Laser annealing of SiGe and Ge based devices

Abstract

The integration of laser annealing in SiGe and Ge based MOS devices is investigated by means of numerical simulations. Our simulation code is based on two modules: the former simulates the interaction between the laser light and the transistor structure to estimate the heating, the latter simulates heat diffusion, phase changes and material redistribution under irradiation. The model is calibrated in the case of different atomic species (namely Si, Ge and common dopant impurities), considering the thermal properties of the materials and the impurity depending diffusivity in the solid, liquid and interfacial region. We present several simulation results obtained by varying materials, implanted impurity profiles and geometry of the CMOS-like structures. With the support of the simulation results we discuss the possible perspectives of the excimer laser annealing application to the fabrication of post-Si CMOS devices. In particular, we show that by using Ge and SiGe materials the process window for a melting process is larger with respect to the case of traditional Si based devices.