In the 6 chamber deposition system amorphous and microcrystalline thin films can be prepared with the PECVD (Plasma Enhanced Chemical Vapour Deposition) technique. The system consists of 9 vakuum moduls, which are allocated in a 3x3 configuration. 6 of the 9 system’s moduls serve as process chambers; while the remaining 3 chambers serve for the means of transportation. The use of multi-chamber technology in the production of silicon thin film solar cells allows to minimise the problem of cross-contamination of the dopant gases into the sensitive intrinsic absorber layers. Thus the different layers can be developed and combined independently. This leads to a higher quality of each individual layer and an improved reproducibility, in comparison with single-chamber systems, can be achieved.
Each individual chamber of the system is dedicated to deposition of a particular type of silicon based films and alloys, which enables different structures (microcrystalline / amorphous) to be developed and tested in solar cells. The layers can be grown with various compositions of process gases and different plasma excitation frequencies, allowing a wide range of thin film materials to be produced. Additionally, doped layers with special functions, such as intermediate reflectors or window layers with an improved light coupling are being developed.
The system is computer-controlled and can be used in a manual mode or a fully automated regime during solar cell deposition, offering a considerable flexibility.
The 6 chamber deposition system with its robust and well-proven technology has been the “workhorse” of the IEF-5 in the development of VHF-PECVD processes, amorphous and microcrystalline silicon films, silicon-germanium alloys, and lately also silicon-oxide alloys. The system continuously delivers top level efficiencies on the highest international standard for single junction and tandem thin film solar cells.