The Increase of the Native Oxide Thickness on H-Terminated Si Surfaces by Gaseous Contamination in a Clean Room Atmosphere

Abstract

Gaseous impurities in a clean room (CR) atmosphere cause an increase in the native oxide thickness on H-terminated Si surfaces. The increase effect of ammonia is greater than other impurities. The increase mechanisms can be explained by a three-stage model. Ammonia generates an OH- group by reacting with H2O. The OH- group etches off H-terminated Si atoms and the effectiveness of the H-termination on reducing the native oxide growth is lost. As a result, the native oxide thickness increases. The native oxide growth can be suppressed by reducing the level of alkaline contamination in the CR atmosphere.