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利用等离子增强化学气相沉积(PECVD)方法沉积了氮化硅薄膜,反应气体为氨气和硅烷。这些薄膜在不同条件(温度、时间和气氛)下进行了炉温或快速退火。对太阳电池而言,氮化硅薄膜不仅是有效的减反射层而且也有表面钝化和体钝化作用。利用椭圆偏振光谱、反射谱、红外吸收谱和准稳态光电导(QSSPC)分析了氮化硅薄膜的特性。实验发现随着退火温度的增加,氮化硅薄膜的厚度下降而折射率增加,可以归因于在退火过程中,薄膜愈加致密。红外吸收谱的研究发现,氮化硅中氢的含量在退火过程中有明显的下降,而QSSPC测量的样品寿命有同样的变化。这些结果显示氮化硅的钝化作用与其中的氢含量有关。
Silicon nitride films were deposited by plasma-enhanced chemical vapor deposition (PECVD) using ammonia and silane as reaction gases. These films were oven-temperature or rapid-annealed under different conditions (temperature, time and atmosphere). For solar cells, the silicon nitride film is not only an effective antireflection layer but also has surface passivation and body passivation. The properties of silicon nitride films were analyzed by ellipsometry, reflection spectra, infrared absorption spectra and quasi-stationary photoconductivity (QSSPC). The experimental results show that as the annealing temperature increases, the thickness of the silicon nitride film decreases while the refractive index increases, which can be attributed to the denser film during the annealing process. Infrared absorption spectroscopy study found that the hydrogen content of silicon nitride in the annealing process decreased significantly, while the life of the samples measured by the QSSPC the same change. These results show that the passivation of silicon nitride is related to the hydrogen content therein.