Low-dielectric-constant SiOC(-H) thin films were prepared on p-type Si(100) substrates by using plasma-enhanced chemical-vapor deposition (PECVD) with triethoxysilane (TES; C6H16O3Si) and oxygen gas as precursors and Ar as a carrier gas. The effects of the radio-frequency (rf) power on the structural and the electrical properties were studied. The films were analyzed by using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron (XPS) spectroscopy and I-V and C-V measurements. FTIR studies were carried out in the absorbance mode in the range of 700 to 4000 cm-1, which showed various bonding configurations, such as Si-O-Si(C), Si-CH 3, -OH and CHn bonds, in the films. The dielectric constants of the SiOC(-H) films were investigated using a metal-insulator- semiconductor [MIS, Al/SiOC(-H)/p-Si(100)] structure at a frequency of 1 MHz.