Evaluation of Dislocation Generation on Silicon Substrates by Selective Oxidation

Abstract

The density of dislocations generated at composite film edges on a silicon substrate as a result of selective oxidation was measured, and the relation between selective oxidation conditions and dislocation generation was investigated. Results show that the dislocation density decreases markedly with increasing oxidation temperature. The transition temperature of this drop becomes low as the thickness of the pad increases. The results are interpreted in terms of the temperature‐related characteristics of viscous flow. A further experiment reveals that the density of dislocations increases with an increase in the depth of Si etching before oxidation. This phenomenon is considered to be due to stress concentration resulting from the volume expansion of film during oxidation. The effect of oxidation pressure on dislocation generation was also investigated. The dependence of the bird's beak length on oxidation temperature and pad thickness was subsequently measured. The results are presented and the temperature dependence is explained using oxidation theory. Finally, suitable conditions for selective oxidation are discussed.