Low-resistivity and high-density molybdenum carbonitride films grown by plasma-enhanced atomic layer deposition

In this study, we successfully fabricated low-resistivity and high-density molybdenum carbonitride (MoCN) films through plasma-enhanced atomic layer deposition (PEALD) at relatively low temperatures of 200–250 °C. The conventional atomic layer deposition (C-ALD) process, which involved alternating pulses of a Mo precursor, bis(ethylbenzene)molybdenum (BEBMo), and NH₃ plasma, yielded nitrogen-rich (N-rich) MoCN films with relatively high resistivity ranging between 1835 and 2024 μΩ cm at a thickness of 7.7–16.8 nm and low density of 6.1 g/cm³. To improve the properties of MoCN films, we employed a modified ALD (M-ALD) process that involves BEBMo and NH₃ plasma pulses, followed by an additional H₂ plasma pulse step. An additional H₂ plasma pulse increased the carbon-to-nitrogen ratio (C/N), producing carbon-rich MoCN films in contrast to the N-rich films via the C-ALD process. Moreover, the as-deposited M-ALD-processed MoCN films demonstrated a significantly higher density of 8.56 g/cm³ than that of the C-ALD MoCN, and enhanced crystallinity. These enhancements are attributed to the densification effects of ion bombardment during the additional H₂ plasma pulse step. Consequently, the M-ALD-prepared MoCN films exhibited a significantly improved resistivity of 389–721 μΩ cm within the 5.7−20.9 nm thickness range, showcasing superior characteristics of the M-ALD-prepared MoCN films to those of previously reported ALD-based MoCN films.