Role of impurities in the formation of silicyne (long-chain silicon): theory and experiment

The short-range order structure of amorphous silicon prepared by various me thods is investigated by electron diffraction analysis. The influence of im purities in the as-prepared films and those irradiated with neon, oxygen, a nd carbon ions at doses up to 1x10(16) cm(-2) on the character of structura l transformations and the formation of interatomic silicon multiple bonds d uring annealing are investigated. The structure of films annealed at 500 de grees C is found to depend on the type of impurities and the nature of thei r chemical bond with silicon atoms. In particular, oxygen (> 0.2 at. %), un like hydrogen and carbon, acts as an inhibitor for the formation of silicyn e. Good agreement is also noted between the experimentally determined short -range order parameters and those calculated by the nonempirical Hartree-Fo ck method. (C) 1999 American Institute of Physics. [S1063- 7826(99)02210-3] .