AVS 57th International Symposium & Exhibition
    Thin Film Tuesday Sessions
       Session TF-TuP

Paper TF-TuP14
Formation of Ti-Doped DLC Films by Inert-gas Ion Beam Assistance in a C10H8 Atmosphere

Tuesday, October 19, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Thin Film Poster Session I
Presenter: S. Narita, Kogakuin University, Japan
Authors: S. Narita, Kogakuin University, Japan
I. Takano, Kogakuin University, Japan
Correspondent: Click to Email
Diamond-like carbon (DLC) has the amorphous structure that is chiefly composed by graphite (sp2) and disordered graphite (sp3) state. Therefore mechanical properties of DLC generally show high hardness and low friction. DLC film has been prepared by various method of chemical vapor deposition (CVD) or physical vapor deposition (PVD) including the sputtering method. Commercial applications of DLC have been already performed as engine parts of an automobile or surface coating of a hard disk.

In this study, Ti-doped DLC films were formed using He+ or Ar+ ion beam assistance in a naphthalene (C10H8) atmosphere. The formation conditions of DLC film were changed with ion-beam accelerating voltage and current density. Ti doping was performed by using the electron-beam deposition method with Ti evaporation rate from 0.0 to 0.2 nm/sec. The mechanical properties of hardness and friction coefficient were determined using the dynamic micro knoop hardness tester and the ball-on-disk tribotester respectively. Atomic concentration and structure of the films were investigated by X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy.

The suitable mechanical property of DLC films was obtained by the condition with accelerating voltage of 5 kV at current density of 10 μA/cm2. The maximum hardness was 5.37 GPa using Ar+ ion beam, while the minimum friction coefficient was 0.117 using He+ ion beam. It was clear that properties of DLC film was changed by ion species. In the case of Ar+ ion beam, the higher hardness film contained much sp3 state, while the film with lower friction coefficient contained much sp2 state. From the other side the higher hardness film has a large crystal grain size as compared with the film with lower friction coefficient.