Numerical Simulation of Non-Equilibrium, Ultra-Rapid Heating of Si-thin films by Nanosecond-Pulse Excimer Lasers
In this paper we present our work on the numerical simulation of ultrarapid heating (with phase-change) of silicon thin-films, which are irradiated with nanosecond-pulsed excimer laser. Our excimer-laserannealing (ELA) modeling capability is based on a standard finite-element CFD software package, which, however, has been modified to accommodate the specific demands of very rapid heating of thin Si films. In that sense, we've abandoned the traditional equilibrium formulation (i.e. enthalpy method), for phase-change computations, and have adopted a new approach that allows superheated solid and undercooled liquid to exist during the various stages of the heating/cooling cycle. Our model has been successfully applied to predict the shape and temporal evolution of temperature profiles in the case of localized melting of silicon thin-films by excimer laser irradiation. Such scenario corresponds to conditions typically encountered in laser-induced lateral crystallization of a-Si films, a process that has recently attracted attention for the formation of high quality poly-Si films.
KeywordsExcimer Laser Lateral Growth Laser Energy Density Undercooled Liquid Molten Silicon
Unable to display preview. Download preview PDF.
- Im, J.S., Kim, H.J. and Thompson, M.O. (1993): Phase transformation mechanisms involved in excimer laser crystallization of a-Si films. Appl. Phys. Lett. 63: 1969– 1971Google Scholar
- Im, J.S. and Kim, H.J. (1994): On the super lateral growth phenomenon observed in excimer laser-induced crystallization of thin Si films: Appl. Phys. Lett., 64: 2303– 2305Google Scholar
- De Unamuno, S. and Fogarassy E. (1989): A thermal description of the melting of c-and a-silicon under pulsed excimer lasers. Appl. Surf. Sci., 36: 1– 11Google Scholar
- Sposili, R., Im, J.S. (1996): Sequential lateral solidification of thin silicon films on Si02. Appl. Phys. Lett., 69: 2864– 2866Google Scholar
- Gupta, V.V., Song H.J., Im J.S. (1997): Numerical analysis of excimer-laser-induced melting and solidification of thin Si films. Appl. Phys. Lett. 71: 99– 101Google Scholar