Ultralow-Resistivity Molybdenum-Carbide Thin Films Deposited by Plasma-Enhanced Atomic Layer Deposition Using a Cyclopentadienyl-Based Precursor

Abstract

As memory devices become ultraminiaturized, the increase in the resistance of the metal line due to the decrease in the line width has become a very critical issue. Mo-based materials have been studied as candidates for next-generation metal line materials because of their low resistivity at low thickness and excellent oxidation resistance. However, the development of precursors suitable for vapor deposition methods (such as atomic layer deposition) is immature. In this study, we propose an ultralow-resistivity MoCx thin film using a cyclopentadienyl-based precursor as a new metal line candidate. Using a halogen-free liquid precursor, MoCx thin films were successfully deposited by plasma-enhanced atomic layer deposition (PEALD) in a wide process window of 200-300 degrees C. We confirmed that uniform and continuous films were deposited on the SiO2 substrates without any significant incubation period. The most important result of this study is that as-deposited MoCx thin films exhibited an ultralow resistivity of 8-20 mu Omega.cm, and such ultralow resistivity was maintained even with a thickness as thin as 4.25 nm and after rapid thermal annealing up to 600 degrees C. This is the lowest resistivity value of the reported metal line candidate materials available at the sub-10 nm device scale level. The ultralow resistivity at a very thin thickness and excellent thermal stability suggest the possibility that the MoCx thin films proposed in this study can be applied in various applications as a next-generation metal line material in the semiconductor industry.