Phase field modeling of excimer laser crystallization of thin silicon films on amorphous substrates

Excimer laser crystallization processing of thin silicon films on amorphous silicon oxide substrates was simulated by means of phase field modeling. The quantitative phase field model was derived from the Gibbs-Thompson equation coupled with energy conservation. Because the adaptive mesh scheme was adopted, the present calculations could accommodate both two-dimensional superlateral growth (SLG) phenomena and the realistic interface thickness (in the order of 10^-10 m). The vertical growth of fine-grained nucleation structures was simulated using one-dimensional calculations, and the results are consistent with those obtained in previous experiments. Two cases of SLG were also simulated, and the evolution of the interface and thermal fields was determined. Based on our simulation results, we conclude that SLG crystallization does not achieve steady growth because of the extremely fast heat dissipation from the substrate. To obtain very uniform electric characteristics for device fabrication, the layout design and the device position should take the SLG laser mask into consideration.