Silicon‐Film Product III is being developed into a low cost, stable device for large scale terrestrial power applications. The Product III structure is a thin (<100 &mgr;m) polycrystalline silicon layer on a non‐conductive supporting ceramic substrate as illustrated in Figure 1. The presence of the substrate allows cells to be isolated and interconnected monolithically. The long term goal for the product is over 18% conversion efficiency on areas greater than 1200 cm2. The high efficiency will be based on polycrystalline thin silicon incorporated into a light trapping structure with a passivated back surface. Short term goals are focused on the development of large area ceramics, a monolithic interconnection process, and fabricating 100 cm2solar cells.