Ion energy distributions and efficiency of sputtering process in HIPIMS system

High-power impulse magnetron sputter deposition of metallic films was investigated. Time-averaged mass spectroscopy was performed to provide information on the energy distribution of individual ions and the composition of total ion fluxes over a wide range of deposition conditions. Chromium and niobium targets were used, the repetition frequency was 50 Hz and 60 Hz, respectively, and argon pressures were 0.29 Pa and 2.7 Pa. The strong effect of the working gas pressure on the ion energy distribution was shown. For low pressure (0.29 Pa) the metal ion energy distribution reveals a significant high energy tail (up to 20 eV). It was also shown that the increase in the average pulse current results in a higher fraction of metal ions in the total ion flux. Argon ions were dominant over niobium ions, while chromium ions became dominant in the total ion flux onto the substrate at high values of target power loading. At a high pressure (2.7 Pa), the high energy tail of metal ion energy distribution became negligible. Film deposition experiments showed that the efficiency of the sputtering process and particle transport to the substrate decreased with increasing target power loading.