PECVD of doped and intrinsic a-Si:H layers for solar cell structures using a (novel) inline deposition system

Industrial PECVD applications for solar cells require high deposition rates over large areas with film thickness uniformity better than 10%. By increasing the excitation frequency from the commonly used 13.56 MHz up to the VHF range, amorphous and microcrystalline silicon films exhibit high growth rates with quite presentable photoelectric properties. On the other hand, the increase of both the plasma frequency and processing area using a conventional PECVD system requires the application of an expensive technology to reduce a) the non-uniformity of the deposition rates and b) power losses within the power feeding system. In this paper we show, that by using a VHF linear plasma source in combination with moving substrates and an optimized power coupling system, the problems regarding power feeding and uniformity of a-Si:H film thickness on a 30 cm × 30 cm sample area can be controlled.