Boron partitioning coefficient above unity in laser crystallized silicon

Abstract

Boron pile-up at the maximum melt depth for laser melt annealing of implanted silicon has been reported in numerous papers. The present contribution examines the boron accumulation in a laser doping setting, without dopants initially incorporated in the silicon wafer. Our numerical simulation models laser-induced melting as well as dopant diffusion, and excellently reproduces the secondary ion mass spectroscopy-measured boron profiles. We determine a partitioning coefficient kp above unity with kp = 1.25 ± 0.05 and thermally-activated diffusivity DB, with a value DB(1687 K) = (3.53 ± 0.44) × 10-4 cm2·s-1 of boron in liquid silicon. For similar laser parameters and process conditions, our model predicts the anticipated boron profile of a laser doping experiment.