The Solar Cell Silicon Nitride Thin Film Preparation And Passivation

Solar cell is a photoelectric translating system, and its fabrication processescontain surface texturing, PN junction doping, plasma edge PN junction removing, PSGcleaning, PECVD coating, screen printing and firing, the PECVD coating which is forthe optical antireflection and electrical passiviation, plays an important role inimproving the cell electrical capability.This thesis is main about the PECVD coating and the related passivationtechnology, and main contents are as follows:At first, the conventional technology is researched, we study how the coatingtemperature, coating pressure, coating power and flow ratio of silane-ammoniainfluence the refraction and minority carriers life, these research make the foundationfor the next new coating and passivation technology research.Then a H-passivation technology using plasma ammonia is studied, we comparethe passivation before coating, the passivation after coating and other passivationparameters, improve the silicon wafer minority carriers life and other electricalparameters, and enhance the cell efficient for0.16%.Finally, the stack coating technology is studied. We research the double layersilicon nitride technology, decrease the reflection, improve the passivation and enhancethe efficient for0.13%, next the three-layer coating is studied, it has the similarpassivation and better anti-reflection capability less than600nm compared withdouble-layer, the more incoming light make the cell efficient be enhanced0.34%, at lastwe mix the ammonia passivation into three-layer coating, and adjust the PN junctiondoping, the efficient is enhanced for more than0.4%compared with conventionalsingle-layer coating.