Properties of low-resistivity molybdenum metal thin film deposited by atomic layer deposition using MoO2Cl2 as precursor

Abstract

Challenges have arisen in selecting suitable candidates for interconnects and metal contacts due to the exponential increase in metal resistivity at scaled pitches. Molybdenum (Mo) has emerged as a promising alternative to the traditional metals such as copper or tungsten owing to its low electrical resistivity and electron mean free path. In this study, we investigated the formation of a molybdenum film grown by thermal atomic layer deposition (ALD) using a MoO2Cl2 solid precursor and H2 and NH3 gases as the reducing agents. A molybdenum nitride film served as the seed layer on a SiO2 substrate before molybdenum film deposition. The analysis focused on the film's phase, morphology, chemical bonding states, and resistivity across various thicknesses. X-ray diffraction (XRD) confirmed the presence of polycrystalline BCC planes. Our analyses confirmed the successful growth of the molybdenum metal thin film, which, at a thickness of 10 nm, exhibited a record-low resistivity of approximately 13 μΩ cm.