Laser thermal processing for ultra shallow junction formation: numerical simulation and comparison with experiments

In the last few years, laser thermal processing (LTP) has become a potential solution for sub-0.1 μm technology requirements, as focused by the international technology roadmap for semiconductors (ITRS). This paper presents a numerical simulation of the propagation of the melting front and regrowth of Si-based structures during excimer (XeCl-308 nm) laser irradiation. The influence of the pulse duration is highlighted in the simulation and compared with experiments. Two different types of XeCl lasers with different pulse durations have been used for the experiments in order to validate the model (SOPRA VEL 15, 200 ns, 15 J and Compex Lambda Physik, 20 ns, 200 mJ). The comparison between the simulation and the experimental results has been carried out using results from in situ reflectance measurements (transient reflectivity), secondary ion mass spectroscopy, spreading resistance profiles and four-point probes. The different implantation conditions used for this study were B+ or BF2+ implanted Si wafers, with or without Ge+ pre-amorphization. Both experimental and simulation results show the potentiality of the LTP annealing technique for realization of ultra shallow junction under 0.1 μm.