The CIGS laboratory at SERIS focuses on the development of CIGS and CZTS thin-film solar cells and mini-modules. Employing a sequential two-stage processing route, the CIGS R&D pilot line at SERIS combines state-of-the-art industrial tools to prepare CIGS and CZTS absorbers on 30 cm × 30 cm glass substrates. The tools operate as stand-alone systems, providing full flexibility for process modifications and the realisation of novel device structures, which is not easily possible in fully integrated industrial production lines.
The CIGS R&D pilot line at SERIS currently consists of the following core tools:
The multi-chamber sputtering tool from FHR Anlagenbau, Germany, has two process chambers for state-of-the-art deposition of metals, transparent conductive oxides (TCOs) and dielectrics on substrates with a size of up to 30 cm × 40 cm. One chamber has three planar magnetron sources for DC sputtering of metals and dielectric layers. The other chamber has single and dual-magnetron rotatable-cylindrical sources equipped with pulsed DC sources for TCOs and dielectric layer deposition, with substrate heating up to 500ºC. While the machine is designed for developing coatings on glass substrates, it is also capable of depositing TCOs and metal films onto silicon wafers.
This in-line sputtering tool from FHR Anlagenbau, Germany, is dedicated for the deposition of Cu-Ga (CG), Cu-In-Ga (CIG), Cu-Zn-Sn and other precursors as well as ZnOS buffer layers onto glass and metal substrates with sizes of up to 30 cm x 40 cm. The system has three planar magnetron sources, whereby two sources are connected to a DC power supply for DC sputtering of metal layers while the third source is connected to an RF power supply for the deposition of ZnOS buffer layers. The substrates can be heated up to 200ºC.
The in-line RTP furnace from Smit Thermal Solutions, The Netherlands, is a state-of-the-art high-temperature furnace, working at atmospheric pressure conditions and using elemental Se and S to convert the metallic CIG precursor into the polycrystalline CIGS absorber (sample size: 30 cm × 30 cm). Unlike the conventional procedure, which requires toxic H2Se and H2S gases for forming CIGS, this in-line RTP furnace uses elemental Se and S for the CIGS absorber formation, providing significantly reduced production costs. The system has four hot zones, whereby three are dedicated for the Se process and the fourth is dedicated for the S process. The system is capable of uniformly heating a glass substrate to temperatures of up to 650ºC, without any breakage.
The wet-chemical coating system (wobbler) from Singulus Technologies AG, Germany, is used for depositing very thin and highly homogeneous buffer layers (such as CdS or ZnOS) onto CIGS absorber layers, to form the hetero-junction solar cells. The system is capable of handling glass substrates with sizes of up to 30 cm x 30 cm.
Unlike the conventional chemical bath deposition process, which requires several litres of chemicals, the wobbler requires small amounts of chemicals (200 ml) for the deposition of a buffer layer. It also offers a lot of flexibility with regards to changing the process recipes.
The hybrid scribing system (Model: MPV-LMM Series) from MDI, Japan, is used for P1, P2 and P3 pattering and preparing mini-modules of sizes ranging from 10 cm x 10 cm to 30 cm x 30 cm. This machine features both laser and mechanical scribing methods to prepare mini-modules and mimic the scribing processes commonly practiced in CIGS PV production. The system is equipped with a laser source for Mo metal scribing (P1 step) and two dedicated mechanical heads for CIGS (P2 step) and front TCO (P3 step) scribing. Both laser and mechanical scribe line widths can be varied from 30 to 60 µm. The system is capable of handling both glass and flexible substrates.
For further information, please contact:
Dr Selvaraj VENKATARAJ