椭偏透射法测量氢化非晶硅薄膜厚度和光学参数

针对多角度椭偏测量透明基片上薄膜厚度和光学参数时基片背面非相干反射光的影响问题，报道了利用椭偏透射谱测量等离子增强化学气相沉积法(PECVD)制备的a-Si:H薄膜厚度和光学参数的方法，分析了基片温度T_s和辉光放电前气体温度T_g的影响.研究表明，用椭偏透射法测量的a-Si:H薄膜厚度值与扫描电镜(SEM)测得的值相当，推导得到的光学参数与其他研究者得到的结果一致.该方法可用于生长在透明基片上的其他非晶或多晶薄膜. 关键词： 椭偏测量 透射法 光学参数 氢化非晶硅薄膜

Thickness and optical constant determination of hydrogenated amorphous silicon thin film from transmittance spectra of ellipsometer

To cope with the problem that the thickness and optical constants of thin film can not be measured accurately when deposited on a transparent substrate due to the incoherent reflected-light from the back-side of the substrate, a method is presented to determine the thickness and optical constants of hydrogenated amorphous silicon (a-Si:H) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) from the transmittance spectra of ellipsometer only. The influence of the substrate temperature (T_s) and the gas temperature (T_g) before glow discharge on the thickness and optical constants of a-Si:H thin films is analysed. The results show that the thickness of a-Si:H thin films determined by transmittance spectra agrees well with that measured by scanning electron microscopy (SEM). The optical constants of the films deduced from the transmittance spectra accord with the results obtained by other researchers. This method can be applied in deposition of amorphous or polycrystal thin films on transparent substrates.