A unique co-evaporation scheme to form complex HTS-coatings
In the beginning 90s we developed a unique co-evaporation scheme at the Technical University of Munich. It allows high vacuum deposition of complex HTS-films (e.g. YBa2Cu3O7) and became the cornerstone for THEVA. Due to its superior efficiency in coating large wafers it became the preferred commercial production technique.
The different metals are evaporated simultaneously from individual sources in a vacuum chamber. Rate monitors control the metal deposition rates to guarantee the desired film composition.
The crucial trick, however, is the oxygen supply through a pocket, which retains the scarce oxygen to enable strong scattering and effective oxidation.
Rapid movement exposes the substrate alternately to the metal vapor and to the reactive oxygen ambient, so that the desired metal oxide is formed (cyclic deposition and reaction).
The following video clip illustrates the film fabrication process.
