Titanium containing DLC coatings from a PACVD process using titanium (IV) isopropylate as a precursor

We report here the plasma activated deposition of Ti-DLC films using titani um (IV) isopropylate as a precursor. Gas phase processes during film deposi tion were analyzed using a differentially pumped quadrupole mass spectromet er (QMS). The film composition and the chemical nature of the film elements Ti, C and O were obtained using X-ray induced photoelectron spectroscopy ( XPS). These measurements were complemented by the determination of the film growth rate. With decreasing U-SB (increasing rf power) the QMS measuremen ts demonstrated a change in the fragmentation pattern of the precursor, esp ecially in the range of U-SB between - 100 and -300 V. These gas phase chan ges correlate with changes in the film composition, film hardness and adhes ion behavior. With XPS we determined for U-SB = -900 V the him composition of TI-O-C:H coatings to be: 48 at% C, 29 at% O and 23 at% Ti. We note that the Ti content of the film is significantly higher than that of the precurs or (5.9 at% Ti). With decreasing self-bias voltage (-100 to -400 V) the C/T i ratio in the films decreases from 2.5 to below 2. Further, we note also a slight decrease of the O/Ti ratio with decreasing U-SB. Analyzing the Ti 2 p doublet with XPS we find that for U-SB = -100 to -200 V, TiO2 is the pred ominant Ti species. For U-SB less than or equal to -200 V a second Ti doubl et evolves at lower binding energy which is related to the presence of TiC. The development of Ti-C bonding is also detected in the C Is spectra. (C) 2000 Published by Elsevier Science S.A. All rights reserved.