Dependence of ion implantation: Induced defects on substrate doping

The characteristics of an ion implantation-induced defect in a silicon subs trate are investigated. This defect is considered to be a complex of a poin t defect and a substrate dopant atom. The experiments are conducted by focu sing on the dependence of the substrate dopant species (phosphorus and boro n) on defect formation. The characteristics of the defect are investigated by measuring the bulk generation lifetime (tau (g)) of metal-oxide-semicond uctor capacitors, in which Si+ has been implanted to form the dopant-relate d defects in the substrate (damaging implantation) after gate oxide formati on. As a result, it is found that the tau (g) of the boron-doped substrate is one to two orders of magnitude smaller than that of the phosphorus-doped substrate for the same N-sub under the same implantation conditions. The t emperature dependence of tau (g) shows that the energy level of the defect is located at the intrinsic Fermi level, independent of the substrate dopan t species and the concentration. By measuring the dependence of tau (g) on the temperature of postdamaging implantation annealing, it is shown that th e defects vanish at about 800 degreesC for both types of substrate. Also, i t is found that the amount of dopant-related defects depends on the implant ation ion species. BF2+ implantation forms more defects than As+ implantati on. (C) 2001 American Institute of Physics.