A model for projection laser crystallization of thin silicon films has been developed. The model is capable of simulating stochastic nucleation and grain growth to predict the extent of lateral growth (LG) in the film and the details of the final microstructure. This model was used to simulate irradiation schemes involving multiple pulses, designed to increase the lateral growth length (LGL) in the irradiated domain. For an irradiation scheme involving two pulses, with an adjustable time delay, our simulation predicted a maximum increase in LGL of about 50% (from 2μm to 3μm) with a maximum film temperature of ~2700 K. For a three-pulse irradiation scheme (without time delay) a 50% increase in LGL was also predicted, but with a maximum film temperature of ~2200 K. These simulations show the efficacy and the relative merit of each of the examined schemes, as well as, their associated process window.
We have developed excimer-laser-annealing modeling capability by broadening the computational ability of a standard finite-element based computational-fluid-dynamics software package to adopt to the specific demands of very rapid heating of thin a-Si films. This was achieved by the incorporation of a subroutine employing a phase function and a set of rules for determining latent heat absorption or release. Wit this enhancement the model was able to correctly calculate the degree of superheating/undercooling in the film and track the melt-solid interface velocity. The model also provided reasonable estimates of the expected poly-Si lateral growth length as a function of the laser irradiation scenario. The model in its current form is a useful tool for first order calculations and for supporting relevant experimental studies.