Electron beam induced chemical vapor deposition (EBI-CVD) is one of the promising methods for nanofabrication. EBI-CVD has generally been carried out in conventional scanning electron microscopes and the minimum size of the deposits was in the range between 20 and 300 nm. In this study, a field emission gun scanning electron microscope (FE-SEM) and a field emission gun transmission electron microscope (FE-TEM) with gas introduction systems were employed for deposition using a W(CO)(6) precursor in order to reduce the size of deposits. Dots, 15-20 nm in diameter, were produced using the FE-SEM. The dots consist mainly of tungsten with small amounts of carbon and oxygen. By using the FE-TEM, the diameter of the dots can be reduced to 3.5 nm. The relationship between probe size and dot diameter is discussed. Rods, the diameter of which was 8 nm, were also fabricated by scanning the beam position in the FE-TEM. Deposits produced by FE-TEM are smaller than those by conventional electron microscopes. (C) 2004 American Vacuum Society.