THE GROWTH AND TRANSPORT IN THERMAL OXIDE-FILMS FORMED ON SILICON

The growth and transport in oxide films formed on (100) Si (p-type) in O2 at 1.33 kPa and 950-degrees-C was studied using the O-18/SIMS technique. Samples were oxidized sequentially in O-18(2) and O-16(2) for times up to 48 h to produce films in the thickness range 2-50 nm. The kinetic data approximate to a linear rate relation apart from an initial more rapid growth region. Sputter profiles of both O-18- and O-16-containing species (Si2O+) showed the distribution of each within the thin oxide films. When samples are oxidized first in O-16(2) and then in O-18(2) the O-18 is concentrated in the vicinity of the gas-SiO2 interface and at the Si-SiO2 interface. The concentration at the latter interface increases with increasing time of exposure to O-18(2) and predominates at longer times. The SIMS profiles confirm that the principal transport process is inward oxygen diffusion through the oxide during oxidation probably along short circuit paths such as micropores.