Structural Characterization of Laser-Annealed Sputtered Poly-Si Films for High Mobility Tfts

ABSTRACTA high mobility of 390 cm2/Vs was successfully obtained for sputtered films, compared with 100 cm2/Vs for CVD films. Then, structural characterization of laser-annealed sputtered silicon films were performed, and compared with that of CVD films. TEM observations show a structural difference between the two film types. In sputtered films, many fine grain-like regions which have slightly different crystal orientation from surrounding regions are observed. On the other hand, in the CVD films, defects are widely spread over the film. X-ray diffraction, Raman scattering, and SIMS yield almost the same results in both films. The above-mentioned structural difference is thought to be essential to obtain high mobility.