Structural investigations of RTA boron-doped thin a-Si layers

The structural changes in as- sputtered thin a-Si layer, and after boron doping with rapid thermal annealing are investigated by transmission electron microscopy. Stable hexagonal amorphous/crystalline series of SiO2 structures, as signed as SiO2 (SnO2-V), not revealed in high temperature SiO2 layers, are observed in all films investigated. Different types of crystalline and high ordered SiO2 structures are obtained in the BSG film, used for doping. Boron penetration in the a-Si layer starts the crystallization at B/Si ratios lower than 10(-3). RTA process leads to inhomogeneous disordered polycrystalline silicon layer, with large areas of poly-and monocrystalline silicon, coexisting with various crystalline SiO2 structures. Faster crystallization and larger monocrystalline silicon regions are observed at higher temperatures and longest durations of the annealing process. (C) 2005 Springer Science + Business Media, Inc.