Analysis of wavelength influence on a-Si crystallization processes with nanosecond laser sources

• Published in: Applied surface science Vol. 278; pp. 214 - 218
• Main Authors: García, O., García-Ballesteros, J.J., Munoz-Martin, David, Núñez-Sánchez, S., Morales, M., Carabe, J., Torres, I., Gandía, J.J., Molpeceres, C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2013; Elsevier
• Subjects: Amorphous silicon; Annealing; COMSOL multiphysics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Laser crystallization; Physics; Amorphous silicon; Annealing; Laser crystallization; COMSOL multiphysics; Crystallization; Silicon; Amorphous state
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.01.061

► Numerical and experimental study of single pulse laser annealing of a-Si using standard DPSS (diode pumped solid state) nanosecond laser sources. ► Experimental Raman measurements and determination of crystalline fraction. ► COMSOL numerical model of pulse laser crystallization of amorphous silicon. ► Experimental crystalline fraction and numerical results from simulation show reasonable agreement for UV-355nm and VIS-532nm wavelengths. ► The numerical model predicts the fluence range within which the annealing process should operate. In this work we present a detailed study of the wavelength influence in pulsed laser annealing of amorphous silicon thin films, comparing the results for material modification at different fluence regimes in the three fundamental harmonics of standard DPSS (diode pumped solid state) nanosecond laser sources, UV (355nm), visible (532nm) and IR (1064nm). The crystalline fraction (% crystalline silicon) profiles resulted from irradiation of amorphous silicon thin film samples are characterized with MicroRaman techniques. A finite element numerical model (FEM) is developed in COMSOL to simulate the process. The crystalline fraction results and the local temperature evolution in the irradiated area are presented and analyzed in order to establish relevant correlation between theoretical and experimental results. For UV (355nm) and visible (532nm) wavelengths, the results of the numerical model are presented together with the experimental results, proving that the process can be easily predicted with an essentially physical model based on heat transport at different wavelengths and fluence regimes. The numerical model helps to establish the optimal operation fluence regime for the annealing process.