Infrared absorption study of a DX-like hydrogen-related center in silicon

An absorption line at 1025.5 cm(-1) has been found in hydrogenated Czochral ski-grown Si crystals after irradiation with fast electrons and annealing i n the temperature range 300-400 degrees C. Substitution of hydrogen by deut erium resulted in a shift of the band to 1027.9 cm(-1), which clearly indic ates H(D) incorporation into the defect which gives rise to the band. It is found that the line is related to a local vibrational mode (LVM) due to a DX-like center, having a shallow donor and a deep acceptor level. The LVM b and is observed only when the center is in the singly negatively charged st ate. Transformation of the defect into the neutral state resulted in disapp earance of the LVM band and appearance of several absorption lines in the r ange 245-325 cm(-1). These lines were interpreted to be associated with gro und-to-excited-state electronic transitions in an effective-mass-like shall ow donor state of the defect. The structure of the center is discussed. (C) 1999 Elsevier Science S.A. All rights reserved.