Role of Hydrogen in Polycrystalline Si by Excimer Laser Annealing
The role of hydrogen in the Si film during excimer laser annealing (ELA) has been successfully studied by using a novel sample structure, which is stacked by a-Si film and SiN film. Hydrogen contents in the Si films during ELA are changed by preparing samples with hydrogen content of 2.3-8.2 at.% in the SiN films with a use of catalytic (Cat)-CVD method. For the low concentration of hydrogens in the Si film, the grain size increases by decreasing hydrogen concentration in the Si film, and the internal stress of the film decreases as increasing the shot number. For the high concentration of hydrogens in the Si film, hydrogen burst was observed at 500 mJ/cm 2 and the dependence of the internal stress on the shot number becomes weak even at 318 mJ/cm 2 . These phenomena can be understood basically using the secondary grain growth mechanism, which we have proposed.
Micro-Scale Characterization of Crystalline Phase and Stress in Laser-Crystallized Poly-Si Thin Films by Raman Spectroscopy
Laser crystallized poly-Si thin films were characterized using micro-Raman spectroscopy. Mapping measurements of the Si optical-phonon line were carried out for large size grains generated by the super-lateral growth, where the mapping interval was as small as 0.2 µm. It was found that the spectral intensity is extremely large at ridges located at grain boundaries. The map of peak-frequency shift indicated that the tensile stress tends to accumulate in grains and relax at grain boundaries. The map of spectral width revealed the abrupt variation of the crystalline phase from large-size grains to microcrystals.
Dictionary of Alaska Place Names
Introduction: This work is an alphabetical list of the geographic names that are now applied and have been applied to to places and features of the Alaska Landscape.