The characteristics of diamond-like carbon (DLC) films deposited on a 4 in. Si(l 0 0) substrate using a magnetron-sputter-type negative ion source (MSNIS) were investigated using an atomic force microscopy. In the MSNIS source, a negative ion beam is generated by a cesium-induced sputter-type secondary negative ion emission process. DLC films deposited using this MSNIS technique were compared with films prepared using a conventional magnetron-sputter process under various deposition conditions. The power dependence and the pressure dependence of the film properties were investigated. The morphology of the surface was examined using an AFM. Ultra smooth surfaces with a root-mean-square (RMS) surface roughness R-RMS < 0.1 nm were observed with a high-energy negative ion beam. As the applied voltage is increased, the surface roughness decreases. Lower pressures result in smoother surfaces. These results show that significant improvements in surface roughness and morphology of DLC films can be obtained using a MSNIS. Furthermore, the results suggest that we can produce high-quality DLC films and control the surface morphology of the film using a MSNIS. (C) 2003 Elsevier B.V. All rights reserved.