The characteristics of an ion implantation-induced defect in a silicon substrate are investigated. This defect is considered to be a complex of a point defect and a substrate dopant atom. The experiments are conducted by focusing on the dependence of the substrate dopant species (phosphorus and boron) on defect formation. The characteristics of the defect are investigated by measuring the bulk generation lifetime (τg) of metal–oxide–semiconductor capacitors, in which Si+ has been implanted to form the dopant-related defects in the substrate (damaging implantation) after gate oxide formation. As a result, it is found that the τg of the boron-doped substrate is one to two orders of magnitude smaller than that of the phosphorus-doped substrate for the same Nsub under the same implantation conditions. The temperature dependence of τg shows that the energy level of the defect is located at the intrinsic Fermi level, independent of the substrate dopant species and the concentration. By measuring the dependence of τg on the temperature of postdamaging implantation annealing, it is shown that the defects vanish at about 800 °C for both types of substrate. Also, it is found that the amount of dopant-related defects depends on the implantation ion species. BF2+ implantation forms more defects than As+ implantation. © 2001 American Institute of Physics.