Effect of Si–OH group on characteristics of SiCOH films prepared by decamethylcyclopentasiloxane electron cyclotron resonance plasma

Abstract

This paper investigates the effect of Si–OH group on dielectric property and leakage current of the SiCOH low dielectric constant films deposited by decamethylcyclopentasiloxane electron cyclotron resonance plasma. The results show that the increasing of Si–OH content in the films can lead to the increasing of dielectric constant k, decreasing of leakage current and stronger dielectric dispersion. Due to the strong polarization of Si–OH group, it leads to the increase of k value of the SiCOH films. The decreasing of leakage current at high Si–OH content is due to the low connecting probability p of networks because the networks break at the terminal Si–OH groups. At the case of high ionization degree of precursor, more Si–OH groups break and form Si–O–Si linkages by condensation chemistry occurring between proximal Si–OH groups. As a result, the k value of SiCOH films can be further reduced.