Laser Crystallization of Silicon Thin Films Using Photo Absorption Layer Formed by Spin Coating of Carbon Particles

Abstract

ABSTRACTWe report crystallization of amorphous silicon films 50∼1400 nm thick formed on glass substrates by irradiation of an infrared semiconductor laser. Carbon particles with a mean diameter of 200 nm were uniformly coated on the silicon films as the optical absorption layer. Samples were irradiated with a 940-nm continuous wave (CW) semiconductor laser with a power of 20 W. A high optical absorbance 76.5% at 940 nm of the carbon particles layers resulted in annealing of silicon films by heat diffusion from the carbon particle layers. After removing the carbon particles layer, Raman scattering spectral measurements were carried out. A high scattering intensity and a sharp crystalline silicon phonon band were observed. The analysis of Raman spectra revealed a crystalline volume ratio almost 1.0. The analysis of the optical reflectivity spectra also revealed that the silicon films were crystallized in the whole thickness by the present method.