Strain relaxation and dislocations in SiGe/Si structures

Mooney, P. M.

doi:10.1016/s0927-796x(96)00192-1

Cited by 136 publications

(88 citation statements)

References 121 publications

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“…Conventional transmission electron microscopy (CTEM) has played an important role in characterizing strained epitaxial films. For example, CTEM studies of defects (dislocations, twins, stacking faults and cracks) and morphology helped to determine the strain relaxation mechanisms in SiGe/Si, InGaAsP/InP, GaAsN/GaAS films, which then facilitated optimization of growth methodology [2][3][4][5]. In recent years, annular dark field scanning transmission electron microscopy (ADF-STEM) has become a widely used and powerful technique for characterizing strained epitaxial layers due to the fact that ADF-STEM image contrast depends strongly on the atomic number Z of the scattering atoms in a simple Z n form (n¼1.6-1.9), which makes composition variation evident through a change in image intensity [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effects of small specimen tilt and probe convergence angle on ADF-STEM image contrast of Si0.8Ge0.2 epitaxial strained layers on (100) Si

Robertson

Kawasaki

et al. 2012

Ultramicroscopy

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The effects of specimen tilt and probe convergence angle on annular dark field (ADF) image contrast of Si 0.8 Ge 0.2 heteroepitaxial strained layers on (100) Si were investigated in a 200 kV scanning transmission electron microscope (STEM) for a TEM specimen thickness of 195 nm. With 0.5 degrees of specimen tilt away from the exact /011S zone-axis orientation, the signal-to-noise level of atomic columns was significantly reduced for both Si 0.8 Ge 0.2 and Si in high resolution ADF-STEM lattice images. When the specimen was tilted 0.5 degrees around the /011S axis, or the STEM probe convergence semiangle was reduced from 14.3 to 3.6 mrad, the ADF-STEM image intensity profiles across the Si 0.8 Ge 0.2 and Si layers changed significantly as compared to those obtained at the exact /011S zone axis orientation, and no longer reflected the composition changes occurring across the layer structure. Multislice image simulation results revealed that the misfit strain between the Si 0.8 Ge 0.2 and Si layers, and strain relaxation near the surface of the TEM specimen, were responsible for the observed changes in image intensity.Crown

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Section: Introductionmentioning

confidence: 99%

Effects of small specimen tilt and probe convergence angle on ADF-STEM image contrast of Si0.8Ge0.2 epitaxial strained layers on (100) Si

Robertson

Kawasaki

et al. 2012

Ultramicroscopy

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“…30,31 With improved quality of Si wafers and low-temperature epitaxial growth techniques, dislocation multiplication via a modified Frank-Reed mechanism (MFR) has been suggested. 32 According to the MFR mechanism, when a defect is generated in order to relieve the strain, 60 • of total dislocations are often energetically unstable compared with Shockley partial dislocations separated by a stacking fault.…”

Section: Resultsmentioning

confidence: 99%

Selective epitaxial growth of stepwise SiGe:B at the recessed sources and drains: A growth kinetics and strain distribution study

et al. 2016

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The selective epitaxial growth of Si1-xGex and the related strain properties were studied. Epitaxial Si1-xGex films were deposited on (100) and (110) orientation wafers and on patterned Si wafers with recessed source and drain structures via ultrahigh vacuum chemical vapor deposition using different growing steps and Ge concentrations. The stepwise process was split into more than 6 growing steps that ranged in thicknesses from a few to 120 nm in order to cover the wide stages of epitaxial growth. The growth rates of SiGe on the plane and patterned wafers were examined and a dependence on the surface orientation was identified. As the germanium concentration increased, defects were generated with thinner Si1-xGex growth. The defect generation was the result of the strain evolution which was examined for channel regions with a Si1-xGex source/drain (S/D) structure.

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“…Recently, "single-shot" readout of individual spins in SiGe quantum dots has been achieved, 26 which is an essential component in the functioning of any quantum computer. There are many materials issues in the SiGe system, such as lattice mismatch, 27 valley degeneracies, 28 and relaxation via misfi t dislocations 29 Both SiGe and AlGaAs exhibit high sensitivity to charge fl uctuation noise, some of which can be minimized by proper device layer engineering.…”

Section: Qubits From Quantum Dotsmentioning

confidence: 99%