36results about How to "Uniform doping concentration" patented technology

A semiconductor device includes a first semiconductor layer and a second semiconductor layer of opposite conductivity type, a first epitaxial layer of the first conductivity type formed on sidewalls of the trenches, and a second epitaxial layer of the second conductivity type formed on the first epitaxial layer where the second epitaxial layer is electrically connected to the second semiconductor layer. The first epitaxial layer and the second epitaxial layer form parallel doped regions along the sidewalls of the trenches, each having uniform doping concentration. The second epitaxial layer has a first thickness and a first doping concentration and the first epitaxial layer and a mesa of the first semiconductor layer together having a second thickness and a second average doping concentration where the first and second thicknesses and the first doping concentration and second average doping concentrations are selected to achieve charge balance in operation.

A method for forming a semiconductor device includes forming a nanotube region using a thin epitaxial layer formed on the sidewall of a trench in the semiconductor body. The thin epitaxial layer has uniform doping concentration. In another embodiment, a first thin epitaxial layer of the same conductivity type as the semiconductor body is formed on the sidewall of a trench in the semiconductor body and a second thin epitaxial layer of the opposite conductivity type is formed on the first epitaxial layer. The first and second epitaxial layers have uniform doping concentration. The thickness and doping concentrations of the first and second epitaxial layers and the semiconductor body are selected to achieve charge balance. In one embodiment, the semiconductor body is a lightly doped P-type substrate. A vertical trench MOSFET, an IGBT, a Schottky diode and a P-N junction diode can be formed using the same N-Epi/P-Epi nanotube structure.

The present invention is directed to methods for depositing doped and/or alloyed semiconductor layers, an apparatus suitable for the depositing, and products prepared therefrom.

The invention relates to a single-mode fiber and a fabrication method thereof. A bare fiber comprises a core layer and a wrapping layer, wherein the core layer comprises a first core layer, a second core layer and an inner wrapping layer, the relative refractivity difference Delta 1 of the first core layer is more than 0.2% but less than 0.35%, the relative refractivity difference Delta 2 of the second core layer is more than or equal to 0.15% but less than or equal to 0.25%, the refractivity radius of the inner wrapping layer is 24-36 micrometers, the relative refractivity difference Delta 3of the inner wrapping layer is more than or equal to -0.12% but less than or equal to 0%, the wrapping layer comprises a sunken wrapping layer and an external wrapping layer, the relative refractivitydifference Delta 4 of the sunken wrapping layer is more than or equal to -0.40% but less than or equal to -0.28%, and the external wrapping layer is a high-hardness pure quartz sleeve. With the adoption of a method for on-line assembly and drawbenching by two sleeves and a core rod, fiber annealing for many times is performed during the drawbenching process, a coating layer with low modulus is coated in a surface of the fiber, a coating layer with high modulus is coated outside the surface of the fiber, and the fiber with low loss, large effective area and high strength is fabricated. The method is simple, the viscosity of the cord rod can be adjusted according to a demand, the fiber attenuation is reduced without employing a pure silicon core scheme, and production on a large scale is facilitated.

The invention discloses a method for preparing a supersaturated-doping semiconductor thin film. The method includes the following steps: step one, a substrate is chosen; step two, the surface of the substrate is cleaned up; step three, at a low growth temperature, a semiconductor amorphous thin film is deposited on the surface of the substrate, wherein through control over a deposition speed ratio of atoms, a supersaturated-doping semiconductor amorphous thin film is obtained; step four, laser annealing is carried out on the supersaturated-doping semiconductor amorphous thin film by the utilization of ultra-fast lasers, and the preparation of the supersaturated-doping semiconductor thin film is completed. According to the preparation method, the molecular beam epitaxy technology is used for preparing the supersaturated-doping thin film which is even in doping concentration. Depth distribution of impurities in the prepared supersaturated-doping silicon thin film is very even.

The invention discloses a silicon carbide epitaxial growth device and a growth process method. The growth device comprises a reaction module and a rotary tray assembly, a reaction cavity is formed in the reaction module, the rotary tray assembly is arranged at the bottom of the reaction cavity, the rotary tray assembly comprises a graphite tray and a rotary supporting part, the graphite tray is provided with a concave part used for containing a substrate, an annular first groove is formed in the concave part, and the rotary supporting part is arranged in the annular first groove. The graphite tray is provided with a first groove, the first groove is configured to enable the projection of the edge of the substrate on the graphite tray to fall in the first groove, the graphite tray is provided with a plurality of edge C source gas flow paths, the edge C source gas flow paths are arranged in the circumferential direction of the first groove, and the first groove is communicated with an inner cavity of the rotary supporting part; the plurality of edge C-source gas flow paths guide the C-source gas injected into the inner cavity of the rotary support part to the first groove, and the C-source gas is guided to the edge side of the substrate through the first groove. Therefore, the C content of the edge side of the substrate is improved, the doping efficiency of the edge N is inhibited, and the purpose of uniform doping concentration is achieved.

The invention discloses a process for preparing a crystalline silicon solar cell by a solution method. The method comprises the steps: adding ethyl alcohol, polyethylene glycol, vinyltrimethoxysilaneand the like into a phosphoric acid solution to serve as a phosphorus diffusion solution source, and uniformly coating the surface of a silicon wafer with diffusion liquid through an ultrasonic atomization spraying method; then diffusing phosphorus at the high temperature to obtain the uniform doping concentration of the surface. According to the invention, the solution spraying method is adoptedto prepare a titanium dioxide anti-reflection film to replace a silicon nitride anti-reflection film prepared by a PECVD method, and a microemulsion composed of anionic polyacrylamide (APAM), isopropanol and the like is added into a titanium tetrachloride solution to serve as a precursor solution of the titanium dioxide film, so that the passivation function of the film on the silicon surface is improved.

The invention discloses a preparation method of a light-emitting diode epitaxial wafer with a p-type composite layer, and belongs to the field of light-emitting diode manufacturing. The p-type composite layer is grown on a multi-quantum well layer, the p-type composite layer comprises a p-type InGaN layer and a p-type GaN layer, the In element has the effect of reducing the activation energy of Mg, and the activation rate of Mg in the p-type InGaN layer and the p-type GaN layer can be improved so as to improve the number of holes. The p-type InGaN layer is inserted in the p-type GaN layer, and the p-type InGaN layer can be used as a low-barrier region, stores part of holes and expands the holes, so that the holes can enter the multi-quantum well layer more uniformly, and the light emitting uniformity of the light emitting diode is improved. The light-emitting efficiency and the light-emitting uniformity of the light-emitting diode can be improved.

The present invention discloses a level shifting structure. The level shifting structure includes an LDMOS, a pass isolation region and a high side region; the pass isolation region includes a first buried layer having a second conductivity type and a second well region having a second conductivity type, wherein the second well region is connected to the bottom first buried layer; a drift region of the LDMOS is composed of a first epitaxial layer, and drift region field oxygen is formed on a surface of the drift region; a surface electric field reduction structure is formed in the drift regionon the bottom of the drift region field oxygen, the surface electric field reduction structure comprises two or more second conductivity type injection layers; the injection depth of the second conductivity type injection layer on the bottommost layer is equal to a connection position between the second well region and the first buried layer, and a third injection region is superimposed at the connection position and is formed simultaneously with the bottommost second conductivity type injection layer. The invention discloses a manufacturing method for the level shifting structure. The invention can reduce the leakage of the pass isolation region while enhancing the effect of reducing the surface electric field and reducing the on-resistance.

The invention discloses a semiconductor structure forming method. The method comprises steps: a substrate with a first area and an adjacent second area is provided, wherein the surface of the substrate in the first area is provided with a first fin part and an adjacent second fin part, the surface of the substrate is provided with an isolation layer, and the minimal distance between the side wall of the first fin part and the side wall of the second fin part is a first distance; a mask layer is formed on the surface of the isolation layer, wherein an opening for enabling the first area to be exposed is arranged in the mask layer, the opening is provided with a first side wall and an opposite second side wall, the minimal distance between the side wall of the first fin part and the first side wall is larger than the minimal distance between the side wall of the second fin part and the first side wall, and the value obtained by dividing the thickness of the mask layer by the minimal distance between the side wall of the first fin part and the first side wall is larger than that obtained by dividing the distance between the top of the second fin part and the surface of the isolation layer by the first distance; and first lightly-doped injection with a first injection angle is carried out on the first fin part from one side of the first side wall, wherein the tangent value of the first injection angle is smaller than or equal to the value obtained of dividing the thickness of the mask layer by the second distance. The formed semiconductor structure is stable in performance.

The invention provides a preparation method of a large-size yttrium aluminum garnet (YAG) laser crystal. The preparation method comprises the following steps: mixing raw materials for preparing yttrium aluminum garnet with raw materials of doping elements, pressing the mixed raw materials into a cake material, and carrying out sintering to obtain a YAG polycrystalline cake material; heating the obtained YAG polycrystalline cake material to a molten state, placing the molten material in a mixed atmosphere of oxygen and inert gas for oxygen diffusion, and then carrying out liquid purification; adding a seed crystal into the molten raw materials subjected to the liquid purification, and carrying out crystal growth by a Czochralski method; and after crystal growth is finished, lifting a growncrystal to the liquid surface, and carrying out cooling to obtain the YAG laser crystal. The preparation method can be used to prepare the YAG laser crystal with high quality, the diameter of the YAGlaser crystal can reach 100 mm, the effective length can reach 200 mm, the doping concentration of crystal active ions is uniform, crystal defects are few, the core is small, the effective utilizationrate of the crystal is greatly improved, and large-size laser slabs and discs can be conveniently processed by cutting. Meanwhile, the process steps of the preparation method is simplified, and costis reduced.

The invention discloses a silicon carbide crystal ingot growing device, and relates to the technical field of silicon carbide crystal ingots, the silicon carbide crystal ingot growing device comprises a cylinder body, a heating liner is arranged in the cylinder body, and a cover body is arranged on the upper part of the cylinder body; a plurality of feeding pipes are arranged on the barrel in a penetrating manner, one end of each feeding pipe penetrates through the heating inner container and extends into the heating inner container, and a crucible is fixed to the end of each feeding pipe; the plurality of crucibles are arranged in the heating inner container to form an inverted heap-shaped structure; each feeding pipe is connected with a material storage box, and a feeding mechanism is arranged between each material storage box and the corresponding feeding pipe; a rotatable silicon carbide crystal ingot growth plate is arranged below the cover body, and a cooling tank is arranged above the silicon carbide crystal ingot growth plate. The invention further provides a method for growing the silicon carbide crystal ingot. The silicon carbide crystal ingot grows in a sublimation mode between silicon carbide and a doping substance. According to the invention, the silicon carbide and the dopant can be synchronously sublimated and mixed in a three-dimensional distribution manner, the semi-insulating silicon carbide crystal ingot with more uniform doping concentration is generated, and the quality of the semi-insulating silicon carbide crystal ingot is improved.