Non-melting annealing of silicon by CO2 laser

In this work we investigate CO2 laser annealing at millisecond time scale for the fabrication of Ultra Shallow Junctions, able to fulfill the requirements imposed for sub-45 nm CMOS nodes. Silicon samples doped with Boron using BF3 plasma implantation technique at low energy (0.4 and 0.6 keV) were used to ensure ultra shallow as implanted boron concentration profiles. Our aim is to achieve high electrical activation level of the dopant, while maintaining the Boron concentration profile as immobile as possible. Samples have been irradiated at a variety of annealing conditions regarding the duration of the irradiation and the power density; however, in every case the peak surface temperature was kept in the range of 1080–1320 °C. Sheet resistance measurements indicate significant enhancement in the activation levels, while chemical characterization by means of SIMS, shows very limited movement of the dopant concentration profile, especially for short pulse duration conditions.