In-situ spectroscopic ellipsometry to control the growth of Ti nitride and carbide thin films

In-situ spectroscopic ellipsometry (SE) was used to control the growth process of Ti nitrides (TiNy) and carbonitrides (TiCxNy). The TiNy (TiCxNy) thin films were deposited using Ti and (TiC) targets with DC (RF) reactive magnetron sputtering. The plasma energy of TiNy films was found to depend strongly on molar y whereas in TiCxNy films, a gradual change in their dielectric response was observed, changing from that of TiC to that of TiN due to replacement of carbon by nitrogen. Analyzing the SE spectra we found the following: (a) Stoichiometric TiN films were produced for N2 flow rate (ΦN2) in the range from 1.9 sccm to 4 sccm, depending on the bias voltage Vb. (b) Increasing Vb from 0 to −120 V, the ΦN2 range within which stoichiometric TiN was deposited, was expanded and (c) in-situ control of the N2 content in TiNy, TiCxNy films is possible.