Atomic structure of the nanocrystalline Si particles appearing in nanostructured Si thin films produced in low-temperature radiofrequency plasmas

Gregorio Viera (1) , Maxime Mikikian (1) , Enric Bertran (2) , Pere Roca I Cabarrocas (3) , Laifa Boufendi (1)

1 GREMI - Groupe de recherches sur l'énergétique des milieux ionisés
2 FEMAN - FEMAN
3 LPICM - Laboratoire de physique des interfaces et des couches minces [Palaiseau]

Nanostructured Si thin films, also referred as polymorphous, were grown by plasma-enhanced chemical vapor deposition. The term “polymorphous” is used to define silicon material that consists of a two-phase mixture of amorphous and ordered Si. The plasma conditions were set to obtain Si thin films from the simultaneous deposition of radical and ordered nanoparticles. Here, a careful analysis by electron transmission microscopy and electron diffraction is reported with the aim to clarify the specific atomic structure of the nanocrystalline particles embedded in the films. Whatever the plasma conditions, the electron diffraction images always revealed the existence of a well-defined crystalline structure different to the diamondlike structure of Si. The formation of nanocrystallinelike films at low temperature is discussed. A Si face–cubic-centered structure is demonstrated here in nanocrystalline particles produced in low-pressure silane plasma at room temperature.

Mots clés: Dusty plasma; Complex Plasma; Silicon; Silane; Radiofrequency; Nanocristalline; Nanoparticle; Atomic structure; Diamond; fcc; TEM; SAED; Polymorphous; Nanostructured materials

Domaines: Plasmas; Physique des plasmas [physics.plasm-ph]

Gregorio Viera, Maxime Mikikian, Enric Bertran, Pere Roca I Cabarrocas, Laifa Boufendi. Atomic structure of the nanocrystalline Si particles appearing in nanostructured Si thin films produced in low-temperature radiofrequency plasmas. Journal of Applied Physics, 2002, 92 (8), pp.4684. ⟨10.1063/1.1506382⟩. ⟨hal-00432375⟩