| Popis: |
Amorphous silicon PV panel mass production will require to mas ter plasma chemical deposition in terms of large sizes, cost, maintenance and all other problems related to industrialization. Since plasma deposition is a novel technique, the development of all this production related know how involves a considerable technical research effort. The major problems related to the design of a production deposi tion machine are the following - deposition should be uniform on very large area substrate (typical dimension 1 meter) ; - the deposited amorphous silicon should have good electronic properties (density of state of the order or less than 16 3 10 cm /eV) and very low impurities concentrations (for exam ple oxygen atomic concentration should idealy be less than 0. 01%) ; - the film stress should be limited, the density of ponctual defects (particulates) should remain reasonable (less than 2 per 100 cm) ; - dopant level control should be stable and efficient ; - silane consumption should remain reasonably efficient - financial cost being important the machine productivity should be high hence deposition rate optimized ; - downtime due to maintenance should be reduced to a minimum. We present here some results on the R&D effort addressed to the above mentioned problems. An original single chamber was designed. This machine will be made available on the market for R&D purposes by a process machine company. Finally the maintenance problem is considered. Plasma cleaning based on a fluorine containing etchant gases is studied and evaluated. 2. |
