Boron redistribution in arsenic-implanted silicon and short-channel effects in metal-oxide-semiconductor field effect transistors

Abstract

When a high dose of As is implanted (e.g., 25 keV, 3×1015 cm-2) into B-doped Si and the sample is subsequently annealed at 900°C/5 min, pronounced segregation of the B into the implanted region occurs. This creates a B-depleted region beyond the As profile. It is demonstrated that the B segregation is driven primarily by the implantation induced damage rather than by As-B chemical and/or by electric field effects. The B segregation is nearly complete after a relatively low temperature (≲600°C/30 min) anneal. Two-dimensional device simulations show that the B depletion observed here can account for ≅50 mV threshold voltage roll off (at a drain bias of 0.1 V) in a Si metal-oxide-semiconductor field effect transistor of 0.2 μm gate length.