DIELECTRIC PROPERTIES OF NICKEL CONTAINING HYDROGENATED AMORPHOUS CARBON FILMS PREPARED BY MICROWAVE PLASMA-ASSISTED DEPOSITION TECHNIQUE

Nickel/hydrogenated amorphous carbon (a-C:H) composite films have been deposited at room temperature on nickel coated (100)-oriented single crystal silicon substrates by combining sputter-deposition of metal and microwave plasma-assisted chemical vapor deposition of carbon from argon-methane mixtures of various concentrations. The sputtering power was varied from 0 W to 45 W. The films have been deposited on either grounded substrates or substrates biased to - 10 V. The dielectric properties of films were investigated as functions of the frequency and temperature varying from 0.1 Hz to 1 MHz and from -150 deg C to 175 deg C, respectively. Pure a-C:H films exhibited a dielectric constant of 2.6 at a wide range of frequency. For Ni/a-C:H composite films of 360 nm in thickness containing 19% of nickel the dielectric constant at a frequency of 1 Hz was higher than 300. The value of the dielectric constant of these composite films was observed to decrease from above 300 to 200 as the frequency increased from 1 Hz to 10 kHz. The effect of temperature and frequency as well as nickel content in the films on the dielectric properties is discussed.