Effect on optical properties and electrical performances of antireflective coating with gradient refractive index based on p-type amorphous SiOx thin films

The electrical performances and optical properties of p-type amorphous silicon oxide (p-SiOx) thin films with gradient refractive index are studied. The composite thin films as antireflective coatings (ARCs) are widely used in solar cells and microelectronic devices. The double-layer p-SiOx thin films are deposited by plasma-enhanced chemical vapor deposition (PECVD) system. To obtain better optical properties, the refractive index of ARCs can be adjusted by SiH4 to N2O ratio. And the electrical performances of composite thin films can be improved by adjustment of B2H6 to SiH4 ratio. The computational model is built to predict the optimized range of reflection spectra corresponding to structure of p-SiOx ARCs with gradient refractive index by finite difference time domain (FDTD) method. It shows the difference of reflection spectra with gradient refractive index distribution. The optimized reflection spectra simulated by FDTD method confirms to agree well with that measured by UV-visible spectroscopy.