Effects of surface oxide layer on nanocavity formation and silver gettering in hydrogen ion implanted silicon

Journal Article · Sun Jul 14 00:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4812736· OSTI ID:22122799

Naczas, Sebastian; Mengbing, Huang ^[1]; Yaqoob, Faisal ^[2]

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1. College of Nanoscale Science and Engineering, University at Albany-SUNY, Albany, New York 12203 (United States)
2. Department of Physics, University at Albany-SUNY, Albany, New York 12222 (United States)

We have made an investigation of the surface oxide effects on nanocavity formation in hydrogen implanted silicon and the influence of resultant nanocavities on diffusion and gettering of implanted silver atoms. A wafer with a 200-nm SiO{sub 2} surface layer was implanted with 22.5 keV H ions to a dose of 1 Multiplication-Sign 10{sup 17} cm{sup -2}, yielding the concentration peak of implanted H ions at {approx}140 nm below the SiO{sub 2}/Si interface. Subsequently, two sets of Si samples were prepared, depending on whether the oxide layer was etched off before (Group-A) or after (Group-B) post-H-implantation annealing. As evidenced by transmission electron microscopy, Group-A samples exhibited an array of large-sized nanocavities in hexagon-like shape, extending from the surface to the depth {approx}140 nm, whereas a narrow band of sphere-shaped nanocavities of small size was present around 140 nm below the surface in Group-B samples. These Si samples with pre-existing nanocavities were further implanted with Ag ions in the surface region ({approx}40 nm projected range) and post-Ag-implantation annealing was conducted in the temperature range between 600 and 900 Degree-Sign C. Measurements based on Rutherford backscattering spectroscopy revealed much different behaviors for Ag redistribution and defect accumulation in these two sets of samples. Compared to the case for Group-B Si, Group-A Si exhibited a lower concentration of residual defects and a slower kinetics in Ag diffusion as well. We discuss the role of thick surface oxide in point defect generation and recombination, and the consequence on nanocavity formation and defect retention in Si. The properties of nanocavities, e.g., their depth distribution, size, and even shape, are believed to be responsible for the observed disparities between these samples, including an interesting contrast of surface vs. bulk diffusion phenomena for implanted Ag atoms.

• OSTI ID: 22122799
• Journal Information: Journal of Applied Physics, Vol. 114, Issue 2; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ANNEALING
CRYSTAL DEFECTS
DIFFUSION
HYDROGEN IONS
INTERFACES
ION IMPLANTATION
KEV RANGE 10-100
LAYERS
NANOSTRUCTURES
POINT DEFECTS
RECOMBINATION
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SEMICONDUCTOR MATERIALS
SILICON
SILICON OXIDES
SILVER
SPATIAL DISTRIBUTION
SURFACES
TRANSMISSION ELECTRON MICROSCOPY