65results about How to "Reduce surface concentration" patented technology

The invention discloses a diffusion method for a solar cell with a polycrystalline silicon selective emitter. The diffusion method includes the following steps: firstly, placing a silicon chip on which a doping agent grows into a diffusion furnace and raising the temperature to 750-800DEG C, wherein the environment in the furnace is N2 with the flow being 10-30slm; secondly, after the temperature is stabilized, uniformly raising the temperature in each temperature zone in the furnace to 850-900DEG C, introducing 0.2-2slm of N2 carrying trichloroethane, 1-5slm of O2 and 10-30slm of N2 while raising the temperature so as to realize heavy doping and controlling the heavily-doped sheet resistance between 30 and 60 omega/m<2>; thirdly, reducing the temperature of each temperature zone to the diffusion temperature of 820-840DEG C and introducing N2 carrying POCl3 for diffusing; fourthly, reducing the temperature of each temperature zone to 780-800DEG C, stopping introducing the N2 carrying the POCl3 so as to realize shallow doping, wherein the propulsion time is 10-25minutes and controlling the shallow-doped sheet resistance between 70-120 omega/m<2>; and fifthly, cooling the silicon chip, taking out the silicon chip and finishing the diffusion process. According to the diffusion method disclosed by the invention, the diffusion of a doping agent is realized at high temperature and the heavy doping and shallow doping of the selective emitter are realized; and meanwhile, the gettering of a polycrystalline silicon is realized, so that the conversion efficiency is greatly increased.

The invention discloses a phosphorus and boron liquid source one-shot perfect diffusion process. The process is mainly implemented through the following steps that one surface of each silicon wafer with two thinned sides is rotated to be coated with a liquid boron source, baked and then rotated again to be coated with a liquid phosphorus source, lamination is conducted after baking, the silicon wafers are stacked on a silicon boat pairwise to be subjected to one-shot perfect diffusion in the mode that each phosphorus source surface is opposite to the corresponding phosphorus source surface and each boron source surface is opposite to the corresponding boron source surface. Diffused junction depth is even, and reverse breakdown voltage of a product can be stable and good in uniformity; the diffusion concentration gradient is reduced, PN junction field intensity can be effectively improved, discharging-resistant capacity of the product is improved, and the reverse surge capacity of the product can be effectively improved; meanwhile, the source return quantity of the edge of the silicon wafer is small, the number of intra defects is small, and product reliability is high. Processing cost is low, the process is simple, and production is easy.

The invention relates to a solar battery diffusion method which is characterized by comprising a step I of first oxidation, a step II of diffusion and a step III of second oxidation. The step II of diffusion comprises primary diffusion, the secondary diffusion and tertiary diffusion. In the solar battery diffusion method provided by the invention, a P-type silicon wafer is used as a diffusion source substrate; through three sub-steps of diffusion in the diffusion stage, the inlet flow of nitrogen and oxygen turns from large to small, and the inletting time turns from long to short; in the step III, the concentration of a phosphorus source is driven into the substrate from high to low, thus the surface concentration is gradually reduced, and the surface recombination and defect concentration is reduced; gradient doping is formed, the P-N junction area is widened, and the open-circuit voltage is increased; and meanwhile, through the relatively deep junction, the series resistance can be reduced, and the conversion efficiency of a solar battery is improved. The solar battery diffusion method does not need an additional process, is relatively low in cost and can be used for improving the conversion efficiency of the crystalline silicon solar battery.

The invention discloses a diffusion method used for a crystalline silicon solar battery. The method comprises the following steps of: (1) placing a silicon wafer into a diffusion furnace; rising the temperature from 780-810 DEG C to 840-860 DEG C; and simultaneously introducing POCL3+O2+N2 for 12 to 14 minutes; (2) simultaneously introducing O2+N2 when rising the temperature in the diffusion furnace to 840-860 DEG C and keeping the constant temperature for 2 to 5 minutes; simultaneously introducing the POCL3+O2+N2 for 8 to 12 minutes when rising the temperature from 840-860 DEG C to 870-890 DEG C; reducing the temperature from 870-890 DEG C to 800 DEG C; introducing the O2+N2 in the process of reducing the temperature; stabilizing for 2 minutes at the temperature of 800 DEG C; and introducing the POCL3+O2+N2; and (3) taking the silicon wafer out of the diffusion furnace. In the method, both the requirements on the doping concentration of an emitting region and the surface concentration of the emitting region in diffusion can be met at the same time; a gettering effect is good; and the distribution of a doping curve is more reasonable.

The invention relates to a diffusing process with low temperature, low surface concentration and high sheet resistance. The diffusing process with low temperature, low surface concentration and high sheet resistance comprises an entering step, a depositing step, a propelling step and an exiting step. The diffusing process with low temperature, low surface concentration and high sheet resistance is characterized in that the reaction temperatures in the entering and depositing steps are lower than 800 DEG C. Preferably, at least one of the depositing step and the propelling step is carried out by steps according to different temperatures. Furthermore, the depositing step is divided into a first depositing step and a second depositing step. The propelling step comprises a first propelling step and a second propelling step. Preferably, an oxidizing step is further carried out between the entering step and the depositing step. The oxidizing step comprises the step of: introducing oxygen into a reactor. By utilizing the diffusing process with low temperature, low surface concentration and high sheet resistance provided by the invention, the reaction temperatures in the depositing and diffusing steps are reduced compared with the that in the conventional process, so that the surface compositing rate is reduced. Meanwhile, impurities are more beneficially migrated to the impurity absorbing point at the lower diffusing temperature in the diffusing process of polycrystalline silicon, so that the battery efficiency is further improved.

The present invention relates to a system for transporting and/or washing and/or pasteurisation thermal treatment of foodstuffs, particularly leaf products comprising at least a treatment section. The treatment section can be comprised of one or more sections of rectilinear tubes and one or more corresponding curved tube sections, wherein products within the treatment section being conveyed by a fluid, such as water, flowing along the tubes.

The invention provides a method for gettering phosphorus in an N-type polysilicon slice by a metallurgical method, and relates to polysilicon. The method is good in gettering effect, low in cost and simple in operation, and is suitable for industrial production. The method for gettering phosphorus in the N-type polysilicon slice by the metallurgical method comprises the following steps of: washing and drying the N-type polysilicon slice; feeding a gas into the obtained polysilicon slice at the temperature of 700 to 1,200 DEG C, performing phosphorous diffusion gettering thermal treatment, and cooling the polysilicon slice; immersing the obtained polysilicon slice into hydrogen fluoride (HF) solution; and corroding a gettering layer on the polysilicon slice by using acid corrosive liquid, washing and drying, and baking so as to obtain the phosphorous-gettered polysilicon slice.

The invention discloses a process for manufacturing an emitter of a solar cell, which comprises the following steps: step A, manufacturing a PN junction on the surface of a matrix silicon wafer (1) by a diffusion process to form a surface impurity distribution layer (2); step B, oxidizing the surface impurity distribution layer (2) obtained in step A to quickly grow an oxidation layer (3) distributed uniformly on the surface of the surface impurity distribution layer (2); and step C, removing the oxidation layer (3) in step B. The process avoids the phenomenon that the ordinary diffusion process cannot avoid generating a 'dead layer', further reduces the surface concentration, improves the minority carrier lifetime and the conversion efficiency of the cell, and reduces the production cost of the solar cell.

A method for manufacturing a selective emitter structure with low surface concentration and a soft doped zone includes the steps that (1) the surface of a substrate to be prepared is corroded and cleaned, and the surface of the substrate is completely dried after cleaning; (2) the clean substrate prepared in the step (1) is soaked in a solution with high oxidability to carry out wet chemical oxidation on the surface of a silicon wafer, and then the surface of the substrate is completely dried; (3) a microcosmic salt aqueous solution of 0.5-20% is deposited on the surface of the substrate in a spin coating and spraying mode, and then the surface of the substrate is dried; (4) phosphorus ink or silicon ink is deposited on an electrode area on the surface of the substrate coated with a phosphorus source in the step (3) in a screen printing mode, and then the surface of the substrate is dried; (5) the temperature of a diffusion furnace rises, nitrogen is introduced into a diffusion quartz tube, when the temperature reaches 780-890 DEG C, the clean substrate prepared in the step (4) is placed into a constant-temperature area of the diffusion quartz tube, a fire door of the diffusion furnace is sealed, and after the temperature of the diffusion furnace is stable, oxygen is introduced into the diffusion quartz tube; (6) the substrate is taken out and cooled after the diffusion process is over.

The present invention discloses a junction termination structure of a thyristor chip, and the problems of low forward voltage withstand value and large leakage current of a chip in an existing thyristor single-face trench are solved. Two inner walls of the voltage groove in the thyristor single-face trench are symmetrically provided with stepped structures. The voltage trench is provided with two-stage stepped structures or three-stage stepped structures, the height is larger than a P2N junction, and the structures extend into an N area for 20um to 70 um. The junction termination structure is suitable for the semiconductor chip production field of all table top structures.

The invention discloses a diffusion process of a solar cell, a preparation method of the solar cell and a silicon wafer, and the diffusion process comprises the steps: introducing small nitrogen carrying phosphorus oxychloride into the textured silicon wafer in a diffusion furnace tube, depositing a phosphorus source at a first temperature, and introducing oxygen and large nitrogen at a second temperature for high-temperature propulsion to obtain a PN junction; introducing small nitrogen carrying phosphorus oxychloride, secondarily depositing a phosphorus source, and further forming a phosphorosilicate glass layer containing a low-concentration phosphorus source on the surface of the silicon wafer; and introducing atmospheric nitrogen to purge, ending diffusion, and obtaining an emitter containing the low-concentration phosphorus source on the surface of the silicon wafer. According to the method, a two-step source deposition mode is adopted, phosphorus oxychloride is deposited in a low-temperature environment, the surface concentration of a silicon wafer can be fully reduced, meanwhile, the uniformity of PN junctions is guaranteed by controlling the gas flow ratio of large nitrogen, oxygen and small nitrogen deposited by a phosphorus source, and the conversion efficiency of a solar cell can be effectively improved.

The invention discloses a polycrystalline silicon solar cell with high photoelectric conversion efficiency and a method for preparing the same. The polycrystalline silicon solar cell includes a polycrystalline silicon wafer, wherein the front surface of the polycrystalline silicon wafer is a textured surface, three layers of silicon nitride are deposited on the upper surface of the textured surface, a positive electrode is printed on the front surface of the polycrystalline silicon wafer, and a negative electrode is printed on the back surface of the polycrystalline silicon wafer. The method for preparing the polycrystalline silicon solar cell comprises performing detection and cleaning; performing texturing; performing diffusion knotting; performing a dephosphorized silicon glass treatment; preparing a silicon nitride reflective layer; printing positive and negative electrodes; and performing sintering. A uniform textured surface can be formed on the surface of the polycrystalline silicon wafer by texturing twice, thereby contributing to improvement in the photoelectric conversion efficiency of the polycrystalline silicon wafer. The three layers of silicon nitride are deposited onthe surface of the polycrystalline silicon wafer so as to achieve a good passivation effect on the surface of the polycrystalline silicon wafer and improve the photoelectric conversion efficiency ofthe polycrystalline silicon wafer. An electrical performance test result shows that the polycrystalline silicon solar cell prepared by the method has high photoelectric conversion efficiency.

The invention discloses a high-sheet resistance cell slice diffusion preparation method. The method comprises steps: a silicon wafer is placed in a diffusion furnace in a nitrogen atmosphere, and in a low temperature condition, low concentration oxygen is inlet to the diffusion furnace; an oxygen flow is enhanced afterwards, a gas carrying a phosphorus source and the nitrogen with a reduced flow are inlet to the diffusion furnace; after temperature rise, the oxygen with the enhanced flow, the nitrogen with the reduced flow and the gas carrying the phosphorus source are inlet continuously to the diffusion furnace; the oxygen flow is enhanced continuously, and the nitrogen flow is reduced; and temperature falls, and the silicon wafer is taken out from the diffusion furnace. A four-step gradient oxygen inletting method is adopted, the silicon wafer surface concentration can be effectively reduced, surface recombination of carriers is reduced, the diffusion sheet resistance is enhanced through reducing the silicon wafer surface concentration, and the solar cell efficiency is further improved.

The invention discloses an H-3 silicon carbide isotope battery and a manufacturing method thereof. The isotope battery comprises an N-type highly-doped SiC substrate and a P-type SiC ohmic contact doped region from bottom to top, wherein a first N-type SiC epitaxial layer is arranged in a partial region on the P-type SiC ohmic contact doped region; a second N-type SiC epitaxial layer is arranged on the first N-type SiC epitaxial layer; a P-type ohmic contact electrode is arranged in a region, except the first N-type SiC epitaxial layer, on the P-type SiC ohmic contact doped region; an N-type ohmic contact doped region is arranged partially in a region on the second N-type SiC epitaxial layer; an N-type ohmic contact electrode is arranged on the N-type ohmic contact doped region; a SiO2 passivation layer is arranged in a region, except the N-type ohmic contact doped region, on the second N-type SiC epitaxial layer; and an H-3 radioactive isotope source is arranged on the SiO2 passivation layer. The design is novel and reasonable, the problem of irradiation generated carrier recombination loss of H-3 on the surface can be effectively solved, and the output power and the energy conversion efficiency of the isotope battery are effectively improved.

The purpose of the present invention is to achieve high efficiency by reducing surface concentration of a light receiving surface and increasing impurity concentration under electrodes, while facilitating concentration control of a diffusion layer. At the time of forming a high concentration diffusion layer (5) on a part of a first surface (1A) of a substrate (1) having formed thereon a diffusion layer (2) of a light receiving surface, an impurity in the outermost surface of the diffusion layer (2) of the light receiving surface is taken into a thermally oxidized film (6) by performing thermal oxidation in a state wherein a diffusion source is formed. Consequently, an impurity concentration of the outermost surface of the diffusion layer (2) of the light receiving surface is set lower than the impurity concentration of the inner side.