Time evolution of boron deactivation with carbon coimplantation in preamorphized silicon

The influence of carbon on the evolution of boron deactivation was experimentally investigated. The peak profiles of implanted boron overlapped that of carbon in preamorphized silicon. Different annealing conditions were applied to modulate the injection of interstitials from end-of-range (EOR) defects to the recrystallized region. Transient enhanced diffusion was evident during rapid thermal annealing (RTA) at 600°C while significant boron deactivation caused by carbon coimplantation was observed after solid-phase epitaxial regrowth. The degree of boron deactivation is proportional to the implantation doses of carbon and boron, indicating that the pairing of carbon and boron atoms prevents boron activation. However, carbon prevented further deactivation during additional furnace annealing at 750°C after RTA because carbon blocked the reaction between boron and excess interstitials that were generated from the EOR defects.