| Transmission electron microscopy study on the formation mechanism of the as-deposited mixed-phase silicon thin films, deposited on SiO₂ at temperature range 570℃-580℃ by low pressure chemical vapor deposition and annealed at 570℃, has been carried out. Though most part of as-deposited films had an amorphous phase, some crystallites which had a random shape were observed at Si/SiO₂ interfaces. The higher the deposition temperature was, the larger the size of the crystallites was. No remarkable growth of preexisting crystallites was observed in the film deposited at 570℃ for 28 min. and annealed at 570℃ for 1 h. Crystallites which had an elongated elliptical shape were observed in the film annealed at 570℃ for 3 h. The size of the elliptical shaped grains was larger than that of the crystallites grown from preexisting crystallites. From above results, it is concluded that as-deposited mixed-phase silicon films are formed not because films, deposited as an amorphous phase, are crystallized during the deposition process but because films are deposited as a crystalline phase at the initial stage of the deposition process and then deposited as an amorphous phase. |
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