| Solar energy is one of the most valuable new energy resources, and crystalline solar cell is one of the most efficiency ways to take advantage of it. For low cost and high efficiency, the passivation technology is particularly important for crystalline solar cells.We first studied the correlation between the micro-structure and the passivation property of silicon nitride passivation film. Basis on this correlation, we did series research about how the thermal treatment affects the passivation property of silicon nitride film. We found that the fixed charge density in silicon nitride film drops first, then rises and then drops sharply with the rising of the annealing temperature. While the hydrogen content at the interface keeps stable at low temperature, then increase obviously, and then decrease sharply when annealing temperature is too high.400℃-450℃is the best annealing temperature. Anneal by this temperature will make both the fixed charge density in the film and the hydrogen content at the interface the highest, which leads to the best passivation property.The research about the silicon oxynitride shows that one can get the best passivation property for the silicon oxynitride film when the flow rate of N2O is30sccm, and under this condition, the composition of silicon oxynitride is Si-O2N2(75%) and Si-SiON2(25%). The existence of oxygen atoms makes the passivation property of silicon oxynitride film better than silicon nitride film. Thermal treatment can increase the fixed charge density in the film and decrease the interface state density and finally improve the passivation property of silicon oxynitride film.a-Si/SiNx stacked film has a better passivation property than amorphous silicon single film, this may owe to the hydrogen in silicon nitride film. With thermal treatment temperature rising, the passivation property of this stacked film is improved first and then reduced sharply.300℃is the best annealing temperature for getting the best passivation property. |
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