Low‐Temperature Dual‐Material Area‐Selective Deposition: Molybdenum Hexafluoride‐Mediated SiO₂ Fluorination/Passivation for Self‐Aligned Molybdenum/Metal Oxide Nanoribbons

Abstract

Area‐selective deposition (ASD) is a forefront nanopatterning technique gaining substantial attention in the semiconductor industry. While current research primarily addresses single‐material ASD, exploring multi‐material ASD is essential for mitigating complexity in advanced nanopatterning. This study describes molybdenum hexafluoride (MoF6)‐mediated fluorination/passivation of the hydroxylated SiO2 (SiO2‒OH) at 250 °C as a new method to pacify nucleation during subsequent ZnO and TiO2 atomic layer deposition (ALD). In contrast, Al2O3 ALD is not passivated on the fluorinated SiO2 (SiO2‒F). The study further shows that Mo ALD using MoF6 and silane (1 wt% SiH4 in Ar) selectively proceeds on hydrogen‐terminated Si (Si‒H), whereas SiO2‒OH becomes fluorine‐passivated without observable Mo deposition. This enables subsequent ZnO and TiO2 ASD on Mo versus SiO2‒F, as confirmed by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM). Proposed growth and inhibition mechanisms highlight the importance of the metal oxide precursor in achieving selectivity. Taken together, self‐aligned Mo/ZnO and Mo/TiO2 nanoribbons are demonstrated on coplanar nanoscale Si‒H/SiO2‒OH patterns by sequentially integrating two individual ASD processes: 1) Mo ASD on Si‒H versus SiO2‒OH; and 2) ZnO or TiO2 ASD on Mo versus SiO2‒F. This work highlights the potential for this approach in new ASD systems.