Excimer Laser Annealing of Ion-Implanted Silicon: Dopant Activation, Diffusion and Defect Formation

Minimization of dopant diffusion during electrical activation is a crucial issue in developing sub-50 nm silicon technology. Excimer laser annealing (ELA) in the melting regime is capable of meeting the requirements on shallow junctions in terms of depth, doping concentration and abruptness. However, in order to be successfully employed it has to be demonstrated that ELA can be integrated in a device processing flow. Especially, the compatibility of ELA with other high temperature processing steps such as rapid thermal annealing (RTA) needs to be addressed. In this contribution, we report on phenomena observed for B redistribution that occur during ELA in B-implanted Si and after subsequent RTA. Specific topics to be covered include (i) B build-up at the maximum melt depth during ELA, and (ii) B activation and diffusion beyond the ELA melt depth.