Relation between the suppression of the generation of stacking faults and the mechanism of silicon oxidation during annealing under argon containing oxygen

The effect of the oxygen partial pressure during annealing under argon on the generation and growth of defects that adversely affect the yield and reliability of thermally grown oxide was investigated by precisely and widely controlling the oxygen partial pressure. Below the critical oxygen partial pressure of 6 x 10(-3) atm, the generation of oxidation-induced stacking faults (OSFs) during a subsequent oxidation step was effectively suppressed from the density of about 10(3) cm(-2) to less than 20 cm(-2). Annealing for 10 min under an appropriate oxygen partial pressure was shown to be sufficient for annihilation of the origin of OSF and this effect continued even during a subsequent oxidation in dry oxygen. Mechanism by which the generation of OSFs is suppressed was discussed considering the oxidation mechanism under the reduced oxygen partial pressures. It is suggested that electric field that builds across the oxide layer when the oxygen partial pressure is below the critical value causes silicon interstitials and impurities such as metals to drift from the substrate to the outer surface of the oxide. During the annealing origins of OSFs such as Si-O clusters and metallic impurities are eliminated and mechanical damage is also annealed out before climbing to be the nuclei of OSFs. (C) 2000 American Institute of Physics. [S0021-8979(00)04414-5].