Hydrogenation-enhanced low temperature activation of boron in silicon

In this work, we report on our study the effect of hydrogen plasma treatment by an ECR plasma on the activation and diffusion of boron in silicon at ultra-shallow depths. Hydrogenated and unhydrogenated samples were implanted with boron, followed by rapid thermal annealing for 20 seconds, at 450, 550, 650 and 850°C. Spreading resistance profiling (SRP) was carried out on all the samples to determine the profile of the electrically active boron. It was seen that there was enhanced activation of boron at the lower annealing temperature of 450°C. However no significant difference was observed at the higher annealing temperatures. The enhancement in boron activation at lower temperature was attributed to the creation of vacancies in the boron-implanted region, in addition to the lattice-relaxation effect by the presence of atomic hydrogen.