We have grown silicon single crystals doped with isotope oxygen of 180 by using a floating zone method with two ellipsoid mirrors. Two lamps through a quartz tube heated the crystal for melting during crystal growth. The isotope oxygen of 180 was doped from the gas phase with argon gas during crystal growth. The isotope of 180 was detected by using Fourier transformation of infrared (FTIR) spectroscopy at room temperature. We succeed in the doping of the isotope of 180 from the gas phase through a liquid-gas interface. (c) 2007 Elsevier B.V. All rights reserved.