Characteristics of radio-frequency magnetron sputtering with Ag target operated near the electron series resonance oscillation

The discharge and plasma characteristics of Ag magnetron sputtering discharge operated near the electron series resonance (ESR) oscillation, which was excited using the driving frequency of 27.12 MHz, was investigated. The imaginary part of impedance was found to undergo a transition from capacitive to inductive on varying radio-frequency (RF) power, and the conditions for the ESR excitation was satisfied. The current–voltage characteristic of discharge showed that the lower discharge voltage and higher current was an important feature of RF magnetron sputtering operated near the ESR oscillation, which was caused by the small impedance Z originated from the mutual compensation between the sheath capacitive reactance and the plasma inductive reactance. The higher electron temperature, ion flux density and ion energy as well as the moderate electron density were obtained. The interaction of higher energy ions on substrate surface improved the crystallographic quality of Ag films. Therefore, the 27.12 MHz magnetron sputtering operated near the ESR oscillation has better deposition characteristics than that of commercial 13.56 MHz RF magnetron sputtering.