X-ray characterization of dislocation density asymmetries in heteroepitaxial semiconductors

Yarlagadda, B.; Rodriguez, A.; Li, P.; Velampati, Ravi Shankar R.; Ocampo, J. F.; Suarez, Ernesto; Rago, P. B.; Shah, Dimple; Ayers, J. E.; Jain, F.

doi:10.1063/1.2936078

Cited by 32 publications

(12 citation statements)

References 20 publications

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“…In thick relaxed semiconductor layers, the dislocation density can be measured and its anisotropy was determined by measuring the FWHM of the layer peak at different azimuthal angles. 14 14 show almost identical dislocation densities to the GaAs/ZnSe/MgS/ZnSe samples studied here.…”

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confidence: 60%

Growth and stability of zinc blende MgS on GaAs, GaP, and InP substrates

Rajan

Moug

Prior

2013

Applied Physics Letters

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The molecular beam epitaxial growth of zinc blende (ZB) MgS on GaAs, GaP, and InP substrates has been investigated by X-ray diffraction and RHEED, with MgS layer strain varying between 3.1% compressive strain (GaP) and 4.4% tensile strain (InP). ZB MgS could be grown on all three substrates. X-ray diffraction showed substantial MgS relaxation during growth before conversion to the rock salt phase. Results are compared with predictions that stable growth on GaP is unlikely and relaxed ZB MgS does not grow in layers over a few Å thick. Our results imply growth of ZB MgS is truly metastable.

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confidence: 60%

Growth and stability of zinc blende MgS on GaAs, GaP, and InP substrates

Rajan

Moug

Prior

2013

Applied Physics Letters

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“…33,34 Type A and type B dislocations will broaden the symmetric rocking curve when the azimuth is such that the projection of the incident beam is parallel to the MD line vector, but not when these directions are normal. 21 If the epitaxial layer is laterally uniform and grown upon an on-axis substrate, and the incident x-ray spot is aligned with the axis of azimuthal rotation, then a variation of the rocking-curve width with azimuth indicates the existence of an asymmetry in the type A and type B dislocation populations. The individual dislocation populations can be estimated from the measured dependence of the rocking-curve width on the azimuth w. For this purpose we assign the zero azimuth (w = 0) to be the case in which the projection of the incident beam is aligned with the [110] direction in the surface of the sample and w = 90°to be the case in which the projection of the incident beam is aligned with the 1 1 0 Â Ã direction in the surface of the sample.…”

Section: Methodsmentioning

confidence: 99%

“…High-resolution x-ray diffraction (HRXRD) was utilized to estimate the dislocation densities on the type A slip systems, with their misfit dislocation (MD) line segments oriented along the ½1 " 11 direction, and type B slip systems, with MD line segments oriented along a [110] direction. 21 …”

Section: Introductionmentioning

confidence: 97%

Asymmetric Dislocation Densities in Forward-Graded ZnS y Se1−y /GaAs (001) Heterostructures

Ocampo

Bertoli

Rago

et al. 2010

Journal of Elec Materi

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We report an experimental and modeling study of ZnS y Se 1Ày /GaAs (001) structures, all of which comprised a uniform top layer of ZnS 0.014 Se 0.986 grown on a compositionally graded buffer layer or directly on the GaAs substrate. High-resolution x-ray diffraction was used to estimate dislocation densities on type A slip systems, with misfit dislocation (MD) line segments oriented along the ½1 " 10 direction, and type B slip systems, with MD line segments oriented along a [110] direction. A control sample having no graded buffer exhibits equal dislocation densities on the two types of slip systems (D A % D B % 1.5 9 10 8 cm À2 ), but a forward-graded (FG) structure (grading coefficient of 27 cm À1 ) exhibits 20% more dislocations on the type B slip systems (D A % 1.6 9 10 8 cm À2 and D B % 1.9 9 10 8 cm À2 ) and a steep forwardgraded structure (grading coefficient of 54 cm À1 ) exhibits 50% more type B dislocations (D A % 2 9 10 8 cm À2 and D B % 3 9 10 8 cm À2 ). The insertion of an overshoot interface reduced the dislocation densities in the uniform top layer by promoting annihilation and coalescence reactions, but type B dislocations were removed more effectively. Based on equilibrium calculations the overshoot graded layer in the steep graded overshoot structure is expected to exhibit large compressive and tensile strains, with a reversal in the sign of the strain near its middle, which may promote annihilation and coalescence reactions between threading dislocations.

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“…The following strategies might promote the asymmetry in the 2D 601 DA formation [36]: (1) nucleation asymmetry, e.g. using appropriate surfactants and substrate off-cuts [8,22,[37][38][39][40]; (2) evolution asymmetry, e.g.…”

Section: A Semiconductor-processing Strategy For Threading Dislocatiomentioning

confidence: 99%

Formation energies and equilibrium configurations of dislocation arrays with alternating Burgers vectors in layered heterostructures

Feng

Freund

2010

Journal of Crystal Growth

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X-ray characterization of dislocation density asymmetries in heteroepitaxial semiconductors

Cited by 32 publications

References 20 publications

Growth and stability of zinc blende MgS on GaAs, GaP, and InP substrates

Growth and stability of zinc blende MgS on GaAs, GaP, and InP substrates

Asymmetric Dislocation Densities in Forward-Graded ZnS y Se1−y /GaAs (001) Heterostructures

Formation energies and equilibrium configurations of dislocation arrays with alternating Burgers vectors in layered heterostructures

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