Characteristics of low-κ SiOC films deposited via atomic layer deposition

Highlight• SiOC thin films prepared by atomic layer deposition (ALD) with O₂, Ar, H₂ plasma. • O₂ plasma is unfavorable to incorporate carbon into SiOC films. • SiOC ALD deposited with Ar plasma showed low k but high leakage property. • H₂ plasma made SiOC ALD thin films with low k and low leakage property. The deposition of SiOC thin films via remote plasma atomic layer deposition was investigated. Octamethylcyclotetrasiloxane (OMCTS) and O₂, Ar, H₂ plasmas were respectively used as a precursor and reactants during the deposition process at 400 °C. Plasma and deposition temperatures had a significant effect on the physical and electrical characteristics of the films. When Ar and H₂ plasma was respectively used during the deposition process, films exhibited low dielectric constants while incorporating carbon; however, O₂ plasma yielded carbon free SiO₂ films. Low dielectric constants resulted in low film densities and the presence of carbon within the films. When Ar and H₂ plasma was used as the reactant gas, pores within the films with loose structures and SiC bonds served to lower the dielectric constant. As a result, Ar and H₂ plasma conditions exhibited low dielectric constants of 2.7 and 3.1 at 100 °C, respectively. Meanwhile, the presence of carbon and low film densities caused leakage paths within the films. X-ray photoelectron spectroscopy supported analyses demonstrating the bonding characteristics of Si, C, O components.