping sources sensitive to the growth condition can be improved on the basis of reducing the influence of the temperature on the doping uniformity of the doping sources sensitive to the growth condition.