Atomic layer deposition (ALD) is an important thin film deposition technique which enables scientists to deposit highly conformal films and control film thickness at angstrom level. Contrary to conventional semiconductor processing, ALD is a bottom-up process. Since multiple lithography and etching are not used, edge placement error is eliminated, and energy consumption can be reduced. Due to these great advantages, ALD can be potentially applied in next-generation device fabrication. In this research, a custom-built quartz crystal microbalance (QCM) was used to study ALD and areaselective ALD (AS-ALD).A novel aluminum precursor and Tris(dimethylamino)cyclopentadienylZirconium (ZyALD) were investigated by using the QCM system. Temperature windows were studied, and pristine ALD recipes were developed. Additionally, both precursors were studied in AS-ALD via competitive adsorption or using small blocking molecules. To suppress the growth of aluminum precursor on the non-growth surface, co-adsorbate was applied to compete with the novel aluminum precursor for available binding sites. Additionally, a silane blocking molecule was introduced to passivate the non-growth surface so that the ALD growth of ZyALD was attenuated.