Low dielectric constant SiOC({single bond}H) films are deposited on p-type Si(100) substrates by plasma enhanced chemical vapor deposition (PECVD) using methyltriethoxysilane (MTES, C 7 H 18 O 3 Si) and oxygen gas as precursors. The SiOC({single bond}H) films are deposited at room temperature, 100, 200, 300 and 400 °C and then annealed at 100, 200, 300 and 400 °C temperatures for 30 min in vacuum. The influence of deposition temperature and annealing on SiOC({single bond}H) films are investigated. Film thickness and refractive index are measured by field emission scanning electron microscopy and ellipsometry, respectively. Chemical bonding characteristics of as-deposited and annealed films are investigated by Fourier transform infrared (FTIR) spectroscopy in the absorbance mode. As more carbon atoms are incorporated into the SiOC({single bond}H) films, both film density and refractive index are decreased due to nano pore structure of the film. In the SiOC({single bond}H) film, CH 3 group as an end group is introduced into {single bond}O{single bond}Si{single bond}O{single bond} network, thereby reducing the density to decrease the dielectric constant thereof. The dielectric constant of SiOC({single bond}H) film is evaluated by C-V measurements using metal-insulator-semiconductor (MIS), Al/SiOC({single bond}H)/p-Si structure and it is found to be as low as 2.2 for annealed samples deposited at 400 °C. © 2007 Elsevier B.V. All rights reserved.