DEVELOPMENT OF CH4-RADIO-FREQUENCY-PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION METHOD WITH A POSITIVELY SELF-BIASED ELECTRODE FOR DIAMOND-LIKE CARBON-FILM

We developed a radio-frequency-plasma-enhanced chemical vapor depositi on (CVD) method with a positively self-biased electrode system. This m ethod enables simultaneous ion-assisted deposition on both sides of a vertically suspended substrate at a grounded electrical potential with one rf generator. In the positively self-biased electrode system, the cathode sheath is located close to the grounded electrode. Accordingl y, positive ions are accelerated toward the grounded electrode, produc ing an ion-assisted reaction on the surface of the substrate. The grou nded substrate is advantageous when transporting a substrate holder su spended vertically in an in-line multilayer deposition system. An impo rtant feature of this electrode is the electrical capacitance between the hollow anode chamber and time ground which is parallel to the shea th capacitance. Application of the electrode to tile deposition proces s of thin film magnetic recording disks in pure methane gas was invest igated. Diamond-like carbon (DLC) films were deposited at a rate of 3 nm/s on the magnetic layer, with uniform film thickness within +/-5% o ver a substrate measuring 95 mm in diameter. Analysis of this film sho wed that its characteristics are essentially the same as those of DLC film deposited by the conventional method using a cathode sheath on a high-voltage electrode.