Using scanning probe microscopy, we have modified a silicon surface and measured its current–voltage (I–V) characteristics. In the modified area, both an increase in film thickness and a decrease in current caused by field-induced oxidation (FIO) have been observed. The I–V characteristics of the FIO film shows a good fit to a Fowler–Nordheim (FN) tunneling current model. The barrier height determined by a FN plot shows a good agreement with that of conventional metal–oxide–semiconductor structure with thermal thick silicon oxide. © 1997 American Vacuum Society.