Effect of energetic particles on the residual stresses in nonhydrogenated amorphous carbon films deposited on grounded substrates by dc magnetron sputtering

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Abstract
Amorphous carbon (a-C) films have been deposited on grounded silicon substrates by magnetron sputtering from a graphite target in pure argon discharges. The characteristics of the magnetron discharge were determined by Langmuir probe measurements as functions of the argon pressure and sputtering power. The flux and energy of argon ions impinging on the grounded substrates were deduced from Langmuir grid probe measurements. The flux of carbon atoms condensed on Si substrates was obtained from Rutherford backscattering spectroscopy measurements. The residual stresses in a-C films were found to be dependent on the argon pressure. The average kinetic energy of carbon atoms ejected from the target was determined from the energy distribution calculated from the model proposed by Thompson. The kinetic energy of carbon atoms condensed on the film surface was determined on the basis of calculation developed from the kinetic gas theory. The intensity of the intrinsic stress developed in a-C films was correlated to the flux and energy of neutral carbon atoms and argon ions impinging on the surface of growing films. The dependence of the intrinsic stress on the energetics of the deposition process matched the prediction deduced from the model of Windischmann.