The characteristics of carbon-doped silicon oxide films with nano-pore structure deposited using UV-assisted PECVD

SiOC(–H) films with low dielectric constant were deposited on p-type Si(100) substrate using ultraviolet (UV)-source assisted plasma-enhanced chemical vapor deposition with a mixture of bis-trimethylsilylmethane (BTMSM: H9C3–Si–CH2–Si–C3H9) and oxygen gases. Fourier transform infrared spectroscopy was used to investigate the bonding configuration and relative carbon content of the SiOC(–H) films. UV illumination of the BTMSM/O2 plasma was used to control the plasma parameters and deposition properties. The addition of He gas to the mixture of BTMSM and O2 raised the electron density from 2.5 × 109 to 9.8 × 109 cm− 3. The lowest dielectric constant was 2.4, and was deposited using a mixture of BTMSM + O2 + He gases with UV illumination. The bonding structure of the SiOC(–H) composite film consists of distinct Si–O–Si and Si–O–C bonds, indicating the existence of caged Si–C bonds, and this enhances the porosity of the film. UV illumination increased the relative content of the ring link mode of the SiOC(–H) films.