Samsung Advanced Institute of Technology

Most of works on area-selective atomic layer deposition (AS-ALD) technique up to now is based on controlling promoting or blocking of precursor molecules on “heterogenous” surfaces consisting of different materials (patterns). Herein, we suggests a new concept of AS-ALD on “homogeneous” surface consisting on a single material. “Heterogeneous” AS-ALD significantly relies on the termination of surface and material system, which would hinder wide application of AS-ALD in next generation device fabrication. To distinguish surface speices before AS-ALD, the homogenous substrate of ZrO₂ films is selectively fluorized by using sulfur hexafluoride (SF₆) gas. SF₆ molecules are decomposed and incorporate oxygen vacancies of ZrO₂, in turn, leading to F-terminated Zr surface on the grain boundaries (GBs). In contrast, at the following step, the remaining area of ZrO₂ surface (mainly hydroxyl group) is covered by the inhibitor of cyclopentadienyl tris(dimethylamino) zirconium (ZAC; ZrCp(NMe₃)₃) for blocking the adsorption of aluminum precursors; trimethylaluminum (TMA; Al(CH₃)₃) and dimethylaluminum isopropoxide (DMAI; (CH₃)₂AlOCH(CH₃)₂). We elucidate surface reaction mechanism by theoretical calculations together with experimental results. Density functional theory (DFT) and Monte Carlo (MC) simulations show that the surface of ZrO₂ is selectively passivated with fluorine, leading to selective the adsorption of ZAC inhibitors. Regarding Al precursor blocking by a ZAC inhibitor, the larger size of DMAI than TMA results in more reduction of Al incorporation. Device performance with AS-ALD shows a significant improvement in the dielectric constants by 30% while maintaining a similar level of leakage current density. These findings provide a fundamental basic knowledge for AS-ALD on homogeonous surface and highlight the potential offering a promising approach for next-generation electronic devices by enhancing dielectric properties and effectively managing leakage currents.