Dissociation Kinetics of Trapped Hydrogen in High-dose Hydrocarbon-Molecular-Ion-Implanted Silicon during Rapid Thermal Annealing

Abstract

We investigated the annealing behavior of hydrogen in a high-dose hydrocarbon-molecular-ion-implanted silicon during rapid thermal annealing (RTA). Gettering sinks in the high-dose hydrocarbon-molecular-ion-implanted region are formed not only at carbon-related defects but also at defects related to the amorphous layer after RTA. The concentration of hydrogen trapped by the defects was analyzed by secondary ion mass spectrometry (SIMS). As a result, the concentration of hydrogen trapped by the amorphous-related defects was found to be higher than that of hydrogen trapped by carbon-related defects with increasing temperature. The dissociation activation energy of trapped hydrogen at each type of defect was estimated using the consecutive reaction model. The dissociation energies at amorphous-related and carbon-related defects are 0.94 ± 0.22 and 0.67 ± 0.12 eV, respectively. The hydrogen trapped in the amorphous-related defects is considered to be in a bonding state with multivacancies, such as H₂–V₆. On the other hand, its bonding state in the carbon-related defects is assumed to be C–H₂ in carbon and self-interstitial silicon (C_s–I) clusters and H₂–V in tetrahedral (T_d) sites. Therefore, a high gettering capability of hydrogen can be expected by forming the amorphous-related defects peculiar to the high-dose implantation conditions.