BORON REDISTRIBUTION IN ARSENIC-IMPLANTED SILICON AND SHORT-CHANNEL EFFECTS IN METAL-OXIDE SEMICONDUCTOR FIELD-EFFECT TRANSISTORS

When a high dose of As is implanted (e.g., 25 keV, 3 X 10(15) cm-2) into B-doped Si and the sample is subsequently annealed at 900-degrees-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 (less than or similar to 600-degrees-C/30 min) anneal. Two-dimensional device simulations show that the B depletion observed here can account for congruent-to 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 mum gate length.