Effect of Frequency and Power of Bias Applied to Substrate on Plasma Property of Very-High-Frequency Magnetron Sputtering

The effect of the frequency and power of the bias applied to the substrate on plasma properties in 60 MHz (VHF) magnetron sputtering was investigated. The plasma properties in- clude the ion velocity distribution function (IVDF), electron energy probability function (EEPF), electron density n e , ion flux Γ i , and effective electron temperature T eff . These parameters were measured by a retarding field energy analyzer and a Langmuir probe in the 60 MHz magnetron sputtering, assisted with 13.56 MHz or 27.12 MHz substrate bias. The 13.56 MHz substrate bias led to broadening and multi-peaks IVDFs, Maxwellian EEPFs, as well as high electron density, ion flux, and low electron temperature. The 27.12 MHz substrate bias led to a further increase of electron density and ion flux, but made the IVDFs narrow. Therefore, the frequency of the substrate bias was a possible way to control the plasma properties in VHF magnetron sputtering.