THE DISTRIBUTION OF CL IMPURITIES IN SIO2-FILMS PRODUCED BY THERMAL-OXIDATION OF SI IN CL-CONTAINING AMBIENTS

Cl was introduced into SiO//2 films by thermally oxidizing (100) Si in either O//2/HCl or O//2/Cl//2 gas mixtures at 1100 degree C. Cl concentration vs. depth profiles in these oxide films were determined by SIMS (secondary ion mass spectrometry). Analysis of the Cl distributions shows that, after incorporation into the SiO//2 network at the interface, in the bulk of the growing oxide the bonded Cl is removed from the network. This process is analyzed quantitatively as a chemical reaction in which H//2O reacts to replace Cl with OH. The kinetics of this replacement reaction and of the oxide film growth determine the Cl concentration vs. depth profiles in the grown films.