title: The reason why thin-film silicon grows layer by layer in plasma-enhanced chemical vapor deposition.
abstract: Thin-film Si grows layer by layer on Si(001)-(2 × 1):H in plasma-enhanced chemical vapor deposition. Here we investigate the reason why this occurs by using quantum chemical molecular dynamics and density functional theory calculations. We propose a dangling bond (DB) diffusion model as an alternative to the SiH3 diffusion model, which is in conflict with first-principles calculation results and does not match the experimental evidence. In our model, DBs diffuse rapidly along an upper layer consisting of Si-H3 sites, and then migrate from the upper layer to a lower layer consisting of Si-H sites. The subsequently incident SiH3 radical is then adsorbed onto the DB in the lower layer, producing two-dimensional growth. We find that DB diffusion appears analogous to H diffusion and can explain the reason why the layer-by-layer growth occurs.
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kuwahara
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kawaguchi
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Nobuki
authors.initials: N
authors.lastname: Ozawa
authors.affiliation: Fracture and Reliability Research Institute (FRRI), Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
authors.forename: Momoji
authors.initials: M
authors.lastname: Kubo