Atomic-layer deposition of Si on SiO2 with a self-limiting growth mode was achieved at substrate temperatures between 355 and 385 °C by means of alternate supply of Si2H6 and SiCl4 gas sources. The growth rate was saturated at 2 ML per cycle at these temperatures and for Si2H6 exposure time over 120 s. The smooth surface (∼0.26 nm in arithmetic average roughness) was obtained under the self-limiting condition irrespective of a film thickness up to 6.5 nm.