Excited states of a hydrogen-intrinsic defect-related double donor in silicon

IR absorption due to electronic excitations of a hydrogen-intrinsic defect- related double donor (H-donor) in proton-implanted silicon is studied. It i s shown that a broad feature at about 600 cm(-1) is due to the ionization o f the E-s approximate to E-c - 0.1 eV and E-t approximate to E-c - 0.06 eV levels while the 375 cm(-1) band is related to the E-s --> E-t excitation. It is concluded that the E-s and E-t levels are connected with ground spin- singlet and excited spin-triplet neutral states of the II-donor. An analysi s of Si-H bond-stretching and bond-bending local vibrational modes allows u s to suggest that the II-donor is an interstitial-type complex with two pos sible configurations with C-2/C-s- or C-2v-symmetry.