RF amplified magnetron source for efficient titanium nitride deposition

Amplified magnetron sources are used to increase the ionization ratio of the sputtered metallic species in a way to avoid shadowing effect during thin film deposition on complex substrates. An radio-frequency (RF) power supplied coil achieves the amplification of the magnetron plasma. In this paper, an amplified magnetron discharge in Ar–N2 mixtures for titanium nitride (TiN) deposition has been studied by energy-resolved mass spectrometry. The purpose of the work is to observe the influence of the RF coil power on the hysteresis phenomenon, the ion energy distributions and the species present in the plasma (mass spectra). Concerning the hysteresis, we observe that the metal–nitride transition shifts to higher values of the nitrogen partial mass flow in the amplified mode. The discharge voltage is also decreased when 500 W r.f. are injected into the plasma. Both these effects are attributed to an increased ion bombardment of the titanium target. The shape of the ion energy distribution function is also changed. Low energy shoulder, due to charge exchange reactions in the sheath, is observed for Ar+, N2+ and N+. Ti+ and N+ signals exhibit high-energy tail. The mass spectra have shown interesting results, the TiN+ molecular ion is present when the RF coil is on.