Low-dielectric constant SiOC(-H) films were deposited on p-type Si(100) substrates by plasma-enhanced chemical-vapor deposition (PECVD) using dimethyldimethoxy silane (DMDMS, C(4)H(12)O(2)Si) and oxygen gas as precursors. To improve the physicochemical properties of the SiOC(-H) films, the deposited SiOC(- H) films were exposed to ultraviolet (UV) irradiation in a vacuum. The bonding structure of the SiOC(-H) films was investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrical characterization of SiOC(- H) films were carried out through I-V measurements using the comb-like patterns of the TiN/Al/Ti/SiOC(H)/TiN/Al/Ti metal-insulator-metal (MIM) structure. Excessive UV treatment adversely affected the SiOC(-H) film, which resulted in an increased dielectric constant. Our results provide insight into the UV irradiation of low-k SiOC(-H) films. (C) 2011 Elsevier B.V. All rights reserved.