The commercial‐scale processing potential for photovoltaic devices based on polycrystalline and amorphous silicon thin films is evaluated by analyzing in detail the semiconductor deposition process for the following material layers: (CdZn)S/CuInSe2, CdS/CdTe, (CdZn)S/Cu2S, and amorphous silicon. The current status of both laboratory‐scale and unit‐operations‐scale experiments is tabulated and the goals required for reasonable commercial‐scale production detailed. The costs of manufacture are estimated and it is shown that all thin‐film materials which have achieved 10% efficiency in the laboratory can be manufactured at a cost well below one dollar per watt, provided the manufacturing facilities can be designed to produce between 100 000 and 1 000 000 square meters per year. The critical thin‐film research areas are identified for each of the materials listed above.