Stress in Pulsed-Laser-Crystallized Silicon Films

Stress in pulsed-laser-crystallized silicon films was investigated using high-resolution Raman scattering measurements. Film stress was evaluated based on the peak shift of transverse optical (TO) phonon of crystalline silicon in Raman scattering spectra. The tensile stress in laser-crystallized 50-nm-thick silicon films on glass substrates increased from 3.5×10 8 Pa to 9.7×10 8 Pa as the film deposition temperature increased from 200°C to 480°C. The peak shift of laser-crystallized microcrystalline silicon (µc-Si) films revealed that the tensile stress introduced by laser irradiation was 2.3×10 8 Pa at most. These results indicate that the strong tensile stress is introduced by the silicon film deposition rather than by the pulsed-laser crystallization. Also, the authors demonstrate that pulsed-laser crystallization maintains the existing stress at the growth initiation sites in the bottom region of silicon films.