First-principles theoretical calculations showed that the hydrogenation of a Si surface caused the segregation of impurity metal atoms from the sub-surface to the surface. Since contamination by metallic impurities was a principal cause of surface defects, it was concluded that, by performing surface hydrogenation, high-purity atomically flat surfaces could be created.

Surface Hydrogenation as a Method to Purify and Flatten a Silicon Surface. S.Higai, T.Ohno: Applied Physics Letters, 2001, 78[24], 3839-41