246 results about "Alkaline etching" patented technology

In a method for generating a textured surface of a semiconductor layer, a surface of the semiconductor layer is etched anisotropically with a first alkaline etching solution to generate a surface of the semiconductor layer including pyramid-shape textures. Subsequently, the surface including the pyramid-shaped textures is etched anisotropically with a second alkaline etching solution, which differs from the first alkaline etching solution, to cause material removal of the pyramid-shaped textures, thereby reducing a height difference between peaks and neighboring valleys of the pyramid-shaped textures. A method for manufacturing a tandem solar cell further includes generating a first solar cell structure of the tandem solar cell including the textured surface, and generating a second solar cell structure of the tandem solar cell on the side of the first solar cell structure on which the textured surface is arranged.

The invention provides a buried resistor circuit board and a preparation method thereof. According to the resistance element, one resistance material is arranged on the dielectric layer to form the first resistance layer, and then the other resistance material is arranged on the first resistance layer to form the second resistance layer, so that the binding force of the resistance layers and the dielectric layer can be enhanced, and the surface flatness of the resistance element can be improved. The resistive layer of the resistive element is protected by using the protective film, so that the shape and the length of the resistive layer are prevented from being influenced by subsequent processes. According to the preparation method, the whole process is a dry process, a differential etching process is omitted, an alkaline etching solution does not need to be used, and the preparation method is environmentally friendly.

The invention discloses a sample preparation method for observing the surface appearance of a medium-high voltage formed foil, which comprises the following steps: cutting the formed foil into a strip-shaped sample with a specific size, grinding and polishing, carrying out primary ultrasonic cleaning, putting into a special alkaline corrosive liquid for treatment, carrying out secondary ultrasonic cleaning, and finally observing by using a scanning electron microscope. The alkaline corrosive liquid comprises various components such as potassium hydroxide and sodium silicate, and the components have a synergistic effect and are prepared under the conditions of optimized temperature, stirring rotation speed and the like. The sample preparation method has remarkable advantages, and compared with a traditional method, the use of chemicals easy to explode is avoided, so that the safety is greatly improved; the operation process is standard, parameters are clear, simplicity and convenience are achieved, and repeatability is good; by accurately controlling the corrosion process, the sample preparation effect is good, and the surface appearance can be clearly presented; meanwhile, the components of the used corrosive liquid are environment-friendly, and environmental pollution is reduced. The method has a wide application prospect in the related scientific research and production fields of electronic materials.

The invention discloses a picosecond processing method for a binding disc at the bottom of a blind slot, which comprises the following steps of: removing a tin layer: putting a circuit board to be subjected to tin removal into tin removal liquid to ensure that the tin layer is completely immersed; according to the characteristics of the tin stripping liquid and the specific condition of the circuit board, proper tin stripping time and temperature are set, the surface of the circuit board is lightly brushed with a brush, and a tin layer is helped to be removed; the dry film is cut into a proper size, it is ensured that the dry film can completely cover the circuit board, through the design that a binding disc is arranged at the bottom of a depth groove, conduction connection of an inner layer product and an outer layer product is facilitated, a component can be embedded into the depth groove, the product space is saved, the product size is reduced, and the depth groove is formed in a hard board through an inner layer adhesive tape and an outer layer uncovering cover; a pattern cannot be manufactured on a tray at the bottom of the tank by using a conventional etching mode, and the problem is solved by applying a tin plating mode and forming the pattern by laser ablation; and the inner layer pattern is protected by using the second tinning-alkaline etching, and pattern formation of other areas is completed.

The invention provides a tungsten and titanium nitride / titanium selective etching solution which comprises the following components in percentage by mass: 5%-30% of an oxidizing agent, 0.5%-10% of an alkaline etching agent, 0.1%-1% of a tungsten corrosion inhibitor, 0.01%-0.05% of a surfactant and the balance of deionized water. According to the etching solution disclosed by the invention, the etching on W can be reduced while the high etching rate of TiN / Ti is maintained.

The invention discloses a manufacturing method of an optical module circuit board and the optical module circuit board, and the manufacturing method of the optical module circuit board comprises the following steps: drilling: drilling through holes for the connection between layers on a PCB (Printed Circuit Board); copper deposition: carrying out oxidation-reduction reaction on the drilled circuit board, and forming a copper layer on the hole wall so as to metallize the through hole; manufacturing an outer-layer circuit, and manufacturing an outer-layer circuit pattern of the circuit board by adopting a negative film process; and manufacturing a metalized half hole, namely manufacturing the metalized half hole of the circuit board by adopting a positive film process. In the optical module circuit board with the half hole, the metalized half hole and the optical module circuit pattern are respectively manufactured by adopting a positive film process and a negative film process, so that the process requirements of the metalized half hole and the optical module circuit pattern are respectively met, and the problem that the metalized half hole is etched to be copper-free by acid etching in the negative film process is avoided; and the requirement of an optical module product on the wire top can be ensured in alkaline etching of a positive film process.

The invention discloses a hollow carbon sphere loaded Ni / NiO heterojunction material, which is prepared by the following steps: firstly preparing a solid carbon sphere loaded Ni / NiO heterojunction material SiO2-NC-Ni / NiO by a template sacrifice method, and then removing a SiO2 template by an alkaline etching method to obtain the hollow carbon sphere loaded Ni / NiO heterojunction material NC-Ni / NiO. The preparation method comprises the following steps: 1, preparing PDA coated silicon dioxide solid spheres; 2, preparing PDA coated silicon dioxide solid sphere loaded nickel ions; 3, preparing a carbon-coated silicon dioxide solid sphere loaded nickel-nickel oxide heterojunction; and 4, preparing the hollow carbon sphere loaded nickel-nickel oxide heterojunction. The invention relates to a preparation method of an NC-Ni / NiO doped lithium aluminum hydride hydrogen storage material, which comprises the following steps of: mixing NC-Ni / NiO serving as a catalyst and lithium aluminum hydride under an argon condition, and performing ball milling to obtain LiAlH4-NC-Ni / NiO. When the material is used as a hydrogen storage material, the initial dehydrogenation temperature is 60-70 DEG C, and the hydrogen desorption amount is 7.0-7.2 wt.%.

There is provided a gallium nitride single crystal substrate, which is a gallium nitride single crystal substrate having a diameter of 50 mm or more, with a low-index crystal plane closest to a main surface being (0001), and in which an average density of etch pits during etching applied to the main surface using an alkaline etching solution is less than 1×106 cm−2; and in histograms of diameters of the etch pits in multiple different regions on the main surface, and among peaks appearing in the histograms, when a diameter of a first peak which is a smallest diameter is denoted as a, a diameter of a second peak which is a second smallest diameter is denoted as b, frequency of the first peak (the number of etch pits) is denoted as A, frequency of the second peak is denoted as B, the number of the etch pits constituting the first peak is denoted as α, and the number of the etch pits constituting the second peak is denoted as β, at least one of the following conditions (1), (2), and (3) is satisfied: (1) variation in a / b values in the multiple histograms is within ±5% of an average value. (2) variation in A / B values in the multiple histograms is within ±15% of an average value. (3) variation in α / β values in the multiple histograms is within ±30% of an average value.

The present invention provides an etching waste liquid recycling and regeneration and cuprous chloride and copper recovery system, wherein the etching waste liquid recycling and regeneration system comprises an acid-base etching waste liquid collecting and neutralizing device, a cuprous chloride filtering and recovering device and an acid-base etching liquid regeneration device which are fixedly connected in sequence, the acid-base etching waste liquid collecting and neutralizing device is respectively connected to the etching waste liquid outlet of the acid etching production line, the etching waste liquid outlet of the alkaline etching production line, and the cuprous chloride filtering and recovering device, the cuprous chloride filtering and recovering device is respectively connected to the acid-base etching liquid regeneration device, the cuprous chloride purification system, and the electrolytic copper recovery system, and the acid-base etching liquid regeneration device is also respectively connected to the acid etching production line and the alkaline etching production line. The beneficial effects of the present invention are: different recycling and regeneration systems of acid-base etching waste liquids are integrated into a set of recycling and regeneration systems, the etching waste liquid recycling and regeneration quality is high, the copper extraction efficiency is high, and the production cost of cuprous chloride is low.

The invention discloses a method for preparing copper sulfate from PCB etching liquid, and belongs to the technical field of PCB etching liquid treatment.The method comprises the following steps that alkaline PCB etching waste liquid and acidic PCB etching waste liquid are mixed to obtain basic copper chloride precipitate; reacting the basic copper chloride precipitate with concentrated sulfuric acid to obtain a copper sulfate crude product; adding a hydrogen peroxide solution into the copper sulfate crude product solution, stirring and reacting for 0.5-2 hours, adding a precipitator to adjust the pH value to 3.5-4, and carrying out solid-liquid separation to obtain an impurity-removed solution; the impurity removal solution is introduced into an adsorption column filled with modified activated carbon, then evaporation concentration, cooling crystallization and reduced-pressure suction filtration are carried out, and copper sulfate is obtained.According to the method, the processes of acid-base neutralization, oxidation impurity removal, adsorption impurity removal and recrystallization are adopted, and the low-cost and efficient recovery and purification technology is achieved; and the recovery efficiency is improved to the maximum extent and the cost is controlled while the high purity of the product is ensured.

The invention discloses an aluminum alloy profile surface highlight corrosion-resistant treatment process which comprises the following steps: S1, pretreatment including degreasing and alkaline etching; s2, anodic oxidation; s3, chemical brightening treatment; s4, surface wiredrawing; s5, carrying out sand blasting; s6, highlight is conducted; s7, treating with a silane coupling agent; s8, carrying out secondary oxidation treatment; s9, performing nano-composite hole sealing; s10, spraying, printing and chemical brightening are used for replacing traditional mechanical polishing, so that the surface of the aluminum alloy profile is smoother, the uniformity of glossiness is improved, scratches possibly generated by mechanical polishing are avoided, stable chemical bonds are formed between the profile and a hole sealing layer through coupling agent treatment, the surface state is optimized, it can be ensured that a hole sealing agent can be attached more firmly, and the service life of the aluminum alloy profile is prolonged. According to the secondary oxidation treatment, an oxidation film is thickened after highlight treatment, the formed highlight surface is not affected, invasion of a corrosion medium is effectively blocked, nano-scale pores in the oxidation film are filled with nano silicon dioxide, a compact hole sealing layer is formed, and therefore the corrosion resistance of the workpiece is improved.

There is provided a gallium nitride single crystal substrate, which is a gallium nitride single crystal substrate having a diameter of 50 mm or more, with a low-index crystal plane closest to a main surface being (0001), and in which Ge concentration in the substrate is 3×1018 cm−3 or more; and among peaks appearing in a histogram of diameters of etch pits during etching applied to the main surface with an alkaline etching solution, a first peak having a smallest diameter is a single peak having no shoulder.

In a method for generating a textured surface of a semiconductor layer, a surface of the semiconductor layer is etched with a first alkaline etching solution to generate a surface of the semiconductor layer having a pyramid-like texture. The surface having the pyramid-like texture is then etched with a second alkaline etching solution different from the first alkaline etching solution to remove material from the pyramid-like texture, thereby reducing a height difference between a peak and an adjacent valley of the pyramid-like texture. A method for manufacturing a tandem solar cell further comprises generating a first solar cell structure produced in this way having tandem solar cells with textured surfaces, and generating a second solar cell structure in series with solar cells on the side of the first solar cell structure on which the textured surface is arranged.

The invention provides a preparation method of high-transparency hydrophobic glass. The preparation method comprises the following steps: etching a micro-nano structure on the surface of glass by adopting an alkaline etching solution; inorganic salt is adopted to treat the micro-nano structure at 500-600 DEG C, and a nano structure is obtained; and coating a low-surface-energy substance on the nano structure to obtain the high-transparency hydrophobic glass. The method can improve the transmittance of the glass on the basis of keeping the hydrophobicity of the glass, and has the advantages of simple process, low cost and low pollution.

The invention discloses a nanosheet heterostructure based on alkali etching, a preparation method of the nanosheet heterostructure and application of the nanosheet heterostructure in an electrochemical oxygen evolution reaction, and belongs to the technical field of water electrolysis catalytic materials. The preparation method comprises the following steps: S1, preparation of a nickel-iron-cobalt-aluminum layered double-metal hydroxide precursor: weighing metal salt, adding water, adding urea, violently stirring, transferring the obtained product into a polytetrafluoroethylene lining, sealing, putting into a stainless steel high-pressure kettle, and heating for reaction; taking out after cooling, and cleaning and drying the obtained product; and S2, preparing the nickel-iron-cobalt-aluminum layered double-metal hydroxide: etching by using an alkali solution. The nanosheet heterostructure is etched by alkali, so that the nanosheet structure is lighter and thinner, the specific surface area of the catalyst and the number of active sites are increased, reaction substances are easier to adsorb and diffuse, chemical reactions such as oxygen evolution reaction (OER) are accelerated, and the catalytic activity of the catalyst is improved.

The invention provides a single-side multi-layer copper-based boss thermoelectric separation printed board preparation technology. The technology comprises the following steps: S1, copper-based boss manufacturing: material taking, drilling, resin hole plugging, baking, grinding, protective film pasting, circuit pretreatment, solder resist ink printing, pre-baking, LED exposure, developing, etching, cleaning and drying, and resin grinding; s2, multi-layer board manufacturing: performing FR-4 board cutting, inner layer patterning, DES, AOI, pressing, target drilling, hole drilling, copper deposition, board electroplating, resin hole plugging, baking, grinding, outer layer L1 circuit manufacturing, etching, AOI, boss position numerical control windowing, cleaning and drying; and S3, laminating the copper-based boss in the step S1 and the multi-layer board in the step S2, then removing the film, manufacturing an outer layer L4 layer circuit, etching, performing AOI, performing resistance welding, writing, performing nickel gold immersion, drilling a copper-based position resin hole, and forming. According to the preparation process of the single-side multi-layer copper-based boss thermoelectric separation printed board, the alkaline etching copper reduction technology, the circuit forming pre-compensation technology and the mixed compression technology are combined, the embedding degree of the boss can be improved, and meanwhile the problem of glue overflowing of the boss is effectively avoided.

The utility model provides an alkaline etching solution electrolysis cathode plate. The alkaline etching liquid electrolysis cathode plate comprises a cathode plate body and a cathode plate electrode, the cathode plate body and the cathode plate electrode are connected and fixed through a dismounting mechanism, a first jack is formed in the cathode plate body, a second jack is formed in the cathode plate electrode, and the first jack is communicated with the second jack; the disassembling and assembling mechanism comprises a hollow inserting cylinder, a fixing ring, a plurality of limiting stopping blocks and an elastic column, the hollow inserting cylinder penetrates through the second inserting hole and extends into the first inserting hole, and the hollow inserting cylinder is matched with the second inserting hole and the first inserting hole. According to the alkaline etching solution electrolysis cathode plate provided by the utility model, the structure is simple by arranging the dismounting mechanism, and the cathode plate body and the cathode plate electrode can be dismounted and fixed without a tool, so that the dismounting difficulty can be reduced.

The utility model discloses an alkaline etching liquid adding device for a circuit board, which relates to the field of circuit board processing and comprises an alkaline etching liquid adding device body, one side of the alkaline etching liquid adding device body is fixedly connected with a liquid inlet, and the other side of the alkaline etching liquid adding device body is fixedly connected with a liquid outlet. According to the automatic liquid discharging device, the automatic liquid discharging assembly is arranged, a hydraulic cylinder in the automatic liquid discharging assembly is electrically connected with a power source, so that a movable plate is stressed to move, the air pressure in a liquid discharging cavity is changed, a second ball is stressed to move by increasing the air pressure, and the second ball and a connecting pipe are separated easily; and when the moving plate stops moving, the first relay and the second relay on the moving plate are in contact with each other, so that the electromagnetic valve is opened, the alkaline etching liquid can be discharged from the liquid outlet, and continuous manual operation is avoided.

The invention provides a semiconductor structure and a forming method thereof. The semiconductor structure includes a plurality of bit line structures laterally spaced apart on a substrate, a landing pad between the bit line structures, a metal oxynitride layer overlying a top surface of the landing pad, and a capacitance structure extending vertically over the landing pad. A method of forming a semiconductor structure includes the following operations. A plurality of bit line structures are received on a substrate. A landing pad is formed between the bit line structures. A metal oxynitride layer is formed covering a top surface of the landing pad. And forming a sacrificial stack structure at the top of the metal oxynitride layer and the bit line structure. A trench is formed in the sacrificial stack structure to expose the metal oxynitride layer. A capacitor structure is formed in the trench. The semiconductor structure with the metal nitrogen oxide layer can protect the landing pad from being etched by the alkaline etchant.

The present invention discloses a silicon-mesoporous titanium dioxide composite negative electrode material, a preparation method and a battery, belonging to the technical field of battery materials; the material comprises mesoporous titanium dioxide, nano-silicon and an outer coated carbon layer, wherein the mesoporous titanium dioxide has a pore diameter of 2-20 nm and a pore volume of 0.2-1.0 cm 3 / g, specific surface area 80-360m 2 / g, the nano-silicon is loaded inside the pores and on the surface of the skeleton of mesoporous titanium dioxide, the nano-silicon loading is 30-70%, the carbon coating amount is 1.5-10%, and the thickness of the silicon layer loaded on the surface of the mesoporous titanium dioxide skeleton is less than 10nm; the present invention increases the loading amount of silicon on titanium dioxide through monosilane vapor deposition, and effectively removes silicon vapor-deposited outside the pores and on the surface of the titanium dioxide carrier through alkaline etching; the obtained negative electrode material has the characteristics of high capacity, small expansion rate, stable structure and good cycle performance.

The invention relates to ultra-high performance concrete for resource utilization of pyrite tailings and a preparation method thereof, and the method comprises the following steps: carrying out a series of treatment processes such as drying desulfurization, alkaline etching and calcium salt complexation on pyrite tailings, mechanically sieving, screening the pyrite tailings after desulfurization according to a range of 25-85 meshes, and preparing the ultra-high performance concrete for resource utilization of pyrite tailings. And finally, mixing according to a set ratio, so as to obtain the ultra-high performance concrete. By combining a series of treatment processes such as drying desulfurization, alkaline etching and calcium salt complexation, free sulfate ions in the pyrite tailings are effectively eliminated, sulfides such as SO2 and SO3 are neutralized, then the physical and chemical compatibility of the pyrite tailings in the alkaline UHPC product is improved, it is ensured that doping of the pyrite tailings does not bring negative influence on the UHPC product, and the UHPC product quality is improved. Therefore, the UHPC product which is excellent in performance, low in carbon and environmentally friendly can be prepared, and the problem of resource utilization of building material products of pyrite tailings can be solved.

The application discloses a kind of preparation ball-in-bowl structure carbon-based materials and preparation method thereof.The carbon material presents hollow composite structure, is composed of inside "carbon bowl" and outside "carbon hollow ball".Gap exists between inside "carbon bowl" and outer carbon ball, and mesoporous channel is distributed on the surface of carbon bowl and carbon ball.The steps of the preparation method are as follows: firstly, using SiO2 nano solid ball as hard template, adopt two-step surface coating method and polymer modification method to obtain phenolic resin (RF) coated SiO2@RF-PS@SiO2@RF composite structure.Then, high-temperature carbonization is carried out to form SiO2@C@SiO2@C composite material.Finally, the two layers of SiO2 template are removed by one-time alkaline etching method to obtain the carbon composite material with ball-in-bowl structure.The ball-in-bowl structure carbon-based material in the application has regular structure, low density, high specific surface area and rich loading sites, and will be widely applied in the fields of catalysis, energy storage and biosensing.This method provides a new reference scheme for the design of carbon nano composite structure.

The invention provides a glass ceramic strengthening method and strengthened glass ceramic, and belongs to the technical field of glass ceramic processing. The glass ceramic strengthening method comprises the following steps: sequentially carrying out first-time surface modification treatment, toughening treatment, second-time surface modification treatment and organic acid treatment on the glass ceramic, the first surface modification treatment and the second surface modification treatment independently comprise at least one of polishing treatment, alkaline etching treatment and inorganic acid liquid etching treatment. The glass ceramic is sequentially subjected to the first surface modification treatment, the toughening treatment, the second surface modification treatment and the organic acid treatment, so that the roughness can be reduced, and the impact resistance of the glass ceramic is remarkably improved.

The invention relates to the technical field of thin base material multicolor vacuum coating, in particular to a thin base material multicolor vacuum coating method. The method comprises the following steps: performing a series of process treatments such as cutting, cleaning, ink coating, baking, curing, exposing, developing, etching, vacuum coating, ink re-coating, laser etching, secondary etching, cleaning, secondary vacuum coating, fingerprint-proof oil coating, film covering, punch forming and the like on a base material to form a first film-coated plate and a second film-coated plate with two color layers; and a specific alkaline etching solution and a cleaning solution containing active components are adopted to meet the high-precision requirement of a fine base material. The technical effects that the coating quality is improved, the coating binding force is high, and the multicolor effect is attractive are achieved.

The utility model relates to the field of wastewater copper recovery, and discloses a PCB alkaline etching plate washing wastewater copper recovery device which comprises a reaction barrel, the top end of the reaction barrel is connected with a barrel cover in a sliding mode, a driving assembly is installed at the top end of the barrel cover, and the left end and the right end of the driving assembly are both fixedly connected with rotating plates. The device comprises two rotating plates, placing grooves are formed in the two rotating plates, a plurality of first telescopic columns are fixedly connected to the interiors of the two placing grooves, second telescopic columns are slidably connected to the interiors of the first telescopic columns, the outer sides of the second telescopic columns are sleeved with first pushing springs, and limiting plates are slidably connected to the interiors of the two placing grooves. According to the device disclosed by the utility model, while the reaction is accelerated by stirring wastewater, dirt adhered to the inner wall of the reaction barrel is cleaned, the treatment process and the recovery efficiency of the wastewater are ensured, the normal operation of equipment is maintained, the filter plate is quickly disassembled, impurities filtered by the filter plate are cleaned, and the filtering efficiency is improved.

The invention relates to the technical field of biomedicine, in particular to a preparation method of sequential targeting mesoporous manganese oxide nano-enzyme and application of the sequential targeting mesoporous manganese oxide nano-enzyme in treatment of ischemia reperfusion induced acute kidney injury. Adding a potassium permanganate solution into the silicon dioxide nanoparticle dispersion liquid under ultrasonic waves, and carrying out alkali etching to obtain mesoporous manganese oxide nanoparticles (HMN); and after surface amination modification, connecting with a mixed PEG spacer layer, and reacting with thiolated SS31 and azidoacyl hyaluronic acid to obtain the nano-enzyme. The preparation can effectively penetrate through a damaged glomerulus filtration barrier and is passively enriched in a damaged kidney, damaged renal tubular epithelial cells over-express CD44 receptor mediated hyaluronic acid modified nano-particle endocytosis is enhanced, SS31 modified nano-particles achieve lysosome escape mitochondrial targeting in cells, the level of active oxygen in mitochondria can be reduced, and the activity of the mitochondria can be improved. The mitochondrial function is recovered, the renal function and tissue pathological injury are improved, and accurate anti-oxidation treatment on the acute kidney injury is realized.

The invention discloses a BiVO4 / Si pyramid array photoelectric catalyst and a preparation method and application thereof, the photoelectric catalyst is composed of BiVO4 nanoparticles and a silicon pyramid array, the BiVO4 nanoparticles are loaded on the surface of the silicon pyramid array, and the BiVO4 nanoparticles are obtained through wet alkaline etching. Specifically, a silicon pyramid array is prepared by adopting a metal-assisted wet alkaline etching method, and then BiVO4 nanoparticles are loaded on the surface of the silicon pyramid array by adopting a spin coating method. According to the preparation method, the oxidative degradation capability of the silicon pyramid array is improved by utilizing the relatively positive valence band position of BiVO4. In addition, the sample prepared by the method is a blocky solid catalyst, and is more favorable for recycling compared with a traditional powder catalyst.

The invention discloses a slotting method of a DDR5 product, and relates to the technical field of packaging substrates. The method comprises the following steps: obtaining a copper-clad substrate, and drilling the copper-clad substrate; manufacturing a circuit and a lead on the surface of the copper-clad substrate; arranging a solder mask layer on the surface of the copper-clad substrate, and windowing the solder mask layer to expose a bonding pad and a lead; attaching a photosensitive dry film on the surface of the solder mask, exposing and developing the photosensitive dry film, exposing the bonding pad, and covering the lead; electroplating a soft gold layer on the bonding pad; removing the photosensitive dry film, and removing the lead through alkaline etching; carrying out layered groove milling on the copper-clad substrate by adopting a left-handed double-edged cutter to form an open groove; carrying out plate milling on the copper-clad substrate to form a formed small plate; and cleaning, detecting and packaging the formed small plate. According to the method provided by the embodiment of the invention, the grooving quality can be improved, and the problems of burr generation or substrate cracking and the like are avoided.

The invention relates to forming a local p-type polycrystalline silicon through an approach of local p-type doping followed by selective alkaline etching enabling five different crystalline silicon-based single junction and bottom structure for tandem architectures solar cells.

An alkaline etching solution containing TMAH, hydrogen peroxide and water but not containing a hydrogen fluoride compound is prepared by mixing TMAH, hydrogen peroxide and water. The prepared etching solution is supplied to a substrate with a polysilicon film and a silicon oxide film exposed, and the polysilicon film is etched while suppressing etching of the silicon oxide film.