In this Letter, we present a study on mapping the morphology of the top interface on Si/buried oxide (BOX) in nanometer scale and the influence of nano-sized Si islands to the electronic properties of the BOX layer in separation by implantation of oxygen with conducting atomic force microscopy (C-AFM). By using GAFM, both the morphology of the top interface on Si/BOX and the electronic properties of the BOX can be obtained simultaneously. Based on the analysis of the current-voltage (I-V) curves, the electronic properties of the BOX are also discussed. (C) 2003 Elsevier B.V. All rights reserved.