The effects of local Ge insertion on the solid-phase crystallization (SPC) of a-Si films have been investigated. Three types of stacked structures, i.e., (a) a-Si/a-Ge/a-Si/SiO<SUB>2</SUB>, (b) a-Si/a-Ge/SiO<SUB>2</SUB>, and (c) SiO<SUB>2</SUB>/a-Ge/a-Si/SiO<SUB>2</SUB>, were annealed at 600°C. For structure (a) with thin (∼5 nm) Ge films, Ge atoms completely diffused into both sides of a-Si regions, and SPC was not enhanced. However, when Ge thickness was increased to more than 10 nm, Ge atoms were localized. Such localization became significant for structures (b) and (c) even for samples with thin Ge films. In addition, significant enhancement of SPC of a-Si was observed. These results indicated that crystal nucleation was initiated in Ge layers, and then propagated into a-Si layers. Therefore, interface-nucleation-driven SPC becomes possible using structures (b) and (c). This will be a useful tool in achieving oriented Si growth on SiO<SUB>2</SUB>.
|ジャーナル||Japanese Journal of Applied Physics, Part 2: Letters|
|出版ステータス||出版済み - 4 30 2004|