Fabrication of Nanocrystalline Silicon Gratings Embedded within a Silicon Nitride Matrix by Femtosecond Laser-Induced Crystallization

Nanocrystalline silicon gratings were fabricated by applying both femtosecond-laser-interference crystallization and post thermal annealing to amorphous silicon (a-Si) nanoclusters embedded within a silicon nitride matrix. Catalytic chemical vapor deposition was used to fabricate the embedded a-Si nanoclusters, and the formation of a-Si nanoclusters was confirmed by photoluminescence spectroscopy. The femtosecond laser interference technique was employed to produce a seed pattern for the spatially-selected crystallization of a-Si nanoclusters. Micro-Raman spectroscopy and selected-area electron diffraction, together with high-resolution transmission-electron microscopy, show that nanocrystalline silicon gratings were formed through an amorphous-to-crystalline transformation with femtosecond laser pulses, and that the degree of crystallization was enhanced by applying post thermal annealing to the seed gratings. (C) 2010 The Japan Society of Applied PhysicsThis research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education, Science and Technology (Quntum Photonic Science Research Center)