The CIGS-Baseline is capable of manufacturing 30 x 30cm² Cu(In,Ga)Se2 PV-modules employing a sequential processing route. Starting with glass cleaning the 30 x 30cm² substrates are coated with a SiOxNy barrier layer followed by molybdenum (Mo) back contact doped with sodium (Na), both using magnetron sputtering technology. In case of module manufacturing a monolithically interconnection is employed; first P1 scribe-lines are created by laser ablation separating the Mo back contact. As next step the metal precursor layer (CuInGa) is deposited again using magnetron sputtering. To finish the stacked elemental precursor layer (SEL) selenium (Se) is coated onto of the metal layers by thermal evaporation in high vacuum. The formation of the chalcopyrite absorber layer is performed in a quartz-lamp heated rapid thermal processing (RTP) furnace. Afterwards the pn hetero-junction is formed by chemical bath deposition (CBD) of a cadmium-sulfide (CdS) buffer layer. Alternative Cd-free buffer layers such as zinc-oxid-sulfide (Zn(O,S)) could also be applied. Finally a transparent intrinsic-ZnO / aluminum doped ZnO (i-ZnO/AZO) bilayer front contact is deposited by magnetron sputtering. Additional interconnection scribe lines (P2,P3) are created after junction formation and front contact deposition either by mechanical scribing or laser ablation. To perform durability-tests of PV modules the active layers can be encapsulated to protected them from environmental impact. An overview poster of our CIGS baseline was presented at the 27. EUPVSEC in Frankfurt/Main, 2012.
Goal of this CIGS-baseline is providing a stable semi-industrial processing route as benchmark for new materials and processes. Currently we are testing new buffer layer deposition techniques and atmospheric pressure selenization processes.
Schematic description of the CIGS baseline process at PVcomB on 30 x 30 cm². Comprehensive analytics of processes, layers and devices are integrated along the whole production line.
Main components of the CIGS baseline
- Leybold Optics Vertical In-line Sputtering Tool (A600V7):
- SiOxNy barrier layer onto glass to prevent Na diffusion
- Mo /Mo:Na layer as back contact for CIGS based solar cells
- In / Cu:Ga as metal precursor layers for the sequential CIGS processing route
- High Vacuum Thermal Evaporation Chamber (BAK550):
- Deposition of Se precursor layer for the sequential CIGS processing route
- Rapid Thermal Processing furnace (RTP):
- Formation of the CIGS absorber layer with the sequential processing route (vacuum or N2 atmosphere)
- Atmospheric Pressure In-line RTP furnace (In-line RTP):
- Formation of the CIGS absorber layer in N2 atmosphere with additional elemental Se or S vapor flow (available in August 2013).
- No use of toxic gases such as H2S or H2Se.
- Chemical Bath Deposition of CdS buffer layer (CBD):
- Batch deposition (6 30x30cm² substrates) of CdS; if applicable selective etching of CuSex /CuS by KCN
- Alternative deposition techniques, such as ILGAR or ALD, of Cd-free buffer layers
- Von Adrenne Anlagentechnik Vertical In-line Sputtering Tool (VISS 300):
- Deposition of transparent conducting ZnO front contact layer
- Monolithic integration of 30x30cm² PV-module by laser or mechanical scribing
- Encapsulation of active layers to create a weather-resistant PV-module
- R&D projects to increase efficiency of sequentially processed CIGS solar cells / modules
- Benchmarking of alternative manufacturing methods (cross experiments)
- Test of novel deposition techniques of precursor, CIGS absorbers, buffer, contact layers employing the PVcomB CIGS-Baseline-Technology
- Optimizing of manufacturing processes
- Test of novel encapsulation materials / methods
Projects & collaborations
In frame of our CIGS activities we are collaborating with several partners from industry and research institutes.
Both public funded projects and bilateral alliances are used to push the CIGS technology and develop future solar module concepts.