PLASMA DEPOSITION AND CHARACTERIZATION OF PHOTOLUMINESCENT FLUORINATED NANOCRYSTALLINE SILICON FILMS

Fluorinated nanocrystalline silicon films, nc-Si:H,F, have been deposi ted from SiF4-SiH4-H-2 mixtures by means of the plasma enhanced chemic al vapor deposition technique. The presence of fluorine atoms, which a re effective etchant species, promotes selective etching giving nanocr ystalline films. These materials, with grain size of 100-200 Angstrom, show a room temperature photoluminescence centered at 1.62 eV. Also, the widening of the optical energy gap (E(g) = 2.12 eV) is mainly due to the presence of nanocrystals rather than to the H content of 4.5 at . %. (C) 1996 American institute of Physics.