Structural and electrical studies of ultrathin layers with Si{sub 0.7}Ge{sub 0.3} nanocrystals confined in a SiGe/SiO{sub 2} superlattice

Journal Article · Tue May 15 00:00:00 EDT 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4722278· OSTI ID:22038967

Vieira, E M. F.; Martin-Sanchez, J; Rolo, A G; Levichev, S; Gomes, M J. M. ^[1]; Parisini, A ^[2]; Buljan, M; Capan, I ^[3]; Alves, E; Barradas, N P ^[4]; Conde, O ^[5]; Bernstorff, S ^[6]; Chahboun, A ^[1]

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1. Centre of Physics and Physics Department, University of Minho, 4710 - 057 Braga (Portugal)
2. CNR-IMM Sezione di Bologna, via P. Gobetti 101, 40129 Bologna (Italy)
3. Rudjer Boskovic Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia)
4. ITN, Ion Beam Laboratory, Unit of Physics and Accelerators, E.N. 10, 2686-953 Sacavem (Portugal)
5. Physics Department and ICEMS, University of Lisbon, 1749-016 Lisboa (Portugal)
6. Sincrotrone Trieste, 34149 Basovizza (Italy)

In this work, SiGe/SiO{sub 2} multi-layer (ML) films with layer thickness in the range of a few nanometers were successfully fabricated by conventional RF-magnetron sputtering at 350 deg. C. The influence of the annealing treatment on SiGe nanocrystals (NCs) formation and crystalline properties were investigated by Raman spectroscopy and grazing incidence x-ray diffraction. At the annealing temperature of 800 deg. C, where well defined SiGe NCs were observed, a thorough structural investigation of the whole ML structure has been undertaken by Rutherford backscattering spectroscopy, grazing incidence small angle x-ray scattering, high resolution transmission electron microscopy, and annular dark field scanning transmission electron microscopy. Our results show that the onset of local modifications to the ML composition takes place at this temperature for annealing times of the order of a few tens of minutes with the formation of defective regions in the upper portion of the ML structure. Only the very first layers over the Si substrate appear immune to this problem. This finding has been exploited for the fabrication of a defect free metal-oxide-semiconductor structure with a well-defined single layer of SiGe NCs. A memory effect attributed to the presence of the SiGe NCs has been demonstrated by high frequency capacitance-voltage measurements.

• OSTI ID: 22038967
• Journal Information: Journal of Applied Physics, Vol. 111, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
CRYSTAL DEFECTS
CRYSTAL GROWTH
GERMANIUM ALLOYS
GERMANIUM SILICIDES
LAYERS
NANOSTRUCTURES
RAMAN SPECTRA
RAMAN SPECTROSCOPY
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SEMICONDUCTOR MATERIALS
SILICON ALLOYS
SILICON OXIDES
SMALL ANGLE SCATTERING
SUBSTRATES
SUPERLATTICES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION