The project focuses on etching properties of the atomic layer deposition (ALD) of Al2O3. For this purpose, etching processes such as plasma etch with sulfur hexafluoride (SF6), gas etch with xenon difluoride (XeF2), wet etch with MIF developer (726 MIF) as well as ion beam etch (IBE) were performed. Then, the second part of the project focuses on the passivation properties of Al2O3 thin layers. An attempt to study the passivation of Al2O3 in contact with different liquids (distilled water, acetone, isopropanol) allows to understand more about the electrical modeling and the feasibility of such an approach.