Formation of hydrogen molecules in crystalline silicon

Abstract

Molecular hydrogen was directly observed by Raman spectroscopy in silicon samples subjected to a hydrogen plasma. At lower hydrogen plasma temperatures (∼150°C) the hydrogen molecules form at tetrahedral interstitial sites within the Si lattice. For higher temperatures (>150°C) the plasma treatment results in hydrogen related platelets which act as sinks to which the molecules diffuse. Once trapped within the extended voids created by the platelets, the H 2 molecules exhibit a vibrational frequency that is practically the same as the well-known value for gaseous H 2.