Plasma polymerized cyclohexane and ethylcyclohexane organic thin films were deposited on Si(100), glass and copper substrates at 25-100 degrees C by PECVD method. In this study, to compare electrical and electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 20-50 W and deposition temperature on both corrosion protection efficiency and electrical properties were mainly studied. We found that the corrosion protection efficiency (P-k) which is one of the important factors for corrosion protection in the interlayer dielectrics of microelectronic devices application, was increased as a function of RF power. The highest P-k value of the ethylcyclohexane and cyclohexane films grown at 50 W were 92.1% and 85.26%, respectively, indicating that the ethylcyclohexane have better corrosion protection ability due to relative high cross-linking. The impedance analyzer was utilized for the measurement of I-V curve for leakage current density. Determination from the electrical property measurements, the best leakage current density of a cyclohexane thin film was around 5.5 x 10(-12) A/cm(2) while that of ethylcyclohexane thin film is about 4.5 x 10(-12) A/cm(2). (c) 2005 Elsevier B.V. All rights reserved.