Structural Changes in Diamond-Like Carbon Films Fabricated by Ga Focused-Ion-Beam-Assisted Deposition Caused by Annealing

Abstract

The desorption processes of H and Ga from diamond-like carbon (DLC) film synthesized by focused-ion-beam chemical vapor deposition (FIB-CVD) were investigated by elementary analysis and local structure analysis after heat treatment under various conditions. The elementary composition of FIB-CVD DLC film was determined using a combination of Rutherford backscattering spectra and elastic recoil detection analysis spectra. Local structure analysis was performed by the measurement of near-edge X-ray absorption fine structure using synchrotron radiation. Desorption of H from FIB-CVD DLC film by heat treatment was found to comprise two types of process. One is the local graphitization along paths, where residual Ga atoms move by annealing. In this process, Ga acts as a catalyst for the graphitization of DLC. The other process is derived from the graphitization of the whole DLC film by heat, regardless of Ga. In this process, the sp² content increases considerably.