Atomic Layer Deposition of Al2O3, TiO2 and ZnO Films into High Aspect Ratio Pores

Atomic layer deposition (ALD) of aluminium, zinc and titanium oxides into high aspect ratio electrochemically etched pores is described. Macroporous silicon was fabricated by electrochemical etching. Aspect ratios of 50:1 were routinely obtained. commercial anodisc alumina pores were used for reference. ALD thin films Al₂O₃, TiO₂ and ZnO were deposited in the pores. The results were studied with scanning electron microscope (SEM). The layer thicknesses were close to the theoretical value calculated from the cycle number, indicating excellent conformality in high aspect ratio structures.