Pulsed laser crystallization of very thin silicon films

We report 308-nm-pulsed-XeCl-excimer laser annealing of 2.2-nm-thick silicon films formed on quartz substrates. Crystallization occurred at laser energy of 150∼170 mJ/cm2. Raman scattering spectra revealed mixed states of small crystalline grains and disordered amorphous regions. Broad optical extinction coefficient was obtained for wavelength from 250 to 400 nm, although it was similar to that of crystalline silicon for wavelength longer than 400 nm. Blue-green photoluminescence was observed for the films annealed at 260 °C for 3 h in 1.3×106 Pa H2O vapor after crystallization.