Four carbon nanometer films ranging from 5 to 60 nm have been prepared by plasma-based ion implantation (PBII) with C on Si (10 0) wafers. Raman spectra and X-ray photoelectron spectroscopy (XPS) indicate these films are diamond-like carbon (DLC) films with high sp(3)/sp(2) bonds ratio. Atomic force microscopy shows that their appearances are smooth and compact, and improved to some extent. Meanwhile, XPS displays that they are naturally connected with the Si substrate by a C-Si transition layer where the implanted C+ ions react with Si to form SiCx. Infrared spectra reveal they contain some hydrogen, and hydrogen mainly combines with carbon to form sp(3) C-H, C-H-2 and C-H-3 bonds. Proper DLC films will be obtained and used as the qualified candidates in some particular engineering applications by actively optimizing PBII parameters. (C) 2003 Elsevier B.V. All rights reserved.