We report studies of the growth of cobalt from cobalt carbonyl (Co-2(CO)(8)) under ultrahigh vacuum conditions on Si(l 0 0) wafers. Thermal desorption mass spectroscopy and reflection high energy electron diffraction have been used for in situ studies of the growth process. Desorption of CO has been observed with a peak desorption rate at approximately 230 degreesC. We extract a sticking coefficient of s = 1.5 x 10(-3) at 100 degreesC on the bare cobalt surface. Growth rate measurements at higher temperatures (175-350 degreesC) are consistent with a higher value for the sticking coefficient. The lower value of the sticking coefficient during growth is attributed to accumulation of decomposition products on the surface. X-ray diffraction studies show that the as-deposited cobalt is fine-grained, and that it reacts to form cobalt disilicide (CoSi2) upon annealing at 800 degreesC if there is no intervening SiO2. (C) 2003 Elsevier B.V. All rights reserved.