Journal of large-scale research facilities, 2, A67 (2016) http://dx.doi.org/10.17815/jlsrf-2-84 Published: 18.04.2016 CISSY: A station for preparation and surface/ interface analysis of thin �lm materials and devices Helmholtz-Zentrum Berlin für Materialien und Energie * Instrument Scientists: - Dr. Iver Lauermann, Helmholtz-Zentrum Berlin für Materialien und Energie, phone: +49 30 8062-15694, - 42343, email: iver.lauermann@helmholtz-berlin.de - Alexander Steigert, Helmholtz-Zentrum Berlin für Materialien und Energie, phone: +49 30 8062-15692, email: alexander.steigert@helmholtz-berlin.de Abstract: The CISSY end station combines thin �lm deposition (sputtering, molecular beam epitaxy ambient-pressure methods) with surface and bulk-sensitive analysis (photo emission, x-ray emission, x-ray absorption) in the same UHV system, allowing fast and contamination–free transfer between deposition and analysis. It is mainly used for the fabrication and characterization of thin �lm devices and their components like thin �lm photovoltaic cells, water-splitting devices and other functional thin �lm materials. 1 Introduction The experimental CISSY setup was constructed for the surface and interface analysis of chalcopyrite Cu(In1−xGax)(SySe)2 “CIGSSe”, or “CIS” thin-�lm solar cells, operable as laboratory surface analysis system using commercial x-ray and UV sources or as beamline end station at the BESSY II synchrotron facility. The station name was derived from CIS and SYnchrotron. It houses an XES-300 (Scienta Gam- madata) x-ray spectrometer for x-ray emission (XES) and a CLAM 4 (VG) electron analyzer for photoe- mission (PES) spectroscopy. These techniques deliver information about the chemical and electronic sample structure on a complementary depth scale. With probing depths up to half a micrometer, XES provides information of the near-surface sample bulk. PES in contrast only probes the �rst monolayers of a sample and hence is very surface sensitive. Using the integrated output signals of either of the two spectrometers, x-ray absorption spectroscopy (XAS) in electron or photon yield modes, respectively, *Cite article as: Helmholtz-Zentrum Berlin für Materialien und Energie. (2016). CISSY: A station for prepara- tion and surface/ interface analysis of thin �lm materials and devices. Journal of large-scale research facilities, 2, A67. http://dx.doi.org/10.17815/jlsrf-2-84 1 http://jlsrf.org/ http://dx.doi.org/10.17815/jlsrf-2-84 http://dx.doi.org/10.17815/jlsrf-2-84 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 2, A67 (2016) http://dx.doi.org/10.17815/jlsrf-2-84 can be performed. The special feature of the CISSY setup is the unique combination of these spectroscopies with in-system sputter and ambient pressure preparation capabilities for thin �lms. In the CISSY end station, some of the crucial steps of the preparation of thin �lm solar cells and other thin �lm devices can be performed in-system, allowing the direct transfer from preparation to the analysis chamber, avoiding contamina- tion. Industrial thin �lm preparation methods like magnetron sputtering (for transparent conductive oxydes) or the Ion Layer gas reaction (ILGAR) process, as well as various wet chemical deposition meth- ods (for extremely thin bu�er layers, e.g between solar absorbers and selective contacts) are available. A physical vapor deposition (PVD) chamber equipped with molecular beam epitaxy (MBE) sources and metal dispensers allows the deposition of thin �lms of various materials. Surface photovoltage (SPV) of device components can be measured under UHV in an additional chamber either spectrally resolved or, using a laser diode, in the time resolved mode. Furthermore, a programmable sample manipulator enables laterally resolved measurements (with the resolution limited by the excitation spot) or measurements on the constantly moved sample, thus re- ducing damage of radiation sensitive material, e.g. organics. This arrangement allows for the charac- terization of real-world sample surfaces and interfaces prepared under controlled conditions such as vacuum or inert gas. Figure 1: View of the CISSY station in the laboratory (glove box partly visible on the right side). 2 Instrument application • Analysis of surface and near surface elemental composition by soft x-ray PES (conductive solid inorganic or organic materials) • Determination of surface chemistry (oxidation states) • Analysis of band line-up in semiconductor multilayers • Bulk analysis by XAS and XES • Determination of surface photo voltage • In-system preparation of thin layers (currently oxides, sul�des, alkali metals and alkali �uorides) 2 http://dx.doi.org/10.17815/jlsrf-2-84 https://creativecommons.org/licenses/by/4.0/ http://dx.doi.org/10.17815/jlsrf-2-84 Journal of large-scale research facilities, 2, A67 (2016) 3 Technical Data Monochromator Flexible Experiment in vacuum Yes Temperature range 100-600 K Detector CLAM 4 hemispherical electron analyzer, XES-300 x-ray spectrometer Manipulators PINK x,y,z, rotation, tilt, heating with resistive heater and cooling with liquid N2, sample current measurement, application of sample bias, thermo- couple Preparation Wet chemistry in glove box, sputter-deposition of oxides, sul�des and other compounds, MBE for metals and compounds, sputter cleaning Table 1: Technical parameters for the CISSY chamber. References Caballero, R., Nichterwitz, M., Steigert, A., Eicke, A., Lauermann, I., Schock, H., & Kauf- mann, C. (2014). Impact of Na on MoSe2 formation at the CIGSe/Mo interface in thin- �lm solar cells on polyimide foil at low process temperatures. Acta Materialia, 63, 54 - 62. http://dx.doi.org/10.1016/j.actamat.2013.09.051 Fu, Y., Sáez-Araoz, R., Köhler, T., Krüger, M., Steigert, A., Lauermann, I., . . . Fischer, C.- H. (2013). Spray-ILGAR ZnS nanodots/In2S3 as defect passivation/point contact bilayer bu�er for Cu(In,Ga)(S,Se)2 solar cells. Solar Energy Materials and Solar Cells, 117, 293 - 299. http://dx.doi.org/10.1016/j.solmat.2013.06.007 Johnson, B., Klaer, J., Merdes, S., Gorgoi, M., Höpfner, B., Vollmer, A., & Lauermann, I. (2013). Lim- itations of near edge x-ray absorption �ne structure as a tool for observing conduction bands in chalcopyrite solar cell heterojunctions. Journal of Electron Spectroscopy and Related Phenomena, 190, Part A, 42 - 46. http://dx.doi.org/10.1016/j.elspec.2013.01.007 Merdes, S., Malinen, V., Ziem, F., Lauermann, I., Schüle, M., Stober, F., . . . Schlatmann, R. (2014). Zn(O,S) bu�er prepared by atomic layer deposition for sequentially grown Cu(In,Ga)(Se,S)2 solar cells and modules. Solar Energy Materials and Solar Cells, 126, 120 - 124. http://dx.doi.org/10.1016/j.solmat.2014.03.044 Muydinov, R., Steigert, A., Schönau, S., Ruske, F., Kraehnert, R., Eckhardt, B., . . . Szyszka, B. (2015). Water-assisted nitrogen mediated crystallisation of ZnO �lms. Thin Solid Films, 590, 177 - 183. http://dx.doi.org/10.1016/j.tsf.2015.07.034 Neuschitzer, M., Sanchez, Y., Olar, T., Thersle�, T., Lopez-Marino, S., Oliva, F., . . . Saucedo, E. (2015). Complex surface chemistry of kesterites: Cu/Zn reordering after low temperature postdeposition annealing and its role in high performance devices. Chemistry of Materials, 27(15), 5279-5287. http://dx.doi.org/10.1021/acs.chemmater.5b01473 Pistor, P., Greiner, D., Kaufmann, C. A., Brunken, S., Gorgoi, M., Steigert, A., . . . Lux-Steiner, M.-C. (2014). Experimental indication for band gap widening of chalcopyrite solar cell absorbers after potassium �uoride treatment. Applied Physics Letters, 105(6). http://dx.doi.org/10.1063/1.4892882 3 http://dx.doi.org/10.17815/jlsrf-2-84 http://dx.doi.org/10.1016/j.actamat.2013.09.051 http://dx.doi.org/10.1016/j.solmat.2013.06.007 http://dx.doi.org/10.1016/j.elspec.2013.01.007 http://dx.doi.org/10.1016/j.solmat.2014.03.044 http://dx.doi.org/10.1016/j.tsf.2015.07.034 http://dx.doi.org/10.1021/acs.chemmater.5b01473 http://dx.doi.org/10.1063/1.4892882 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 2, A67 (2016) http://dx.doi.org/10.17815/jlsrf-2-84 Sarmiento-Pérez, R., Botti, S., Schnohr, C. S., Lauermann, I., Rubio, A., & Johnson, B. (2014). Local versus global electronic properties of chalcopyrite alloys: X-ray absorption spectroscopy and ab initio calculations. Journal of Applied Physics, 116(9). http://dx.doi.org/10.1063/1.4893579 4 http://dx.doi.org/10.17815/jlsrf-2-84 http://dx.doi.org/10.1063/1.4893579 https://creativecommons.org/licenses/by/4.0/ Introduction Instrument application Technical Data