Residual stress in diamond-like carbon films: Role of growth conditions and ion irradiation

Abstract

The dependence of the internal residual stress in thin diamond-like carbon films grown by the plasma-enhanced chemical vapor deposition technique on the most important growth parameters, namely, the radio-frequency (RF) power and direct-current (DC) bias voltage, was studied. It was shown that the compressive stress reaches its highest value of 2.7 GPa at the low RF power and DC bias values. Both increase and decrease of these parameters result in stress decrease. The stress increases with increase in the growth temperature from 250 to 350°C. Thermal annealing of up to 350°C does not affect the stress value. Subsequent irradiation of the films by In + and P + ions with the energy of 350 and 120 keV, respectively, results in the decrease in the compressive stress followed by its inversion to the tensile one. The stress linearly depends on the effective dose of up to 0.5 DPA with the slope of (8.7 ± 1.3) Gpa/DPA.