In order to compete with established crystalline silicon technologies, thin-ยฎlm photovoltaics must achieve comparable performance with the promise of substantially lower cost. Low costs will only be achieved with manufacturing volumes of at least several MW p per year. Due to the high investment required for such a factory, there are a number of prerequisites that must be demonstrated to reduce the risk of this investment. The product requirements must be clearly identiยฎed, and are likely to be dictated by the existing silicon technologies. The process must be shown to be capable of producing a high-eciency, high-yield, stable product. Estimated manufacturing costs must be substantially lower than the costs projected for the crystalline silicon competition to justify the investment in an unproven technology. Once these prerequisites are satisยฎed, the increase in volume to a manufacturing scale remains a challenge due to the specialized nature of the equipment needed to perform these new processes. Nonetheless, many of these prerequisites have now been demonstrated and new thin-ยฎlm manufacturing facilities are being constructed.