A new mass production technology for high-efficiency thin-film CIS-absorber formation

Abstract

A new mass production technology for CIS-absorber formation yielding high-average module efficiencies is introduced. A novel custom-designed oven very successfully exploits the principle of forced convection during heating, CIS formation reaction, and cooling. Cu(In,Ga)(Se,S)2 absorbers are formed by metal precursor deposition on soda lime glass followed by reaction in selenium/sulfur atmosphere. Processing is performed in a multiple-chamber equipment which handles corrosive, flammable, and toxic process gases from atmospheric pressure to vacuum at high durability. The substrates (size: 50 cm × 120 cm) are processed in batches up to 102 substrates, applying forced convection for very homogenous heat transfer and high heating and cooling rates. Multiple-chamber design and batch size yield high throughput at cycle times above 1 h. This approach combines the specific advantages of batch type and inline processing. An excellent average efficiency of 14.3% with a narrow distribution (+/-0.31%) and a peak efficiency of 15.1% is shown with this technology. Module characteristic distributions during pilot production are presented. Detailed layer analytics is discussed. This straightforward reliable mass production technology is a key for highest module performance and for upscaling. Module efficiencies of 17% can be reached, enabling production costs below 0.38 US/Wp in a projected GWp plant. © 2011-2012 IEEE.