Abstract
Focused ion-beam chemical vapor deposition (FIB-CVD) method has been very attractive as fabrication technique of three dimensional micro- and/or nano-structures. Diamond-like carbon (DLC) is one of the attractive materials which can be made by FIB-CVD, since DLC has superior properties. In view of practical applications with the combination of FIB-CVD and DLC for NEMS/MEMS, it is very important to investigate microstructure of interface between DLC structure and substrate, since the microstructure provides valuable information for adhesion property. In this study, therefore, microstructures of interface in DLC/Si were investigated by high-resolution transmission electron microscopy (HRTEM) in detail. DLC films were deposited on Si(100) substrates by FIB system with an irradiation apparatus of a Ga+ ion-beam. Source gas was supplied by heating phenanthrene (C14H10) powder. Microstructure was analyzed by HRTEM equipped with energy dispersion microscopy (EDS). Bright field images showed that a transition layer existed at DLC/Si interface. From EDS analysis, it was found that the transition layer consisted of C and Si atoms and had thickness of about 100 nm. In addition, HRTEM image and convergence electron diffraction pattern revealed that the transition layer contained an about 5 nm thickness crystalline layer to the side of Si substrate.
