Plasma diagnostic studies of S bend filtered cathodic vacuum arc system for the deposition of tetrahedral amorphous carbon films

The plasma parameters obtained using Langmuir probe of the vacuum arc generated in the outer region of an S bend filtered cathodic vacuum arc system developed for the deposition of tetrahedral amorphous carbon (ta-C) film and also hydrogen and nitrogen incorporated ta-C films have been reported. The effects of varying arc current and the magnetic field have been studied on the plasma parameters of the vacuum arc used in depositing ta-C, ta-C:H and ta-C:N films at different hydrogen and nitrogen partial pressures. The values of ion-saturation current (I_is), electron temperature (T_e) and electron density (n_e) are found to be in the range 1.50×10^-7-2.63×10^-6 A, 1.90-2.29 eV and 3.6×10⁹-7.4×10^-6 cm^-3, respectively, of the vacuum arc generated for the deposition of as grown ta-C films. Hydrogen and nitrogen incorporation of the precursors are found to reduce the values of I_is, T_e and n_e of the arc generated. The presence of magnetic field is found to increase the values of I_is and n_e and reduce those of T_e in depositing as grown ta-C films whereas hydrogen and nitrogen incorporation of the precursors decrease the values of I_is and n_e and enhances those of T_e. The properties of ta-C film so grown are also briefly summarized and found to have some novel features.