Thin film silicon PV: From R&D to large-area production equipment

In the first step, silicon deposition processes are developed and optimized in smaller R&D KAI™-M systems. Combined with our high quality in-house developed LPCVD (Low Pressure Chemical Vapor Deposition) ZnO stabilized record cell efficiencies of 10.09% have been realized for a single-junction amorphous silicon solar cell device and of 11.91% for a Micromorph (amorphous/microcrystalline silicon) tandem cell. Both stabilized efficiencies have been independently confirmed by NREL (Golden, USA) and represent record champion cells. In the next phase these process parameters are transferred to industrial size PECVD reactors of 1.4 m² (KAI™-1200) area. We achieved in R&D for 1.4 m² amorphous silicon p-i-n single-junction modules initial output powers of 139.1 W respectively 163 W for Micromorph tandems. The Micromorph module has been indoor light-soaked and resulted in a stabilized output power of remarkable 143 W corresponding to an overall stabilized module efficiency of 10.0%. For the a-Si:H p-i-n module we expect a module output power of 115.2 W after light-soaking based on our stability experience on small area modules. Both large area modules were manufactured using our in-house developed LPCVD TCO. At present Oerlikon customers produced in total more than 4.5 Mio modules (a-Si single-junction or Micromorph tandems) which all together correspond to a cumulated total power of at least 450 MW_p. Recently Oerlikon Solar introduced its new improved production fab concept, the so-called ThinFab™, which brings total module production costs down to remarkable 0.5 €/W_p at a 120 MW_p output capacity.