Gettering of Fe, Cu, and Ni by high dose boron buried layers

The effectiveness of boron as a gettering agent for iron, nickel, and copper has been investigated. Metals were implanted with a dose of 1×10¹³ cm^-2 into silicon wafers containing co-implants of silicon (700 keV) and boron (1.5 MeV). After a brief RTA anneal, Fe and Cu are strongly segregated to the boron peak. Smaller double peaks at the silicon end-of-range (EOR) region indicate that proximity gettering by the silicon is less significant compared to segregation gettering by the boron for these metals. Ni is found in significant quantities near both peaks, indicating that proximity gettering dominates for this impurity