(262h) Functionalization of Silicon with Tunable Bilayered Molecular System for Subsequent Photopatterning and Phosphorus-Based Dopant Attachment

The ability to efficiently couple pattern-specific monolayers with dopants that demonstrate great structural variability is desired in the manufacturing of novel logic switching elements. In this study, we demonstrate a reliable protocol for the delivery of a phosphorus-based dopant onto functionalized silicon with precise spatial control at the microscale. This method relies on selective surface reactions which provide terminal functionalities that can be photochemically modified via UV-assisted contact printing between the modified surface and an elastomeric stamp inked with a molecular dopant. Spectroscopic measurements combined with high-resolution imaging microscopy was used to characterize the dopant attachment and patterning ability of this technique. Several notable features were observed in the resulting x-ray photoelectron spectroscopy (XPS) spectra that are indicative of the bonding behavior between dopant and monolayer including an increase in the atomic percentage of phosphorus on the silicon surface observed after photochemical printing. Scanning electron microscopy (SEM) analysis of the corresponding surface structures demonstrated high fidelity pattern transfer. The stability of the photopatterned surface in an ambient environment was also characterized using XPS and goniometry measurements, which demonstrated the high structural durability of the patterned surface across 72 hours of air exposure. Furthermore, an improved resistance to oxidation of the underlying silicon surface relative to unfunctionalized hydrogen-terminated silicon was also observed. Overall, this gentle approach to atomic precision surface processing has the potential to inform future development of next-generation devices in applications such as; quantum electronics, surface passivation techniques, nano-optics, and biosensors.