Granular metals with SiN _x dielectrics

Abstract Understanding and controlling nanoscale interface phenomena, such as band bending and secondary phase formation, is crucial for electronic device optimization. In granular metal (GM) studies, where metal nanoparticles are embedded in an insulating matrix, the importance of interface phenomena is frequently neglected. We demonstrate that GMs can serve as an exemplar system for evaluating the role of secondary phases at interfaces through a combination of x-ray photoemission spectroscopy (XPS) and electrical transport studies. We investigated SiN _x as an alternative to more commonly used oxide-insulators, as SiN _x -based GMs may enable high temperature applications when paired with refractory metals. Comparing Co-SiN _x and Mo-SiN _x GMs, we found that, in the tunneling-dominated insulating regime, Mo-SiN _x had reduced metal-silicide formation and orders-of-magnitude lower conductivity. XPS measurements indicate that metal-silicide and metal-nitride formation are mitigatable concerns in Mo-SiN _x . Given the metal-oxide formation seen in other GMs, SiN _x is an appealing alternative for metals that readily oxidize. Furthermore, SiN _x provides a path to metal-nitride nanostructures, potentially useful for various applications in plasmonics, optics, and sensing.