Research On Key Technologies Of Polycrystalline Silicon Solar Cell

According to polycrystalline silicon structure, key technologies of polycrystalline silicon cells have been studied in this thesis, which are: texture, diffusion and passivatiaon etc.Because of poor quality of textured surface of some grain by alkali etching, the anti-reflect effect of polycrystalline silicon wafer is not good as single-crystalline silicon's. By acid etching method, the quality of textured surface is improved. The reflection has been reduced to less than 15% at wave range of 600nm to 1000nm, the reflection rate is less 8% than that of alkali etched surface.The sheet resistivity of polycrystalline silicon varies with temperature more shaper than single-crystalline after diffusion. With lower diffusion temperature, sheet resistivity of diffused polycrystalline silicon is larger than the single-crystalline silicon's diffused at same condition; nevertheless, when diffusion temperature is higher, the sheet resistivity of diffused polycrystalline silicon is smaller than the diffused single-crystalline silicon's. Oxided with temperature 800℃, the sheet resistivity of polycrystalline silicon wafer rose, and with 900℃), sheet resistivity dropped. The two phenomena have been explained in this thesis.It is discovered in experiment that polycrystalline silicon cell's property can be improved by changed-temperature diffusing. The initial temperature is between900℃ and 950℃, and then 850-870℃. In this thesis, technics of PECVD SiNx film passivation has been studied. According to trait of SiNx antireflection film, technics of making polycrystalline silicon cells have been improved. With optimized technics, property of polycrystalline silicon cells is improved, and conversion efficiency of polycrystalline silicon cells has been reached 14%.