Effect of Pulse Number on Dopant Activation in Silicon during Shallow p+/n Junction Formation by Non-Melt Excimer Laser Annealing

Shallow p+/njunctions were formed using Ge-PAI and low-energy/high-dose boron-ion implantation, followed by thermal annealing involving nanosecondnon-melt excimer laser annealingandrapidthermal annealing. The effect of laser pulse number on dopant activation and regrowth of a-Si layer are discussed.We found that laser annealing aloneis insufficient to regrow a-Si layer and activate dopant. In contrast, activationwas observed in the samples that were subjected to preannealingrapid thermal annealing followed by non-melt laser annealing; with slight increase of sheet resistance valuewhen the number of laser pulse shot was increased. This is considered due to the interaction of dopant and supersaturated defect in the remaining a-Si layer.The percentage of defect-dopant interaction increased with the pulse shot numbers which contributed to the decrease in activation level.