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Pushing thin-film deposition techniques beyond their conformality limits or towards strong gradients

Plasma enhanced chemical vapor deposition (PECVD) is gaining momentum in many areas, spanning from microelectronics (thin films in integrated circuits and memories) to biomedical applications (surface finishes for biosensors or implants). Higher integration in the case of microelectronics and sensing devices, as well as complex porous structures of implanted materials, pushes the technologies towards higher deposition conformality, enabling uniform coatings on 3D microstructures. PECVD cannot offer as high deposition uniformity as atomic layer deposition (ALD), but understanding the deposition mechanisms and using precursors that produce depositing species with low sticking coefficients can push the process towards high conformality. On the contrary, the knowledge gained about the processes can tune the deposition towards defined gradients in the film properties, an attractive approach for bottom-up structuring. The project will involve dedicated experiments with well-defined 3D microstructures to obtain information about the sticking coefficient of deposition species and the role of ions, as well as parallel tests of ALD conformality. The experiments should be supported by calculations, e.g., Monte Carlo or molecular dynamics simulations.