In a lengthy review, it was pointed out that the structure of the H molecule in Si was not fully understood. For example, there were uncertainties about the alignment within the lattice, and about whether the infra-red active species were complexes with other impurities or defects. The observation of only one defect (H2*), and the absence of complexes with vacancies, was considered to be surprising. It contrasted with results on the electron irradiation of plasma-treated material; which led to a large number of VnHm defects.

The Interaction of Hydrogen with Deep Level Defects in Silicon R.Jones, B.J.Coomer, J.P.Goss, B.Hourahine, A.Resende: Solid State Phenomena, 1999, 71, 173-248