Effect of Ramp Rates During Rapid Thermal Annealing of Ion Implanted Boron for the Formation of Ultra-Shallow P-Type Junctions

Over the last couple of years manufacturers of rapid thermal annealing (RTA) equipment have been aggressively developing lamp-based furnaces capable of achieving ramp-up rates of the order of hundreds of degrees per second. One of the driving forces for such a strategy was the experimental demonstration of 30-nm p-type junctions using a ~400C/s ramp-up rate during a spike-anneal (zero soak-time at temperature). It was proposed that the ultra-fast ramp-up was suppressing transient enhanced diffusion (TED) of boron caused by implantation damage. Ultra-fast ramp rate capability was thus embraced as an essential requirement for the next generation of RTA equipment. In this paper, we review more recent experimental data examining the effect of the ramp-up rate during spike- and soak-anneals on enhanced diffusion and ultra-shallow junction formation.