Rigid amorphous silicon network from hydrogenated and fluorinated precursors in ECR-CVD

Structural rigidity in Si-network prepared from hydrogenated and fluorinated silicon precursors produced by low-pressure electron-cyclotron-resonance plasma has been studied. Chemical annealing of the Si-network by the atomic H of the plasma promotes the solid-state reactions for hydrogen elimination and network modification to obtain a rigid structure. However, Si-network produced from SiH4 feedstock keeps on maintaining a mostly amorphous feature up to a large extent, on the contrary, a radical transformation of the network towards a more rigid microcrystalline structure happens to take place easily when SiF4 is used as the source gas. F acts as an efficient scavenger of H from the network and enhances the network relaxation process significantly with the assistance of atomic hydrogen, and produces a rigid amorphous silicon network while used in limited dose for structural modulation. (C) 2003 Elsevier B.V. All rights reserved.