The structural and dielectric properties of SiOx/a-C,F/SiOx multi-layer thin films deposited by microwave electron cyclotron resonance plasma method

Abstract SiO x /a-C,F/SiO x multi-layer films were prepared by microwave electron cyclotron resonance plasma method using SiH 4 (20% diluted by Ar) and O 2 , CHF 3 and CH 4 as precursor gases, respectively. The Fourier transform infrared (FTIR) absorption spectroscopy shows the typical C–F, CC, Si–O, and C–H configurations in the multi-layer films. Meanwhile, because of the “history effect” of the chamber wall rather than interface reaction between a-C,F film and SiO x film, a small amount of Si–C and Si–F components exists in the middle a-C,F film layer, which is confirmed by profile analysis of Auger electron spectroscopy. Furthermore, no obvious structural changes occur for SiO x /a-C,F/SiO x multi-layer films in the FTIR spectra after thermal annealing, while only 8% of increase in the film dielectric constant happens due to some expansion for the film thickness after 400 °C annealing. SiO x /a-C,F/SiO x sandwich structure might be regarded as one of the low- k dielectric candidates for interlayer dielectrics in ultra-large-scale integrated circuit.