The Effect of DC Pulse Frequency and Pulse-off Time on the Structure and Mechanical Properties of Chromium Nitride Deposited by Pulsed DC Reactive Magnetron Sputter Deposition

摘要

DC pulsed magnetron sputtering is now a widely used process for thin film deposition. Pulsed DC sputtering is known to produce high levels of energetic ion bombardment due to the fluctuations in plasma potential, which occur during the pulse off time. What is not well known, however, is how the ion fluxes change with pulse conditions. The fluxes of metal, neutral gas and reactive gas ions have been measured during the reactive deposition of chromium nitride using a type II unbalanced magnetron. These were found to vary significantly as a function of pulse repetition frequency. It was found that the main distribution of ions occurred at energies over 150 Ev even with no substrate bias and also the ratio of the flux of N_2 ions compared to Ar ions varied from ～ 3% to ～ 32% over the frequency range 50-350 kHz with fixed pulse off time. The effect of the different ion bombardment regimes on film microstructure and mechanical properties is also measured.