We report on the influence of substrate temperature on SiOC(-H) thin films deposited on p-type Si(100) substrates by plasma enhanced chemical vapor deposition (PECVD) with dimethoxydimethylsilane (DMDMS) and oxygen gas as precursors. The films were deposited at various substrate temperatures with a radio frequency (rf) power of 500 W and working pressure of 700 mTorr. Fourier transform infrared (FTIR) spectroscopy was used in the absorbance mode over the range of 400 to 4000 cm-1 which showed the various bonding configurations such as Si-O-Si(C), Si-CH3,-OH, and CHn bonds in the SiOC(-H) films. The X-ray photoelectron spectroscopy (XPS) was used to study the binding energies of Si-C, SiO-C3, SiO2-C2, SiO3-C, Si-O2, C-C, C-H and C-O bonds in the SiOC(-H) films as a function of the substrate temperature. The dielectric constant of the SiOC(-H) films was measured using a metal insulator semiconductor (MIS, Al/SiOC(-H)/p-Si) structure at 1 MHz frequency. The lowest dielectric constant of the films deposited at room temperature was 2.22 and was achieved with DMDMS/O2 precursor. © 2007 Elsevier B.V. All rights reserved.