title: The microstructure of Si surface layers after plasma-immersion He+ion implantation and subsequent thermal annealing.
abstract: The structural changes in the surface layer of p-type Cz-Si(001) samples after high-dose low-energy (2 keV) He+plasma-immersion ion implantation and subsequent thermal annealing were studied using a set of complementary methods: high-resolution X-ray reflectometry, high-resolution X-ray diffraction, transmission electron microscopy and atomic force microscopy. The formation of a three-layer structure was observed (an amorphous a-SiOxlayer at the surface, an amorphous a-Si layer and a heavily damaged tensile-strained crystalline c-Si layer), which remained after annealing. Helium-filled bubbles were observed in the as-implanted sample. The influence of annealing on the evolution of the three-layer structure and the bubbles is considered. The bubbles are shown to grow after annealing. Their characteristic size is determined to be in the range of 5-20 nm. Large helium-filled bubbles are located in the amorphous a-Si layer. Small bubbles form inside the damaged crystalline Si layer. These bubbles are a major source of tensile strain in the c-Si layer.
authors.affiliation: Institute of Physics and Technology, Russian Academy of Sciences , Moscow, Russian Federation.
authors.forename: Andrey
authors.initials: A
authors.lastname: Lomov
authors.affiliation: National University of Science and Technology (MISiS) , Moscow, Russian Federation.
authors.forename: Kirill
authors.initials: K
authors.lastname: Shcherbachev
authors.affiliation: Institute of Microelectronics Technology , Chernogolovka, Russian Federation.
authors.forename: Yurii
authors.initials: Y
authors.lastname: Chesnokov
authors.affiliation: National University of Science and Technology (MISiS) , Moscow, Russian Federation.
authors.forename: Dmitry
authors.identifier: https://orcid.org/0000-0003-1047-3007
authors.initials: D
authors.lastname: Kiselev
keywords: helium-filled bubbles; plasma-immersion ion implantation; silicon