Deposition of nickel films by TVA

Plasma diagnostic techniques are essential for understanding of process parameters. In plasma-assisted deposition, ion energy and deposition rate are key parameters for technological control. In this paper, a systematic study of the correlation of electrical parameters of plasma with ion energy distributions and deposition rate is presented. The deposition method used in this study is Thermionic Vacuum Arc (TVA) ignited in nickel vapors. The TVA deposition method briefly consists in obtaining of plasma in vapors of the material to be evaporated. The vapors are obtained by heating the material with thermoelectrons generated by an externally heated filament. An in-house, computer-controlled RFA analyzer was used for determination of ion energy distributions at a point situated about 25 cm from the anode. The retarding field analyzer (RFA) is an electrical probe capable of providing ion energy distributions in plasmas. AFM analysis has shown that nickel films obtained by TVA are very smooth. It was found that the ion energy increases with the power introduced into the system and it decreases with decreasing filament current. The adhesion for the films deposited by TVA was found to be very good. A clear picture of the optimal TVA plasma conditions for the highest adhesion and deposition rate was obtained.