The effect of nitrogen ion implantation on the nanomechanical properties of single crystal Si was evaluated by means of a conventional Vickers indentation and nanoindentation tests. The images of Si surfaces before and after nitrogen implantation were observed and their average surface roughnesses were measured by an atomic force Microscope (AFM), while the changes in the Morphology and microstructure of the single crystal Si by N implantation were examined by field emission scanning electron microscope (SEM) and X-ray diffractometer (XRD). In addition, the hydrophilic/hydrophobic surface property of the N-doping Si film was determined from the measurement of water contact angle by the sessile drop technique. Furthermore, the effects of the doping energy on the Surface contact angle and the surface toughness and the Vickers hardness of the film are also investigated. (C) 2009 Elsevier B.V. All rights reserved.