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The application of Perovskite Technology in Photovoltaics will require the transformation from laboratory research to pilot or industrial production. Numerous materials within the PVSK cell stack are shown to be compatible with thermal vacuum evaporation processes. However upscaling under industrial conditions often introduces challenges to adapt to a certain process or material. Thermal evaporation is already shown for several candidates on laboratory level and the potential for upscaling to industrial production is acknowledged. Linear evaporators of Von Ardenne are actively involved in this progress [1]. We would like to give an overview on the actual state of this component. This update considers stable operation under or close to industrial conditions as well as results on new materials like the inorganic PVSK precursors.

The basic design of a linear evaporator is illustrated in figure1. It is quite different from a point source and consists of:

• a crucible comprising the evaporation material
• a vapor guiding tube with
• the vapor emitting nozzles
• a rate nozzle serving as vapor source for a Quartz Crystal Microbalance (QCM) and
• a substrate shutter

The QCM is used for deposition rate monitoring. The heating system of linear evaporator can be operated in power, temperature (measured by attached thermocouples) or rate controlled mode. Reproducibility and process stability are realized by a Programmable Logic Controller (PLC). Since halogens are known to be corrosive, crucible and nozzle tube are manufactured from inert material.

During operation, crucible and tube are heated up and the material to be coated starts to sublimate or evaporate. The vapor is guided along the nozzle tube and emitted via the nozzles to the substrate, which is moving across the line of nozzles. This principle allows for a bottom-up as well as top-down coating geometry, the latter being impossible for a point source. Moreover, even arrangements for coevaporation of up to four materials are possible. Each linear evaporator is equipped with a shutter in front of the nozzles. Shutters are useful to protect the surrounding chamber parts from undesired coating during heating up, conditioning/soaking or in standby mode. Another application is the on/off switching of the vapor stream to easily realize different film compositions in coevaporation mode.

The linear evaporators can be operated a temperatures up to 700 °C. An adjusted configuration for temperatures 100°C to 250°C is also available. This temperature range covers a wide range of materials used in PVSK and other technologies. A summary of the already evaporated materials is illustrated in figure 2. As expected, the dynamic deposition rates (DDR) increase exponentially with temperature, pointing out the importance of a precise temperature control.

The contribution will give an overview on possible arrangements (parallel and coevaporation units, bottom-up, top-down), challenges and solutions for stable operation as well as uniformity data for different materials.