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 i n the native oxide thickness on H-terminated Si surfaces. The increase effect of ammonia is greater than other impurities. The increase mech anisms can be explained by a three-stage model. Ammonia generates an O H- group by reacting with H2O. The OH- group etches off K-terminated S i atoms and the effectiveness of the H-termination on reducing the nat ive oxide growth is lost. As a result, the native oxide thickness incr eases. The native oxide growth can be suppressed by reducing the level of alkaline contamination in the CR atmosphere.