How to make monocrystalline silicon solar panels? Begged: specific steps
Surface fleeceThe preparation of single crystal silicon wafer is the use of anisotropic etching of silicon on the surface of the silicon per square centimeter to form several million square pyramidal structure, namely, the Pyramid structure. Due to the multiple reflection and refraction of incident light on the surface, the absorption of light is increased, and the short circuit current and conversion efficiency are improved. Anisotropic etching of silicon in alkaline solution liquid is usually hot, available alkali sodium hydroxide, potassium hydroxide, lithium hydroxide and ethylenediamine etc.. Most of them were prepared by using dilute sodium hydroxide solution with a concentration of about 1%, and the corrosion temperature was 70-85. In order to obtain a uniform texture, but also in the solution add alcohols such as ethanol and isopropanol as complexing agent to accelerate the corrosion of silicon. In the preparation of velvet, the silicon chip must be first surface corrosion, alkaline or acidic etching solution to about 20 ~ 25 m, corrosion in the face, the general chemical cleaning. After surface preparation of silicon wafers are not suitable for long-term storage in the water, in order to prevent contamination, should be spread as soon as possible.
Wafer inspectionSilicon wafer is the carrier of solar cell, the quality of silicon wafer directly determines the conversion efficiency of solar cell. This procedure is mainly used to measure the technical parameters of silicon wafer on line. These parameters mainly include the surface roughness of the silicon wafer, the lifetime of the minority, the resistivity, the P/N type and the micro crack. The device is divided into four parts: automatic loading and unloading, silicon wafer transmission, system integration part and. The silicon photovoltaic detector on the silicon wafer surface roughness were detected, and the size and appearance of diagonal parameter detection chip; micro crack detection module is used to detect silicon micro cracks; another two detecting module, a [url=] module [/url] online test mainly test wafer resistivity and wafer type, on the other a module for lifetime test wafer. The detection of the diagonal and micro cracks of the silicon wafer is needed before the sub lifetime and resistivity measurement. Wafer inspection equipment can automatic loading and unloading, and substandard products in a fixed position, so as to improve the detection accuracy and efficiency.
Phosphate glassThe process is used for solar cell production in the manufacturing process, through chemical etching silicon that is immersed in hydrofluoric acid solution, complexes six fluorosilicic acid to produce chemical reaction to produce soluble phosphorus silicon glass layer, a diffusion system to remove the node after the formation of the surface of the silicon wafer. In the diffusion process, POCL3 reacts with O2 to form P2O5 on the surface of silicon wafer. P2O5 reacted with Si to produce SiO2 and phosphorus atoms, which form a layer of phosphorus containing SiO2 on the surface of the silicon wafer. Removing phosphorosilicate glass equipment is generally composed of a main body, a cleaning tank, manipulator, servo drive system, electric control system and the automatic mixing acid system components, the main power source of hydrofluoric acid, nitrogen, compressed air, water, wastewater and exhaust heat. Hydrofluoric acid is capable of dissolving silicon dioxide because of the reaction of hydrofluoric acid and silica to produce volatile four fluorinated silicon gas. If the hydrofluoric acid is too heavy, the reaction of four fluorinated silicon will further react with hydrofluoric acid to produce soluble complex and the material of the six fluorine acid.
Diffusion bondingSolar cells require a large area of PN junction to achieve the conversion of light energy to electrical energy, while the diffusion furnace is a special equipment for manufacturing solar cell PN junction. Tube type diffusion furnace is mainly composed of quartz boat download four parts part, gas chamber, a furnace body part and a holder part etc.. Generally, the liquid source of three phosphorus oxychloride is used as the diffusion source. The P type silicon wafer is placed in a quartz tube of a tube type diffusion furnace, and three nitrogen oxychloride is used in the quartz vessel at the temperature of 850---900 degrees Celsius, and the phosphorus atom is obtained through the reaction of the phosphorus oxychloride and the silicon wafer through the reaction of the phosphorus and the phosphorus. After a certain time, the phosphorus atom from the surrounding surface layer into a silicon wafer, and wafer to internal diffusion through the void between the silicon atoms, forming a N type semiconductor and P type semiconductor interface, namely PN junction. The PN junction made by this method has good uniformity, the uniformity of box resistance is less than ten percent, and the lifetime of less than 10ms. The manufacture of PN junction is the most basic and most important process in the production of solar cells. Because it is the formation of PN junction, so that the electrons and holes in the flow is no longer back to the original place, so that the formation of the current, using the wire will lead to the current, dc.
