AVS 50th International Symposium
    Advanced Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM1
Influence of Sputtering Condition and Target Material on the Microstructure and Properties of Ti-Si-N Coatings Prepared by r.f.-reactive Sputtering

Tuesday, November 4, 2003, 8:20 am, Room 323

Session: Nanostructured, Nanocomposite, and Functionally Gradient Coatings
Presenter: M. Nose, Takaoka National College, Japan
Authors: M. Nose, Takaoka National College, Japan
Y. Deguchi, Toyama University, Japan
T. Mae, Toyama National College of Technology, Japan
E. Honbo, Toyama Industrial Research Center, Japan
W.A. Chiou, University of California, Irvine
K. Nogi, Osaka University, Japan
Correspondent: Click to Email
Since Veprek et al. presented a theoretical concept to design super-hard nano-crystalline composite materials on the TM-Si-N (TM = transition metal) systems consisting of nano-crystalline transition metal nitrides embedded in amorphous Si@sub 3@N@sub 4@, many studies on these kinds of films deposited by PVD have been reported. Although most of them used r.f.- or d.c.-reactive sputtering in an Ar/N@sub 2@ gas mixture, the results were not always consistent with each other. This suggests that the structure of films depends sensitively on the deposition conditions. Hence, we decided to examine the effect of sputtering condition and target material on the microstructure and mechanical properties of Ti-Si-N coatings prepared by r.f.-reactive sputtering. We used the composite targets conisting of Ti (99.99%) plate and Si@sub 3@N@sub 4@ chips as well as the target consisting of Ti plate and Si chips. Thin films were synthesized by r.f. sputtering machine in a facing target-type (FTS) on the substrates of high speed steel. During the deposition, the substrate was heated from room temperature up to ~300 °C and a d.c. bias up to -100V was applied. In the case of films deposited from the Ti-Si target without bias application, the hardness of high Si films (containing ~20 at %Si) showed the lower value of 20 GPa. The hardness of the films increased and reached to a maximum value of 40 GPa around at a bias of -30V, but the crystallite size of the film increased to ~30nm. On the other hand, the hardness of the films (containing ~20 at %Si) deposited from the Ti-Si@sub 3@N@sub 4@ target increased with increasing negative bias voltage, being saturated at a level of ~40 GPa over -80V. Although the crystallite size of the films increased gradually with increasing negative bias, it still remains about 7nm at -80V. The characteristics of the latter film could be attributed to the formation of nano-composite structure defined by Veprek et al.