Three-dimensional simulation of rapid melting and resolidification of thin Si films by excimer laser annealing

Abstract

A model has been developed for the rapid melting and resolidification of thin Si films induced by excimer-laser annealing. The key feature of this model is its ability to simulate lateral growth and random nucleation. The first component of the model is a set of rules for phase change. The second component is a set of functions for computing the latent heat and the displacement of the solid–liquid interface resulting from the phase change. The third component is an algorithm that allows for random nucleation based on classical nucleation theory. Consequently, the model enables the prediction of lateral growth length (LGL), as well as the calculation of other critical responses of the quenched film such as solid–liquid interface velocity and undercooling. Thin amorphous Si films with thickness of 30, 50, and 100 nm were annealed under various laser fluences to completely melt the films. The resulting LGL were measured using a scanning electron microscope. Using physical parameters that were consistent with previous studies, the simulated LGL values agree well with the experimental results over a wide range of irradiation conditions. Sensitivity analysis was done to demonstrate the behavior of the model with respect to a select number of model parameters. Our simulations suggest that, for a given fluence, controlling the film’s quenching rate is essential for increasing LGL. To this end, the model is an invaluable tool for evaluating and choosing irradiation strategies for increasing lateral growth in laser-crystallized silicon films.

Modelling of flash-lamp-induced crystallization of amorphous silicon thin films on glass

“…(7), I hetero has a correction factor which accounts for the catalytic surface's role in lowering the energy barrier for nucleation. The contact angle y is defined in this case as 701 [17].…”

Ultrafast crystallization kinetics in (Pb,La)(Zr0.30Ti0.70)O3 thin films by pulsed excimer laser annealing

“…Indeed, laser annealing enables crystallization of silicon with controlled doping, microstructure, and electrical properties [7], [8]. Two main theories have been proposed to explain the crystallization process of thin films using excimer lasers: 1) local melting, accompanied by diffusion across the solid-liquid interface, with nucleation due to under-cooling [9], and 2) spatially random nucleation and growth [10], [11]. In either case, local crystallization develops because of the heating induced by absorption of the laser energy on the surface.…”

Pulsed-laser-induced nanoscale island formation in thin metal-on-oxide films

“…The rapid heating and subsequent phase transitions that occur during short pulse irradaition can be complex, and have been the subject of theoretical and experimental investigations. [2][3][4][5] However, the majority of these studies of laser irradiation of materials concentrate on the surface melting and ablation of thick films and do not consider the effect of the material-substrate interaction.…”