Zeitaufgelöste Mikroskopie und simulationsgestützte Analyse der Ablation dünner transparenter leitender Schichten mittels ultrakurzgepulster Laserstrahlung

The aim of this project is to develop a fundamental understanding of partial and indirectly induced laser ablation of transparent conductive layers using ultra-short pulse laser radiation applied to ITO (indium tin oxide). Partially and indirectly induced laser ablation are subtypes of confined laser ablation, in which an ultrafast laser pulse generates a stress confinement situation. The aim of the project is to develop a metamodel description based on simulations and experimental data. The selective use of laser-induced ablation separates or structures electrically conductive structures to create functional surfaces for components, such as the front electrodes of a light-emitting diode. Since the components often consist of several thin films with layer thicknesses in the range of a few tens of nanometres up to 100 nanometres, defects such as the formation of ridges at the edge of the ablation site can lead to short circuits and thus to failure of the component. To influence or even prevent such defects, a thorough understanding of the ablation process and the physical interactions involved is required. Experimental process observables will be studied to identify these mechanisms of action and the essential driving forces of the ablation process, as well as to guide the development of a mathematical-physical model. These observations describe both the dynamics of the process (transient observations) and the energy study (steady state measurement). The steady-state parameters determine the ablation criteria with respect to the quality of the ablated craters. Ultrafast time-resolved pump-probe microscopy experiments will shed light on the physical processes during laser ablation. This will provide crucial information for the development of the metamodel. The simulated and experimental results will be used for the iterative development of a metamodel. A metamodel is a computational look-up table for the continuous approximation of the relationship between parameters and criteria (process map). Compared to the analysis of data from single simulation runs or experiments, metamodels facilitate a global analysis of interpolated, arbitrarily dense data using rigorous mathematical methods. At the end of the project, the developed metamodel is expected to predict measurable and verifiable target variables, such as ridge heights, substrate damage, insulation resistances and crack lengths as a function of process parameters.