The increase of the native oxide thickness on H-terminated Si surfaces by gaseous contamination in a clean room atmosphere

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 H 2 O. 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.