As predicted by Moore’s Law, the density of transistors on an integrated circuit approximately doubles every two years. Atomic Layer Deposition (ALD) has emerged as a process capable of depositing thin films with atomic precision and conformality across complex 3-D microstructures to keep up with the fast-paced advances in semiconductor device microstructures. The development of area-selective ALD (AS-ALD) allows for more precise film deposition on substrates as an advanced development in ALD technology. In this study, a custom-built vacuum reactor with a quartz crystal microbalance (QCM) was utilized to enable real-time monitoring of the deposition process. Additional ex-situ characterization methods X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) measurements, and spectroscopic ellipsometry (SE) were used. In the first part of this thesis, pristine ALD using trimethylaluminum (TMA) and an alternative Al precursor (BDMADA-Al) was studied. Based on previous research, water and tert-butanol were utilized as co-reactants. Comparable growth patterns, growth rate, density, roughness, and film composition indicate BDMADA-Al is a valid alternative of TMA. In the second part of this thesis, the blocking performance of the two blocking molecules, octadecyltrichlorosilane (ODTS) and dimethylamino-trimethylsilane (DMATMS), were studied. Findings from QCM, WCA, XPS indicated that ODTS consistently demonstrated excellent blocking performance under all tested conditions. In contrast, DMATMS failed to maintain effective blocking in certain situations. To address this, a new ABC reapplication recipe of DMATMS was developed. The repeated application of DMATMS throughout each cycle resulted in significant improvements in blocking performance under all conditions.