Complementary Metal-Oxide-Semiconductor Compatible Deposition of Nanoscale Transition-Metal Nitride Thin Films for Plasmonic Applications

Transition-metal nitrides have received significant interest for use within plasrnonic and optoelectronic devices because of their tunability and environmental stability. However, the deposition temperature remains a significant barrier to widespread adoption through the integration of transition-metal nitrides as plasmonic materials within coinplementary metal oxide-semiconductor (CMOS) fabrication processes. Binary, ternary, and layered plasmonic transition-metal nitride thin films based on titanium and niobium nitride are deposited using high-power impulse magnetron sputtering (HIPIMS) technology. The increased plasma densities achieved in the HIPIMS process allow thin films with high plasmonic quality to be deposited at CMOS-compatible temperatures of less than 300 degrees C. Thin films are deposited on a range of industrially relex'ant substrates and display-tunable plasma frequencies in the ultraviolet to visible spectral ranges. Strain-mediated tunability is discovered in layered films compared to that in ternary films. The thin film quality, combined with the scalability of the deposition process, indicates that HIPIMS deposition of nitride films is an industrially viable technique and can pave the way toward the fabrication of next-generation plasmonic and optoelectronic devices.