Organic polymer thin films deposited on silicon and copper by plasma-enhanced chemical vapor deposition method and characterization of their electrochemical and optical properties

Polymer-like thin films have been deposited on glass, silicon, and copper substrates at a room temperature to 100 °C by the plasma-enhanced chemical vapor deposition method using cyclohexane (C₆H₁₂) as a precursor for analysis of these substrates electrochemical and optical characteristics. Cyclohexane was utilized as an organic precursor and hydrogen and Ar (argon) were used as a bubbler and carrier gases, respectively. In order to compare the difference between the corrosion-resistant and the optical properties of the plasma-polymerized organic thin films, conditions of various radio frequencies (rf) using 13.56 MHz power in the range of 20–50 W and deposition temperature were used. The optical and electrical properties of the as-grown plasma polymerized thin films were analyzed by Fourier transform infrared spectrophotometer, ultraviolet-visible spectroscopy, current–voltage, and capacitance-voltage curves. The corrosion-protective abilities of cyclohexane were also examined by ac impedance measurements in a 3.5 wt. % NaCl solution. 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-device application, was increased with increasing rf power. The highest P_k value of plasma-polymerized cyclohexane film was (85.26% at 50 W), atomic-force-microscope, and scanning electron microscopy showed that the polymer films with smooth surfaces and sharp interfaces could be grown under various deposition conditions.