Defect structure of Ge(111)/cubic Pr{sub 2}O{sub 3}(111)/Si(111) heterostructures: Thickness and annealing dependence

Journal Article · Thu Oct 01 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3224947· OSTI ID:21361861

Giussani, A; Zaumseil, P; Rodenbach, P; Weidner, G; Schubert, M A; Schroeder, T ^[1]; Geiger, D; Lichte, H ^[2]; Storck, P ^[3]; Wollschlaeger, J ^[4]

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1. IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany)
2. Technical University Dresden, Zellescher Weg 16, 01062 Dresden (Germany)
3. Siltronic AG, Hanns-Seidel-Platz 4, 81737 Muenchen (Germany)
4. University of Osnabrueck, Barbarastrasse 7, 49076 Osnabrueck (Germany)

The defect structure of Ge(111) epilayers grown by molecular beam epitaxy on cubic Pr{sub 2}O{sub 3}(111)/Si(111) support systems was investigated by means of transmission electron microscopy and laboratory-based x-ray diffraction techniques. Three main types of defects were identified, namely, rotation twins, microtwins, and stacking faults, and studied as a function of Ge film thickness and after annealing at 825 deg. C in ultrahigh vacuum. Rotation twins were found to be localized at the Ge(111)/cubic Pr{sub 2}O{sub 3}(111) interface and their amount could be lowered by the thermal treatment. Microtwins across (111) were detected only in closed Ge films, after Ge island coalescence. The fraction of Ge film volume affected by microtwinning is constant within the thickness range of approx20-260 nm. Beyond 260 nm, the density of microtwins is clearly reduced, resulting in thick layers with a top part of higher crystalline quality. Microtwins resulted insensitive to the postdeposition annealing. Instead, the density of stacking faults across (111) planes decreases with the thermal treatment. In conclusion, the defect density was proved to diminish with increasing Ge thickness and after annealing. Moreover, it is noteworthy that the annealing generates a tetragonal distortion in the Ge films, which get in-plane tensely strained, probably due to thermal mismatch between Ge and Si.

• OSTI ID: 21361861
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 106; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CHALCOGENIDES
COALESCENCE
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
DIFFRACTION
DIMENSIONS
ELECTRON MICROSCOPY
ELEMENTS
EPITAXY
FILMS
GERMANIUM
HEAT TREATMENTS
LAYERS
MATERIALS
METALS
MICROSCOPY
MOLECULAR BEAM EPITAXY
OXIDES
OXYGEN COMPOUNDS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RARE EARTH COMPOUNDS
SCATTERING
SEMICONDUCTOR MATERIALS
STACKING FAULTS
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION