Deposition of a-Si:H devices in a RTR system for photovoltaic and macroelectronic applications

This work presents first results of potential manufacturing processes for integrated series connected hydrogenated amorphous silicon (a-Si:H) thin film solar modules and/or pin-diode/TFT based macroelectronic circuits on flexible tapes. A RTR (Reel-To-Reel) deposition system on laboratory scale has been built. The system consists of seven metal sealed UHV stainless steel chambers to obtain ultra high vacuum as a basis for high quality a-Si:H layers. In order to support continuous movement of the tape in the RTR process the chambers cannot be isolated from each other. The necessary pressure difference between the sputtering chambers and the PECVD (Plasma Enhanced Chemical Vapor Deposition) chambers is provided by pressure stages. They are optimized for high molecular flow resistance without any influence on the moving substrate tape. The back metal contacts and the semitransparent TCO (Transparent Conductive Oxide) contacts are deposited by rf magnetron sputtering, the a-Si:H film system is deposited by PECVD. Parallel to the film deposition a Nd:YAG laser patterning system is coupled into one chamber. This allows for instance a total manufacturing of integrated series connected solar modules in one system without breaking the vacuum. The present investigations focus on the deposition of doped and intrinsic high quality a-Si:H based layersmore » in neighboring chambers. The quality of semiconducting films deposited in adjacent chambers is studied with regard to potential contamination effects.« less