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射频磁控溅射法制备a-Si:H薄膜,利用椭圆偏振光谱对不同气压下a-Si:H薄膜的厚度、折射率和消光系数进行了测试和研究。薄膜采用双层光学模型,通过Forouhi-Bloomer模型对椭圆偏振光谱参数进行拟合,获得450-850 nm光谱区域的a-Si:H薄膜光学参数值。结果表明,随着工作气压增加,薄膜厚度增厚,沉积速率升高;相同工作气压下,随偏振光波长增大,折射率呈下降趋势;相同波长偏振光下,折射率随工作气压上升而下降,折射率变化范围在3.5-4.1;消光系数随着工作气压增大呈略微增大的趋势。根据吸收系数与消光系数的关系,获得了薄膜的吸收谱,测算出不同工作气压下a-Si:H薄膜的光学带隙为1.63 eV-1.77 eV。
A-Si: H films were prepared by RF magnetron sputtering. The thickness, refractive index and extinction coefficient of a-Si: H films under different pressures were measured by ellipsometry. The double-layer optical model of the film was used to fit the parameters of the elliptical polarization spectrum by the Forouhi-Bloomer model to obtain the optical parameters of the a-Si: H film in the 450-850 nm spectral region. The results show that with the increase of working pressure, the thickness of the film increases and the deposition rate increases. Under the same working pressure, the refractive index decreases with the increase of the wavelength of polarized light. Under the same wavelength, the refractive index increases with the working pressure Drop, the refractive index changes in the range of 3.5-4.1; extinction coefficient slightly increased with increasing operating pressure trend. According to the relationship between absorption coefficient and extinction coefficient, the absorption spectrum of the film was obtained. The optical band gap of a-Si: H film was 1.63 eV-1.77 eV under different working pressures.