Binding energy of vacancies to clusters formed in Si by high-energy ion implantation

Measurements of the binding energy (E-b) of vacancies to vacancy clusters f ormed in silicon following high-energy ion implantation are reported. Vacan cy clusters were created by 2 MeV, 2x10(15) cm(-2) dose Si implant and anne aling. To prevent recombination of the excess vacancies (V-ex) with interst itials from the implant damage near the projected range (R-p), a Si-on-insu lator substrate was used such that the R-p damage was separated from the V- ex by the buried oxide (BOX). Two V-ex regions were observed: one in the mi ddle of the top Si layer (V-1(ex)) and the other at the front Si/BOX interf ace (V-2(ex)). The rates of vacancy evaporation were directly measured by A u labeling following thermal treatments at temperatures between 800 and 900 degreesC for times ranging from 600 to 1800 s. The rate of vacancy evapora tion from V-2(ex) was observed to be greater than from V-1(ex). The binding energy of vacancies to clusters in the middle of the silicon top layer was 3.2 +/-0.2 eV as determined from the kinetics for vacancy evaporation. (C) 2001 American Institute of Physics.