Formation of edge misfit dislocations in Ge{sub x}Si{sub 1-x}(x{approx}0.4-0.8) films grown on misoriented (001){yields}(111) Si substrates: Features before and after film annealing

Journal Article · Tue Jun 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3446296· OSTI ID:21476318

Bolkhovityanov, Yu B; Deryabin, A S; Gutakovskii, A K; Sokolov, L V ^[1]

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1. Institute of Semiconductor Physics, Novosibirsk 630090 (Russian Federation)

The dislocation structure at the initial stage of relaxation of Ge{sub x}Si{sub 1-x} films (x{approx}0.4-0.8) grown on Si(001) substrates tilted at 6 deg. to the nearest (111) plane is studied. One of the directions along which edge dislocations are formed is no longer in the plane of the interface but crosses the latter at the angle of miscut. Therefore, long edge misfit dislocations (MDs) cannot exist in the direction of substrate misorientation, because their ends move away from the interface during dislocation propagation. Two different mechanisms of formation of short segments of edge (90 deg. ) MDs in the direction of substrate misorientation are found. The first mechanism is the correlated nucleation of complementary 60 deg. dislocation half-loops manifested in the form of the so-called Y-center consisting of a short segment of the 90 deg. MD and 60 deg. MDs diverging from this segment in form of two rays in the miscut direction. In the second mechanism, the 90 deg. MD segment is formed owing to intersection of already existing complementary 60 deg. MDs slipping in mirrorlike inclined planes {l_brace}111{r_brace}. Samples annealed at higher temperatures contain MD segments, which lose their contrast on one of the TEM images taken to detect edge dislocation segments in the two-wave diffraction mode but do not coincide with the direction [110] (they pass along the intersections of the mirrorlike inclined planes {l_brace}111{r_brace} with the surface of the misoriented Si substrate). To explain this phenomenon, a model is proposed, where one of the pair of complementary 60 deg. MDs propagating at an angle to each other continuously approaches the other by the cross-slip mechanism. Formation of a chain of edge MD segments connected by a pair of 60 deg. MDs becomes possible. The averaged direction of such a dislocation structure coincides with the direction of one of the 60 deg. MDs.

• OSTI ID: 21476318
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 12; Other Information: DOI: 10.1063/1.3446296; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CONCENTRATION RATIO
CRYSTAL GROWTH
EDGE DISLOCATIONS
GERMANIUM ALLOYS
INTERFACES
NUCLEATION
RELAXATION
SILICON
SILICON ALLOYS
SLIP
SUBSTRATES
SURFACES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIMENSIONLESS NUMBERS
DISLOCATIONS
ELECTRON MICROSCOPY
ELEMENTS
FILMS
HEAT TREATMENTS
LINE DEFECTS
MICROSCOPY
SEMIMETALS