Highly controlled crystallization of silicon thin films on low cost substrate by pulsed laser annealing process

Abstract

This paper presents heat transfer simulation and annealing process of microscale thin silicon (Si) film on low cost substrate using COMSOL Multiphysics. Two different types (Gaussian and Gate) of controlled (time controlled and laser intensity controlled) input laser power source have been applied on the top surface of the thin film for its crystallization. Comparison has been done for these two types input laser power intensity. The results show that at various laser power density with different times Gate input pulse melts higher thickness from top surface than the Gaussian input pulse. At any specific position inside the film melts faster in case of Gate input pulse rather than the Gaussian input pulse. Also the Gate input pulse shows the longer melted phase duration than Gaussian input pulse. Therefore, the annealing depth and temperature at any depth can be precisely controlled by optimizing power density of the heat source, pulse width, pulse type and exposure time. Finally, it is possible to crystallize Si films by controlled melting without melting the substrate.