Low-k silicon carbonitride (SiCxNy) films with k of 3.6-4.6 were prepared by radio frequency plasma-enhanced chemical vapor deposition at 25 to 400 degrees C under low power density of 0.15 W/cm(3), using a single source precursor, 1, 3, 5-trimethyl-1,3,5-trivinylcyclotrisilazane (VSZ), and Ar. At lower deposition temperatures (<= 200 degrees C), most cyclic VSZ structures were preserved in the SiCxNy films, resulting in a lower density (1.60-1.76 g/cm(3)), a lower dielectric constant (k similar to 3.6-3.9) and a fairly good elastic modulus of 22.0-25.0 GPa. When the deposition temperature was raised to 400 degrees C, the cyclic N-Si-N linkages were reformed to a dense Si-N structure, with the desorption of CHx bonds, resulting in higher density (2.0 g/cm(3)), a dielectric constant of 4.6, and an excellent elastic modulus of 65.2 GPa. The leakage current density of SiCxNy films was reduced from 1.5x10(-6) to 4.0x10(-8) A/cm(2) at 1 MV/cm, upon increasing the deposition temperature from 25 degrees C to 400 degrees C. The conduction mechanism of the SiCxNy films, except the film deposited at 400 degrees C and tested under higher electric field, exhibited Schottky emission due to few charged defects by using a cyclic VSZ precursor and a lower plasma power density of 0.15 W/cm(3). (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.085205jes] All rights reserved.