Laser thermal processing for ultra-shallow junction formation: Experiment and modelling

The doping technology requirements for the MOSFET source and drain regions of the future CMOS generations lead to a major challenge. In the present paper Laser Thermal Processing (LTP) experiments have been performed with two different XeCl excimer lasers (λ= 308nm) with different pulse characteristics (25 ns and 200 ns). Here we examine the influence of the pulse duration on LTP of B + (with and without Ge+ preamorphizing implantation) implanted silicon wafers on the basis of real-time optical monitoring of the laser-induced heating process, four-point probe resistivity measurements and secondary ion mass spectroscopy (SIMS) depth profiles. Experimental results are compared to model calculations. The activated dopant dose regarding sheet resistance and junction depth confirm the efficiency of laser processing to realize highly doped junctions required for the future CMOS generations. The submelting regime of LTP is also discussed regarding the laser pulse duration.