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.
A Novel Phase-Modulated Excimer-Laser Crystallization Method of Silicon Thin Films
We propose a novel excimer-laser crystallization method that uses a phase-shift mask for large-grain growth of Si thin films on the glassy substrate. Due to interference effects of the laser light, the phase difference of light at the mask results in spatial modulation of light intensity at the sample surface, which triggers the lateral grain growth. Grains as large as 7 µm could be grown by a single-shot irradiation.
HRTEM study of orthorhombic zirconia in MgO-PSZ
High-resolution transmission electron microscopy (HRTEM) was used to study the phase of orthorhombic ZrO2 formed in magnesia partially stabilized zirconia (MgO-PSZ) during HRTEM specimen preparation. Based on the three reported crystal structures of orthorhombic ZrO2, with the space groups Pbcm, Pbc21 and Pbca, here it is shown that orthorhombic ZrO2 formed in MgO-PSZ has the Pbcm structure.